CAPACITY-COMPENSATION ELECTROLYTE, SECONDARY BATTERY CONTAINING THE SAME AND APPLICATION

Abstract

The present disclosure discloses a capacity-compensation electrolyte, comprising: an organic solvent, an electrolyte salt and an electrolyte additive capable of compensating ions and electrons simultaneously; wherein the electrolyte additive comprises: a component capable of compensating ions and electrons simultaneously, or a composition of a component capable of compensating ions and a component capable of compensating electrons; the component capable of compensating ions and electrons simultaneously refers to a component capable of decomposing and releasing active ions and electrons simultaneously in the electrolyte during the working process of the battery; the component capable of compensation ions refers to a component capable of decomposing and releasing active ions in the electrolyte during the working process of the battery solution; and the component capable of compensation electrons refers to a component capable of decomposing and releasing electrons in the electrolyte during the working process of the battery solution.

Claims

1. A capacity-compensation electrolyte for a secondary battery, comprising: a non-aqueous organic solvent, an electrolyte salt and an electrolyte additive capable of compensating ions and electrons simultaneously; wherein the electrolyte additive comprises: a component capable of compensating ions and electrons simultaneously, or a composition of a component capable of compensating ions and a component capable of compensating electrons; the component capable of compensating ions and electrons simultaneously refers to a component capable of decomposing and releasing active ions and electrons simultaneously in the electrolyte during the working process of the battery; the component capable of compensation ions refers to a component capable of decomposing and releasing active ions in the electrolyte during the working process of the battery; and the component capable of compensation electrons refers to a component capable of decomposing and releasing electrons in the electrolyte during the working process of the battery.

2. The capacity-compensation electrolyte according to claim 1, wherein the component capable of compensating ions and electrons simultaneously is selected from salts which contain active ions and have oxidation potential lower than that of a cathode material; the component capable of compensating ions is selected from salts containing active ions; and the component capable of compensating electrons is selected from one or more of ethers, sulfones, esters and thiophenes with oxidation potential lower than that of the cathode material.

3. The capacity-compensation electrolyte according to claim 1, wherein the secondary battery comprises a lithium-ion battery, a sodium-ion battery or a potassium-ion battery; when the secondary battery is the lithium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of Li.sub.xP.sub.y and Li.sub.mS.sub.n, where, 0<x≤3, 0<y≤11, 2≤m≤4, and 2≤n≤8; when the secondary battery is the sodium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of Na.sub.pP.sub.q, where, 0<p≤3, and 0<q≤11; and when the secondary battery is the potassium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of K.sub.eP.sub.f, where, 0<e≤3, and 0<f≤11.

4. The capacity compensation electrolyte according to claim 3, wherein when the secondary battery is the lithium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of Li.sub.xP.sub.y and Li.sub.mS.sub.n, where, 1≤x<3, 4≤y≤10, 2≤m≤4, and 2≤n≤6; when the secondary battery is the sodium-ion battery, the component capable of compensation ions and electrons simultaneously comprises one or more of Na.sub.pP.sub.q, where, 1≤p<3, and 4≤q≤10; and when the secondary battery is the potassium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of K.sub.eP.sub.f, where, 1≤e≤3, and 4≤f≤10.

5. The capacity-compensation electrolyte according to claim 1, wherein the component capable of compensating electrons comprises one or more of dimethoxyethane (DME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TEGDME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2′,2′,2′-trifluoroethyl ether (HFE), ethyl nonafluorobutyl ether (EFE), diethylene glycol diethyl ether (G2E), 1,1,1,3,3,3-hexafluoroisopropyl methyl ether (HFPM), 1H,1H,5H-ocafluorentyl-1,1,2,2-tetrafluoroethyl ether (OFE), 2,2,2-trifluoroethyl ether (BTFE), methyl nonafluorobutyl ether (MFE), diethyl sulfone (DES), dimethyl sulfone (DMS), tris(trimethylsilyl) phosphite (TMSP), tri(pentafluorophenyl) phosphine (TPFPP), terthiophene (3THP), vinylene carbonate (VC) and phosphite; wherein a general formula of the phosphite is P(X)(Y)(Z); where, X, Y and Z are respectively selected from OH, R, OR, Cl, SH, SR and R.sub.2N; where, R is selected from one or more of C.sub.nH.sub.2n+1, phenyl and derivatives thereof, and silyl and derivatives thereof.

6. The capacity-compensation electrolyte according to claim 1, wherein the secondary battery comprises a lithium-ion battery, a sodium-ion battery or a potassium-ion battery; when the secondary battery is the lithium-ion battery, the component capable of compensating electrons comprises one or more of Na.sub.pP.sub.q and K.sub.eP.sub.f, where, 0<p≤3, 0<q≤11, 0<e≤3, and 0<f≤11; and when the secondary battery is the potassium-ion battery, the component capable of compensating electrons comprises one or more of Na.sub.pP.sub.q, where, 0<p≤3, and 0<q≤11.

7. The capacity-compensation electrolyte according to claim 1, wherein the secondary battery comprises a lithium-ion battery, a sodium-ion battery or a potassium-ion battery; when the secondary battery is the lithium-ion battery, the component capable of compensating ions is selected from one or more of lithium hexafluorophosphate (LiPF.sub.6), lithium tetrafluoroborate (LiBF.sub.4), lithium perchlorate (LiClO.sub.4), lithium hexafluoroarsenate (LiAsF.sub.6), lithium bis(oxalate) borate (LiBOB), lithium difluoro(oxalato) borate (LiDFOB), lithium bis(fluorosulfonyl) imide (LiFSI), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), lithium trifluoromethanesulfonate (LiCF.sub.3SO.sub.3), lithium bis(trifluoromethylsulfonyl) imide (LiN(CF.sub.3SO.sub.2).sub.2) and lithium tetrafluorooxalate phosphate (LiPF.sub.4(C.sub.2O.sub.4)); when the secondary battery is the sodium-ion battery, the component capable of compensating ions is selected from NaClO.sub.4 and/or NaPF.sub.6; and when the secondary battery is the potassium-ion battery, the component capable of compensating ions is selected from one or more of potassium hexafluorophosphate (KPF.sub.6), potassium bis(trifluoromethanesulfonly) imide (KTFSI) and potassium bis(fluorosulfonyl) imide (KFSI).

8. The capacity-compensation electrolyte according to claim 1, wherein the mass of the electrolyte additive is 0.1%-25% of the total mass of the electrolyte solution.

9. The capacity-compensation electrolyte according to claim 1, wherein the non-aqueous organic solvent is selected from one or more of an ester solvent, an ether solvent, a sulfone solvent and a nitrile solvent; the ester solvent is selected from one or more of ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), Chloroethylene carbonate (Chloro-EC), ethyl propionate (EP) and propyl propionate (PP); the ether solvent is selected from one or more of dimethoxyethane (DME) and 1,3-dioxolane (DOL); the sulfone solvent is selected from one or more of sulfolane (SL) and dimethyl sulfoxide (DMSO); and the nitrile solvent is selected from one or more of succinonitrile (SN) and hexanedinitrile (HN).

10. A secondary battery, comprising a cathode, an anode, a separator and an electrolyte solution, wherein the electrolyte is the capacity-compensation electrolyte according to claim 1.

