All-Solid-State Battery Binder Layout for Adhesion and Cycle Retention
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Solution Overview
Problem
All-solid-state batteries with silicon-based negative electrode active materials face challenges such as cracks in the negative electrode layer and separation from the current collector, leading to reversible capacity loss due to low adhesive strength and increased resistance.
Innovation Solution
The battery design incorporates a negative electrode layer with a first layer having a high binder content and a second layer with a low binder content, both featuring nonpolar main chains and polar functional groups, to enhance adhesive strength and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a nonpolar binder is used to be compatible with sulfide-based solid electrolytes, then compatibility is improved, but adhesive strength deteriorates
Solution Approach 1:
The binder is designed as a composite material combining a nonpolar main chain (for compatibility with sulfide-based solid electrolytes) and polar functional groups (for enhanced adhesive strength). This composite structure allows the binder to simultaneously achieve compatibility with the solid electrolyte and strong adhesion to the current collector, resolving the technical contradiction between these two requirements.
2Strength
If the amount of binder is increased to improve adhesive strength, then adhesive strength is improved, but resistance increases
Solution Approach 1:
The invention changes the chemical parameter of the binder by introducing polar functional groups to the nonpolar main chain. This parameter change enables the binder to achieve high adhesive strength at lower concentrations, thereby reducing the harmful effect of resistance in the negative electrode layer while still maintaining sufficient adhesion.
3Quantity of substance
If silicon-based negative electrode active materials are used to increase charge capacity, then charge capacity is improved, but cycle characteristics deteriorate
Solution Approach 1:
The invention applies local quality by creating a negative electrode layer with spatially varying binder content - a first layer with high binder content for strong adhesion to the current collector, and a second layer with lower binder content for reduced resistance. This local differentiation in binder distribution helps maintain the structural integrity of silicon-based materials during cycling, thereby improving cycle characteristics while preserving high charge capacity.
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 configuration achieves high adhesive strength between the negative electrode layer and the current collector, while minimizing resistance, thereby improving the cycle characteristics and capacity retention rate of the all-solid-state batteries.
Implementation Method 1
Each of the first binder and the second binder has a nonpolar main chain and a polar functional group bound to the nonpolar main chain... achieves high adhesive strength between the negative electrode layer and the current collector
Data Source
AI summary
An all-solid-state battery includes a negative electrode current collector, a negative electrode layer disposed on the negative electrode current collector, a solid electrolyte layer disposed on the negative electrode layer, a positive electrode layer disposed on the solid electrolyte layer, a positive electrode current collector disposed on the positive electrode layer, and a binder having a polar functional group.