Electrochemical cells and metal salt-based electrolytes
Ion transport in electrochemical cells or energy storage devices may take place in metal salt-based electrolytes. The metal salt-based electrolytes may comprise high doping metal salt formulations. Electrochemical cells or energy storage devices comprising metal salt-based electrolytes may be used as single-use or rechargeable power sources.
1. An electrochemical cell, comprising:
a positive electrode;
a negative electrode; and
a printed electrolyte between the positive electrode and the negative electrode, the printed electrolyte comprising:
an ionic liquid comprising at least one anion selected from the group consisting of bis(fluoromethanesulfonyl) imide, bis(fluorosulfonyl) imide, bis(trifluoromethanesulfonyl) imide, triflate, trifluoromethanesulfonate, and tetrafluoroborate; and
a metal salt that releases multivalent cations when dissolved in the ionic liquid; wherein the multivalent cations are selected from at least one of zinc, aluminum, magnesium, and yttrium;
wherein the molarity of the multivalent cations in the ionic liquid is greater than 1 molar (M);
wherein the electrochemical cell is rechargeable.
2. The electrochemical cell of claim 1 , wherein the molarity of the multivalent cations in the ionic liquid is greater than about 1.2 M.
3. The electrochemical cell of claim 1 , further comprising (i) ethylene glycol or a related low molecular weight ethylene oxide derivative that increases ionic conductivity of the printed electrolyte, reduces viscosity of the electrolyte, or a combination thereof; or (ii) a fluorinated polyether that increases ionic conductivity of the printed electrolyte, reduces viscosity of the printed electrolyte, or a combination thereof.
4. The electrochemical cell of claim 1 , wherein:
(a) the metal salt comprises a mixture of anion types, and wherein the metal salt has a lower melting point than a neat metal salt comprising only one of the anion types; or
(b) a ternary, quaternary or higher order mixture of anions has a lower melting point than (i) any individual binary mixture of the anions or (ii) a mixture comprising only one of the anions or any lower order mixture of the anions.
5. The electrochemical cell of claim 1 , wherein the printed electrolyte comprises a mixture of cations and anions, and wherein the mixture comprises one or more cation types.
6. The electrochemical cell of claim 5 , wherein a ternary, quaternary or higher order mixture of the cations and anions has a lower melting point than any individual binary, ternary, or lower order mixture of the cations and anions.
7. The electrochemical cell of claim 1 , wherein the ionic liquid comprises at least one cation selected from the group consisting of imidazolium, pyrrolidinium, alkylammonium, pyridinium, piperidinium, phosphonium, and sulfonium.
8. The electrochemical cell of claim 1 , wherein the printed electrolyte further comprises a carrier.
9. The electrochemical cell of claim 8 , wherein the carrier comprises an ionic liquid, a carbonate, a fluorinated carbonate, or any combination thereof.
10. The electrochemical cell of claim 1 wherein the printed electrolyte forms a heterogeneous gel electrolyte mixture in a flowable state.
11. The electrochemical cell of claim 1 , wherein the printed electrolyte comprises water under ambient conditions.
12. The electrochemical cell of claim 11 , wherein the printed electrolyte comprises no more than about 5 weight percent of water under ambient conditions.
13. The electrochemical cell of claim 1 , wherein the positive electrode comprises a metal oxide selected from the group consisting of manganese dioxide, vanadium pentoxide, cobalt oxide, and lead oxide.
14. The electrochemical cell of claim 8 , wherein the molarity of the metal salt in the carrier exceeds the solubility limit of the metal salt in the carrier.
15. An electrochemical cell comprising:
a positive electrode;
a negative electrode; and
a printed electrolyte between the positive electrode and negative electrode, the printed electrolyte comprising:
an ionic liquid comprising at least one anion selected from the group consisting of bis(fluoromethanesulfonyl) imide, bis(fluorosulfonyl) imide, bis(trifluoromethanesulfonyl) imide, triflate, trifluoromethanesulfonate, and tetrafluoroborate; and
at least one metal salt that releases multivalent cations when dissolved in the ionic liquid; wherein the multivalent cations are selected from ions of at least one of zinc, aluminum, magnesium, and yttrium;
wherein the electrochemical cell has a capacity of at least about 1.5 milliampere-hour per square centimeter (mAh/cm 2 );
wherein the electrochemical cell is rechargeable.
16. The electrochemical cell of claim 15 , wherein the printed electrolyte forms an electrolyte film, and wherein the printed electrolyte comprises a dispersion of particles with a particle size that is less than a thickness of the electrolyte film.
17. The electrochemical cell of claim 16 , wherein the particles are solid.
18. The electrochemical cell of claim 16 , wherein the particles comprise (i) oxide particles, or (ii) solid polymer particles with a low solubility for liquid constituents of the printed electrolyte.
19. The electrochemical cell of claim 16 , wherein at least a portion of the particles comprises a particle surface modified to increase an affinity of liquid constituents of the printed electrolyte to the particle surface.
20. The electrochemical cell of claim 16 , wherein, in (c), the cation or the anion of the particle has an equal or higher affinity to a counterion in the printed electrolyte than other ions in the printed electrolyte.