11. The secondary battery according to claim 10, wherein the secondary battery comprises a lithium-ion battery, a sodium-ion battery or a potassium-ion battery; when the secondary battery is the lithium-ion battery, the cathode is selected from one or more of LiCoO.sub.2, LiNiO.sub.2, LiMn.sub.2O.sub.4, LiNi.sub.0.5Mn.sub.1.5O.sub.4, Li.sub.3V.sub.2(PO.sub.4).sub.3, LiFePO.sub.4, a nickel-cobalt-manganese ternary material LiNi.sub.aCo.sub.bMn.sub.1-−a−bO.sub.2, LiNi.sub.cCo.sub.dAl.sub.1−c−dO.sub.2 and S, where, 0<a<1, 0<b<1, 0<c<1, and 0<d<1; when the secondary battery is the sodium-ion battery, the cathode is selected from one or more of sodium cobaltate, sodium manganate, sodium nickelate, sodium vanadate, sodium manganese phosphate, sodium iron phosphate, sodium vanadium phosphate, nickel-iron sodium manganate and sodium-rich sodium manganate; and when the secondary battery is the potassium-ion battery, the cathode is selected from one or more of a Prussian blue analogue, KMO.sub.2, K.sub.3V.sub.2(PO.sub.4).sub.2F.sub.3, KVOPO.sub.4, KVPO.sub.4F, K.sub.4Fe.sub.3(PO.sub.4).sub.2(P.sub.2O.sub.7), KFeC.sub.2O.sub.4 and K.sub.4Fe.sub.3(C.sub.2O.sub.4).sub.3(SO.sub.4).sub.2, where, M is a transition metal.

12. The secondary battery according to claim 10, wherein the anode is selected from one or more of artificial graphite, natural graphite, a carbon-based anode, a carbon nanotube, silicon and alloys thereof, tin and alloys thereof, germanium and alloys thereof, a phosphorus-based anode, a lithium metal, Li.sub.4Ti.sub.5O.sub.12 and a transition metal compound M.sub.iX.sub.k, where, M is a metal element, X is selected from O, S, F and N, 0<i<3, and 0<k<4.

13. An application of a capacity-compensation electrolyte for a secondary battery, comprising: a non-aqueous organic solvent, an electrolyte salt and an electrolyte additive capable of compensating ions and electrons simultaneously; wherein the electrolyte additive comprises: a component capable of compensating ions and electrons simultaneously, or a composition of a component capable of compensating ions and a component capable of compensating electrons; the component capable of compensating ions and electrons simultaneously refers to a component capable of decomposing and releasing active ions and electrons simultaneously in the electrolyte during the working process of the battery; the component capable of compensation ions refers to a component capable of decomposing and releasing active ions in the electrolyte during the working process of the battery; and the component capable of compensation electrons refers to a component capable of decomposing and releasing electrons in the electrolyte during the working process of the battery, and a secondary battery, comprising a cathode, an anode, a separator and an electrolyte solution, wherein the electrolyte is the capacity-compensation electrolyte.

14. The secondary battery of claim 10, wherein the component capable of compensating ions and electrons simultaneously is selected from salts which contain active ions and have oxidation potential lower than that of a cathode material; the component capable of compensating ions is selected from salts containing active ions; and the component capable of compensating electrons is selected from one or more of ethers, sulfones, esters and thiophenes with oxidation potential lower than that of the cathode material.

15. The secondary battery of claim 10, wherein the secondary battery comprises a lithium-ion battery, a sodium-ion battery or a potassium-ion battery; when the secondary battery is the lithium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of Li.sub.xP.sub.y and Li.sub.mS.sub.n, where, 0<x≤3, 0<y≤11, 2≤m≤4, and 2≤n≤8; when the secondary battery is the sodium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of Na.sub.pP.sub.q, where, 0<p≤3, and 0<q≤11; and when the secondary battery is the potassium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of K.sub.eP.sub.f, where, 0<e≤3, and 0<f≤11.

16. The secondary battery of claim 15, wherein when the secondary battery is the lithium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of Li.sub.xP.sub.y and Li.sub.mS.sub.n, where, 1≤x<3, 4≤y≤10, 2≤m≤4, and 2≤n≤6; when the secondary battery is the sodium-ion battery, the component capable of compensation ions and electrons simultaneously comprises one or more of Na.sub.pP.sub.q, where, 1≤p<3, and 4≤q≤10; and when the secondary battery is the potassium-ion battery, the component capable of compensating ions and electrons simultaneously comprises one or more of K.sub.eP.sub.f, where, 1≤e≤3, and 4≤f≤10.

17. The secondary battery of claim 10, wherein the component capable of compensating electrons comprises one or more of dimethoxyethane (DME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TEGDME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2′,2′,2′-trifluoroethyl ether (HFE), ethyl nonafluorobutyl ether (EFE), diethylene glycol diethyl ether (G2E), 1,1,1,3,3,3-hexafluoroisopropyl methyl ether (HFPM), 1H,1H,5H-ocafluorentyl-1,1,2,2-tetrafluoroethyl ether (OFE), 2,2,2-trifluoroethyl ether (BTFE), methyl nonafluorobutyl ether (MFE), diethyl sulfone (DES), dimethyl sulfone (DMS), tris(trimethylsilyl) phosphite (TMSP), tri(pentafluorophenyl) phosphine (TPFPP), terthiophene (3THP), vinylene carbonate (VC) and phosphite; wherein a general formula of the phosphite is P(X)(Y)(Z); where, X, Y and Z are respectively selected from OH, R, OR, Cl, SH, SR and R.sub.2N; where, R is selected from one or more of C.sub.nH.sub.2n+1, phenyl and derivatives thereof, and silyl and derivatives thereof.

18. The secondary battery of claim 10, wherein the secondary battery comprises a lithium-ion battery, the sodium-ion battery or the potassium-ion battery; when the secondary battery is the lithium-ion battery, the component capable of compensating electrons comprises one or more of Na.sub.pP.sub.q and K.sub.eP.sub.f, where, 0<p≤3, 0<q≤11, 0<e≤3, and 0<f≤11; and when the secondary battery is the potassium-ion battery, the component capable of compensating electrons comprises one or more of Na.sub.pP.sub.q, where, 0<p≤3, and 0<q≤11.

19. The secondary battery of claim 10, wherein the secondary battery comprises a lithium-ion battery, the sodium-ion battery or the potassium-ion battery; when the secondary battery is the lithium-ion battery, the component capable of compensating ions is selected from one or more of lithium hexafluorophosphate (LiPF.sub.6), lithium tetrafluoroborate (LiBF.sub.4), lithium perchlorate (LiClO.sub.4), lithium hexafluoroarsenate (LiAsF.sub.6), lithium bis(oxalate) borate (LiBOB), lithium difluoro(oxalato) borate (LiDFOB), lithium bis(fluorosulfonyl) imide (LiFSI), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), lithium trifluoromethanesulfonate (LiCF.sub.3SO.sub.3), lithium bis(trifluoromethylsulfonyl) imide (LiN(CF.sub.3SO.sub.2).sub.2) and lithium tetrafluorooxalate phosphate (LiPF.sub.4(C.sub.2O.sub.4)); when the secondary battery is the sodium-ion battery, the component capable of compensating ions is selected from NaClO.sub.4 and/or NaPF.sub.6; and when the secondary battery is the potassium-ion battery, the component capable of compensating ions is selected from one or more of potassium hexafluorophosphate (KPF.sub.6), potassium bis(trifluoromethanesulfonly) imide (KTFSI) and potassium bis(fluorosulfonyl) imide (KFSI).

20. The secondary battery of claim 10, wherein the mass of the electrolyte additive is 0.1%-25% of the total mass of the electrolyte solution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0102] FIG. 1 is a comparison diagram of cycle properties of Embodiment 1 and Comparative Example 1.

[0103] FIG. 2 is a comparison diagram of cycle properties of Embodiment 6 and Comparative Example 2.

DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE

[0104] Specific implementations of the present disclosure will be described below. Apparently, the described embodiments are only a part of embodiments of the present disclosure rather than all embodiments. All other embodiments obtained by those ordinarily skilled in the art without involving inventive effort based on the embodiments in the present disclosure fall within the protection scope of the present disclosure.

[0105] The present disclosure provides a capacity-compensation electrolyte, including a non-aqueous organic solvent, an electrolyte salt and a capacity-compensation electrolyte additive capable of compensating ions and electrons, which can compensate for active ions and electrons lacked by SEI formed in the first cycle and active substance losses in the cycle process.

