Si-Based Anode Slurry pH Control to Suppress Coating Gas Defects
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Solution Overview
Problem
Lithium-ion secondary battery negative electrode composite material slurries experience gas production, leading to dot-shaped defects in the negative electrode active material layer, even without lithium-doped silicon, necessitating a reduction in gas production.
Innovation Solution
A negative electrode composite material slurry is developed comprising a Si-based active material, auxiliary materials like polyacrylic acid, styrene-butadiene rubber, carboxymethylcellulose, and carbon nanotubes, with a pH range of 4.5 to 7.3, and optionally including a buffer agent such as phosphoric acid, acetic acid, or citric acid, to minimize gas production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative electrode composite material slurry containing Si-based active material is used, then the battery capacity and performance are improved, but gas production occurs leading to dot-shaped defects in the coating
Solution Approach 1:
The patent adjusts the pH parameter of the slurry to a specific range (4.5-7.3) to suppress gas production from Si-based active material while maintaining coating quality and battery performance
Solution Approach 2:
The patent introduces buffer agents (phosphoric acid, acetic acid, or citric acid) as intermediaries to control the chemical environment and prevent harmful gas generation from the Si-based active material
2Stability of the object's composition
If Li-doped silicon material is used to enhance stability, then gas production is reduced during high-temperature storage, but hydrogen gas may be produced when lithium ions are eluted
Solution Approach 1:
The patent changes the chemical environment by controlling pH and introducing buffer agents to suppress both gas production mechanisms (from Li-doped Si and from Si-based active material) while maintaining storage stability
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 slurry reduces gas production and subsequent dot-shaped defects in the negative electrode active material layer, enhancing the stability and performance of lithium-ion secondary batteries.
Implementation Method 1
the negative electrode composite material slurry has a pH from 4.5 to 7.3
Implementation Method 2
one or more auxiliary materials selected from the group consisting of polyacrylic acid, styrene-butadiene rubber, carboxymethylcellulose, and carbon nanotubes
Data Source
AI summary
A negative electrode composite material slurry comprises a negative electrode active material including a Si-based active material, one or more auxiliary materials selected from the group consisting of polyacrylic acid, styrene-butadiene rubber, carboxymethylcellulose, and carbon nanotubes, and water. The negative electrode composite material slurry has a pH from 4.5 to 7.3.