Positive electrode coating material for lithium secondary battery, preparation method thereof, and positive electrode and lithium secondary battery comprising the coating material
AssigneesLG Energy Solution, Ltd., Seoul National University R&Db Foundation
InventorsSoohyun Kim, Jong-Chan Lee, Kihyun Kim, Kwonnam Sohn, Daun Jeong
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Abstract
Disclosed are a positive electrode coating material for a lithium secondary battery including graphene oxide surface-modified with cationic functional groups, a preparation method thereof, and a positive electrode and a lithium secondary battery comprising the coating material. The positive electrode coating material prevents the leaching of lithium polysulfide, thereby improving battery performance.
Claims14
A positive electrode coating material for a lithium secondary battery comprising:
- graphene oxide surface-modified with cationic functional groups,
- wherein the cationic functional group is bonded to graphene oxide in a state of being contained in a hydrocarbon group having 4 to 70 carbon atoms and 0 to 4 oxygen atoms,
- wherein the cationic functional group is bonded to the graphene oxide by a carbon atom, and
- wherein the cationic functional group is represented by Formula 1 below:
- wherein:
- R1, R2, R3, R4, and R5 are hydrogen or an alkyl group having 1 to 4 carbon atoms,
- X is a halogen group,
- o, p, and q are each independently an integer from 0 to 4, and
- n is a natural number from 1 to 5.
A method for preparing a positive electrode coating material for a lithium secondary battery, comprising the steps of:
- (a) preparing a surface modified graphene oxide by reacting graphene oxide containing one or more of a —COOH group and a —OH group on its surface with a hydrocarbon structural unit having 1 to 10 carbon atoms and comprising 0 to 2 oxygens which comprises a functional group that forms a bond with the —COOH group or —OH group and a functional group that forms a bond with a vinyl group contained in a (meth)acrylate compound;
- and
- (b) reacting the surface-modified graphene oxide with a (meth)acrylate structural unit grafted with a hydrocarbon group having 2 to 10 carbon atoms and comprising a cationic group,
- wherein the hydrocarbon group having 2 to 10 carbon atoms and comprising a cationic group is a compound represented by Formula 2 below:
- wherein:
- R4 and R5 are hydrogen or an alkyl group having 1 to 4 carbon atoms,
- X is a halogen group, and
- p and q are each independently an integer from 0 to 4.
Dependencies are inferred from the claim text.