Electrochemical cell with TMCCC electrodes in an acetonitrile solvent including a dinitrile additive
A system and method for a liquid electrolyte used in secondary electrochemical cells having at least one electrode including a TMCCC material, the liquid electrolyte enabling an increased lifetime while allowing for fast discharge to extremely high depth of discharge. The addition of dinitriles to liquid electrolytes in electrochemical cells in which energy storage is achieved by ion intercalation in transition metal cyanide coordination compounds (TMCCC) has the advantage of increasing device lifetime by inhibiting common chemical and electrochemical degradation mechanisms.
1. An electrochemical cell, comprising:
an electrolyte;
an anode electrode in electrical communication with said electrolyte; and
a cathode electrode in electrical communication with said electrolyte;
wherein said anode electrode includes a transition metal cyanide coordination compound material;
wherein said electrolyte includes one or more solvents and one or more alkali metal salts in solution with said one or more solvents, and an additive disposed within said one or more solvents;
wherein at least one solvent of said one or more solvents includes a methyl cyanide having a formula X-W wherein X identifies a functional group including one or more species CN, O, F, and W identifies a linear alkane or alkene group and wherein said additive of said electrolyte includes a general formula X-W′-X with W′ different from W;
wherein said additive includes a dinitrile material;
wherein said transition metal cyanide coordination compound material includes a composition A x P y [R(CN) (6) ] z n(H 2 O), wherein A includes an alkali metal cation, wherein P includes a transition metal cation, wherein R includes a transition metal cation, and wherein 0≤x≤2, y=1, 0.75≤z≤1, and 0≤n≤6; and
wherein R includes Mn; and
wherein said electrolyte further includes a quantity Q of water, Q>0.
2. The electrochemical cell of claim 1 in which said dinitrile material includes a linear dinitrile material.
3. The electrochemical cell of claim 2 in which said linear dinitrile material includes succinonitrile.
4. The electrochemical cell of claim 2 in which said linear dinitrile material includes adiponitrile.
5. The electrochemical cell of claim 1 having a weight ratio N of said solvent to said additive wherein 70:30<N<99:1.
6. The electrochemical cell of claim 1 wherein A includes one or more of Li, Na, K, Rb, and Cs cations.
7. The electrochemical cell of claim 1 wherein P of said anode electrode includes at least one of manganese and iron.
8. The electrochemical cell of claim 1 wherein said at least one solvent includes acetonitrile.
9. The electrochemical cell of claim 3 wherein said at least one solvent includes acetonitrile.