Binder Aqueous Solution for Lithium-Ion Battery Electrodes
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Solution Overview
Problem
Lithium-ion battery electrodes face challenges with volume changes during charging and discharging, leading to deteriorated electrical characteristics, and existing binder resins struggle with adhesion and dispersion stability, while also requiring good initial Coulombic efficiency.
Innovation Solution
A binder aqueous solution comprising an acidic group-containing water-soluble polymer and an amino group-containing water-soluble polymer, with specific molecular weight ranges and pH levels, is used to enhance adhesion, dispersion stability, and initial Coulombic efficiency of lithium-ion battery electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a crosslinker is added to a particulate resin binder to suppress expansion and contraction, then volume change is reduced, but flexibility of the binder resin is reduced and adhesion to the electrode deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the binder resin by incorporating specific functional groups (carboxyl, hydroxyl, amine) in controlled ratios. This allows the binder to achieve both volume stability through crosslinking capability and adhesion through hydrogen bonding, resolving the contradiction between stability and strength
Solution Approach 2:
The patent creates a composite binder system combining particulate resin with specific functional additives (polyacrylic acid, polyvinyl alcohol, chitosan) in defined weight ratios. This composite structure provides both the volume stability from crosslinked networks and the adhesion from hydrogen-bonding functional groups
2Productivity
If polyacrylamide is used as a water-soluble binder resin, then good charge and discharge characteristics are obtained, but dispersion stability of the slurry is insufficient
Solution Approach 1:
The patent modifies the binder composition by replacing polyacrylamide with water-soluble polymers containing specific functional groups (carboxyl, hydroxyl, amine) with controlled molecular weights and ratios. This change maintains charge-discharge characteristics while significantly improving slurry dispersion stability through enhanced interparticle interactions
3Stability of the object's composition
If the binder resin is made more rigid to suppress expansion, then volume stability improves, but flexibility is reduced leading to poor adhesion
Solution Approach 1:
The patent applies local quality by creating different functional zones within the binder structure: crosslinked regions provide volume stability while hydrogen-bonding regions (carboxyl, hydroxyl, amine groups) provide flexibility and adaptability. This dual-zone structure resolves the contradiction between rigidity and flexibility
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 excellent dispersion stability, adhesion, and initial Coulombic efficiency for lithium-ion battery electrodes, improving their performance and longevity.
Implementation Method 1
an acidic group-containing water-soluble polymer (A)... and an amino group-containing water-soluble polymer (B)... an acidic group to amino group molar ratio... is 1 to 15
Data Source
AI summary
Provided are a binder aqueous solution for a lithium-ion battery electrode, a slurry for a lithium-ion battery negative electrode, a negative electrode for a lithium-ion battery, and a lithium-ion battery. The binder aqueous solution for a lithium-ion battery electrode contains an acidic group-containing water-soluble polymer (A) and an amino group-containing water-soluble polymer (B). The acidic group-containing water-soluble polymer (A) is a polymer of a monomer group containing, with respect to 100 mol% of the monomer group, 30 mol% to 90 mol% of a (meth)acrylamide group-containing compound (a), 3 mol% to 20 mol% of an unsaturated organic acid (b), and 5 mol% to 40 mol% of an alkali metal or alkaline earth metal salt (c) of the unsaturated organic acid. A 1% by mass aqueous solution of the amino group-containing water-soluble polymer (B) has a pH of 9 or higher.