All-solid-state battery carboxyl carbon adhesion
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Solution Overview
Problem
All-solid-state batteries face capacity durability issues due to expansion and contraction stress of active materials during charging and discharging, leading to peel-off and crack formation at the solid interface, which reduces battery performance.
Innovation Solution
Incorporating a conductive auxiliary material with a carbon material C1 having a carboxyl group on its surface, with a weight ratio of 8% or more, and optionally including cup-stacked-type carbon nanofibers, to enhance adhesion and dispersibility, thereby maintaining electron conductivity and preventing capacity deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte layer is used to simplify safety devices and eliminate flammable organic solvents, then safety and production cost are improved, but expansion and contraction stress of active materials causes peel-off and crack formation at the solid interface, deteriorating capacity durability
Solution Approach 1:
The patent introduces a conductive auxiliary material as an intermediary substance between the active material and the solid electrolyte layer. This conductive auxiliary material serves as a mediator that maintains contact between the active material and solid electrolyte during expansion and contraction cycles, preventing direct peel-off and crack formation at the solid interface while preserving ionic conductivity.
Solution Approach 2:
The patent employs a composite structure consisting of active material, conductive auxiliary material, and solid electrolyte layer. This composite material system combines the mechanical flexibility of the conductive auxiliary material with the ionic conductivity of the solid electrolyte, creating a structure that can accommodate volume changes while maintaining functional performance.
2Power
If conventional carbon materials are used as conductive auxiliary materials, then electron conductivity is maintained, but adhesion to active material is insufficient, leading to poor dispersibility and reduced capacity durability
Solution Approach 1:
The patent modifies the surface properties of carbon materials by introducing oxygen-containing functional groups (carboxyl groups with weight ratio of 0.03 or more). This parameter change in surface chemistry enhances the adhesion between the conductive auxiliary material and active material, improving dispersibility while preserving electron conductivity.
Solution Approach 2:
The patent applies oxidation treatment to carbon materials to introduce oxygen-containing functional groups on the surface. This accelerated oxidation process modifies the surface characteristics of the carbon material, enhancing its adhesion to active material and improving overall dispersibility in the electrode structure.
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 carbon materials with high carboxyl group content improves adhesion and dispersibility, leading to excellent capacity durability by maintaining electron conductivity and preventing structural disintegration, even with a small content of conductive auxiliary material.
Implementation Method 1
the conductive auxiliary material includes a carbon material C1 having a carboxyl group on its surface; and a weight ratio of the carboxyl group to overall of the carbon material C1 is 8 weight % or more
Data Source
AI summary
A main object of the present disclosure is to provide an all-solid-state battery with an excellent capacity durability. The present disclosure achieve the object by providing an all-solid-state battery comprising: a cathode active material layer, an anode active material layer, and a solid electrolyte layer formed between the cathode active material layer and the anode active material layer; wherein at least one of the cathode active material layer and the anode active material layer contains a sulfide solid electrolyte and a conductive auxiliary material; the conductive auxiliary material includes a carbon material C1 having a carboxyl group on its surface; and a weight ratio of the carboxyl group to overall of the carbon material C1 is 8 weight % or more.