[0106] Wherein the electrolyte additive includes:

[0107] a component capable of compensation ions and electrons simultaneously, or

[0108] a composition of a component capable of compensating ions and a component capable of compensating electrons;

[0109] the component capable of compensating ions and electrons simultaneously refers to a component capable of decomposing and releasing active ions and electrons simultaneously in the electrolyte during the working process of the battery;

[0110] the component capable of compensating ions refers to a component capable of decomposing and releasing active ions in the electrolyte during the working process of the battery; and

[0111] the component capable of compensating electrons refers to a component capable of decomposing and releasing electrons in the electrolyte during the working process of the battery.

[0112] The active ions refer to ions capable of being reversibly deintercalated between a cathode and an anode of a secondary battery.

[0113] In reported lithium compensation technologies, the lithium compensation additive is mostly added to electrodes, while lithium compensation in the electrodes has the risk of irreversible damage to electrode plates in the decomposition process. Negative effects on the electrodes can be avoided in a lithium compensation mode of the electrolyte. However, existing reports on the lithium compensation mode of the electrolyte have the phenomenon of poor compatibility between some lithium salts and an electrolyte solvent, so that a co-solvent needs to be additionally added. In the existing reports, usually the lithium compensation effect can be achieved only in the first cycle, and capacity losses caused by the reasons such as volume expansion and pulverization in the cycle process cannot be compensated.

[0114] The present disclosure creatively provides a solution capable of compensating ions and electrons simultaneously, the purpose of compensating electrons is to perform decomposition prior to other components in the electrolyte in the cycle process of the secondary battery, so as to supply needed electrons to capacity compensation, and the purpose of compensating ions is to supply needed ions to capacity compensation in the cycle process of the secondary battery. The component capable of compensating electrons is independently added, so that the active ions needed by capacity compensation cannot be supplied; and the component capable of compensating ions is independently added, it cannot decompose prior to other components in the electrolyte solution, so that active ions cannot be supplied. The electrons and the active ions needed by capacity compensation can be supplied in time when the active ion losses are generated in the cycle process of the battery only by compensating ions and electrons simultaneously, so as to ensure the good cycle property of the battery.

[0115] According to some implementations of the present application, the component capable of compensating ions and electrons simultaneously is selected from salts which contain active ion elements and have oxidation potential lower than that of a cathode material; and such salts can decompose prior to delithiation of the cathode material in the electrolyte during the working process of the battery to supply the active ions and the electrons needed by capacity compensation.

[0116] The component capable of compensating ions is selected from salts containing active ion elements; and such salts can supply additional active ions in the electrolyte during the working process of the battery, but they need to fit in with the component capable of compensation electrons to supply additional electrons for capacity compensation as their oxidation potential is high.

[0117] The component capable of compensating electrons is selected from one or more of ethers, sulfones, esters and thiophenes with oxidation potential lower than that of the cathode material; the ethers, the sulfones, the esters and the thiophenes can supply additional electrons in the electrolyte during the working process of the battery as their oxidation potential is usually low, and can achieve capacity compensation in combination with the component capable of compensating ions.

[0118] According to some implementations of the present application, in the lithium-ion battery, the component capable of compensating ions and electrons simultaneously includes one or more combinations of Li.sub.xP.sub.y and Li.sub.mS.sub.n, where, 0<x≤3, 0<y≤11, 0<m≤3, and 0<n≤11;

[0119] according to some implementations of the present application, in the lithium-ion battery, preferably, 1≤x<3, and 4≤y≤10 in Li.sub.xP.sub.y, more preferably, Li.sub.xP.sub.y is selected from LiP.sub.4, LiP.sub.5, LiP.sub.7, LiP.sub.8 and LiP.sub.10, and most preferably, is selecting from LiP.sub.5 and LiP.sub.7; and

[0120] according to some implementations of the present application, in the lithium-ion battery, preferably, 2≤m≤4, and 2≤n≤6 in Li.sub.mS.sub.n, more preferably, Li.sub.mS.sub.n is selected from Li.sub.2S.sub.4, Li.sub.2S.sub.6 and Li.sub.2S.sub.8, and most preferably, is selected from Li.sub.2S.sub.4 and Li.sub.2S.sub.6.

[0121] The preferred additives can be compatible with common electrolyte solvents and electrolyte salts, and all can achieve the capacity compensation effect in various systems of the lithium-ion batteries.

[0122] According to some implementations of the present application, in the sodium-ion battery, preferably, 1≤p<3, and 4≤q≤10 in the component Na.sub.pP.sub.q capable of compensating sodium and electrons simultaneously, and more preferably, Na.sub.pP.sub.q is selected from NaP.sub.4, NaP.sub.5, NaP.sub.7 and Na.sub.3P.sub.7, and most preferably, is selected from NaP.sub.5 and NaP.sub.7. The preferred additives can be compatible with the common electrolyte solvents and electrolyte salts, and all can achieve the capacity compensation effect in various systems of the sodium-ion battery.

[0123] According to some implementations of the present application, in the potassium-ion battery, preferably, 1≤e≤3, and 4≤f≤10 in the component K.sub.eP.sub.f capable of compensating potassium and electrons simultaneously, more preferably, K.sub.eP.sub.f is selected from KP.sub.4, KP.sub.5, KP.sub.7 and K.sub.3P.sub.7, and most preferably, is selected from KP.sub.5 and K.sub.3P.sub.7. The preferred additives can be compatible with the common electrolyte solvents and electrolyte salts, and all can achieve the capacity compensation effect in various systems of the potassium-ion battery.

[0124] Electrolyte lithium compensation additives in the prior art have the defects of poor compatibility with the electrolyte solvents. Researches on lithium polyphosphide mostly remain in these common lithium polyphosphide compounds such as Li.sub.3P and Li.sub.5P, which are mostly used to compensate lithium in electrodes or to modify lithium metal surfaces. The applicant tried to add Li.sub.3P, Li.sub.5P and the like to the electrolyte solution, but a large number of experiments have verified that these conventional lithium polyphosphide solids are hardly dissolved in the appropriate electrolyte, and the solubility of the currently available electrolyte solvents is very poor, so such lithium polyphosphide solids are not suitable to be used as the electrolyte lithium compensation additives.

[0125] After a long period of creative work, the applicant has developed an electrolyte formula in which soluble lithium polyphosphide and lithium polysulfide are used as the electrolyte additives. In the electrolyte formula, LiP.sub.4, LiP.sub.5, LiP.sub.7, LiP.sub.8, LiP.sub.10, Li.sub.2S.sub.4, Li.sub.2S.sub.6 and Li.sub.2S.sub.8 with good compatibility with the electrolyte solution, and especially LiP.sub.5, LiP.sub.7, Li.sub.2S.sub.4 and Li.sub.2S.sub.6, are used as the additives to be dissolved in the common ester, ether, sulfone or nitrile organic solvents. Meanwhile, the applicant also has found that by adding one or more of lithium polyphosphide and lithium polysulfide capable of being dissolved in the electrolyte solvents to the electrolyte, the lithium polyphosphide and the lithium polysulfide can decompose on the surfaces of the electrodes prior to the electrolyte solvents, so as to achieve the excellent effect of compensating lithium and electrons, thereby compensating for capacity losses caused by SEI formed in the cycle process of the battery and dead lithium generated in the follow-up cycle process.

[0126] In the sodium-ion battery, the applicant has developed that by adding sodium polyphosphide, such as NaP.sub.4, NaP.sub.5, NaP.sub.7 and NaP.sub.10, capable of being dissolved in the electrolyte solvents to the electrolyte to be used as the additive, the additive can be compatible with the common electrolyte solvents and electrolyte salts and decomposes prior to the solvents in the electrolyte solution, so as to achieve the effect of compensating sodium and electrons, thereby compensating for capacity losses caused by SEI formed in the cycle process of the battery and dead sodium generated in the follow-up cycle process.

