Polymer solid electrolyte and method for manufacturing same
AssigneeLG Energy Solution, Ltd.
InventorsSunghyun Nam, Hyeaeun Han, Dong Kyu Kim
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Abstract
A polymer solid electrolyte and a method for preparing the same are provided. The method includes preparing a polymer solid electrolyte, defining a correlation between an added amount of a lithium salt and ionic conductivity of the polymer solid electrolyte, and adjusting the added amount of the lithium salt depending on the ionic conductivity of the prepared solid electrolyte, and is thereby capable of preparing a polymer solid electrolyte having high ionic conductivity through a large-capacity continuous process.
Claims13
A polymer solid electrolyte comprising:
- a polymer containing a cross-linkable functional group;
- a lithium salt;
- and
- a solvent,
- wherein the polymer solid electrolyte comprises a cross-linked structure;, and an amorphous polymer chain containing the cross-linkable functional group,
- the cross-linked structure contains (a) a cross-linkage between cross-linkable functional groups, (b) a cross-linkage between the cross-linkable functional group and the solvent, and (c) a bond between the cross-linkable functional group and the lithium salt,
- the polymer solid electrolyte has ionic conductivity (σ), which is defined by the following Equation 1, of more than 108 S/cm:
- σ
- =
- σ
- 0
- (
- N
- -
- Nc
- )
- S
- [
- Equation
-
- 1
- ]
- wherein σ0 is a maximum ionic conductivity that the polymer solid electrolyte can exhibit, N is a molar ratio ([Li]/[G]) of lithium (Li) of the lithium salt to the cross-linkable functional group ([G]) of the polymer, NC is a percolation threshold and 0<Nc≤0.15, and S is a critical exponent and 1.9≤S≤3.0.
A method for preparing a polymer solid electrolyte, the method comprising:
- (S1) forming a solution by adding a lithium salt to an aqueous solution of a polymer containing an oxygen-containing cross-linkable functional group;
- (S2) forming a coating film by applying the solution on a substrate;
- (S3) preparing a polymer solid electrolyte by freezing and thawing the coating film to form a physical cross-linkage of the polymer containing the cross-linkable functional group;
- (S4) measuring ionic conductivity of the polymer solid electrolyte;
- and
- (S5) adjusting the added amount of the lithium salt of the step (S1), by comparing the ionic conductivity measured in the step (S4) and ionic conductivity calculated by the following Equation 1 such that the ionic conductivity (σ) calculated by the following Equation 1 is more than 10−8 S/cm:
- σ
- =
- σ
- 0
- (
- N
- -
- Nc
- )
- S
- [
- Equation
-
- 1
- ]
- wherein σ0 is maximum ionic conductivity that the polymer solid electrolyte can exhibit, N is a molar ratio ([Li]/[G]) between of lithium (Li) of the lithium salt to the cross-linkable functional group ([G]) of the polymer, NC is a percolation threshold and 0<NC≤0.15, and S is a critical exponent and 1.9≤S≤3.0.
Dependencies are inferred from the claim text.