Battery with an anode preload with consumable metals

Abstract

A method is provided for fabricating a battery using an anode preloaded with consumable metals. The method forms an ion-permeable membrane immersed in an electrolyte. A preloaded anode is immersed in the electrolyte, comprising Me.sub.aX, where X is a material such as carbon, metal capable of being alloyed with Me, intercalation oxides, electrochemically active organic compounds, and combinations of the above-listed materials. Me is a metal such as alkali metals, alkaline earth metals, and combinations of the above-listed metals. A cathode is also immersed in the electrolyte and separated from the preloaded anode by the ion-permeable membrane. The cathode comprises M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O. After a plurality of initial charge and discharge operations are preformed, an anode is formed comprising Me.sub.bX overlying the current collector in a battery discharge state, where 0b<a.

Claims

1. A method for fabricating a battery using an anode preloaded with consumable metals, the method comprising: forming an electrolyte; forming an ion-permeable membrane immersed in the electrolyte; forming preloaded anode immersed in the electrolyte, comprising Me.sub.aX, where X is a material selected from the group consisting of carbon, metal capable of being alloyed with Me, intercalation oxides, electrochemically active organic compounds, and combinations of the above-listed materials, and Me is a metal selected from the group consisting of alkali metals, alkaline earth metals, silver (Ag), aluminum (Al), and a combination of the above-listed metals; forming a cathode immersed in the electrolyte and separated from the preloaded anode by the ion-permeable membrane, where the cathode comprises M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O; where M1 and M2 are independently selected from the group consisting of transition metals, calcium (Ca), magnesium (Mg), strontium (Sr), and barium (Ba); where Y is less than or equal to 1; where Z is less than or equal to 1; where N is less than or equal to 6; where M is less than or equal to 20; performing a plurality of initial charge and discharge operations, where a charge operation uses an external power source to create a current from the preloaded anode to the cathode, and a discharge operation connects an external load between the preloaded anode and cathode; and, forming an anode comprising Me.sub.bX overlying the current collector in a battery discharge state, where 0b<a.

2. The method of claim 1 wherein performing the plurality of initial charge and discharge operations includes consuming the metal (Me) in the preloaded anode; wherein forming the anode includes forming an anode in the battery charged state comprising Me.sub.cX, where c<a; and, the method further comprising: forming solid electrolyte interface (SEI) layers overlying an electrode selected from a group consisting of the anode, the cathode, and both the anode and cathode.

3. The method of claim 1 wherein Me is selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), calcium (Ca), strontium (Sr), barium (Ba), and magnesium (Mg).

4. The method of claim 1 wherein M1 and M2 are independently selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).

5. The method of claim 1 further comprising: subsequent to performing the plurality of initial charge and discharge operations, forming a cathode in a battery discharged state comprising Me.sub.XM1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O; where X is greater than zero.

6. The method of claim 1 further comprising: subsequent to performing the plurality of initial charge and discharge operations, forming an anode in a battery charged state comprising a material selected from the group consisting of X with intercalated Me metal ions and X alloyed with Me metal.

7. The method of claim 1 wherein performing the plurality of initial charge and discharge operations includes not consuming the metal (Me) in the preloaded anode; and, wherein forming the anode includes forming an anode in a battery charged state comprising Me.sub.aX.

8. A preloaded battery with an anode preloaded with consumable metals, the preloaded battery comprising: an electrolyte; a preloaded anode comprising: a conductive current collector; Me.sub.aX overlying the current collector, where X is a material selected from the group consisting of carbon, metals able to be electrochemically alloy with metal (Me), intercalation oxides, electrochemically active organic compounds, and combinations of the above-listed materials, and Me is a metal selected from the group of consisting of alkali metals, alkaline earth metals, silver (Ag), aluminum (Al), and combinations thereof; a cathode comprising: a conductive current collector; M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O overlying the current collector; where M1 and M2 are independently selected from the group consisting of transition metals, calcium (Ca), magnesium (Mg), strontium (Sr), and barium (Ba); where X is less than or equal to 2; where Y is less than or equal to 1; where Z is less than or equal to 1; where N is less than or equal to 6; where M is less than or equal to 20; an ion-permeable membrane immersed in the electrolyte, interposed between the anode and the cathode; and, wherein the battery is configured such that in a steady state discharged condition occurring after a plurality of initial charge and discharge cycles the anode comprises Me.sub.bX overlying the anode current collector, where 0ba.