[0127] In the potassium-ion battery, the applicant has developed that by adding potassium polyphosphide, such as KP.sub.4, KP.sub.5, KP.sub.7 and K.sub.3P.sub.7, capable of being dissolved in the electrolyte solvents to the electrolyte to be used as the additive, the additive can be compatible with the common electrolyte solvents and electrolyte salts and decomposes prior to the solvents in the electrolyte solution, so as to achieve the effect of compensating potassium and electrons, thereby compensating for capacity losses caused by SEI formed in the cycle process of the battery and dead potassium generated in the follow-up cycle process. These achievements and technical solutions are discovered and reported by the applicant for the first time.

[0128] The additive has high solubility in the common electrolyte solvents, has a low LUMO energy and a high HOMO energy, and can decompose prior to the electrolyte solvents. The additive decomposes on an anode side prior to the electrolyte solvents due to the LUMO energy lower than that of the electrolyte solvents, so that stable SEI is preferentially formed on the surface of the anode. The additive decomposes on a cathode side prior to the electrolyte solvents due to the HOMO energy higher than that of the electrolyte solvents, so that stable CEI is preferentially formed on the surface of the cathode. Thus, the additive can improve the stability of an electrode-electrolyte interface in the battery and improve the cycle property of the battery.

[0129] According to some implementations of the present application, the component capable of supplying electrons includes diethyl sulfone (DES), dimethyl sulfone (DMS), tris(trimethylsilyl) phosphite (TMSP), tri(pentafluorophenyl) phosphine (TPFPP), terthiophene (3THP), vinylene carbonate (VC) and phosphite P(X)(Y)(Z), where, X, Y and Z are equal to one or more combinations of OH, R, OR, Cl, SH, SR and R.sub.2N (R═C.sub.nH.sub.2n+1, phenyl and derivatives thereof and silyl and derivatives thereof). The component capable of supplying electrons contains low-valent phosphorus, sulfur and other elements or easily oxidized structures, and decomposes prior to the electrolyte solvents and the electrolyte salts in the cycle process of the battery, so as to supply electrons to capacity compensation.

[0130] According to some implementations of the present application, the component capable of supplying electrons further includes ether micromolecules with low oxidation potential: dimethoxyethane (DME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TEGDME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2′,2′,2′-trifluoroethyl ether (HFE), ethyl nonafluorobutyl ether (EFE), diethylene glycol diethyl ether (G2E), 1,1,1,3,3,3-hexafluoroisopropyl methyl ether (HFPM), 1H,1H,5H-ocafluorentyl-1,1,2,2-tetrafluoroethyl ether (OFE), 2,2,2-trifluoroethyl ether (BTFE) and methyl nonafluorobutyl ether (MFE). The ether micromolecules have low oxidization potential, and can decompose prior to the electrolyte solvents and the electrolyte salts in the cycle process of the battery, so as to provide electrons to capacity compensation.

[0131] According to some implementations of the present application, the component capable of supplying electrons in the ester solvent is selected from the group consisting of tris(trimethylsilyl) phosphite (TMSP), tri(pentafluorophenyl) phosphine (TPFPP) or phosphite P(X)(Y)(Z), where, X, Y and Z are equal to one or more combinations of OH, R, OR, Cl, SH, SR and R.sub.2N (R═C.sub.nH.sub.2n+1, phenyl and derivatives thereof and silyl and derivatives thereof), and dimethoxyethane (DME), diethylene glycol dimethyl ether (DEGDME) and triethylene glycol dimethyl ether (TEGDME). The additive capable of supplying electrons is well compatible with the ester solvent, has approximate oxidation potential, and can preferentially decompose in a voltage window of the ester solvent, so as to supply electrons.

[0132] According to some implementations of the present application, in the ether electrolyte solvent, the component capable of supplying electrons is diethyl sulfone (DES), dimethyl sulfone (DMS), tris(trimethylsilyl) phosphite (TMSP), tri(pentafluorophenyl) phosphine (TPFPP) or vinylene carbonate (VC). The additive capable of supplying electrons is well compatible with the ether solvent, has approximate oxidation potential, and can preferentially decompose in a voltage window of the ether solvent, so as to supply electrons.

[0133] According to some implementations of the present application, when the secondary battery is the lithium-ion battery, the component capable of compensating electrons is selected from one or more of Na.sub.pP.sub.q and K.sub.eP.sub.f, where, 0<p≤3, 0<q≤11, 0<e≤3, and 0<f≤11; and

[0134] according to some implementations of the present application, in Na.sub.pP.sub.q and K.sub.eP.sub.f, 1≤p<3, 4≤q≤10, 1≤e≤3, and 4≤f≤10.

[0135] According to some implementations of the present application, preferably, Na.sub.pP.sub.q is selected from NaP.sub.4, NaP.sub.5, NaP.sub.7 and NaP.sub.10, and most preferably, is selected from NaP.sub.5 and NaP.sub.7. Preferably, the oxidation potential of Na.sub.pP.sub.q is lower than the decomposition potential of the solvent in the lithium-ion battery system, and Na.sub.pP.sub.q can decompose prior to the solvent, so as to supply electrons for capacity compensation.

[0136] According to some implementations of the present application, preferably, K.sub.eP.sub.f is selected from KP.sub.4, KP.sub.5, KP.sub.7 and K.sub.3P.sub.7, and most preferably, is selected from KP.sub.5 and K.sub.3P.sub.7. Preferably, the oxidation potential of K.sub.eP.sub.f is lower than the decomposition potential of the solvent in the lithium-ion battery system, and K.sub.eP.sub.f can decompose prior to the solvent, so as to supply electrons for capacity compensation.

[0137] According to some implementations of the present application, when the secondary battery is the potassium-ion battery, the component capable of compensating electrons is selected from one or more of Na.sub.pP.sub.q, where, 0<p≤3, and 0<q≤11.

[0138] According to some implementations of the present application, preferably, Na.sub.pP.sub.q is selected from NaP.sub.4, NaP.sub.5, NaP.sub.7 and NaP.sub.10, and most preferably, is selected from NaP.sub.5 and NaP.sub.7. Preferably, the oxidation potential of Na.sub.pP.sub.q is lower than the decomposition potential of the solvent in the potassium-ion battery system, and Na.sub.pP.sub.q can decompose prior to the solvent, so as to supply electrons for capacity compensation.

[0139] According to some implementations of the present application, in the lithium-ion battery, active ions needed to be supplemented are lithium ions, and the component capable of compensating lithium is selected from one or more combinations of lithium hexafluorophosphate (LiPF.sub.6), lithium tetrafluoroborate (LiBF.sub.4), lithium perchlorate (LiClO.sub.4), lithium hexafluoroarsenate (LiAsF.sub.6), lithium bis(oxalate) borate (LiBOB), lithium difluoro(oxalato) borate (LiDFOB), lithium bis(fluorosulfonyl) imide (LiFSI), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), lithium trifluoromethanesulfonate (LiCF.sub.3SO.sub.3), lithium bis(trifluoromethylsulfonyl) imide (LiN(CF.sub.3SO.sub.2).sub.2) and lithium tetrafluorooxalate phosphate (LiPF.sub.4(C.sub.2O.sub.4)) The additive capable of supplying active ions is well compatible with the common electrolyte solvents, and can act in cooperation with the additive capable of supplying electrons, so as to achieve the capacity compensation effect.

[0140] According to some implementations of the present application, in the lithium-ion battery, the component capable of compensating lithium is selected from one or more combinations of LiPF.sub.6, LiBOB, LiDFOB, LiFSI and LiTFSI; and preferably, the component capable of compensating lithium is selected from LiTFSI. The additive capable of supplying lithium ions is well compatible with the common electrolyte solvents and the additive capable of supplying electrons, can decompose in the voltage window of the battery to release active ions, and can achieve the capacity compensation effect under the combined action of the additive and the additive capable of compensating electrons.

[0141] According to some implementations of the present application, in the sodium-ion battery, active ions needed to be supplemented are sodium ions, the component capable of compensating sodium is selected from one or more combinations of sodium perchlorate (NaClO.sub.4) and sodium hexafluorophosphate (NaPF.sub.6), and preferably, the component capable of compensating sodium is NaPF.sub.6. The additive capable of supplying sodium ions is well compatible with the common electrolyte solvents and the additive capable of supplying electrons, can decompose in the voltage window of the battery to release active ions, and can achieve the capacity compensation effect under the combined action of the additive and the additive capable of compensating electrons.

