Electrochemical cells for high-energy battery use

Abstract

Components and structures for a rechargeable electrochemical cell and an electrochemical cell having an S02 solvent based electrolyte comprising any of said components and structures are provided. The cathode (2) may comprise one or more elemental transition metals and/or one or more partially oxidized transition metals. The S02 solvent based electrolyte (3) may comprise halide-containing salt additive as an SEI-forming additive. The anode current collector (5) may comprise a carbon coated metal, an alloy of two or more metals or a carbon coated alloy of two or more metals. The electrochemical cell may comprise excess non-dissolved/solid alkali halides. The components, structures and cell may bay used in a device.

Claims

1. An electrochemical cell comprising: an anode current collector, the anode current collector comprising: a carbon coated metal, an alloy of two or more metals, or a carbon coated alloy of two or more metals; an SO.sub.2 solvent based electrolyte; and a cathode, wherein the anode current collector is configured such that one or more alkali metals are deposited in metallic form on the anode current collector during charging.

2. The electrochemical cell of claim 1, wherein the cathode comprises one or more partially oxidized transition metals including a mixture of a metallic form of one or more transition metals and an oxidized form of the one or more transition metals.

3. The electrochemical cell of claim 2, wherein at least one of the one or more partially oxidized transition metals is a component of a partially oxidized transition metal compound.

4. The electrochemical cell of claim 3, wherein at least one of the one or more partially oxidized transition metal compounds is of the form, M.sub.yA, where M is a partially oxidized transition metal, A is an oxidizer and y is the ratio of M/A such that said transition metal is in a partially oxidized state.

5. The electrochemical cell of claim 4, wherein at least one of the one or more oxidizers, A, is oxygen, nitrogen, sulfur, antimony or cyanide or any combination thereof.

6. The electrochemical cell of claim 2, wherein at least one of the one or more partially oxidized transition metal compounds is an oxide, a sulfide, a halide, a cyanide, a nitride or any combination thereof.

7. The electrochemical cell of claim 6, wherein the cathode comprises one or more halides, and wherein at least one of the one or more halides comprise Cu.sub.yBr, Cu.sub.yl, Cu.sub.yCl, Cu.sub.yF, where y is greater than 0.5, or any combination thereof.

8. The electrochemical cell of claim 2, wherein at least one of the one or more partially oxidized transition metal oxides comprises a combination of metallic copper and oxidized copper, wherein the combination has an overall formula Cu.sub.yO where y is greater than 1.

9. The electrochemical cell of claim 2, wherein at least one of the one or more transition metals comprises Cu.

10. The electrochemical cell of claim 2, wherein the cathode comprises one or more alkali halides.

11. The electrochemical cell of claim 10, wherein the one or more alkali halides comprise NaF, NaC1, NaBr, NaI, LiF, LiBr, LiI, or any combination thereof.

12. The electrochemical cell of claim 10, wherein, at the time of assembly, the alkali halide:transition metal compound molar ratio is from 1:1 to 5:1.

13. The electrochemical cell of claim 1, wherein the SO.sub.2 solvent based electrolyte comprises a halide-containing salt additive as an SEI-forming additive.

14. The electrochemical cell of claim 13, wherein the halide-containing salt additive comprises a fluorine-containing salt additive.

15. The electrochemical cell of claim 14 wherein the fluorine-containing salt additive comprises Na-DFOB (Sodium-difluoro-oxalato-borate), Li-DFOB (Lithium-difluoro-oxalato-borate), Na-Triflate (Sodium-trifluoromethane-sulfonate), or Li-Triflate (Lithium-trifluoromethane-sulfonate) or a combination thereof.

16. The electrochemical cell of claim 1, wherein the SO.sub.2 solvent based electrolyte comprises a mixture of alkali metal electrolyte salts.

17. The electrochemical cell of claim 16, wherein the alkali metal electrolyte salts are lithium and sodium electrolyte salts.