9. The preloaded battery of claim 8 wherein Me is selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), calcium (Ca), strontium (Sr), barium (Ba), and magnesium (Mg).

10. The preloaded battery of claim 8 wherein Me.sub.aX is selected from the group consisting of: Li.sub.RVO.sub.2, where 0<R<1; Na.sub.SMnO.sub.2, where 0<s<1; a NaSn alloy; a mixture of lithium powder and tin particles; a mixture of sodium particles and hard carbon powder; a compound of hard carbon and lithium; a compound of hard carbon and sodium; a LiSn alloy; a LiSb alloy; a NaSb alloy; a compound of Fe.sub.3O.sub.4 and Li; and, a compound of Fe.sub.3O.sub.4 and Na.

11. The preloaded battery of claim 8 wherein M1 and M2 are independently selected from a the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).

12. A battery with a steady state capacity, the battery comprising: an electrolyte; an anode comprising: a conductive current collector; wherein the battery is configured such that in an initial condition, Me.sub.aX overlies the current collector, where X is a material selected from the group consisting of carbon, metals able to be electrochemically alloy with metal (Me), intercalation oxides, electrochemically active organic compounds, and combinations of the above-listed materials, and Me is a metal selected from the group consisting of alkali metals, alkaline earth metals, silver (Ag), aluminum (Al), and combinations thereof; wherein the battery is configured such that in a steady state discharged condition occurring after a plurality of initial charge and discharge cycles, Me.sub.bX overlies the current collector, where 0b<a; a cathode comprising: a conductive current collector; charged in both the initial condition and steady state conditions, M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O overlying the current collector; where M1 and M2 are independently selected from the group consisting of transition metals, calcium (Ca), magnesium (Mg), strontium (Sr), and barium (Ba); where X is less than or equal to 2; where Y is less than or equal to 1; where Z is less than or equal to 1; where N is less than or equal to 6; where M is less than or equal to 20; and, an ion-permeable membrane immersed in the electrolyte, interposed between the anode and the cathode.

13. The battery of claim 12 wherein Me is selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), calcium (Ca), strontium (Sr), barium (Ba), and magnesium (Mg).

14. The battery of claim 12 wherein Me.sub.aX is selected from the group consisting of: Li.sub.RVO.sub.2, where 0<R<1; Na.sub.SMnO.sub.2, where 0<s<1; a NaSn alloy; a mixture of lithium powder and tin particles; a mixture of sodium particles and hard carbon powder; a compound of hard carbon and lithium; a compound of hard carbon and sodium; a LiSn alloy; a LiSb alloy; a NaSb alloy; a compound of Fe.sub.3O.sub.4 and Li; and, a compound of Fe.sub.3O.sub.4 and Na.

15. The battery of claim 12 wherein M1 and M2 are independently selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).

16. The battery of claim 12 further comprising: wherein the battery is configured such that in the steady state condition, solid electrolyte interface (SEI) layers overlie an electrode selected from the group consisting of the anode, the cathode, and both the anode and cathode; and, wherein the battery is configured such that the anode, charged in the steady state condition, comprises Me.sub.cX, where c<a.

17. The battery of claim 12 wherein the battery is configured such that the cathode, discharged in the steady state condition, comprises: Me.sub.XM1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O; where X is greater than zero.

18. The battery of claim 12 wherein the battery is configured such the anode, charged in the steady state condition, comprises a material selected from the group consisting of X with intercalated Me metal ions and X alloyed with Me metal.

19. The battery of claim 12 wherein the battery is configured such that the anode, charged in the steady state condition, and in absence of SEI layers overlying an electrode selected from the group consisting of the anode, the cathode, and both the anode and cathode, comprises Me.sub.aX.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagram depicting the crystal structure of a metal hexacyanometallate (MHCM) (prior art).

(2) FIG. 2 is a partial cross-sectional view of a preloaded battery with an anode preloaded with consumable metals.

(3) FIGS. 3A and 3B are partial cross-sectional views of a battery with a steady state capacity.

(4) FIG. 4 is a partial cross-section view of an exemplary sodium-ion battery (NIB) with a Berlin Green cathode and a sodium-loaded hard carbon anode, as it is discharging.

(5) FIG. 5 is a graph depicting the behavior of the hard carbon anode with the sodium counter electrode.

