Solid Electrolyte Copolymer Ion Conductivity
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Solution Overview
Problem
Current solid electrolytes face a trade-off between high ion conductivity and high cation transport number, with neither achieving both effectively due to structural limitations in polyether and polycarbonate electrolytes.
Innovation Solution
A solid electrolyte comprising a copolymer with specific carbonate and ether units, along with a metal salt, is developed, where the copolymer's composition and molecular weight are optimized to balance ion conductivity and cation transport number, using a random copolymer structure and specific lithium salts like lithium-bis(trifluoromethanesulfonyl)imide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a polyether electrolyte is used to achieve high flexibility and good electrolyte performance, then the electrolyte forms a strong solvation structure with cations, but the cation transport number becomes low
Solution Approach 1:
The patent uses a copolymer comprising both polyether units and polycarbonate units to create a composite electrolyte material. The polyether units provide flexibility and solvation capability, while the polycarbonate units provide high cation transport number, achieving a balance between the two properties that cannot be obtained with single-component electrolytes.
2Quantity of substance
If a polycarbonate electrolyte is used to achieve high cation transport number, then the ion conductivity improves, but the polymer flexibility becomes low
Solution Approach 1:
The copolymer electrolyte combines polycarbonate units (providing high cation transport number) with polyether units (providing flexibility), creating a composite material that simultaneously achieves both high ion conductivity and good polymer flexibility, resolving the trade-off between these two properties.
3Adaptability or versatility
If a polyether electrolyte is used to achieve high flexibility, then the ion conductivity improves, but the cation transport number becomes low
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using a copolymer with specific ratios of polyether and polycarbonate units. By adjusting the compositional parameters, the electrolyte achieves optimal balance between flexibility and cation transport number, overcoming the limitations of pure polyether or pure polycarbonate electrolytes.
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 solution provides a solid electrolyte with enhanced ion conductivity and cation transport number, suitable for high-performance batteries, while preventing strong solvation structures and decomposition reactions, thus improving heat resistance and conductivity.
Implementation Method 1
a solid electrolyte comprising: a copolymer having a constituent unit represented by a formula (1) below and a constituent unit represented by a formula (2) below; and a metal salt
Implementation Method 2
a solid electrolyte comprising: a copolymer having a constituent unit represented by a formula (1) below and a constituent unit represented by a formula (2) below; and a metal salt
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A solid electrolyte contains: a copolymer having a constituent unit represented by a formula (1) below and a constituent unit represented by a formula (2) below; and a metal salt. In the formula (1), m is 2 or 3, and R1 each independently represent a hydrogen atom or a methyl group. In the formula (2), n is 2 or 3, and R2 each independently represent a hydrogen atom or a methyl group.