18. The electrochemical cell of claim 17, wherein the alkali metal electrolyte salts comprise a mixture of LiAlCl.sub.4 and NaAlCl.sub.4.

19. The electrochemical cell of claim 1, further comprising: one or more excess non-dissolved/solid alkali halides; or a spacer or separator between the anode current collector and the cathode.

20. The electrochemical cell of claim 19, wherein the excess non-dissolved/solid alkali halide comprises NaF, NaCl, NaBr, NaI, LiF, LiCl, LiBr, LiI, or any mixture thereof.

21. The electrochemical cell of claim 1, wherein the anode current collector comprises a copper-nickel alloy.

22. The electrochemical cell of claim 1, further comprising an anode active material in contact with the anode current collector, wherein the anode active material comprises an alkali metal in metallic form.

23. The electrochemical cell of claim 1, wherein the anode current collector is configured such that the one or more alkali metals are deposited in a dendrite-free metallic form on the anode current collector during charging.

24. The electrochemical cell of claim 1, wherein the anode current collector comprises a carbon coated metal or a carbon coated alloy of two or more metals.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a cross section of an electrochemical cell in charged state or semi-charged state according to the invention having an anode (1), a cathode (2), an electrolyte (3) and which may also comprise one or more SEI layers (4), an anode current collector (5) and/or a cathode current collector (6).

(2) FIG. 2 shows a cross section of an electrochemical cell in discharged state according to the invention having an a cathode (2), an electrolyte (3) and which may also comprise one or more SEI layers (4), an anode current collector (5) and/or a cathode current collector (6)

(3) FIG. 3 shows the average discharge voltage evolution of the cell employing a NaCl based cathode and plain Constantan metal foil anode substrate. The horizontal axis indicates the number of cycles. The employed electrolyte is NaAlCl.sub.4.Math.2SO.sub.2. The geometric area of the working electrode is 2.5 cm.sup.2.

(4) FIG. 4 shows the average discharge voltage evolution of the cell employing a 2NaCl:Cu formulation based cathode and Na metal anode. The horizontal axis indicates the number of cycles. The employed electrolyte is NaAlCl.sub.4.Math.2SO.sub.2. The geometric area of the working electrode is 2.5 cm.sup.2.

(5) FIG. 5 shows one cycle voltage evolution of the cell employing a 2NaCl:Cu formulation based cathode and Na metal anode. The employed electrolyte is NaAlCl.sub.4.Math.2SO.sub.2. The geometric area of the working electrode is 2.5 cm.sup.2.

(6) FIG. 6 shows one cycle voltage evolution of the cell employing a 2LiF:Cu formulation based cathode and Li metal anode. The employed electrolyte is LiAlCl.sub.2.Math.2SO.sub.2 with 1 wt % LiDFOB additive. The geometric area of the working electrode is 2.5 cm.sup.2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(7) Detailed embodiments of the present invention are disclosed herein with the reference to accompanying drawings. The following paragraphs describe improvements related to high energy-density battery cells, where the electrolyte is based on SO.sub.2 solvent.

(8) A cathode for a discharged state assembled or semi-charged state assembled rechargeable electrochemical cell having an SO.sub.2 solvent based electrolyte comprising one or more elemental transition metals and/or one or more partially oxidized transition metals is described. At least one of the one or more partially oxidized transition metals may be a component of a partially oxidized transition metal compound. At least one of the one or more partially oxidized transition metal compounds may be of the form, M.sub.yA, where M is a partially oxidized transition metal, A is an oxidizer and y is the ratio of M/A such that said transition metal is in a partially oxidized state. At least one of the one or more oxidizers, A, may be oxygen, nitrogen, sulfur, antimony or cyanide or any combination thereof. At least one of the one or more partially oxidized transition metal compounds may be an oxide, a sulfide, a halide, a cyanide, a nitride or any combination thereof. At least one of the one or more transition metal halides may comprise Cu.sub.yBr, Cu.sub.yI, Cu.sub.yCl, Cu.sub.yF, where y is greater than 0.5 or any combination thereof. At least one of the one or more partially oxidized transition metal oxides may comprise Cu.sub.yO where y is greater than 1. At least one of the one or more elemental transition metals may comprise Cu. The cathode may further comprise one or more alkali halides. The one or more alkali halides may comprise NaF, NaCl, NaBr, NaI, LiF, LiCl, LiBr, LiI, or any combination thereof. At the time of assembly, the alkali halide:transition metal compound molar ratio may be greater than 1:0.