(6) FIGS. 6A and 6B depict the capacitance of a full cell using a Berlin Green cathode and a sodium-loaded hard carbon anode.

(7) FIG. 7 is a flowchart illustrating a method for fabricating a battery using an anode preloaded with consumable metals.

DETAILED DESCRIPTION

(8) FIG. 2 is a partial cross-sectional view of a preloaded battery with an anode preloaded with consumable metals. The preloaded battery 200 comprises an electrolyte 202 and a preloaded anode 204. The preloaded anode 204 comprises a conductive current collector 206 with Me.sub.aX 208 overlying the current collector. X is a material such as carbon, metals able to be electrochemically alloy with metal (Me), intercalation oxides, electrochemically active organic compounds, and combinations of the above-listed materials. Me is a metal such as alkali metals, alkaline earth metals, and a combination of alkali and alkaline earth metals.

(9) The cathode 210 comprises a conductive current collector 212 with M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O 214 overlying the current collector, where:

(10) M1 and M2 are transition metals;

(11) X is less than or equal to 2;

(12) Y is less than or equal to 1;

(13) Z is less than or equal to 1;

(14) N is less than or equal to 6; and,

(15) M is less than or equal to 20.

(16) An ion-permeable membrane 216, immersed in the electrolyte, is interposed between the anode 204 and the cathode 210.

(17) More explicitly, Me may be one of the following metals: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), calcium (Ca), strontium (Sr), barium (Ba), silver (Ag), aluminum (Al), or magnesium (Mg). M1 and M2 are each independently derived, meaning they may be the same or different metals, and are typically one of the following: titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), Ca, Mg, strontium (Sr), or barium (Ba).

(18) A short list of possible Me.sub.aX 208 materials are as follows:

(19) Li.sub.RVO.sub.2, where 0<R<1;

(20) Na.sub.SMnO.sub.2, where 0<s<1;

(21) a NaSn alloy;

(22) a mixture of lithium powder and tin particles;

(23) a mixture of sodium particles and hard carbon powder;

(24) a compound of hard carbon and lithium;

(25) a compound of hard carbon and sodium;

(26) a LiSn alloy;

(27) a LiSb alloy;

(28) a NaSb alloy;

(29) a compound of Fe.sub.3O.sub.4 and Li; and,

(30) a compound of Fe.sub.3O.sub.4 and Na.

(31) Other materials include Sb.sub.2O.sub.4, Li.sub.4Ti.sub.5O.sub.12, Na.sub.2+xTi.sub.3O.sub.7, TiO.sub.2, VO.sub.2, Na.sub.4+xTi.sub.5O.sub.12, Ti.sub.2(PO.sub.4).sub.3, NiCo.sub.2O.sub.4, Ni.sub.3S.sub.2, FeS.sub.2, Na.sub.xTiS.sub.2, Na.sub.xVS.sub.2, and FeF.sub.3.

(32) It should be understood that the battery 200 may be enabled using other Me.sub.aX 208 materials, using the general categories of X and Me materials listed above, as would be understood by one with ordinary skill in the art.

(33) Not shown, a polymeric binder such as polytetrafluoroethylene (PTFE) or polyvinylidene difluoride (PVDF) may be used to provide adhesion between electrode materials and current collectors to improve the overall physical stability.

(34) The electrolyte 202 may be non-aqueous, such as an organic liquid electrolyte, or alternatively, gel electrolyte, polymer electrolyte, solid (inorganic) electrolyte, etc. Common examples of non-aqueous (liquid) electrolytes include organic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), etc., although many other organic carbonates and alternatives to organic carbonates exist. Typically, gel electrolytes consist of polymeric materials which have been swelled in the presence of liquid electrolytes. Examples of polymers employed as gel electrolytes include, but are not limited to, poly(ethylene)oxide (PEO) and fluorinated polymers such as poly(vinylidene) fluoride (PVDF)-based polymers and copolymers, etc. In contrast, (solid) polymer electrolytes may be prepared using the same classes of polymers for forming gel electrolytes although swelling of the polymer in liquid electrolytes is excluded. Finally, solid inorganic (or ceramic) materials may be considered as electrolytes, which may be employed in combination with liquid electrolytes. Overall, the appropriate electrolyte system may consist of combinations (hybrid) of the above classes of materials in a variety of configurations. In some instances not shown, the ion-permeable membrane 216 and the electrolyte 202 can be the same material, as may be the case for polymer gel, polymer, and solid electrolytes.

