All-solid-state Battery Negative Electrode Layer Binder Adsorption Control
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Solution Overview
Problem
All-solid-state batteries face challenges in achieving low resistance in their negative electrode layers, particularly when using lithium titanate as the active material and a rubber binder, due to high binder adsorption leading to increased reaction area and resistance.
Innovation Solution
A negative electrode layer composition including lithium titanate, a sulfide solid electrolyte, and a rubber binder with a controlled ratio of binder adsorption, where the rubber binder is preferentially adsorbed on the sulfide solid electrolyte rather than the lithium titanate, reducing the reaction area and thus the resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rubber binder is used in the negative electrode layer, then the structural integrity is improved, but the resistance increases due to high binder adsorption on lithium titanate
Solution Approach 1:
The sulfide solid electrolyte acts as an intermediary substance that preferentially adsorbs the rubber binder, preventing direct adsorption between the binder and lithium titanate. This mediator approach reduces the reaction area between binder and active material while maintaining structural integrity through adequate binder distribution.
Solution Approach 2:
The invention controls the adsorption ratio parameter (amount of binder on lithium titanate versus total binder content) to be within a specific range. By adjusting this parameter through the introduction of sulfide solid electrolyte, the resistance is reduced while maintaining sufficient binder for structural integrity.
2Strength
If the rubber binder content is increased, then the structural integrity is improved, but the reaction area increases leading to higher resistance
Solution Approach 1:
The sulfide solid electrolyte serves as a mediator that redirects binder adsorption preference. Instead of increasing binder content to improve integrity, the intermediary causes the binder to adsorb preferentially on the solid electrolyte surface, reducing direct contact with lithium titanate and thus reducing the harmful reaction area.
3Strength
If the binder adsorption on lithium titanate is high, then the structural integrity is improved, but the conductivity decreases due to increased resistance
Solution Approach 1:
The sulfide solid electrolyte acts as an intermediary that changes the adsorption distribution. The binder preferentially adsorbs on the solid electrolyte surface rather than directly on lithium titanate, reducing the reaction area that causes resistance increase, thereby improving conductivity while maintaining structural integrity.
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 approach results in a negative electrode layer with reduced resistance, enhancing the input and output performance of all-solid-state batteries by minimizing binder adsorption on lithium titanate, thereby decreasing the reaction area and improving conductivity.
Implementation Method 1
a ratio (A/B) of an amount A of the rubber binder adsorbed on the lithium titanate to a total content B of the rubber binder in the negative electrode layer is 1.35% or less
Data Source
AI summary
A negative electrode layer that is used for an all-solid-state battery includes: lithium titanate; a sulfide solid electrolyte; and a rubber binder. The ratio of the amount A of the rubber binder adsorbed on the lithium titanate to the total content B of the rubber binder in the negative electrode layer is 1.35% or less.