(9) An SO.sub.2 solvent based electrolyte comprising a halide-containing salt additive as para SEI-forming additive is described. The halide-containing salt additive may comprise a fluorine-containing salt additive. The fluorine-containing salt additive may comprise Na-DFOB (Sodium-difluoro-oxalato-borate), Li-DFOB (Lithium-difluoro-oxalato-borate), Na-Triflate (Sodium-trifluoromethane-sulfonate), or Li-Triflate (Lithium-trifluoromethane-sulfonate) or a combination thereof.

(10) An SO.sub.2 solvent based electrolyte comprising a mixture of alkali metal electrolyte salts is described. The alkali metal electrolyte salts may be lithium and sodium electrolyte salts. The electrolyte salts may comprise a mixture of LiAlCl.sub.4 and NaAlCl.sub.4.

(11) An anode current collector for a rechargeable electrochemical cell having an SO.sub.2 solvent based electrolyte comprising a carbon coated metal, an alloy of two or more metals or a carbon coated alloy of two or more metals is described. The carbon coated metal may comprise carbon coated aluminium and/or wherein the alloy comprises a copper-nickel alloy.

(12) An electrochemical cell having at least a cathode, an anode and an electrolyte comprising any of the described electrolytes and/or any of the described cathodes and/or any of the described anode current collectors is described.

(13) An electrochemical cell comprising, at least, said anode and electrolyte and a cathode is described. The cathode may comprise one or more elemental transition metals and/or one or more partially oxidized transition metals. At least one of the one or more partially oxidized transition metals may be a component of a partially oxidized transition metal compound. At least one of the one or more partially oxidized transition metal compounds may be of the form, M.sub.yA, where M is a partially oxidized transition metal, A is an oxidizer and y is the ratio of M/A such that said transition metal is in a partially oxidized state. At least one of the one or more oxidizers, A, may be oxygen, nitrogen, sulfur, antimony or cyanide or any combination thereof. At least one of the one or more partially oxidized transition metal compounds may be an oxide, a sulfide, a halide, a cyanide, a nitride or any combination thereof. At least one of the one or more transition metal halides may comprise Cu.sub.yBr, Cu.sub.yI, Cu.sub.yCl, Cu.sub.yF, where y is greater than 0.5 or any combination thereof. At least one of the one or more partially oxidized transition metal oxides may comprise Cu.sub.yO where y is greater than 1. At least one of the one or more elemental transition metals comprises Cu. The cathode may further comprise one or more alkali halides. The one or more alkali halides may comprise NaF, NaCl, NaBr, NaI, LiF, LiCl, LiBr, LiI, or any combination thereof. At the time of assembly, the alkali halide:transition metal compound molar ratio may be greater than 1:0. The SO.sub.2 solvent based electrolyte may comprise a halide-containing salt additive as an SEI-forming additive. The halide-containing salt additive may comprise a fluorine-containing salt additive. The fluorine-containing salt additive may comprise Na-DFOB (Sodium-difluoro-oxalato-borate), Li-DFOB (Lithium-difluoro-oxalato-borate), Na-Triflate (Sodium-trifluoromethane-sulfonate), or Li-Triflate (Lithium-trifluoromethane-sulfonate) or a combination thereof. The SO.sub.2 solvent based electrolyte may comprise a mixture of alkali metal electrolyte salts. The alkali metal electrolyte salts may be lithium and sodium electrolyte salts. The electrolyte salts may comprise a mixture of LiAlCl.sub.4 and NaAlCl.sub.4. One or more excess non-dissolved/solid alkali halides may be added to the cell. The excess non-dissolved/solid alkali halide may comprise NaF, NaCl, NaBr, NaBr, NaI, LiF, LiCl, LiBr, LiI, or any mixture thereof. The cell may further comprise a spacer/separator between the anode current collector and the cathode.

