Solid-state battery anode binder system for adhesion stability
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Solution Overview
Problem
Current solid-state battery preparation methods, such as powder compression molding and coating, face challenges in increasing electrode area and maintaining adhesion between the anode and solid-state electrolyte due to the expansion and contraction of silicon-based active materials, leading to reduced battery lifetime and potential internal short-circuits.
Innovation Solution
Incorporating a combination of binders in the anode, where a first binder is inactive to the solid-state electrolyte and a second binder with higher tensile modulus and binding force, specifically a highly elastic resin like polyimide, to enhance adhesion and stability at the anode-electrolyte interface, thereby constraining the expansion and contraction of the anode active material during charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If powder compression molding is used to prepare solid-state battery, then the battery structure is simple, but the electrode area cannot be increased
Solution Approach 1:
The anode is divided into multiple layers with different binder types (first binder inactive to solid-state electrolyte, second binder with high binding force). This segmentation allows each layer to perform specific functions: the first binder provides chemical inertness while the second binder provides strong mechanical adhesion, enabling both large electrode area and structural stability
2Area of stationary object
If coating method is used to increase electrode area, then the electrode area can be enlarged, but adhesion between anode and solid-state electrolyte deteriorates due to expansion and contraction of silicon-based active materials
Solution Approach 1:
The anode uses a composite binder system combining two different binders: a first binder that is chemically inactive to the solid-state electrolyte and a second binder with high binding force and high tensile modulus. This composite approach allows the anode to maintain strong adhesion to the solid-state electrolyte while accommodating the expansion and contraction of silicon-based active materials during charge-discharge cycles
Solution Approach 2:
The invention changes the mechanical parameters of the binder system by selecting a second binder with high tensile modulus. This high modulus binder can withstand the stress generated by silicon-based active material expansion and contraction, maintaining adhesion stability over time while allowing the electrode area to be enlarged through coating methods
3Reliability
If single binder is used in anode, then the manufacturing process is simple, but adhesion to solid-state electrolyte and constraint of active material expansion cannot be simultaneously achieved
Solution Approach 1:
The anode is divided into multiple layers with different binder types (first binder inactive to solid-state electrolyte, second binder with high binding force). This segmentation allows each layer to perform specific functions: the first binder provides chemical inertness while the second binder provides strong mechanical adhesion, enabling both large electrode area and structural 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
This approach significantly improves the adhesion at the anode-electrolyte interface, maintaining stable adhesion and preventing internal short-circuits, thereby enhancing the lifetime characteristics of the solid-state battery.
Implementation Method 1
the second binder has a binding force which is greater than a binding force of the first binder
Data Source
AI summary
A solid-state battery including a cathode, an anode, and a solid-state electrolyte layer including a solid-state electrolyte, wherein the solid-state electrolyte layer is disposed between the cathode and the anode, wherein the anode includes an anode active material, a first binder, and a second binder, the first binder is inactive to the solid-state electrolyte, the second binder has a tensile modulus greater than a tensile modulus of the first binder, and the second binder has a binding force which is greater than a binding force of the first binder.