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 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 quantity Q<10,000 ppm.
9. The electrochemical cell of claim 8 wherein said quantity Q>1,000 ppm.
10. The electrochemical cell of claim 1 wherein said quantity Q includes water released from at least one of said electrodes.
11. The electrochemical cell of claim 10 wherein said quantity Q<10,000 ppm.
12. The electrochemical cell of claim 11 wherein said quantity Q>1,000 ppm.