(14) An electrochemical cell having at least a cathode, an anode and an electrolyte comprising an SO.sub.2 solvent based electrolyte; and any of the described cathodes and/or anode current collectors is described.

(15) Any of the described electrochemical cells, wherein, one or more excess non-dissolved/solid alkali halides are added to the cell is described. The excess non-dissolved/solid alkali halide may comprise NaF, NaCl, NaBr, NaI, LiF, LiCl, LiBr, LiI, or any mixture thereof. The cell may further comprise a spacer/separator between the anode current collector and the cathode.

(16) The use of any of the described electrolytes, any of the described cathodes, any of the described anode current collectors and/or any of the described electrochemical cells in a device is described. The use of the described anode current collector and/or any of the described electrochemical cells in a device is described.

(17) FIG. 1 shows a cross section of an embodiment of an electrochemical cell according to the invention in charged state or semi-charged state according to the invention having an anode (1), a cathode (2), an electrolyte (3) and which may also comprise one or more SEI layers (4), an anode current collector (5) and/or a cathode current collector (6). The cell may additionally have a spacer and/or a separator (7, not shown) between any of the anode (1), the anode current collector (5), SEI layer 4a or SEI layer 4b and any of the cathode (2), the cathode current collector (6), SEI layer 4b, SEI layer 4c or SEI layer 4d. According to the invention 0, 1, 2, 3 or 4 SEI layers may be present.

(18) FIG. 2 shows a cross section of an embodiment of an electrochemical cell according to the invention in discharged state or semi-charged state according to the invention having a cathode (2), an electrolyte (3) and which may also comprise one or more SEI layers (4), an anode current collector (5) and/or a cathode current collector (6). The cell may additionally have a spacer and/or a separator (7) which is here shown to be between SEI layer 4a and SEI layer 4b but which may be between any of the anode current collector (5), SEI layer 4a or SEI layer 4b and any of the cathode (2), the cathode current collector (6), SEI layer 4b, SEI layer 4c or SEI layer 4d. According to the invention 0, 1, 2, 3 or 4 SEI layers may be present. The spacer/separator may serve to allow space for the anode to grow during charging. The spacer/separator may serve to physically separate the anode and the cathode and/or their associated SEI layers. The spacer/separator may serve to allow space for the electrolyte to exist inside the cell. According to one embodiment of the invention, the spacer/separator may be composed of a porous material or otherwise contain a significant amount of void space. Preferably the fraction of void space is greater than 10% and more preferably greater than 20% and more preferably greater than 40% and more preferably greater than 60% and more preferably greater than 70% and most preferably greater than 80%. The spacer/separator may comprise any material compatible with the electrolyte. The spacer/separator may comprise cellulose and/or SiO.sub.2. Other materials for the spacer/separator are possible according to the invention.

(19) Any combination of the cell structures shown in FIG. 1 and FIG. 2 are possible according to the invention. Any components 1-7 in FIG. 1 and FIG. 2 may overlap or be intermingled with another component according to the invention.

(20) It has been surprisingly discovered that LiCl may be used reversibly as active cathode material in battery cells comprising cells using LiAlCl.sub.4.Math.xSO.sub.2 type electrolyte. LiCl-based cathodes have been constructed by LiCl infusion into a carbon-based framework. Upon cycling such LiCl active cathode material based battery cells, close to 90% of the theoretical 600 mAh/g discharge capacity with respect to the LiCl mass has been obtained.