[0142] According to some implementations of the present application, in the potassium-ion battery, active ions needed to be supplemented are potassium ions, and the component capable of compensating potassium is selected from one or more combinations of potassium hexafluorophosphate (KPF.sub.6), potassium bis(trifluoromethanesulfonly) imide (KTFSI) and potassium bis(fluorosulfonyl) imide (KFSI), and preferably, the component capable of compensating potassium is KFSI. The additive capable of supplying potassium ions is well compatible with the common electrolyte solvents and the additive capable of supplying electrons, can decompose in the voltage window of the battery to release active ions, and can achieve the capacity compensation effect under the combined action of the additive and the additive capable of compensating electrons.

[0143] According to some implementations of the present application, in the lithium-ion battery, the composition of the components capable of compensating lithium and electrons is selected from LiPF.sub.6/TMSP, LiDFOB/MFE, LiFSI/VC and LiTFSI/TMSP. The components capable of compensating lithium and electrons have good compatibility, and can achieve the good capacity compensation effect when co-used in the lithium-ion battery.

[0144] According to some implementations of the present application, in the sodium-ion battery, the composition of the components capable of compensating sodium and electrons is selected from NaClO.sub.4/EFE, NaPF.sub.6/TMSP and NaPF.sub.6/HFPM. The components capable of compensating lithium and electrons have good compatibility, and can achieve the good capacity compensation effect when co-used in the sodium-ion battery.

[0145] According to some implementations of the present application, in the potassium-ion battery, the composition of the component capable of compensating potassium and electrons is selected from KPF.sub.6/TMSP, KTFSI/TMPi and KFSI/TPPi. The components capable of compensating potassium and electrons have good compatibility, and can achieve the good capacity compensation effect when co-used in the potassium-ion battery.

[0146] According to some implementations of the present application, the mass ratio of the component capable of compensating ions to the component capable of compensating electrons is 1:20-20:1, preferably, 1:5-5:1, and most preferably, 1:2-1:1. The ratio of the component capable of compensating ions to the component capable of compensating electrons can ensure that when the composition decomposes in the voltage window of the battery, the mutually-matched active ions and electrons are supplied simultaneously to carry out capacity compensation on the battery.

[0147] According to some implementations of the present application, the additives capable of compensating ions and electrons can be dissolved in one or more combinations in the organic solvent, there is no specific limitation on the ratio of mixed solvents, for example, EC:DEC=1:1, and EC:EMC:DMC=1:1:1.

[0148] According to some implementations of the present application, a mass percent of the electrolyte additive dissolved in the electrolyte is 0.1%-25%;

[0149] according to some implementations of the present application, the mass percentage of the electrolyte additive dissolved in the electrolyte is 8%-12%; and

[0150] according to some implementations of the present application, most preferably, the mass percentage of the electrolyte additive dissolved in the electrolyte is 10%. Too few additives may result in insufficient compensation for capacity losses caused by volume expansion and pulverization of electrodes in the cycle process, while introduction of too many additives may result in excessive additive mass, leading to reduction in whole energy density of the battery.

[0151] According to some implementations of the present application, the non-aqueous organic solvent in the electrolyte is selected from one or more of an ester solvent, an ether solvent, a sulfone solvent and a nitrile solvent;

[0152] preferably, the ester solvent is selected from one or more of ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), Chloroethylene carbonate (Chloro-EC), ethyl propionate (EP) and propyl propionate (PP);

[0153] preferably, the ether solvent is selected from one or more of dimethoxyethane (DME) and 1,3-dioxolane (DOL);

[0154] preferably, the sulfone solvent is selected from one or more of sulfolane (SL) and dimethyl sulfoxide (DMSO); and

[0155] preferably, the nitrile solvent is selected from one or more of succinonitrile (SN) and hexanedinitrile (HN).

[0156] The additive capable of compensating ions and electrons simultaneously, the additive capable of compensating ions and the additive capable of compensating electrons are well compatible with one another in the solvents of the above types, and can achieve the effect of the electrolyte additive under a certain concentration.

[0157] According to some implementations of the present application, in the ester solvent, the solvent is selected from a combination of EC/DEC, EC/EMC, EC/EMC/DMC and PC/DMC;

[0158] according to some implementations of the present application, in the ester solvent, the adaptive additive capable of compensating ions and electrons simultaneously is selected from one or more of LiP.sub.5, LiP.sub.7, NaP.sub.5, NaP.sub.7, KP.sub.5 and K.sub.3P.sub.7;

[0159] according to some implementations of the present application, in the ester solvent, the composition of the adaptive components capable of compensating lithium and electrons is selected from LiPF.sub.6/TMSP and LiDFOB/MFE;

[0160] according to some implementations of the present application, in the ester solvent, the composition of the adaptive components capable of compensating sodium and electrons is selected from NaPF.sub.6/TMSP and NaPF.sub.6/HFPM; and

[0161] according to some implementations of the present application, in the ester solvent, the composition of the adaptive components capable of compensating potassium and electrons is selected from KPF.sub.6/TMSP and KTFSI/TMPi.

[0162] In the ester solvent, the additives capable of compensating ions and electrons simultaneously and the composition of the additives capable of compensating ions and electrons have high solubility, so that they can be dissolved prior to the solvent, so as to achieve the capacity compensation effect.

[0163] According to some implementations of the present application, in the ether solvent, the solvent is selected from a combination of DME/DOL;

[0164] according to some implementations of the present application, in the ether solvent, the adaptive additive capable of compensating ions and electrons simultaneously is selected from one or more of LiP.sub.5, LiP.sub.7, NaP.sub.5, NaP.sub.7, KP.sub.5 and K.sub.3P.sub.7;

[0165] according to some implementations of the present application, in the ether solvent, the composition of the adaptive components capable of compensating lithium and electrons is selected from LiFSI/VC and LiTFSI/TMSP;

[0166] according to some implementations of the present application, in the ether solvent, the composition of the adaptive components capable of compensating sodium and electrons is selected from NaPF.sub.6/TMSP and NaClO.sub.4/EFE; and

[0167] according to some implementations of the present application, in the ether solvent, the composition of the adaptive components capable of compensating potassium and electrons is selected from KTFSI/TMPi and KFSI/TPPi.

[0168] In the ether solvent, the additives capable of compensating ions and electrons simultaneously and the composition of the additives capable of compensating ions and electrons have high solubility, so that they can be dissolved prior to the solvent, so as to achieve the capacity compensation effect.

[0169] According to some implementations of the present application, in the sulfone solvent, the solvent is selected from DMSO;

[0170] according to some implementations of the present application, in the sulfone solvent, the adaptive additive capable of compensating ions and electrons simultaneously is selected from one or more of LiP.sub.5, NaP.sub.5, NaP.sub.7 and KP.sub.5; and

[0171] according to some implementations of the present application, in the sulfone solvent, the composition of the adaptive components capable of compensating lithium and electrons is selected from the group consisting of LiFSI/VC and LiTFSI/TMSP.

[0172] In the sulfone solvent, the additive capable of compensating ions and electrons simultaneously and the composition of the additives capable of compensating ions and electrons have high solubility, so that they can be dissolved prior to the solvent, so as to achieve the capacity compensation effect.

[0173] According to some implementations of the present application, the nitrile solvent is selected from AN and SN, and the adaptive additive is selected from one or more of LiP.sub.7, NaP.sub.7 and K.sub.3P.sub.7.

[0174] According to some implementations of the present application, in the nitrile solvent, the adaptive additive capable of compensating ions and electrons simultaneously is selected from one or more of LiP.sub.5, NaP.sub.5, NaP.sub.7 and KP.sub.5; and

[0175] according to some implementations of the present application, in the nitrile solvent, the adaptive composition of the components capable of compensating lithium and electrons is selected from LiFSI/VC and LiTFSI/TMSP.

