Copolymer Dispersant for Stable Conductive Electrode Slurries
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Solution Overview
Problem
Existing dispersants for lithium-ion secondary batteries fail to maintain good conductive material dispersion and network robustness during electrode film formation, leading to poor battery performance and cycle life.
Innovation Solution
A copolymer dispersant with specific structural units, including an aliphatic hydrocarbon, nitrile, and carbamoyl groups, is used to achieve both good dispersibility and robustness, ensuring effective conductive material distribution and network formation in the electrode film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nanocarbon with large specific surface area is used as conductive material, then conductive network efficiency is improved, but dispersibility in slurry deteriorates
Solution Approach 1:
A copolymer dispersant comprising a conjugated diene structural unit and a carboxyl group-containing structural unit is introduced as an intermediary substance. The dispersant adsorbs onto the nanocarbon surface through the conjugated diene units while the carboxyl groups provide steric hindrance and electrostatic repulsion, preventing nanocarbon aggregation and enabling stable dispersion in the slurry without compromising the conductive network efficiency.
2Ease of manufacture
If conventional dispersants are used, then initial dispersibility is improved, but dispersion state is lost during electrode film formation
Solution Approach 1:
The dispersant design incorporates a specific ratio of conjugated diene structural units to carboxyl group-containing structural units, where the conjugated diene content is 5-95 mass% and carboxyl group content is 5-95 mass%. This parameter optimization ensures sufficient adsorption capacity while maintaining stable dispersion throughout the electrode film formation process, preventing the loss of dispersion state that occurs with conventional dispersants.
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 copolymer dispersant enhances the rate and cycle characteristics of lithium-ion secondary batteries by maintaining a stable conductive network with a small addition amount of conductive material, improving output and cycle life.
Implementation Method 1
the copolymer dispersant enhances the rate and cycle characteristics of lithium-ion secondary batteries by maintaining a stable conductive network
Implementation Method 2
nanocarbon having a large specific surface area has a high cohesive force, it is difficult to favorably disperse the nanocarbon in the slurry for electrode film
Implementation Method 3
the content of the carboxyl group-containing structural unit is 5 mass % or more and 95 mass % or less based on the total content of structural units
Data Source
AI summary
Provided is a dispersant containing a copolymer that includes an aliphatic hydrocarbon structural unit, a nitrile group-containing structural unit, and a substituted or unsubstituted carbamoyl group-containing structural unit. The aliphatic hydrocarbon structural unit includes an alkylene structural unit. The content of the aliphatic hydrocarbon structural unit is 40 mass % or more and less than 85 mass % based on the mass of the copolymer, the content of the nitrile group-containing structural unit is 15 mass % or more and 50 mass % or less based on the mass of the copolymer, and the content of the substituted or unsubstituted carbamoyl group-containing structural unit is 10 mass % or less based on the mass of the copolymer. The weight-average molecular weight of the polymer is 5,000 or more and 400,000 or less.