(21) In the case of LiCl based cathode with LiAlCl.sub.4.Math.xSO.sub.2 type electrolyte, the required charging voltage may be in the range of 4.4-4.6 V vs. the Li/Li+ reference. The use of NaCl cathode material has been described in FI 20150270 in conjunction with an anode substrate facilitating the deposition of metallic Na in the anode side. The equivalent approach for metallic lithium deposition is known to be problematic because of the tendency for dendritic lithium deposition. Several complementary methods have been surprisingly discovered for achieving highly reversible, dendrite free metallic Li deposition. even in LiAlCl.sub.4.Math.xSO.sub.2 type electrolyte. Firstly, it has been surprisingly discovered that Cu—Ni alloys are stable in SO.sub.2 based electrolytes during the entire charging cycle, and that the Na-over-substrate and Li-over-substrate depositions yield a smoother surface than in the case of a Ni substrate. This results in improved Coulombic Efficiency and better longevity of the cell operation. Possible Cu:Ni ratios are between 10:90 and 90:10, and more preferably between 20:80 and 80:20 and more preferably between 40:60 and 60:40 and most preferably approximately the 55:45 ratio which is known as Constantan. Additional alloy constituents in addition to or instead of Cu and Ni are possible according to the invention. As alternative to the Cu—Ni alloys, it has been discovered that carbon-coated metals and alloys are also stable in SO.sub.2 based electrolytes during the entire charging cycle, and that the Na-over-substrate and Li-over-substrate depositions over carbon-coated metals and alloy substrates are sufficiently smooth in these SO.sub.2 based electrolytes for stable cell cycling. In particular, aluminum and aluminum alloys have been discovered to be stable in based electrolytes during the entire charging cycle, and that the Na-over-substrate and Li-over-substrate depositions over carbon-coated metals and alloy substrates are sufficiently smooth in these SO.sub.2 based electrolytes for stable cell cycling. Aluminum-based substrates have an advantage over Cu—Ni alloys due to lower cost and lighter mass. Secondly, it has been surprisingly discovered that the presence of sodium salts, such as NaAlCl.sub.4, in the electrolyte improves the smoothness and reversibility of Li deposition. Without intending to be bound by theory, the electrolyte's NaAlCl.sub.4 content causes an initial deposition of smooth metallic Na at the early phase of charging, which improves the smoothness and reversibility of subsequent metallic Li deposition. Possible LiAlCl.sub.4:NaAlCl.sub.4 ratios are between 10:90 and 99.999:0.001, and more preferably between 90:10 and 95:5. Thirdly, it has been discovered that the presence of a fluorine-containing salt additive improves the Coulombic efficiency and longevity of battery cells disclosed in this invention. Without intending to be hound by theory, the fluorine-containing salt additive is thought to improve the anode SEI during the initial charging of alkali-halide cathodes. Na-DFOB (Sodium-difluoro-oxalato-borate), Li-DFOB (Lithium-difluoro-oxalato-borate), Na-Initiate (Sodium-trifluoromethane-sulfonate), or Li-Triflate (Lithium-trifluoromethane-sulfonate) are particularly preferable additive salts. The fluorine-containing salts additive may be added to the electrolyte preferably between 0.0001% and 5% mass ratio, and more preferably between 0.1% and 3% mass ratio, and most preferably between 0.5% and 2% mass ratio. The abovesaid three discoveries may be employed individually or in any combination in order to achieve a suitable deposition and cycling of metallic Li on the anode side.