[0176] In the nitrile solvent, the additive capable of compensating ions and electrons simultaneously and the composition of the additives capable of compensating ions and electrons have high solubility, so that they can be dissolved prior to the solvent, so as to achieve the capacity compensation effect.

[0177] According to some implementations of the present application, in the lithium-ion battery, the electrolyte salt is selected from one or more combinations of LiPF.sub.6, LiBOB, LiDFOB, LiFSI and LiTFSI. The lithium salt and the additive do not undertake a chemical reaction, thereby achieving high compatibility.

[0178] According to some implementations of the present application, in the sodium-ion battery, the electrolyte salt is selected from one or more combinations of sodium perchlorate (NaClO.sub.4) and sodium hexafluorophosphate (NaPF.sub.6); and

[0179] according to some implementations of the present application, in the sodium-ion battery, the electrolyte salt is NaPF.sub.6. The sodium salt and the additive do not undertake a chemical reaction, thereby achieving high compatibility.

[0180] According to some implementations of the present application, in the potassium-ion battery, the electrolyte salt is selected from one or more combinations of potassium hexafluorophosphate (KPF.sub.6), potassium bis(trifluoromethanesulfonly) imide (KTFSI) and potassium bis(fluorosulfonyl) imide (KFSI); and

[0181] according to some implementations of the present application, in the potassium-ion battery, the electrolyte salt is KFSI. The potassium salt and the additive do not undertake a chemical reaction, thereby achieving high compatibility.

[0182] The present application further discloses a secondary ion battery, including a cathode, an anode, a separator and the electrolyte.

[0183] According to some implementations of the present application, the secondary ion battery includes a lithium-ion battery, a sodium-ion battery or a potassium-ion battery; and

[0184] according to some implementations of the present application, the cathode of the lithium-ion battery is selected from one or more of LiCoO.sub.2, LiNiO.sub.2, LiMn.sub.2O.sub.4, LiNi.sub.0.5Mn.sub.1.5O.sub.4, Li.sub.3V.sub.2(PO.sub.4).sub.3, LiFePO.sub.4, LiNi.sub.xCo.sub.yMn.sub.1−x−yO.sub.2, LiNi.sub.xCo.sub.yAl.sub.1−x−yO.sub.2 and S. The cathode material of the lithium-ion battery and the additive do not undertake a side reaction, thereby achieving high compatibility.

[0185] According to some implementations of the present application, the cathode of the sodium-ion battery is selected from one or more of sodium cobaltate, sodium manganate, sodium nickelate, sodium vanadate, sodium manganese phosphate, sodium iron phosphate, sodium vanadium phosphate, nickel-iron sodium manganate and sodium-rich sodium manganate. The cathode material of the sodium-ion battery and the additive do not undertake a side reaction, thereby achieving high compatibility.

[0186] According to some implementations of the present application, the cathode of the potassium-ion battery is selected from one or more of a potassium-containing Prussian blue analogue, KMO.sub.2, K.sub.3V.sub.2(PO.sub.4).sub.2F.sub.3, KVOPO.sub.4, KVPO.sub.4F, K.sub.4Fe.sub.3(PO.sub.4).sub.2(P.sub.2O.sub.7), KFeC.sub.2O.sub.4 and K.sub.4Fe.sub.3(C.sub.2O.sub.4).sub.3(SO.sub.4).sub.2, where, M in KMO.sub.2 is a transition metal. The cathode material of the potassium-ion battery and the additive do not undertake a side reaction, thereby achieving high compatibility.

[0187] According to some implementations of the present application, the anode is selected from artificial graphite, natural graphite, a carbon-based anode, a carbon nanotube, silicon and alloys thereof, tin and alloys thereof, germanium and alloys thereof, a phosphorus-based anode, a lithium metal, Li.sub.4Ti.sub.5O.sub.12 or a transition metal compound M.sub.iX.sub.k, where, M is a metal element, X is selected from O, S, F or N, 0<i<3, and 0<k<4. Preferably, M.sub.iX.sub.k is selected from Fe.sub.2O.sub.3, Co.sub.3O.sub.4, MoS.sub.2 and SnO.sub.2. The anode material of the secondary battery and the additive do not undertake a side reaction, thereby achieving high compatibility.

[0188] According to some implementations of the present application, a cathode/anode system is selected from the group consisting of LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2/artificial graphite, LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2/nano-silicon, LiNi.sub.0.5 Co.sub.0.2Mn.sub.0.3O.sub.2/red phosphorus-CNT, LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2/graphite, LiMn.sub.2O.sub.4/Li metal, LiCoO.sub.2/red phosphorus-CNT, LiCoO.sub.2/SnO.sub.2, LiCoO.sub.2/Co.sub.3O.sub.4, LiFePO.sub.4/graphite, LiFePO.sub.4/lithium metal, LiFePO.sub.4/silicon, LiFePO.sub.4/SnO.sub.2, a sodium manganate/black phosphorus-graphite compound, sodium vanadium phosphate/hard carbon, potassium-containing Prussian blue/graphite and K.sub.4Fe.sub.3(C.sub.2O.sub.4).sub.3(SO.sub.4).sub.2/soft carbon. In the battery system, the additive capable of compensating ions and electrons simultaneously can preferentially decompose on a cathode, anode and electrolyte interface to carry out capacity compensation, and can form uniform and stable CEI and SEI films on surfaces of the cathode and the anode.

[0189] According to some implementations of the present application, the concentration of the electrolyte salt is not limited, and may be 1.0 mol/L, 1.2 mol/L, 1.5 mol/L, etc. as listed in embodiments.

[0190] The present disclosure will be described in detail below with reference to specific embodiments. Apparently, the listed embodiments are only a part of embodiments rather than all embodiments. Features in the embodiments can be mutually combined. All other embodiments obtained by those ordinarily skilled in art based on the present disclosure without involving creative labor should fall within the protection scope of the present disclosure. Conditions used by comparative examples are shown in Table 1.

Embodiment 1

[0191] A capacity-compensation electrolyte, 10 wt % of LiP.sub.5 was added to 1.0 mol/L of a LiPF.sub.6-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2, and an anode material of the battery was artificial graphite.

Embodiment 2

[0192] A capacity-compensation electrolyte, 5 wt % of LiP.sub.7, 2 wt % of LiP.sub.8 and 2 wt % of LiP.sub.10 were added to 1.2 mol/L of a LiBF.sub.4-EC/DEC (volume ratio: 2/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2, and an anode material of the battery was nano-silicon.

Embodiment 3

[0193] A capacity-compensation electrolyte, 5 wt % of LiP, 5 wt % of LiP.sub.4 and 5 wt % of LiP.sub.8 were added to 1.0 mol/L of a LiPF.sub.6-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2, and an anode material of the battery was a ball milling material with a mass ratio of red phosphorus to CNT being 7:3.

Embodiment 4

[0194] A capacity-compensation electrolyte, 0.1 wt % of LiP.sub.4, 0.1 wt % of LiP.sub.5 and 0.1 wt % of Li.sub.3P.sub.7 were added to 1.2 mol/L of a LiTFSI-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiCoO.sub.2, and an anode material of the battery was SnO.sub.2.

Embodiment 5

[0195] A capacity-compensation electrolyte, 10 wt % of LiP, 10 wt % of LiP.sub.5 and 5 wt % of LiP.sub.7 were added to 1.0 mol/L of a LiBOB-DOL/DME (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiMn.sub.2O.sub.4, and an anode material of the battery was a Li metal.

Embodiment 6

[0196] A capacity-compensation electrolyte, 4 wt % of LiP.sub.5, 2 wt % of LiP.sub.7 and 2 wt % of Li.sub.3P.sub.7 were added to 1.0 mol/L of a LiPF.sub.6-EC/EMC/DMC (volume ratio: 1/1/1) electrolyte under an inert gas atmosphere. The materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was graphite.

