LOWER FLAMMABILITY ELECTROLYTE COMPOSITIONS
Electrolyte compositions comprising electrolyte additives and/or solvents for reduction of thermal propagation in lithium-ion batteries are disclosed. Energy storage devices comprising the electrolyte compositions comprise a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode may be a Si-based electrode, a separator between the first electrode and the second electrode, and the electrolyte composition.
1 . An energy storage device comprising:
a first electrode and a second electrode, wherein one or both of the first electrode and the second electrode is a Si-based electrode;
a separator between the first electrode and the second electrode; and
an electrolyte composition, wherein said electrolyte composition reduces thermal propagation; and
wherein said electrolyte composition comprises one or more solvents, one or more lithium-containing salts, and one or more optional additives; and
wherein said solvent comprises one or more phosphorous-based compounds.
2 . The energy storage device of claim 1 , wherein said one or more phosphorous-based compound is of the structure:
where R1-3 can be any combination of CH 3 , CF 3 , or any C1-C10 alkyl/fluoroalkyl group (perfluorinated/partially fluorinated);
or
where R1-6 can be any combination of F, CH 3 , CF 3 , R, OR, or any C1-C10 alkyl/fluoroalkyl (perfluorinated/partially fluorinated) and where R denotes any C1-C10 alkyl/fluoroalkyl (perfluorinated/partially fluorinated).
3 . The energy storage device of claim 2 , wherein said one or more phosphorous-based compound is a phosphazene compound of structure:
where R1-6 can be any combination of F, CH 3 , CF 3 , R, OR, or any C1-C10 alkyl/fluoroalkyl (perfluorinated/partially fluorinated) and where R denotes any C1-C10 alkyl/fluoroalkyl (perfluorinated/partially fluorinated).
4 . The energy storage device of claim 1 , wherein said one or more phosphorous-based compound is present in a concentration of 15-90 vol %.
5 . The energy storage device of claim 1 , wherein said electrolyte composition further comprises carbonate-based solvent system.
6 . The energy storage device of claim 5 , wherein said carbonate-based solvent system comprises one or more of Ethylene Carbonate (EC), Fluoroethylene Carbonate (FEC), Propylene Carbonate (PC), Dimethyl Carbonate (DMC), Ethyl Methyl Carbonate (EMC), and Diethyl Carbonate (DEC).
7 . The energy storage device of claim 1 , wherein said one or more lithium-containing salts are selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium nitrate (LiNO 3 ), lithium perchlorate (LiClO 4 ), Lithium difluoro(oxalato)borate (LiDFOB) and Lithium bis(oxalato)borate (LiBOB).
8 . The energy storage device of claim 7 , wherein the amounts of said one or more lithium-containing salts comprise a majority of either LiPF 6 or LiBF 4 or a combination of the two.
9 . The energy storage device of claim 8 , wherein the combined molarity of LiPF 6 or LiBF 4 or a combination of the two ranges from about 0.8-2M.
10 . The energy storage device of claim 9 , further comprising other salts making up <0.5M.
11 . An energy storage device comprising:
a first electrode and a second electrode, wherein one or both of the first electrode and the second electrode is a Si-based electrode;
a separator between the first electrode and the second electrode; and
an electrolyte composition, wherein said electrolyte composition reduces thermal propagation; and
wherein said electrolyte composition comprises one or more solvents, one or more lithium-containing salts, and one or more optional additives; and
wherein said solvent comprises at least one hydrofluoroether solvent.
12 . The energy storage device of claim 11 , wherein said hydrofluoroether solvent comprises one or more of the following compounds:
13 . The energy storage device of claim 11 , wherein said hydrofluoroether solvent is present in a concentration of 15-90 vol %.
14 . The energy storage device of claim 11 , wherein said electrolyte composition further comprises a phosphazene compound.
15 . The energy storage device of claim 11 , wherein said electrolyte composition further comprises carbonate-based solvent system.
16 . The energy storage device of claim 15 , wherein said carbonate-based solvent system comprises one or more of Ethylene Carbonate (EC), Fluoroethylene Carbonate (FEC), Propylene Carbonate (PC), Dimethyl Carbonate (DMC), Ethyl Methyl Carbonate (EMC), and Diethyl Carbonate (DEC).
17 . The energy storage device of claim 1 , wherein said one or more lithium-containing salts are selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium nitrate (LiNO 3 ), lithium perchlorate (LiClO 4 ), Lithium difluoro(oxalato)borate (LiDFOB) and Lithium bis(oxalato)borate (LiBOB).
18 . The energy storage device of claim 17 , wherein the amounts of said one or more lithium-containing salts comprise a majority of either LiPF 6 or LiBF 4 or a combination of the two.
19 . The energy storage device of claim 18 , wherein the combined molarity of LiPF 6 or LiBF 4 or a combination of the two ranges from about 0.8-2M.
20 . The energy storage device of claim 19 , further comprising other salts making up <0.5M.