Preformation of stable solid electrolyte interface films on graphite-material electrodes

Patent metadata

Field	Value
Publication number	US-2016126582-A1
Application number	US-201414529840-A
Country	US
Kind code	A1
Filing date	Oct 31, 2014
Priority date	Oct 31, 2014
Publication date	May 5, 2016
Grant date	—

Abstract

Disclosed are preformed solid electrolyte interface (SEI) film graphite electrodes in lithium-sulfur based chemistry energy storage systems and methods of making the preformed SEI films on graphite electrodes to expand the use of graphite-based electrodes in previously non-graphite anode energy systems, such as lithium-sulfur battery systems. Also disclosed are lithium-ion sulfur battery systems comprising electrolytes that do not include an alkyl carbonate, such as those that do not include EC, and graphite anodes having preformed alkyl carbonate, such as EC-based SEI films.

First claim

We claim:

1 . A device comprising:
a lithium-ion sulfur battery system comprising
a graphite anode having a preformed SEI film, preformed in an alkyl carbonate pretreatment solution; and
an electrolyte not including an alkyl carbonate.

2 . The lithium-ion sulfur battery system of claim 1 wherein the preformed SEI film alkyl carbonate pretreatment solution comprises EC.

3 . The lithium-ion battery sulfur system of claim 1 wherein the preformed SEI film alkyl carbonate pretreatment solution comprises DMC.

4 . The lithium-ion sulfur battery system of claim 1 , wherein the preformed SEI film pretreatment solution further comprises SO 2 , Li 2 CO 3 , K 2 CO 3 , LiBOB, ES, PS, VES, PES, VTC, FEC, VC, VEC, or mixtures thereof.

5 . The lithium-ion sulfur battery system of claim 1 wherein the electrolyte comprises an ether-based electrolyte.

6 . The lithium-ion sulfur battery system of claim 1 wherein the electrolyte comprises lithium bis-trifluoromethanesulfonamide (LiTFSI), lithium bis(fluorosulfonyl)amide (LiFSI), lithium 4,5-dicyano-2-(trifluoromethyl) imidazole (LiTDI) and/or lithium triflate and a solvent comprising dimethyl ether, 1,2-dimethoxyethane (DME), 1,3-dioxolane (DOL), dimethyl sulfoxide (DMSO), diethylene glycol dimethyl ether (diglyme), Triethylene glycol dimethyl ether (triglyme), tetra ethylene glycol dimethyl ether (tetraglyme), sulfone and their binary or ternary mixtures, and mixtures thereof.

7 . The lithium-ion sulfur battery system of claim 1 wherein the graphite anode is a substantially pure graphite anode.

8 . A device comprising:
a lithium-ion sulfur battery system further comprising
a graphite anode having a preformed SEI film; and
a non-alkyl carbonate electrolyte useful for charging and discharging the lithium-ion sulfur battery system without significant decline in specific capacity in over 10 cycles.

9 . The lithium-ion sulfur battery system of claim 8 wherein the preformed SEI film comprises an EC-based SEI film.

10 . The lithium-ion sulfur lithium-ion sulfur battery system of claim 8 wherein the preformed SEI film consists essentially of an EC-based SEI film.

11 . A method comprising:
making a graphite electrode capable of use in a lithium-ion sulfur battery system by
providing an untreated graphite electrode, the graphite electrode having a surface;
providing an alkyl carbonate pretreatment solution;
prior to placing the graphite electrode in the lithium-ion sulfur battery system, immersing the untreated graphite electrode in the alkyl carbonate pretreatment solution thereby preforming a SEI film on the surface of the graphite electrode;
removing the graphite electrode having the preformed SEI film thereon from the pretreatment solution; and
placing the graphite electrode having the preformed SEI film thereon in an electrolyte, wherein the electrolyte does not comprise an alkyl carbonate.

12 . The method of claim 11 further comprising charging and discharging the lithium-ion sulfur battery system with the preformed SEI film graphite electrode in the lithium-ion sulfur battery system.

13 . The method of claim 11 further comprising placing the graphite electrode having the preformed SEI film thereon into a lithium-sulfur supercapacitor having an electrolyte that does not comprise alkyl carbonate.

14 . The method of claim 11 wherein the SEI film pretreatment solution comprises EC, DMC, EMC, DEC, EC/DMC, EC/EMC, EC/DEC, EC/PC or mixtures thereof.

15 . The method of claim 11 wherein the providing the alkyl carbonate pretreatment solution comprises providing a pretreatment solution comprising EC, EC and a co-solvent, EC and EMC, EC/DEC, EC and PC or EC and DMC.

16 . The method of claim 15 wherein the providing the EC pretreatment solution comprises providing EC at a sufficient temperature that the EC is a liquid in the absence of a solvent.

17 . A method comprising:
making a preformed SEI film graphite electrode by
providing an untreated graphite electrode;
providing an alkyl carbonate pretreatment solution;
precycling the untreated graphite electrode in the alkyl carbonate pretreatment solution thereby preforming an SEI film on the surface of the graphite electrode;
placing the preformed SEI film graphite electrode into a lithium-sulfur battery system; and
cycling the preformed SEI film graphite electrode in the lithium-sulfur battery system in an electrolyte, wherein the electrolyte does not comprise an alkyl carbonate.

18 . The method of claim 17 wherein the preformed SEI film pretreatment solution comprises EC.

19 . The method of claim 17 wherein the electrolyte comprises an ether compound.

20 . The method of claim 17 wherein the electrolyte comprises lithium bis-trifluoromethanesulfonamide (LiTFSI), lithium bis(fluorosulfonyl)amide (LiFSI), lithium 4,5-dicyano-2-(trifluoromethyl) imidazole (LiTDI) and/or lithium triflate and a solvent comprising dimethyl ether, 1,2-dimethoxyethane (DME), 1,3-dioxolane (DOL), dimethyl sulfoxide (DMSO), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetra ethylene glycol dimethyl ether (tetraglyme), sulfone and their binary or ternary mixtures, and mixtures thereof.

Assignees

• Battelle Memorial Institute

Inventors

• Xiao Jie
• Shao Yuyan
• Lu Dongping
• Bennett Wendy D
• Liu Jun
• Zhang Ji-Guang
• Graff Gordon L

Classifications

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M10/058

  Construction or manufacture · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/04

  Construction or manufacture in general (H01M10/058, H01M10/12, H01M10/28, H01M10/38 take precedence) · CPC title

• H01M2300/0028

  characterised by the solvent · CPC title