Embodiment 7

[0197] A capacity-compensation electrolyte, 2.5% by mass of LiFSI and 2.5% by mass of VC were added to 1.2 mol/L of a LiTFSI-EC/DEC (volume ratio: 2/1) electrolyte under an inert gas atmosphere. The electrolyte was injected into a battery, where, a cathode material of the battery was LiCoO.sub.2, and an anode material of the battery was red phosphorus-CNT.

Embodiment 8

[0198] A capacity-compensation electrolyte, 2.5 wt % of LiTFSI and 2.5% by mass of TMSP were added to 1.0 mol/L of a LiPF.sub.6-EC/EMC/DMC (volume ratio: 1/1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was graphite.

Embodiment 9

[0199] A capacity-compensation electrolyte, 4 wt % of LiDFOB and 4 wt % of MFE were added to 1.5 mol/L of a LiFSI-DOL/DME (volume ratio: 1/1) electrolyte under an inert gas atmosphere. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was a lithium metal.

Embodiment 10

[0200] A capacity-compensation electrolyte, 0.1 wt % of LiP.sub.7 and 2 wt % of DME were added to 1.0 mol/L of a LiBOB-PC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was silicon.

Embodiment 11

[0201] A capacity-compensation electrolyte, 5 wt % of LiP.sub.5 and 5 wt % of Li.sub.2S.sub.4 were added to 1.0 mol/L of a LiTFSI-DOL/DME (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was SnO.sub.2.

Embodiment 12

[0202] A capacity-compensation electrolyte, 2 wt % of NaP.sub.5 and 5 wt % of LiTFSI were added to 1.0 mol/L of a LiPF.sub.6-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiCoO.sub.2, and an anode material of the battery was Co.sub.3O.sub.4.

Embodiment 13

[0203] A capacity-compensation electrolyte, 5% by mass of NaP.sub.5 and 5% by mass of NaP.sub.7 were added to 1.0 mol/L of a NaPF.sub.6-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was sodium manganate, and an anode material of the battery was a black phosphorus-graphite compound.

Embodiment 14

[0204] A capacity-compensation electrolyte, 7 wt % of NaPF.sub.6 and 7 wt % of TMSP were added to 1.0 mol/L of a NaClO.sub.4-EC/DMC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was sodium vanadium phosphate, and an anode material of the battery was hard carbon.

Embodiment 15

[0205] A capacity-compensation electrolyte, 8 wt % of NaPF.sub.6 and 2 wt % of HFPM were added to 1.0 mol/L of a NaClO.sub.4-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was nickel-iron sodium manganate, and an anode material of the battery was hard carbon.

Embodiment 16

[0206] A capacity-compensation electrolyte, 2 wt % of KFSI and 8 wt % of TPPi were added to 1.0 mol/L of a KTFSI-EC/DEC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was potassium-containing Prussian blue, and an anode material of the battery was graphite.

Embodiment 17

[0207] A capacity-compensation electrolyte, 5 wt % of KP.sub.5 and 5 wt % of K.sub.3P.sub.7 were added to 1.2 mol/L of a KTFSI-EC/DMC (volume ratio: 1/1) electrolyte under an inert gas atmosphere, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was K.sub.4Fe.sub.3(C.sub.2O.sub.4).sub.3(SO.sub.4).sub.2, and an anode material of the battery was soft carbon.

Comparative Example 1

[0208] No additive was added to 1.0 mol/L of a LiPF.sub.6-EC/DEC (volume ratio: 1/1) electrolyte under an inert condition. The electrolyte was injected into a battery, where, a cathode material of the battery was LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2, and an anode material of the battery was artificial graphite.

Comparative Example 2

[0209] No additive was added to 1.0 mol/L of a LiPF.sub.6-EC/EMC/DMC (volume ratio: 1/1/1) electrolyte under an inert condition. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was graphite.

Comparative Example 3

[0210] 2.5 wt % of LiTFSI was added to 1.0 mol/L of a LiPF.sub.6-EC/EMC/DMC (volume ratio: 1/1/1) electrolyte under an inert condition, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was graphite.

Comparative Example 4

[0211] 2.5 wt % of TMSP was added to 1.0 mol/L of a LiPF.sub.6-EC/EMC/DMC (volume ratio: 1/1/1) electrolyte under an inert condition, and the materials were evenly mixed. The electrolyte was injected into a battery, where, a cathode material of the battery was LiFePO.sub.4, and an anode material of the battery was graphite.

Comparative Example 5

[0212] No additive was added to 1.0 mol/L of a NaPF.sub.6-EC/DEC (volume ratio: 1/1) electrolyte under an inert condition. The electrolyte was injected into a battery, where, a cathode material of the battery was NaMnO2, and an anode material of the battery was a black phosphorus-graphite compound.

Comparative Example 6

[0213] No additive was added to 1.0 mol/L of a KTFSI-EC/DEC (volume ratio: 1/1) electrolyte under an inert condition. The electrolyte was injected into a battery, where, a cathode material of the battery was potassium-containing Prussian blue, and an anode material of the battery was graphite.

[0214] A constant current charge and discharge test of the battery was carried out in an environment under the temperature of 25° C. The battery was activated at a current of 20 mA/g, and the battery was tested at a current of 100 mA/g. The capacity of the activated battery after the first discharge was D1, meanwhile, the capacity of the battery after 100 cycles was recorded as D200, D200/D1 was the capacity retention rate of the battery, and obtained results were shown in Table 2.

TABLE-US-00001 TABLE 1 Additive capable Additive Additive of compensating capable of capable of ions and electrons compensating compensating Electrolyte No. Group simultaneously ions electrons salt Solvent Cathode/anode 1 Embodiment 1 10 wt % LiP.sub.5 — — 1.0 mol/L EC/DEC = 1/1 LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2/ LiPF.sub.6 artificial graphite 2 Embodiment 2 5 wt % LiP.sub.7, — — 1.2 mol/L EC/DEC = 2/1 LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2/ 2 wt % LiP.sub.8, LiBF.sub.4 nano-silicon 2 wt % LiP.sub.10 3 Embodiment 3 5 wt % LiP, — — 1.0 mol/L EC/DEC = 1/1 LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2/ 5 wt % LiP.sub.4, LiPF.sub.6 red phosphorus-CNT 5 wt % LiP.sub.8 4 Embodiment 4 0.1 wt % LiP.sub.4, — — 1.2 mol/L EC/DEC = 1/1 LiCoO.sub.2/SnO.sub.2 0.1 wt % LiP.sub.5, LiTFSI 0.1 wt % Li.sub.3P.sub.7 5 Embodiment 5 10 wt % LiP, — — 1.0 mol/L DOL/DME = 1/1 LiMn.sub.2O.sub.4/Li metal 10 wt % LiP.sub.5, LiBOB 5 wt % LiP.sub.7 6 Embodiment 6 4 wt % LiP.sub.5, — — 1.0 mol/L EC/EMC/DMC = LiFePO.sub.4/graphite 2 wt % LiP.sub.7, LiPF.sub.6 1/1/1 2 wt % Li.sub.3P.sub.7 7 Embodiment 7 — 2.5 wt %.sup.  2.5 wt %.sup.  1.2 mol/L EC/DEC = 2/1 LiCoO.sub.2/red LiFSI VC LiTFSI phosphorus-CNT 8 Embodiment 8 — 2.5 wt %.sup.  2.5 wt %.sup.  1.0 mol/L EC/EMC/DMC = LiFePO.sub.4/graphite LiTFSI TMSP LiPF.sub.6 1/1/1 9 Embodiment 9 — 4 wt % 4 wt % 1.0 mol/L DOL/DME = 1/1 LiFePO.sub.4/lithium LiDFOB MFE LiFSI metal 10 Embodiment 10 — 0.1 wt %.sup.  2 wt % 1.0 mol/L PC/DEC = 1/1 LiFePO.sub.4/silicon LiPF.sub.6 TMSP LiBOB 11 Embodiment 11 5 wt % LiP.sub.5 — — 1.0 mol/L DOL/DME = 1/1 LiFePO.sub.4/SnO.sub.2 5 wt % Li.sub.2S.sub.4 LiTFSI 12 Embodiment 12 — 5 wt % 2 wt % 1.0 mol/L EC/DEC = 1/1 LiCoO.sub.2/Co.sub.3O.sub.4 LiTFSI NaP.sub.5 LiPF.sub.6 13 Embodiment 13 5 wt % NaP.sub.5 — — 1.0 mol/L EC/DEC = 1/1 Sodium manganate/ 5 wt % NaP.sub.7 NaPF.sub.6 black phosphorus- graphite compound 14 Embodiment 14 — 7 wt % 7 wt % 1.0 mol/L EC/DMC = 1:1 Sodium vanadium NaPF.sub.6 TMSP NaClO.sub.4 phosphate/hard carbon 15 Embodiment 15 — 8 wt % 2 wt % 1.0 mol/L EC/DEC = 1/1 Nickel-iron sodium NaPF.sub.6 HFPM NaClO.sub.4 manganate/hard carbon 16 Embodiment 16 — 2 wt % 8 wt % 1.0 mol/L EC/DEC = 1/1 Potassium-containing KFSI TPPi KTFSI Prussian blue/graphite 17 Embodiment 17 5 wt % KP.sub.5 — — 1.2 mol/L EC/DMC = 1:1 K.sub.4Fe.sub.3(C.sub.2O.sub.4).sub.3(SO.sub.4).sub.2/ 5 wt % K.sub.3P.sub.7 KFSI soft carbon 18 Comparative — — — 1.0 mol/L EC/DEC = 1/1 LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2/ Example 1 LiPF.sub.6 artificial graphite 19 Comparative — — — 1.0 mol/L EC/EMC/DMC = LiFePO.sub.4/graphite Example 2 LiPF.sub.6 1/1/1 20 Comparative — 2.5 wt %.sup.  — 1.0 mol/L EC/EMC/DMC = LiFePO.sub.4/graphite Example 3 LiTFSI LiPF.sub.6 1/1/1 21 Comparative — — 2.5 wt %.sup.  1.0 mol/L EC/EMC/DMC = LiFePO.sub.4/graphite Example 4 TMSP LiPF.sub.6 1/1/1 22 Comparative — — — 1.0 mol/L EC/DEC = 1/1 Sodium manganate/ Example 5 NaPF.sub.6 black phosphorus- graphite compound 23 Comparative — — — 1.0 mol/L EC/DEC = 1/1 Potassium-containing Example 6 KTFSI Prussian blue/graphite