(22) Other alkali salt based cathodes may be constructed analogously NaCl or LiCl, by infusing NaF, LiF, NaBr, LiBr, NaI, LiI, or mixtures thereof, respectively into a carbon-based framework. In the case of NaCl or LiCl based cathode, a mixture of dissolved Cl.sub.2 and SO.sub.2Cl.sub.2 is generated in the electrolyte upon charging. In the case of NaBr or LiBr based cathode, mainly dissolved Br.sub.2 and is generated in the electrolyte upon charging, and the Coulombic efficiency of cell cycling is lower than in case NaCl or LiCl based cathode. In the case of NaI or LiI based cathode, mainly dissolved I.sub.2 and is generated in the electrolyte upon charging, and the Coulombic efficiency or cell cycling is also lower than in case NaCl or LiCl based cathode. In the case of NaF or LiF based cathode, a mixture of dissolved Cl.sub.2 and SO.sub.2Cl.sub.2 is generated in the electrolyte upon charging, and the AlCl.sub.4.sup.− electrolyte salt anion is correspondingly transformed into AlCl.sub.3F.sup.− through the uptake of F.sup.− from the cathode salt. The chargeable amount of NaF or LiF is, thus, limited by the available AlCl.sub.4.sup.− electrolyte salt. The preferred alkali halide cathode materials are based on NaCl/LiCl, or a mixture between NaCl/LiCl and NaF/LiF.

(23) It has been furthermore discovered that, upon adding certain transition metals into the alkali salt containing cathode, such metals facilitate the uptake of chloride, and/or fluoride, and/or bromide, and/or iodide during the charging cycle, and allow a highly reversible subsequent battery cycling. Not to be bound by theory, it is understood that such metal additives remove or reduce the necessity of oxidized halide uptake by the electrolyte, and furthermore open the possibility for the use of alkali-fluoride based cathode compositions. Among the transition metals, elemental copper has been discovered to be a particularly preferred cathode constituent. Without intending to be bound by theory, the useful role of copper is thought to arise from its ability to be reversibly transformed between elemental +1 oxidized copper halides, such as CuF, CuCl, CuBr, or CuI and +2 oxidized copper halides, such as CuF.sub.2, CuCl.sub.2, CuBr.sub.2, or CuI.sub.2, without being reduced to elemental copper at the anode side in SO.sub.2 based electrolytes. FIGS. 3 and 4 show the difference in cell voltage depending on the presence of copper, highlighting the different cell chemistry operation with the presence of copper. It has been surprisingly discovered that SO.sub.2 based electrolytes facilitate such reversible conversion reaction starting from elemental copper, allowing the assembly of the cell in discharged state. The high round-trip energy efficiency of the resulting battery cells, which is in the range of 90-95%, and their very high cycling stability are particularly surprising aspects, since previously known conversion-type cathode based battery cells suffer from poor energy efficiency and fast capacity fading. FIG. 5 shows the cell voltage evolution of a cell comprising a 2NaCl:Cu cathode, and a metallic Na anode. FIG. 6 shows the cell voltage evolution of a cell comprising a 2LiF:Cu cathode and a metallic Li anode. The cell discharge data corresponding to FIG. 6 indicates the feasibility of fully utilizing the theoretical capacity of the 2LiF:Cu cathode. According to the invention, the SO.sub.2 based electrolytes may comprise NaAlCl.sub.4.Math.xSO.sub.2 or LiAlCl.sub.4.Math.xSO.sub.2 formulations, or any mixtures thereof. The cathode active material may be comprised of alkali-halide:copper preferably between the 1:1 and 10:1 molar ratio range, and more preferably between the 1.5:1 and 3:1 molar ratio range, and most preferably between the 1.9:1 and 2.1:1 molar ratio range. In case of other transition metals and other alkali-halides, the preferred alkali-halide:metal molar ratio may be the same as in case of copper.

(24) An alternative construction method to the discharged state assembly is to build the cells in the charged state. For instance, it has been surprisingly discovered that lithium-based batteries can also be assembled in the charged state using an anode already comprising metallic lithium, and a cathode comprising, a transition metal halide. The transition metal may be, for instance, copper. Other transition metals are possible according to the invention. For instance, copper-fluoride (CuF.sub.2) may be infused into a conductive carbon framework to form a CuF.sub.2 containing cathode. Other transition metal halides are possible according to the invention. During assembly, the metallic lithium anode may be an anode current collector already having a deposit or layer of lithium metal. The charged-state cell is operable with the same electrolyte which has been used for the discharged state cell construction. Any of the described anode current collectors are possible according to the invention.

