ELECTROLYTE FORMULATIONS FOR GRAPHENE BASED LITHIUM ION CELL ANODES
An electrolyte of a lithium ion electrochemical cell, the electrolyte including a non-aqueous solvent, a lithium salt, and an additive. The solvent may include a solution of ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate.
1 . An electrochemical cell, comprising:
a negative electrode comprising a first component comprising graphene, graphene oxide, reduced graphene oxide, or a combination thereof, and a second component different than the first component;
a positive electrode comprising lithium; and
an ionically conductive electrolyte in which the negative and positive electrodes are immersed, the electrolyte comprising a solvent, a salt comprising an alkali metal, and an electrolyte additive configured to stabilize a solid electrolyte interphase layer that forms on a surface of the negative electrode.
2 . The electrochemical cell of claim 1 , wherein the solvent comprises a solution comprising at least two of ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate.
3 . The electrochemical cell of claim 2 , wherein the solvent solution comprises ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate in a volume ratio of 3:5:2, 2:5:3, 5:2:3, 5:3:2, 3:2:5, or 2:3:5.
4 . The electrochemical cell of claim 2 , wherein the solvent solution comprises ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate, each of which comprising from about 5 percent to about 90 volume percent, based on the total volume of the solvent solution.
5 . The electrochemical cell of claim 1 , wherein the electrolyte additive is selected from the group consisting of propene sultone (PS), ethylene sulfite (ES), tetravinyl methylsilane (TVMS), LiBF 2 , trimethyl phosphate (TMP), triethyl phosphate (TEP), and lithium bis(fluorosulfonyl)imide (LiFSI), and combinations thereof.
6 . The electrochemical cell of claim 5 , wherein the electrolyte additive comprises from about 1 wt % to about 10 wt % of the electrolyte, based on the total weight of the electrolyte.
7 . The electrochemical cell of claim 1 , wherein the salt is selected from the group consisting of LiPF 6 , LIBOB, 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.
8 . The electrochemical cell of claim 1 , wherein a molarity of the salt in the solvent solution ranges from about 0.1 to about 1.5.
9 . The electrochemical cell of claim 1 , wherein:
the negative electrode comprises particles comprising the second component encapsulated by the first component; and
the negative electrode has an average particle size that ranges from about 0.5 μm to about 10 μm.
10 . The electrochemical cell of claim 1 , wherein the second component is selected from the group consisting of silicon, silicon oxide, tin, tin oxide, antimony, aluminum, silver, germanium, gallium, magnesium, zinc, lead, bismuth, carbon, titanium oxide, lithium titanium oxide, alloys thereof, intermetallics thereof, and mixtures thereof.
11 . The electrochemical cell of claim 2 , wherein:
the negative electrode is graphite free;
the second component comprises silicon particles encapsulated by the first component; and
the additive comprises ethylene sulfite (ES).
12 . The electrochemical cell of claim 10 , wherein the second component has an average particle size that ranges from about 30 nm to about 500 nm.
13 . The electrochemical cell of claim 2 , wherein:
the second component comprises silicon particles encapsulated by the first component;
the negative electrode further comprises graphite; and
the additive comprises triethyl phosphate (TEP).
14 . The electrochemical cell of claim 1 , wherein:
the negative electrode comprises from about 15 weight percent to about 85 weight percent of the first component, based on the total weight of the negative electrode; and
the negative electrode comprises from about 15 weight percent to about 85 weight percent of the second component, based on the total weight of the negative electrode.
15 . The electrochemical cell of claim 1 , wherein the negative electrode comprises from about 0.01 weight percent to about 5 weight percent of a non-active carbon material, based on the total weight of the negative electrode.
16 . An electrolyte for a lithium ion electrochemical cell, the electrolyte comprising:
a solvent solution comprising ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate;
a salt comprising alkali metal; and
an electrolyte additive configured to stabilize a solid electrolyte interphase layer that forms on a surface of a negative electrode of the electrochemical cell.
17 . The electrolyte of claim 16 , wherein the solvent solution comprises the ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate in a volume ratio of 3:5:2, 2:5:3, 5:2:3, 5:3:2, 3:2:5 or 2:3:5.
18 . The electrolyte of claim 16 , wherein the electrolyte additive is selected from the group consisting of propene sultone (PS), ethylene sulfite (ES), tetravinyl methylsilane (TVMS), LiBF 2 , trimethyl phosphate (TMP), triethyl phosphate (TEP), and lithium bis (fluorosulfonyl) imide (LiFSI), and combinations thereof.
19 . The electrolyte of claim 16 , wherein the electrolyte comprises from about 1 wt % to about 10 wt % of the electrolyte additive, based on the total weight of the electrolyte.
20 . The electrolyte of claim 16 , wherein the salt is selected from the group consisting of LiPF 6 , LIBOB, 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.
21 . The electrolyte of claim 16 , wherein a molarity of the salt in the solvent solution ranges from about 0.1 to about 1.5.