TABLE-US-00002 TABLE 2 First-cycle Coulomb Capacity efficiency D1 retention rate No. Group (%) (mAh g.sup.−1) (%) 1 Embodiment 1 81.5 188.6 74.3 2 Embodiment 2 84.5 207.5 71.0 3 Embodiment 3 84.7 211.9 72.6 4 Embodiment 4 85.0 212.4 73.4 5 Embodiment 5 84.9 143.4 69.2 6 Embodiment 6 88.2 145.8 79.9 7 Embodiment 7 80.3 144.0 68.4 8 Embodiment 8 87.6 145.1 75.6 9 Embodiment 9 94.5 158.0 76.4 10 Embodiment 10 85.2 157.7 70.1 11 Embodiment 11 84.6 150.0 75.3 12 Embodiment 12 78.4 132.5 60.4 13 Embodiment 13 78.8 147.5 76.5 14 Embodiment 14 76.2 93.6 82.1 15 Embodiment 15 74.5 94.5 79.6 16 Embodiment 16 73.5 92.4 75.8 17 Embodiment 17 86.4 87.0 86.7 18 Comparative Example 1 78.1 185.3 58.8 19 Comparative Example 2 84.1 142.9 67.0 20 Comparative Example 3 84.3 143.0 67.3 21 Comparative Example 4 84.0 143.2 66.8 22 Comparative Example 5 73.6 142.7 68.7 23 Comparative Example 6 65.4 87.6 63.4

[0215] It could be shown from comparison between Comparative Example 1 and Embodiment 1 in FIG. 1 that after 10 wt % of LiP.sub.5 was added to the ester electrolyte solution, the cycle stability and the capacity retention rate of the LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2/artificial graphite full battery were both improved. It could be shown from data shown in Table 2 that the initial Coulomb efficiency of the full battery was also improved, which showed that LiP.sub.5 could achieve the capacity compensation effect.

[0216] FIG. 2 illustrates cycle-specific capacity curves of Embodiment 6 and Comparative Example 2. It could be shown that after 8 wt % of Li.sub.xP.sub.y mixture was added, the initial Coulomb efficiency, the cycle reversible specific capacity and the capacity retention rate of the LiFePO.sub.4/graphite full battery were all higher than those of Comparative Example 2, which showed that in the cycle process of the battery, active ions and electrons could be decomposed out of Li.sub.xP.sub.y to compensate for capacity losses in each process and achieve the effect of stabilizing the electrode-electrolyte interface, thereby improving the cycle property of the battery. It could be shown from data of Embodiment 8 and Comparative Examples 2, 3 and 4 shown in Table 2 that after the additive LiTFSI capable of compensating ions or the additive TMSP capable of compensating electrons was independently added, the initial Coulomb efficiency and the capacity retention rates of Comparative Examples 3 and 4 were similar to those of Comparative Example 2 without the additive, which showed that the battery could not be effectively subjected to capacity compensation by independently adding the additive capable of compensating ions or electrons, and ions and electrons could be supplemented simultaneously only when the additive capable of compensating ions or the additive capable of compensating electrons is used in combination as in Embodiment 8, thereby improving electrochemical properties of the battery.

[0217] It could be shown from data of the Li.sub.xP.sub.y compound added to the lithium-ion battery in Table 1 and Table 2 that the solubilities of LiP.sub.4, LiP.sub.5, LiP.sub.7, LiP.sub.8 and LiP.sub.10 in the common electrolyte solvents such as the ester solvent and the ether solvent were high, and they could be used as the electrolyte additive to release active lithium ions and electrons for capacity compensation through decomposition. Li.sub.xP.sub.y could make the battery achieve the stable cycle effect in each battery system.

[0218] It could be shown from the comparison of the capacity retention rate data of the lithium-ion battery system in Table 2 that the capacity retention rates of Embodiments 1, 6, 9 and 11 were high, which showed that when the mass percent of the additive was 8%-12%, the good capacity compensation effect could be achieved.

[0219] It could be shown from comparison between Comparative Example 5 and Embodiment 13 that after 5 wt % of NaP.sub.5 and 5 wt % of NaP.sub.7 were added to the sodium-ion battery system to be used as the capacity compensation additive, the two components could achieve the effect of compensating ions and electrons simultaneously, thereby improving the initial Coulomb efficiency and the cycle stability of the full battery.

[0220] It could be shown from comparison between Comparative Example 6 and Embodiment 16 that after 2 wt % of KFSI and 8 wt % of TPPi were added to the potassium-ion battery system, the components capable of compensating ions and electrons could act together to supply needed active ions and electrons to capacity losses caused in the cycle process, thereby improving the initial Coulomb efficiency and the cycle stability of the full battery.

[0221] It could be shown from Embodiment 12 that sodium polyphosphate was selected as the additive capable of compensating electrons in the lithium-ion battery LiCoO.sub.2/Co.sub.3O.sub.4 system, and meanwhile, could achieving the capacity compensation function in conjunction with LiTFSI as the additive capable of compensating ions.

[0222] It could be shown from Embodiment 11 that lithium polyphosphate and lithium polysulfide were selected as the additives capable of compensating ions and electrons simultaneously together in the lithium-ion battery LiFePO.sub.4/SnO.sub.2 system, and could synergistically act, thereby improving the initial Coulomb efficiency and the cycle stability of the full battery.

[0223] Obviously, the embodiments are only used for clearly illustrating examples of the present disclosure rather than limiting it. Those skilled in the art can modify, combine and transform the embodiments.