Aqueous Li-Ion Battery Binder for Suppressing Water Side Reactions
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Solution Overview
Problem
Aqueous electrolyte lithium-ion secondary batteries face challenges with electrolysis of water, leading to reduced lithium ion availability for charge and discharge, increased resistance due to solid decomposition products, and deteriorated battery capacity, especially when using lithium manganese oxide and lithium titanium oxide as electrode materials.
Innovation Solution
Incorporating a first binder composed of a fluorine-based resin and an acrylic resin in at least one of the positive or negative electrodes, which provides high hydrophobicity and covering properties to suppress contact between active materials and water, thereby reducing side reactions and enhancing cycle life performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If aqueous electrolyte is used with lithium manganese oxide and lithium titanium oxide electrodes, then high energy density and theoretical electromotive force are achieved, but electrolysis of water occurs and side reactions increase
Solution Approach 1:
A coating layer comprising fluorocarbon and carboxylic acid group-containing polymer is introduced as an intermediary between the electrode materials and the aqueous electrolyte. This coating layer acts as a mediator that prevents direct contact and harmful side reactions while allowing lithium ion transport, thus resolving the contradiction between achieving high energy density and preventing water electrolysis.
Solution Approach 2:
The coating layer is formed as a composite material combining fluorocarbon (providing hydrophobicity and electrochemical stability) and carboxylic acid group-containing polymer (providing lithium ion conductivity and adhesion). This composite structure enables simultaneous prevention of water electrolysis and maintenance of high lithium ion availability, resolving the technical contradiction.
2Device complexity
If conventional aqueous electrolyte batteries are used, then simplicity of structure is maintained, but solid decomposition products increase resistance and deteriorate battery capacity
Solution Approach 1:
A thin film coating layer is applied to the electrode surfaces to prevent contact between electrode materials and water. This thin film barrier prevents formation of solid decomposition products that would increase resistance, thereby maintaining battery capacity while keeping the overall structure simple and avoiding complex additional components.
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 use of the fluorine-based and acrylic resin binder effectively suppresses side reactions, improves hydrophobicity, and enhances the cycle life performance of the battery by maintaining lithium ion availability and reducing resistance.
Implementation Method 1
Incorporating a first binder composed of a fluorine-based resin and an acrylic resin in at least one of the positive or negative electrodes, which provides high hydrophobicity and covering properties to suppress contact between active materials and water
Implementation Method 2
Incorporating a first binder composed of a fluorine-based resin and an acrylic resin in at least one of the positive or negative electrodes, which provides high hydrophobicity and covering properties to suppress contact between active materials and water
Implementation Method 3
Studies have been made on formation of an electrolytic solution as an aqueous solution
Data Source
AI summary
In general, according to an embodiment, a secondary battery is provided. The secondary battery includes an aqueous electrolyte, a positive electrode, and a negative electrode. At least one of the positive electrode or the negative electrode includes a first binder. The first binder includes a fluorine-based resin and an acrylic resin.