1. Field of the Invention
This invention generally relates to electrochemical cells and, more particularly, to a method of fabrication and associated battery with an anode that is preloaded with consumable metals.
2. Description of the Related Art
The rechargeable lithium ion battery (LIB) has triggered the portable electronic devices revolution due to its high power density, long cycling life, and environmental compatibility. The rechargeable LIB consists of a cathode (positive electrode) and an anode (negative electrode), separated by a Li+-ion permeable membrane. A solution or polymer containing lithium-ions is also used in the battery so that Li+-ions can “rock” back and forth between the positive and negative electrode freely. The positive materials are typically transition-metal oxides such as lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), and their derivatives. Lithium-ions can move in their interstitial space freely and reversibly. The negative electrode materials can use lithium-metal, alloys, and carbonaceous materials. During discharge, Li+-ions are extracted from the negative electrode and inserted into the positive electrode. In the meantime, electrons pass through an external circuit from the negative electrode to the positive electrode and generate electric power. During a charge, ions and electrons move along the reverse direction and go back to their original places.
Although LIBs have been successfully used, the conflict between lithium demand and its scarcity surges its cost, which hinders the further application of lithium-ion batteries on a large scale. Therefore, a low-cost rechargeable battery is urgently needed as an alternative to expensive LIBs. Under the circumstance, sodium-ion batteries are attracting more attention because sodium has very similar properties to lithium, but a cheaper cost. Like lithium-ion batteries, sodium-ion batteries need Na+-host materials as their electrode. Much effort has been expended to directly duplicate the Li+-host structures, using Na+-host electrode materials for the sodium-ion batteries. For example, NaCoO2, NaMnO2, NaCrO2 and Na0.85Li0.17Ni0.21Mn0.64O2, all having a layered-structure similar to LiCoO2, have been developed for sodium-ion batteries. Similarly, Co3O4 with a Spinel structure, Na3V2(PO4)3 with a NASICON structure, and NaFePO4 with an Olivine structure have been employed in sodium batteries. In addition, sodium fluorophosphates, such as Na2PO4F, NaVPO4F and Na1.5VOPO4F0.5, have also used as the positive electrode in sodium batteries.
However, it is impractical to copy the structures of Li+-host compounds for Na+ or K+-host compounds. Sodium and potassium ions are much larger than lithium ions, and severely distort the structure of the Li*-host compounds. Thus, it is very important for the advancement of sodium/potassium-ion batteries to develop new Na+/K+-host materials with large interstitial spaces in which sodium/potassium-ions can easily and reversibly move. Na+/K+— ions have been observed to intercalate into metal cyanide compounds. Transition metal hexacyanoferrates (TMHCFs) with large interstitial spaces have been investigated as cathode materials for rechargeable lithium-ion batteries [1,2], sodium-ion batteries [3,4], and potassium-ion batteries [5]. With an aqueous electrolyte containing proper alkali-ions or ammonium-ions, copper and nickel hexacyanoferrates [(Cu,Ni)-HCFs]demonstrated robust cycling life with 83% capacity retention after 40,000 cycles at a charge/discharge current of 17C [6-8]. In spite of this, the materials demonstrated low capacities and energy densities because (1) only one sodium-ion can be inserted/extracted into/from per Cu-HCF or Ni-HCF formula, and (2) these TM-HCFs electrodes must be operated below 1.23 V due to the water electrochemical window. The electrochemical window of a substance is the voltage range between which the substance is neither oxidized nor reduced. This range is important for the efficiency of an electrode, and once out of this range, water becomes electrolyzed, spoiling the electrical energy intended for another electrochemical reaction.
In order to compensate for such shortcomings, manganese hexacyanoferrate (Mn-HCF) and iron hexacyanoferrate (Fe-HCF) have been used as cathode materials in a non-aqueous electrolyte [9, 10]. When assembled with a sodium-metal anode, Mn-HCF and Fe-HCF electrodes cycled between 2.0V and 4.2 V delivered capacities of ˜110 mAh/g.
Without the interstitial ions, Berlin Green and its analogues can be used as cathode in any metal-ion batteries. The electrochemical reactions during discharge can be expressed as follows,
Cathode:
M1x[M2(CN)z]y.dH2O+bMea++bae−=MebM1x[M2(CN)z]y.dH2O
Anode:
Me−Ø=Mea++ae−+Ø.
Where Me is the alkali, alkaline earth, or aluminum, and Me−Ø is the metal loaded anode that has been described in parent application entitled, BATTERY ANODE WITH PRELOADED METALS, Serial No. 14/198,663, which is incorporated herein by reference.