(35) FIGS. 3A and 3B are partial cross-sectional views of a battery with a steady state capacity. The battery 300 comprises an electrolyte 202 and an ion-permeable membrane 216, as described above in the explanation of FIG. 2. In short, the battery 300 may be described as having an initial condition or initial capacity, and a steady state condition or steady state capacity. The anode and cathode in the initial condition are as described in the explanation of FIG. 2, and their description is not repeated here in the interest of brevity.

(36) In the steady state discharged condition, which occurs after a plurality of initial charge and discharge cycles, Me.sub.bX 302 overlies the anode current collector 206, where 0b<a. When charged in either the initial condition or steady state condition, assuming no SEI layer exists over the cathode, M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O 214 overlies the cathode current collector 212. The cathode 210, discharged in the steady state condition, comprises:
Me.sub.XM1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O;

(37) where X is greater than zero.

(38) In one aspect, as shown in FIG. 3B, a solid state interface (SEI) 304 may overlie the electrodes in the steady state condition, meaning that some Me material has been consumed during the initial charge/discharge cycles. Although SEI 304 is shown as overlying both the cathode 210 and the anode 204 in this figure, it should be understood that SEI, if it forms at all, may form on just the anode or just the cathode. In this aspect, when the anode 204 is charged in the steady state condition, it comprises Me.sub.cX, where c<a.

(39) SEI formation depends on the potentials of the anodes. For example, Li.sub.4Ti.sub.5O.sub.12 may be used as the anode in a sodium ion battery. Its potential is about 1V (vs. Na), at which potential no SEI layer forms on the anode. In absence of SEI layers (FIG. 3A), the anode 204 charged in the steady state condition comprises Me.sub.aX. Either with or without SEI layers, the anode 204 charged in the steady state condition, comprises either X with intercalated Me metal ions or X alloyed with Me metal.

(40) The positive electrode (cathode) in FIGS. 2, 3A, and 3B may be Berlin Green or one of its analogues, M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O. The materials M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O demonstrate frameworks that consist of M1-NC-M2 skeletons and large interstitial space as shown in FIG. 1. Metal-ions can easily and reversibly move into their interstitial spaces. Metal-loaded anode materials can be one of carbonaceous materials, oxides, sulfides, or nitrides. As mentioned above, the metals can be Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ag, or Al. In order to obtain a high voltage for the battery, a non-aqueous electrolyte, such as organic electrolyte, gel electrolyte, polymer electrolyte, or solid electrolyte may be used.

(41) FIG. 4 is a partial cross-section view of an exemplary sodium-ion battery (NIB) 400 with a Berlin Green cathode 402 and a sodium-loaded hard carbon anode 404, as it is discharging. The positive electrode (cathode) 402 comprises Fe.sub.YFe.sub.Z(CN).sub.N.MH.sub.2O and a sodium-loaded negative electrode (anode) 404 is separated from the cathode by a Na.sup.+-ion permeable membrane 216. To obtain a high voltage, a Na.sup.+ soluble non-aqueous solution, polymer, gel or all-solid electrolyte 202 is used in the NIB 400. Meanwhile, the sodium-loaded negative electrode 404 can be selected from carbonaceous materials, oxides, sulfides, and so on. The sodium-ion battery 400 is discharged first. The Na.sup.+-ions 406 are disassociated from the sodium-loaded anode 404 and inserted into the Berlin Green cathode 402. The reactions in the battery are:

(42) at the positive electrode

(43) Fe.sub.YFe.sub.Z(CN).sub.N.MH.sub.2O+Na.sup.++be.sup.=Na.sub.bFe.sub.YFe.sub.Z(CN).sub.N.MH.sub.2O;

(44) at the negative electrode
Na-=Na.sup.++e.sup.+;

(45) where is hard carbon.

(46) Here, sodium has been electrochemically loaded onto/into hard carbon before assembled into the cell with the Berlin Green cathode.

(47) FIG. 5 is a graph depicting the behavior of the hard carbon anode with the sodium counter electrode. Before the hard carbon was put into the full (steady state condition) cell, it was cycled five times, and then discharged to 5 millivolts (mV), which made the hard carbon electrode stable and fully sodiated. To assemble the full cell, excess hard carbon was used, so the Berlin Green electrode determined the capacity of the full cell. In the full cell, hard carbon electrode capacity at low voltage is indicated in region 500.

