Solid Electrolyte Sheet Composition for Stable Dispersion and Adhesion
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Solution Overview
Problem
Existing all-solid state secondary batteries face issues with dispersion stability and binding force between solid particles, leading to defects like chipping, breakage, and peeling, which deteriorate battery performance and cycle characteristics, especially in high-productivity manufacturing methods.
Innovation Solution
An inorganic solid electrolyte-containing composition with a polymer binder having a glass transition temperature of 50°C or higher and an SP value of 20.0 to 25.0 MPa1/2, dissolved in a dispersion medium, enhances dispersion stability and firm binding of solid particles, forming a uniform constitutional layer with improved adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic solid electrolyte is used in an all-solid state secondary battery, then safety and reliability are significantly improved compared to non-aqueous electrolyte batteries, but dispersion stability and binding force between solid particles and base materials deteriorate
Solution Approach 1:
The patent introduces a polymer binder as an intermediary substance between the inorganic solid electrolyte particles and the base material. This binder mediates the interaction between solid particles and the substrate, providing adequate binding force while maintaining dispersion stability. The polymer binder acts as a bridge that connects the inorganic solid electrolyte to the base material without compromising the safety and reliability improvements gained from using inorganic solid electrolytes.
2Reliability
If an inorganic solid electrolyte is used in an all-solid state secondary battery, then safety and reliability are significantly improved, but manufacturing defects such as chipping and peeling occur
Solution Approach 1:
The polymer binder serves as a mediator that prevents manufacturing defects like chipping and peeling by providing a flexible bonding interface between the rigid inorganic solid electrolyte particles and the base material. This intermediary layer accommodates manufacturing variations and reduces stress concentration, thereby eliminating defects while preserving the safety benefits of inorganic solid electrolytes.
Solution Approach 2:
The patent creates a composite material system combining inorganic solid electrolyte particles with a polymer binder matrix. This composite structure leverages the advantages of both materials: the inorganic solid electrolyte provides safety and reliability, while the polymer binder provides defect-free manufacturing characteristics and good adhesion. The composite material approach resolves the contradiction between reliability improvement and manufacturing precision.
3Reliability
If a constitutional layer using inorganic solid electrolyte is formed, then ion conductivity can be maintained at levels comparable to organic electrolytic solutions, but adhesion between solid particles and base material is insufficient
Solution Approach 1:
The polymer binder acts as an intermediary that maintains both ion conductivity and adhesion. It provides a bonding interface between solid particles and the base material without significantly impeding ion transport, thereby preserving the high ion conductivity characteristic of inorganic solid electrolytes while adding the necessary adhesion strength.
Solution Approach 2:
The composite material comprising inorganic solid electrolyte particles dispersed in a polymer binder matrix achieves both high ion conductivity and strong adhesion. The inorganic solid electrolyte maintains ion conductivity comparable to organic electrolytic solutions, while the polymer binder provides the necessary adhesion strength between particles and base material.
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 composition achieves a low-resistance, high-conductivity, and excellent cycle characteristics in all-solid state secondary batteries, suitable for industrial manufacturing methods like roll-to-roll, with reduced defects and peeling.
Implementation Method 1
firm adhesion between solid particles and the base material
Implementation Method 2
polymer binder having a glass transition temperature of 50° C. or higher and an SP value of 20.0 to 25.0 MPa1/2, dissolved in a dispersion medium
Data Source
AI summary
There are provided an inorganic solid electrolyte-containing composition including an inorganic solid electrolyte having an ion conductivity of a metal belonging to Group 1 or Group 2 in the periodic table, a polymer binder, and a dispersion medium, where the inorganic solid electrolyte-containing composition contains a polymer which has a constitutional component having a glass transition temperature (TgHP) of 50° C. or higher and an SP value of 20.0 MPa1/2 or more in a case where the constitutional component is formed into a homopolymer and is dissolved in a dispersion medium. There are also provided a sheet for an all-solid state secondary battery and an all-solid state secondary battery, in which this inorganic solid electrolyte-containing composition is used, and manufacturing methods for a sheet for an all-solid state secondary battery, and an all-solid state secondary battery.