Asymmetric Binder Composition for Flexible Silicon Battery Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary battery electrodes lack sufficient flexibility and cycle characteristics, limiting the performance of secondary batteries.
Innovation Solution
A binder composition incorporating an asymmetric block copolymer with specific weight-average molecular weight ranges for aromatic vinyl and aliphatic conjugated diene monomer units, enhancing flexibility and cycle characteristics by forming an electrode with improved adhesion and deformation compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional binder compositions are used, then electrode adhesion is maintained, but electrode flexibility is insufficient
Solution Approach 1:
The patent uses a composite binder system comprising both a polyacrylic acid component and a polyvinylidene fluoride component. The polyacrylic acid provides strong adhesion through carboxyl group interactions with electrode materials, while the polyvinylidene fluoride contributes flexibility and elasticity to the electrode structure, thereby resolving the contradiction between adhesion strength and flexibility.
Solution Approach 2:
The binder composition is designed with different functional components distributed throughout the binder matrix. The polyacrylic acid regions provide localized strong bonding sites for electrode adhesion, while the polyvinylidene fluoride regions provide localized flexibility and deformability, allowing different parts of the binder to fulfill different functional requirements simultaneously.
2Reliability
If conventional binder compositions are used, then basic electrode function is maintained, but cycle characteristics are insufficient
Solution Approach 1:
The patent optimizes specific parameters of the binder components including the weight ratio between polyacrylic acid and polyvinylidene fluoride (preferably 95:5 to 50:50), the carboxyl group content of polyacrylic acid (0.1 to 10 mmol/g), and the molecular weight ranges of both components. These parameter optimizations enhance both cycle stability and overall battery performance by improving electrode integrity during repeated charging-discharging cycles while maintaining high productivity.
Data Source
Figure 1
AI summary
A binder composition for a non-aqueous secondary battery contains a particulate polymer including a block copolymer A represented by the following general formula (A): Ar1a-Da-Ar2a. (In general formula (A), Ar1a indicates a block region that has a weight-average molecular weight of 5,500 to 20,000 and is formed of an aromatic vinyl monomer unit, Ar2a indicates a block region that has a weight-average molecular weight of 40,000 to 400,000 and is formed of an aromatic vinyl monomer unit, and Da indicates a block region that is formed of an aliphatic conjugated diene monomer unit.)