(48) There are two purposes for the use of excess hard carbon, or in general, excess X material. One is to use its plateau at a low voltage, as indicated in FIG. 5. The other is that the excess hard carbon ensures that all sodium-ions from cathode are able to totally intercalate into the hard carbon electrode, so that no sodium dendrite forms on the anode surface. However, the various X materials used in the anode have different behaviors, and it is not necessary that all types of anode materials be in excess, as compared to the cathode, in full cells.

(49) FIGS. 6A and 6B depict the capacitance of a full cell using a Berlin Green cathode and a sodium-loaded hard carbon anode. In FIG. 6A, with the charge/discharge current of 100 mAh/g, the cell in its initial condition delivered a capacity of 138 milliamp hours per gram (mAh/g). After 9 cycles (steady state condition), the current increased to 300 mA/g, and the capacity decreased to 131 mAh/g. After 665 cycles the capacity retained was still above 104 mAh/g. FIG. 6A demonstrates the capacity retention of the full cell with the current of 300 mA/g. The initial 9 cycles with the current of 100 mA/g have been subtracted in FIG. 6B. The experimental result shows that the capacity was 80.1% of the initial capacity at the 656th cycle with the current of 300 mA/g.

(50) FIG. 7 is a flowchart illustrating a method for fabricating a battery using an anode preloaded with consumable metals. Although the method is depicted as a sequence of numbered steps for clarity, the numbering does not necessarily dictate the order of the steps. It should be understood that some of these steps may be skipped, performed in parallel, or performed without the requirement of maintaining a strict order of sequence. Generally however, the method follows the numeric order of the depicted steps. The descriptions of FIGS. 2, 3A, and 3B aid in the understanding of the method described below. The method starts at Step 700.

(51) Step 702 forms an electrolyte. Step 704 forms an ion-permeable membrane immersed in the electrolyte. Step 706 forms a preloaded anode immersed in the electrolyte, comprising Me.sub.aX. X is a material such as carbon, metal capable of being alloyed with Me, intercalation oxides, electrochemically active organic compounds, or combinations of the above-listed materials. Me is a metal such as alkali metals, alkaline earth metals, or combinations of the above-listed metals. Step 708 forms a cathode immersed in the electrolyte and separated from the preloaded anode by the ion-permeable membrane. The cathode comprises M1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O: where M1 and M2 are transition metals; where Y is less than or equal to 1; where Z is less than or equal to 1; where N is less than or equal to 6; and, where M is less than or equal to 20.

(52) More explicitly, Me may be lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), calcium (Ca), strontium (Sr), barium (Ba), gold (Ag), aluminum (Al), or magnesium (Mg). M1 and M2 are each independently derived, and are typically titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), Ca, Mg, strontium (Sr), or barium (Ba).

(53) Step 710 performs a plurality of initial charge and discharge operations. A charge operation uses an external power source to create a current from the preloaded anode to the cathode, and a discharge operation connects an external load between the preloaded anode and cathode. Step 712 forms an anode comprising Me.sub.bX overlying the current collector in a battery discharge state, where 0b<a. Subsequent to performing the plurality of initial charge and discharge operations in Step 710, Step 716 forms a cathode in a battery discharged state comprising Me.sub.XM1.sub.YM2.sub.Z(CN).sub.N.MH.sub.2O, where X is greater than zero.

(54) In one aspect, performing the plurality of initial charge and discharge operations in Step 710 includes consuming the metal (Me) in the preloaded anode. Then, Step 711 forms SEI layers overlying the anode, the cathode, or both the anode and cathode. In this aspect, Step 714a forms an anode in the battery charged state comprising Me.sub.cX, where c<a. Alternatively, in the absence of Step 711, Step 714b forms an anode in the battery charged state comprising Me.sub.aX. With or without the SEI layer(s), Steps 714a and 714b both form an anode in the battery charged state comprising X with intercalated Me metal ions or X alloyed with Me metal.

(55) A battery and associated fabrication method using an anode preloaded with consumable metals, and a battery with a steady state capacity have been provided. Examples of particular materials and process steps have been presented to illustrate the invention. However, the invention is not limited to merely these examples. Other variations and embodiments of the invention will occur to those skilled in the art.