Electrolyte additives for electrochemical devices

Abstract

A system and method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

What is claimed as new and desired to be protected by Letters Patent of the United States is: 
     
         1 . A rechargeable electrochemical device, comprising:
 a first electrode;   a second electrode;   an electrolyte coupled with said electrodes; and   a first additive in communication with said electrolyte;   wherein a first particular one electrode of said electrodes includes a first variable potential material; and   wherein said first additive participates in a first predetermined side-reaction with a first single one of said electrodes degrading a charging efficiency of said first single one of said electrodes for a duration of said first predetermined side-reaction.   
     
     
         2 . The rechargeable electrochemical device of  claim 1  wherein said duration is preconfigured for a reduction in a relative state-of-charge imbalance between said electrodes after charging of said electrodes. 
     
     
         3 . The rechargeable electrochemical device of  claim 1  wherein said first particular one electrode includes a first transition metal cyanide coordination compound (TMCCC). 
     
     
         4 . The rechargeable electrochemical device of  claim 1  further comprising a second additive in communication with said electrolyte wherein a second particular one electrode of said electrodes, different from said first particular one electrode of said electrodes, includes a second variable potential material; and wherein said second additive participates in a second predetermined side-reaction with a second single one of said electrodes. 
     
     
         5 . The rechargeable electrochemical device of  claim 4  wherein said second particular one electrode includes a second transition metal cyanide coordination compound (TMCCC). 
     
     
         6 . The rechargeable electrochemical device of  claim 3  wherein said TMCCC material includes a composition having the general chemical formula A x M y [R(CN) 6-j L j ] z .nH 2 O, wherein:
 A includes one or more cations; 
 M includes one or more metal cations; 
 R includes one or more transition metal cations; and 
 L is a ligand substituted in the place of a CN −  ligand; where 
 0≤x≤2; 
 0<y≤4; 
 0<z≤1; 
 0≤j<6; and 
 0≤n≤5. 
 
     
     
         7 . The rechargeable electrochemical device of  claim 3  wherein said electrolyte includes a total electrolyte volume V including a first quantity of water comprising a first fraction V1 of said total electrolyte volume V and including a second quantity of one or more organic cosolvents together comprising a second fraction V2 of said total electrolyte volume V, wherein V1>0.02, and wherein said electrolyte consists essentially of a single phase. 
     
     
         8 . The rechargeable electrochemical device of  claim 7  wherein V2>V1. 
     
     
         9 . The rechargeable electrochemical device of  claim 8  wherein said one or more organic solvents includes a solvent containing a cyanide group. 
     
     
         10 . The rechargeable electrochemical device of  claim 9  wherein said second quantity V2 includes acetonitrile. 
     
     
         11 . The rechargeable electrochemical device of  claim 8  wherein said one or more organic cosolvents includes a solvent containing a sulfone group. 
     
     
         12 . The rechargeable electrochemical device of  claim 11  wherein said sulfone group includes sulfolane. 
     
     
         13 . The rechargeable electrochemical device of  claim 8  wherein a concentration of said additive is included within a range of 10 to 10,000 parts per million. 
     
     
         14 . The rechargeable electrochemical device of  claim 8  wherein said additive includes one or more organic molecules. 
     
     
         15 . The rechargeable electrochemical device of  claim 14  wherein said one or more organic molecules are configured to participate in a reversible electrochemical redox reaction at one or more of said electrodes during an application of charging energy to said electrodes. 
     
     
         16 . The rechargeable electrochemical device of  claim 15  wherein said additive includes a quinone group. 
     
     
         17 . The rechargeable electrochemical device of  claim 14  wherein said one or more organic molecules are configured to participate in an irreversible electrochemical redox reaction at one or more of said electrodes during an application of charging energy to said electrodes. 
     
     
         18 . The rechargeable electrochemical device of  claim 17  wherein said irreversible electrochemical redox reaction results in a polymerization of said one or more organic molecules. 
     
     
         19 . The rechargeable electrochemical device of  claim 18  wherein said one or more organic molecules include a pyrrole group. 
     
     
         20 . The rechargeable electrochemical device of  claim 8  wherein said additive includes a transition metal salt. 
     
     
         21 . The rechargeable electrochemical device of  claim 20  wherein said salt is configured to participate in a reversible electrochemical redox reaction at one or more of said electrodes during an application of charging energy to said electrodes. 
     
     
         22 . The rechargeable electrochemical device of  claim 20  wherein said salt is configured to participate in an irreversible reaction at one or more of said electrodes during an application of charging energy to said electrodes. 
     
     
         23 . The rechargeable electrochemical device of  claim 22  wherein said salt includes a transition metal cation. 
     
     
         24 . The rechargeable electrochemical device of  claim 22  wherein said salt includes a transition metal polyanion. 
     
     
         25 . The rechargeable electrochemical device of  claim 8  wherein said additive includes an organometallic molecule. 
     
     
         26 . The rechargeable electrochemical device of  claim 25  wherein said organometallic molecule is configured to participate in a reversible electrochemical redox reaction at one or more of said electrodes. 
     
     
         27 . The rechargeable electrochemical device of  claim 25  wherein said organometallic molecule includes a metallocene. 
     
     
         28 . The rechargeable electrochemical device of  claim 25  wherein said organometallic molecule is configured to participate in an irreversible reaction at one or more of said electrodes during an application of charging energy at said electrodes. 
     
     
         29 . The rechargeable electrochemical device of  claim 8  wherein said additive includes a surfactant. 
     
     
         30 . A method for reducing a relative state-of-charge imbalance of a set of electrodes of a rechargeable electrochemical device during a recharging process, the set of electrodes coupled to an electrolyte and wherein at least one electrode of the set of electrodes includes a first variable potential material, comprising:
 a) performing the recharging process for a recharging duration which charges the electrodes at different relative rates to tend to produce a relative state-of-charge imbalance for the set of electrodes; and   b) reducing said relative state-of-charge imbalance by interfering with a charging of at least one electrode of the set of electrodes.