Battery Electrode Base Layer for Peel-Resistant High Loading
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Solution Overview
Problem
Non-aqueous electrolyte rechargeable batteries face challenges in achieving high energy density due to the peeling or falling off of the electrode mixture layer from the current collector, especially after immersion in electrolyte solution, and existing solutions do not adequately address this issue while maintaining a thin base layer.
Innovation Solution
A negative electrode with a conductive base layer comprising a styrene-acrylic acid ester-based copolymer, carbon material, and poly(meth)acrylic acid, where the styrene-acrylic acid ester-based copolymer content is between 70% to 90% and the poly(meth)acrylic acid carboxyl groups are mostly unneutralized, is used to prevent peeling and falling off of the electrode mixture layer, even after immersion in electrolyte solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the weight per unit area of the electrode mixture layer is increased to achieve higher energy density, then the energy density is improved, but the electrode mixture layer is likely to fall off or peel off from the current collector
Solution Approach 1:
A base layer is introduced as an intermediary between the current collector and the electrode mixture layer. This base layer serves as a mediator that enhances adhesion and prevents peeling when the electrode mixture layer has high weight per unit area. The base layer includes a conductive polymer and inorganic particles that provide mechanical support and bonding interface.
Solution Approach 2:
The base layer is constructed as a composite material consisting of a conductive polymer matrix (such as polyani 1e, polypyrrole, or polythiophene) combined with inorganic particles (such as metal oxides or carbon materials). This composite structure provides both mechanical strength for adhesion and electrical conductivity for battery operation.
2Reliability
If a base layer is provided between the current collector and the electrode mixture layer to prevent peeling, then the adhesion is improved, but the thickness of the base layer must be minimized to maintain high energy density
Solution Approach 1:
The base layer is designed as a thin film structure that provides sufficient adhesion functionality with minimal thickness. The conductive polymer matrix forms a continuous thin coating that bonds the electrode mixture layer to the current collector while maintaining flexibility and electrical conductivity throughout the thin structure.
Solution Approach 2:
The thickness, composition ratio, and physical properties of the base layer are optimized to achieve the minimum necessary thickness for effective adhesion. By adjusting the molecular weight, crosslinking degree, and inorganic particle content of the conductive polymer composite, the base layer provides maximum adhesion with minimal thickness to preserve energy density.
3Ease of operation
If the electrode is immersed in electrolyte solution for actual battery operation, then the battery functionality is enabled, but the electrode mixture layer becomes easier to peel from the current collector especially in the case of the negative electrode mixture layer
Solution Approach 1:
The base layer is pre-formed on the current collector before the electrode mixture layer is applied. This pre-formed base layer provides a stable bonding interface that is already in place to counteract the peeling forces that will occur during electrolyte immersion and battery operation. The base layer acts as a cushion against the detrimental effects of electrolyte exposure.
Solution Approach 2:
The base layer serves as an intermediary protective layer between the current collector and the electrode mixture layer during electrolyte immersion. It mediates the interaction between the electrolyte and the electrode mixture layer, preventing direct contact that would cause peeling, while still allowing ionic transport for battery operation.
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 effectively suppresses the peeling or falling off of the electrode mixture layer from the current collector, allowing for higher energy density while maintaining a thin base layer, thereby enhancing the performance and stability of non-aqueous electrolyte rechargeable batteries.
Implementation Method 1
a base layer that can sufficiently prevent the electrode mixture layer from falling off or peeling off from the current collector
Implementation Method 2
in the poly(meth)acrylic acid, carboxyl groups included in the poly(meth)acrylic acid are not neutralized, or a proportion of neutralized carboxyl groups neutralized by alkali metal ions among the carboxyl groups is less than or equal to about 25%
Data Source
AI summary
Provided are an electrode for a non-aqueous electrolyte rechargeable battery that has a base layer that can sufficiently suppress separation or peeling of the electrode mixture layer from the electrode current collector after being immersed in an electrolyte solution while reducing the thickness as much as possible. The electrode for a non-aqueous electrolyte rechargeable battery includes a current collector, an electrode mixture layer, and a conductive base layer between the current collector and the electrode mixture layer, wherein the base layer includes at least a styrene-acrylic acid ester-based copolymer, a carbon material, and poly(meth)acrylic acid, a content of the styrene-acrylic acid ester-based copolymer in the base layer is greater than or equal to about 70 mass% and less than or equal to about 90 mass%, in the poly(meth)acrylic acid, carboxyl groups included in the poly(meth)acrylic acid are not neutralized, or a proportion of neutralized carboxyl groups neutralized by alkali metal ions among the carboxyl groups is less than or equal to about 25%, and a weight per unit area of the electrode mixture layer per one surface of the current collector is greater than or equal to about 10 mg/cm2 and less than or equal to about 35 mg/cm2.