It would be advantageous if a metal-ion battery with a cathode of Berlin Green or its analogues could be made with a metal preloaded in the anode, for higher energy, longer cycling life, and lower costs.
Disclosed herein is a metal-ion battery with a transition metal hexacyanometallate (TMHCM) cathode and a metal-loaded anode separated by a metal-ion permeable membrane. The membrane can be a liquid electrolyte-soaked separator, polymer, gel, or solid electrolyte. The materials for the positive electrode (cathode) are Berlin Green or its analogues (M1YM2Z(CN)N.
Accordingly, 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 and comprises MeaX. X is a material such as carbon, metals 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. A cathode is also immersed in the electrolyte and separated from the preloaded anode by the ion-permeable membrane. The cathode comprises M1YM2Z(CN)N.
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.
A plurality of initial charge and discharge operations are performed. 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. As a result, an anode is formed comprising MebX overlying the current collector in a battery discharge state, where 0≦b<a.
Subsequent to performing the plurality of initial charge and discharge operations, the cathode formed in a battery discharged state comprises MeXM1YM2Z(CN)N.
In one case, if the performance of initial the charge and discharge operations consumes the metal (Me) in the preloaded anode, the anode formed in the battery charged state comprises MecX, where c<a. Further, solid electrolyte interface (SEI) layers are formed overlying the anode, the cathode, or both the anode and cathode. Otherwise, if the Me metal is not consumed, the anode formed in the battery charged state comprises MeaX. Either way, the anode formed in the battery charged state comprises either X with intercalated Me metal ions or X alloyed with Me metal.
Additional details of the above-described method, a battery with a preloaded anode, and a battery with a steady state capacity are presented below.
The cathode 210 comprises a conductive current collector 212 with M1YM2Z(CN)N.
M1 and M2 are transition metals;
X is less than or equal to 2;
Y is less than or equal to 1;
Z is less than or equal to 1;
N is less than or equal to 6; and,
M is less than or equal to 20.
An ion-permeable membrane 216, immersed in the electrolyte, is interposed between the anode 204 and the cathode 210.
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).
A short list of possible MeaX 208 materials are as follows:
LiRVO2, where 0<R<1;
NaSMnO2, where 0<s<1;
a Na—Sn 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 Li—Sn alloy;
a Li—Sb alloy;
a Na—Sb alloy;
a compound of Fe3O4 and Li; and,
a compound of Fe3O4 and Na.
Other materials include Sb2O4, Li4Ti5O12, Na2+xTi3O7, TiO2, VO2, Na4+xTi5O12, Ti2(PO4)3, NiCo2O4, Ni3S2, FeS2, NaxTiS2, NaxVS2, and FeF3.
It should be understood that the battery 200 may be enabled using other MeaX 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.
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.
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.
In the steady state discharged condition, which occurs after a plurality of initial charge and discharge cycles, MebX 302 overlies the anode current collector 206, where 0≦b<a. When charged in either the initial condition or steady state condition, assuming no SEI layer exists over the cathode, M1YM2Z(CN)N.
MeXM1YM2Z(CN)N.
where X is greater than zero.
In one aspect, as shown in
SEI formation depends on the potentials of the anodes. For example, Li4Ti5O12 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 (
The positive electrode (cathode) in
at the positive electrode
FeYFeZ(CN)N.
at the negative electrode
Na-Ø=Na++e−+Ø;
where Ø is hard carbon.
Here, sodium has been electrochemically loaded onto/into hard carbon before assembled into the cell with the Berlin Green cathode.
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
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 MeaX. 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 M1YM2Z(CN)N.
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).
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 MebX overlying the current collector in a battery discharge state, where 0≦b<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 MeXM1YM2Z(CN)N.
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 MecX, where c<a. Alternatively, in the absence of Step 711, Step 714b forms an anode in the battery charged state comprising MeaX. 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.
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.
