LITHIUM ELECTROCHEMICAL CELL ACTIVATED WITH AN ELECTROLYTE CONTAINING DBC, LiBOB AND FEC ADDITIVES

Patent metadata

Field	Value
Publication number	US-2021359343-A1
Application number	US-202117246861-A
Country	US
Kind code	A1
Filing date	May 3, 2021
Priority date	May 15, 2020
Publication date	Nov 18, 2021
Grant date	—

Abstract

An electrochemical cell having a casing housing an electrode assembly of a separator residing between a lithium anode and a cathode comprising silver vanadium oxide and fluorinated carbon is described. The electrode assembly is activated with a nonaqueous electrolyte comprising a lithium salt dissolved in a solvent system of propylene carbonate mixed with 1,2-dimethoxyethane, dibenzyl carbonate (DBC), lithium bis(oxalato)borate (LiBOB), and fluoroethylene carbonate (FEC). Preferably DBC is present in an amount ranging from about 0.005 moles (M) to about 0.25M, LiBOB is present in an amount ranging from about 0.005 wt. 5 to about 5 wt. %, and FEC is present in an amount ranging from about 0.01 wt. % to about 10 wt. %. This electrolyte formulation is more conductive than the conventional or prior art binary and ternary solvent system electrolytes while being chemically and electrochemically stable toward Li/SVO cells, Li-SVO/CFx mixture cells, and Li-SVO/CFx sandwich cathode primary electrochemical cells.

First claim

What is claimed is:

1 . An electrochemical cell, comprising:
a) a casing; b) an electrode assembly housed inside the casing, the electrode assembly comprising:
i) a lithium anode;
ii) a cathode comprising silver vanadium oxide; and
iii) a separator residing between the anode and the cathode to prevent them from direct physical contact with each other; and
c) a nonaqueous electrolyte provided in the casing in physical contact with the anode and the cathode, the electrolyte comprising:
i) a lithium salt dissolved in a solvent system comprising at least one low viscosity solvent mixed with at least one high permittivity solvent;
ii) dibenzyl carbonate (DBC);
iii) lithium bis(oxalato)borate (LiBOB); and
iv) fluoroethylene carbonate (FEC).

2 . The electrochemical cell of claim 1 , wherein the lithium salt is selected from the group of LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiClO 4 , LiO 2 , LiAlCl 4 , LiGaCl 4 , LiC(SO 2 CF 3 ) 3 , LiN(SO 2 CF 3 ) 2 , LiSCN, LiO 3 SCF 3 , LiC 6 FSO 3 , LiO 2 CCF 3 , LiSO 6 F, LiB(C 6 H 5 ) 4 , LiCF 3 SO 3 , and mixtures thereof.

3 . The electrochemical cell of claim 1 , wherein the lithium salt is dissolved in the solvent system in a molar ratio ranging from about 0.8M to about 1.5M.

4 . The electrochemical cell of claim 1 , wherein the at least one low viscosity solvent and the high permittivity solvent are present in the solvent system in a ratio ranging from about 20:80 to about 50:50, by volume.

5 . The electrochemical cell of claim 1 , wherein the at least one low viscosity solvent is selected from the group of tetrahydrofuran (THF), methyl acetate (MA), diglyme, trigylme, tetragylme, dimethyl carbonate (DMC), 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), 1-ethoxy,2-methoxyethane (EME), ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, diethyl carbonate, dipropyl carbonate, and mixtures thereof, and wherein the at least one high permittivity solvent is selected from the group of propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate, acetonitrile, dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, γ-valerolactone, γ-butyrolactone (GBL), N-methyl-pyrrolidinone (NMP), and mixtures thereof.

6 . The electrochemical cell of claim 1 , wherein the DBC is present in the electrolyte in an amount ranging from about 0.005 moles (M) to about 0.25M, the LiBOB is present in the electrolyte in an amount ranging from about 0.005 wt. % to about 5 wt. %, and the FEC is present in the electrolyte in an amount ranging from about 0.01 wt. % to about 10 wt. %.

7 . The electrochemical cell of claim 1 , wherein the cathode further comprises fluorinated carbon.

8 . The electrochemical cell of claim 7 , wherein the fluorinated carbon is (C 2 F) n or has the formula (CF x ) n with x ranging from about 0.1 to about 1.9, and mixtures thereof.

9 . The electrochemical cell of claim 7 , wherein the silver vanadium oxide is mixed with the fluorinated carbon.