EXAMPLES

Preparation of Electrolytes

Example 1

(25) The NaAlCl.sub.4.Math.2SO.sub.2 electrolyte was synthesized according to The LiAlCl.sub.4.Math.2SO.sub.2 electrolyte through the same procedure, with the use of LiCl precursor instead of NaCl.

Example 2

(26) The electrolyte with the desired NaAlCl.sub.4:LiAlCl.sub.4 ratio was prepared by mixing NaAlCl.sub.4.Math.2SO.sub.2 and LiAlCl.sub.4.Math.2SO.sub.2 electrolytes in the corresponding ratio. Specifically, a 1:10 ratio of NaAlCl.sub.4:LiAlCl.sub.4 was used for the Li based cells.

Example 3

(27) The electrolyte with the LiDFOB additive has been prepared by mixing 1 wt % of LiDFOB into the electrolytes of examples 1 and 2. Electrolytes with NaDFOB, LiTriflate, or NaTriflate additive were prepared analogously.

Preparation of the Active Material

Example 4

(28) The alkali halide material based cathodes have been prepared by making a saturated solution of NaCl, LiCl, NaBr, LiBr, NaI, or LiI in methanol, dispersing porous carbon into the saturated solution, and evaporating the solvent. In case of NaF and LiF, propylene carbonate was used instead of methanol.

Example 5

(29) To obtain cathode material based on alkali halide:copper formulation, copper was infused into the materials of example 4 from copper-nitrate dissolved in ethanol, according to the procedure described in [2]. The amount of the copper precursor was adjusted to obtain a 2:1 molar ratio between the alkali halide and copper.

Preparation of the Positive Electrode

Example 6

(30) The electrode was prepared from a mixture of 94 wt % of the active materials from examples 4 and 5, and 6 wt % of PTFE. This mixture was dry-pressed onto carbon-coated aluminum current collector, according to the dry-pressing procedure of [3].

Preparation of the Rechargeable Batteries

Example 7

(31) A rechargeable NaCl active material based battery was prepared having a Constantan anode current collector, a glass microfiber separator of 200 micron of thickness, which is soaked in NaAlCl.sub.4.Math.2SO.sub.2 electrolyte and, the NaCl based cathode obtained through the procedures described in Examples 4 and 6. The battery prepared for this example exhibited the average discharge voltage evolution shown in FIG. 3.

Example 8

(32) A rechargeable 2NaCl:Cu active material formulation based battery was prepared having a metallic Na anode, a glass microfiber separator of 200 micron of thickness, which is soaked in NaAlCl.sub.4.Math.2SO.sub.2 electrolyte and, the 2NaCl:Cu formulation based cathode obtained through the procedures described in Examples 4, 5, and 6. The battery prepared for this example exhibited the average discharge voltage evolution shown in FIG. 4, and the details of one cycle charge-discharge voltage evolution is shown in FIG. 5.

Example 9

(33) A rechargeable 2LiF:Cu active material formulation based battery was prepared having a metallic Li anode, a glass microfiber separator of 200 micron of thickness, which is soaked in LiAlCl.sub.4.Math.2SO.sub.2 electrolyte with 1 wt % LiDFOB additive and, the 2LiF:Cu formulation based cathode obtained through the procedures described in Examples 4, 5, and 6. FIG. 6 shows one cycle charge-discharge voltage evolution of the battery prepared for this example.

REFERENCES

(34) 1. DOI: 10.1038/srep12827

(35) 2. DOI: 10.1002/adfm.201304156

(36) 3. Patent number DE 10 2012 203 019 A1