Separation Membrane Composition for Dual-Electrolyte Li-Ion Batteries
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Solution Overview
Problem
In lithium ion secondary batteries with different electrolytes in the positive and negative electrodes, there is a need for a separation membrane that effectively separates solvents while allowing lithium ions to pass through, as existing solutions fail to achieve optimal solvent separation and lithium ion conductivity.
Innovation Solution
A lithium ion secondary battery configuration that includes a separation membrane with a polymer containing a specific monomer unit and a third lithium salt, positioned between the positive and negative electrode mixture layers, which contains different solvents, ensuring excellent solvent separation and lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different types of electrolytes are contained in the positive electrode and the negative electrode, then battery performance is improved, but solvent mixing occurs
Solution Approach 1:
The separation membrane acts as an intermediary barrier positioned between the positive and negative electrode electrolytes. It selectively blocks solvent molecules from crossing between electrodes while permitting lithium ion transport, thus maintaining the stability of different electrolyte compositions in each electrode region while still enabling the performance benefits of dual electrolyte systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed configuration provides a separation membrane with superior solvent separation capability and lithium ion conductivity, preventing solvent mixing and enhancing battery performance.
Implementation Method 1
it is necessary that lithium ions pass through the separation membrane, but the solvent in the electrolyte has characteristics of being hardly passed through the separation membrane
Implementation Method 2
a polymer having a hydrophobic nature and a specific affinity for a cyclic carbonate solvent
Implementation Method 3
a polymer having a hydrophobic nature and a specific affinity for a cyclic carbonate solvent
Implementation Method 4
a polymer having a hydrophobic nature and a specific affinity for a cyclic carbonate solvent
Data Source
AI summary
One aspect of the present invention provides a lithium ion secondary battery which sequentially comprises a positive electrode mixture layer, a separation membrane, and a negative electrode mixture layer in the stated order, wherein: the positive electrode mixture layer contains a positive electrode active material, a first lithium salt, and a first solvent; the negative electrode mixture layer contains a negative electrode active material, a second lithium salt, and a second solvent that is different from the first solvent; and the separation membrane contains a third lithium salt and a polymer that comprises, as a monomer unit, a monomer represented by formula (1).[wherein, in formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a divalent organic group, R3, R4 and R5 each independently represents a hydrogen atom or a monovalent organic group, and X− represents a counter anion.]