10 . The electrochemical cell of claim 7 , wherein the silver vanadium oxide and the fluorinated carbon are contacted to opposite sides of at least one current collector in a configuration selected from:
a) SVO/current collector/CF x , with the SVO facing the anode; b) CF x /first current collector/SVO, with the CF x facing the anode; c) SVO/CF x /current collector/CF x /SVO; d) SVO/first current collector/CF x /second current collector/SVO; e) SVO/first current collector/SVO/CF x /SVO/second current collector/SVO; f) CF x /first current collector/SVO/second current collector/CF x ; and g) CF x /first current collector/CF x /SVO/CF x /second current collector/CF x .

11 . An electrochemical cell, comprising:
a) a casing; b) an electrode assembly housed inside the casing, the electrode assembly comprising:
i) a lithium anode;
ii) a cathode comprising silver vanadium oxide and fluorinated carbon; and
iii) a separator residing between the anode and the cathode to prevent them from direct physical contact with each other; and
c) a liquid, nonaqueous electrolyte provided in the casing in physical contact with the anode and the cathode, the electrolyte comprising:
i) a lithium salt dissolved in a solvent system comprising propylene carbonate mixed with 1,2-dimethoxyethane;
ii) dibenzyl carbonate (DBC);
iii) lithium bis(oxalato)borate (LiBOB); and
iv) fluoroethylene carbonate (FEC).

12 . The electrochemical cell of claim 11 , wherein the DBC is present in the electrolyte in an amount ranging from about 0.005 moles (M) to about 0.25M, the LiBOB is present in the electrolyte in an amount ranging from about 0.005 wt. % to about 5 wt. %, and the FEC is present in the electrolyte in an amount ranging from about 0.01 wt. % to about 10 wt. %.

13 . The electrochemical cell of claim 11 , wherein the fluorinated carbon is (C 2 F) n or has the formula (CF x ) n with x ranging from about 0.1 to about 1.9, and mixtures thereof.

14 . The electrochemical cell of claim 11 , wherein the silver vanadium oxide is mixed with the fluorinated carbon.

15 . The electrochemical cell of claim 11 , wherein the silver vanadium oxide and the fluorinated carbon are contacted to opposite sides of at least one current collector in a configuration selected from:
a) SVO/current collector/CF x , with the SVO facing the anode; b) CF x /first current collector/SVO, with the CF x facing the anode; c) SVO/CF x /current collector/CF x /SVO; d) SVO/first current collector/CF x /second current collector/SVO; e) SVO/first current collector/SVO/CF c /SVO/second current collector/SVO; f) CF x /first current collector/SVO/second current collector/CF x ; and g) CF x /first current collector/CF x /SVO/CF x /second current collector/CF x .

16 . A nonaqueous electrolyte, comprising:
a) a lithium salt dissolved in a solvent system comprising at least one low viscosity solvent mixed with at least one high permittivity solvent; b) dibenzyl carbonate (DBC); c) lithium bis(oxalato)borate (LiBOB); and d) fluoroethylene carbonate (FEC).

17 . The electrolyte of claim 16 , wherein the lithium salt is selected from the group of LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiCLO 4 , LiO 2 , LiAlCl 4 , LiGaCl 4 , LiC (SO 2 CF 3 ) 3 , LiN (SO 2 CF 3 ) 2 , LiSCN, LiO 3 SCF 3 , LiC 6 FSO 3 , LiO 2 CCF 3 , LiSO 6 F, LiB(C 6 H 5 ) 4 , LiCF 3 SO 3 , and mixtures thereof.

18 . The electrolyte of claim 16 , wherein the lithium salt is dissolved in the solvent system in a molar ratio ranging from about 0.8M to about 1.5M.

19 . The electrolyte of claim 16 , wherein the at least one low viscosity solvent and the high permittivity solvent are present in the solvent system in a ratio ranging from about 20:80 to about 50:50, by volume.

20 . The electrolyte of claim 16 , wherein the at least one low viscosity solvent is selected from the group of tetrahydrofuran (THF), methyl acetate (MA), diglyme, trigylme, tetragylme, dimethyl carbonate (DMC), 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), 1-ethoxy,2-methoxyethane (EME), ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, diethyl carbonate, dipropyl carbonate, and mixtures thereof, and wherein the at least one high permittivity solvent is selected from the group of propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate, acetonitrile, dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, γ-valerolactone, γ-butyrolactone (GBL), N-methyl-pyrrolidinone (NMP), and mixtures thereof.

2

Assignees

• Greatbatch Ltd

Inventors

• Rubino Robert S
• Lehnes Joseph M
• Palazzo Marcus J
• Spillman David M
• Yun Ho-Chul

Classifications

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M2300/0034

  Fluorinated solvents · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title