Silicon-based energy storage devices with electrolyte containing sulfonate or carboxylate salt based compounds
Electrolytes and electrolyte additives for energy storage devices comprising sulfonate or carboxylate salt based compounds are disclosed. The energy storage device comprises a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode, an electrolyte comprising at least two electrolyte co-solvents, wherein at least one electrolyte co-solvent comprises a sulfonate or carboxylate salt based compound.
1. An energy storage device comprising:
a first electrode;
a second electrode;
a separator between the first electrode and the second electrode; and
an electrolyte system comprising:
a carboxylate salt based compound;
a linear carbonate;
a cyclic carbonate; and
a Li-containing salt; wherein
the carboxylate salt based compound has the following formula:
wherein R 2 is a C 1 —C 20 ) alkyl or a C 1 —C 20 ) heteroalkyl, substituted by one or more-F;
A 2 is a cation; and
n is the oxidation state of A 2 and the stoichiometric number of carboxylate anions bonded to A 2 ; and further wherein
A 2 is Li or Cu.
2. The energy storage device of claim 1 , wherein the carboxylate salt based compound lithium perfluorooctanoate (LPFO).
3. The energy storage device of claim 1 , wherein the linear carbonate is selected from the group consisting of ethyl methyl carbonate (EMC), methyl acetate, dimethyl carbonate (DMC), and diethyl carbonate (DEC).
4. The energy storage device of claim 1 , further comprising a co-solvent selected from the group consisting of methyl acetate (MA), ethyl acetate (EA), methyl propanoate, and gamma butyrolactone (GBL).
5. The energy storage device of claim 1 , wherein the cyclic carbonate is selected from the group consisting of fluoroethylene carbonate (FEC), di-fluoroethylene carbonate (DiFEC), Trifluoropropylene carbonate (TFPC), ethylene carbonate (EC), vinyl carbonate (VC), and propylene carbonate (PC).
6. The energy storage device of claim 1 , wherein the cyclic carbonate is a fluorine containing cyclic carbonate.
7. The energy storage device of claim 6 , wherein the fluorine containing cyclic carbonate is FEC at a concentration of about 5% or more.
8. The energy storage device of claim 1 , wherein the electrolyte is substantially free of non-fluorine containing cyclic carbonate.
9. The energy storage device of claim 1 , wherein the Li-containing salt is a fluorinated Li salt.
10. The energy storage device of claim 1 , wherein the Li-containing salt has a concentration of about 1 M or more.
11. The energy storage device of claim 1 , wherein at least one of the first electrode and the second electrode is a Si-based electrode.
12. The energy storage device of claim 11 , wherein the Si-based electrode is an anode.
13. The energy storage device of claim 12 , wherein the anode is a Si-dominant anode.
14. The energy storage device of claim 12 , wherein the anode comprises:
greater than 0% and less than about 99% by weight of Si particles, and
greater than 0% and less than about 90% by weight of one or more types of carbon phases, wherein at least one of the one or more types of carbon phases is a substantially continuous phase that holds the composite material film together such that the silicon particles are distributed throughout the composite material film.
15. The energy storage device of claim 14 , wherein the anode comprises greater than 50% and less than about 97% by weight of Si particles.