This application is a Continuation-in-Part of an application entitled, BATTERY ANODE WITH PRELOADED METALS, invented by Long Wang et al, Serial No. 14/198,663, filed Mar. 6, 2014, attorney docket No. SLA3363; which is a Continuation-in-Part of an application entitled, METAL BATTERY ELECTRODE WITH PYROLYZED COATING, invented by Yuhao Lu et al, Serial No. 14/193,782, filed Feb. 28, 2014, attorney docket No. SLA3353; which is a Continuation-in-Part of an application entitled, METAL HEXACYANOMETALLATE ELECTRODE WITH SHIELD STRUCTURE, invented by Yuhao Lu et al, Serial No. 14/193,501, filed Feb. 28, 2014, attorney docket No. SLA3352; which is a Continuation-in-Part of an application entitled, CYANOMETALLATE CATHODE BATTERY AND METHOD FOR FABRICATION, invented by Yuhao Lu et al, Serial No. 14/174,171, filed Feb. 6, 2014, attorney docket No. SLA3351; This application is a Continuation-in-Part of an application entitled, SODIUM IRON(II)-HEXACYANOFERRATE(II) BATTERY ELECTRODE AND SYNTHESIS METHOD, invented by Yuhao Lu et al, Serial No. 14/067,038, filed Oct. 30, 2013, attorney docket No. SLA3315; which is a Continuation-in-Part of an application entitled, TRANSITION METAL HEXACYANOMETALLATE-CONDUCTIVE POLYMER COMPOSITE, invented by Sean Vail et al., Serial No. 14/059,599, filed Oct. 22, 2013, attorney docket No. SLA3336; which is a Continuation-in-Part of an application entitled, METAL-DOPED TRANSITION METAL HEXACYANOFERRATE (TMHCF) BATTERY ELECTRODE, invented by Yuhao Lu et al., Ser. No. 13/907,892, filed Jun. 1, 2013, attorney docket No. SLA3287; which is a Continuation-in-Part of an application entitled, HEXACYANOFERRATE BATTERY ELECTRODE MODIFIED WITH FERROCYANIDES OR FERRICYANIDES, invented by Yuhao Lu et al., Ser. No. 13/897,492, filed May 20, 2013, attorney docket No. SLA3286; which is a Continuation-in-Part of an application entitled, PROTECTED TRANSITION METAL HEXACYANOFERRATE BATTERY ELECTRODE, invented by Yuhao Lu et al., Ser. No. 13/872,673, filed Apr. 29, 2013, attorney docket No. SLA3285; which is a Continuation-in-Part of an application entitled, TRANSITION METAL HEXACYANOFERRATE BATTERY CATHODE WITH SINGLE PLATEAU CHARGE/DISCHARGE CURVE, invented by Yuhao Lu et al., Ser. No. 13/752,930, filed Jan. 29, 2013, attorney docket No. SLA3265; which is a Continuation-in-Part of an application entitled, SUPERCAPACITOR WITH HEXACYANOMETALLATE CATHODE, ACTIVATED CARBON ANODE, AND AQUEOUS ELECTROLYTE, invented by Yuhao Lu et al., Ser. No. 13/603,322, filed Sep. 4, 2012, attorney docket No. SLA3212. Ser. No. 13/752,930 is also a Continuation-in-Part of an application entitled, IMPROVEMENT OF ELECTRON TRANSPORT IN HEXACYANOMETALLATE ELECTRODE FOR ELECTROCHEMICAL APPLICATIONS, invented by Yuhao Lu et al., Ser. No. 13/523,694, filed Jun. 14, 2012, attorney docket No. SLA3152; which is a Continuation-in-Part of an application entitled, ALKALI AND ALKALINE-EARTH ION BATTERIES WITH HEXACYANOMETALLATE CATHODE AND NON-METAL ANODE, invented by Yuhao Lu et al., Ser. No. 13/449,195, filed Apr. 17, 2012, attorney docket no. SLA3151; which is a Continuation-in-Part of an application entitled, ELECTRODE FORMING PROCESS FOR METAL-ION BATTERY WITH HEXACYANOMETALLATE ELECTRODE, invented by Yuhao Lu et al., Ser. No. 13/432,993, filed Mar. 28, 2012, attorney docket no. SLA3146. All these applications are incorporated herein by reference.
Number | Date | Country | |
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Parent | 14198663 | Mar 2014 | US |
Child | 14198702 | US |
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Parent | 14193782 | Feb 2014 | US |
Child | 14198663 | US | |
Parent | 14193501 | Feb 2014 | US |
Child | 14193782 | US | |
Parent | 14174171 | Feb 2014 | US |
Child | 14193501 | US | |
Parent | 14067038 | Oct 2013 | US |
Child | 14174171 | US | |
Parent | 14059599 | Oct 2013 | US |
Child | 14067038 | US | |
Parent | 13907892 | Jun 2013 | US |
Child | 14059599 | US | |
Parent | 13897492 | May 2013 | US |
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Parent | 13872673 | Apr 2013 | US |
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Parent | 13752930 | Jan 2013 | US |
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Parent | 13603322 | Sep 2012 | US |
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Parent | 13449195 | Apr 2012 | US |
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