Solid Electrolyte Composition for Low-Resistance Battery Interfaces
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Solution Overview
Problem
All-solid state secondary batteries face issues with interface contact and resistance due to poor binding properties between solid particles and current collectors, leading to decreased battery performance, especially in high-energy applications like electric vehicles.
Innovation Solution
A solid electrolyte composition incorporating a branched polymer with a fluoroalkylene group or siloxane structure is used, which enhances dispersibility and binding properties between inorganic solid electrolyte particles and active material layers, improving contact with current collectors and reducing interface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If solid particles are dispersed in a dispersion medium to achieve excellent dispersibility, then the dispersibility is improved, but the interface contact state between solid particles becomes low and interface resistance increases
Solution Approach 1:
A binder is introduced as an intermediary substance between solid particles to improve interface contact. The binder forms a matrix that holds solid particles together, ensuring good contact between particles and between the electrode and current collector, thereby reducing interface resistance while maintaining dispersibility.
Solution Approach 2:
The patent creates a composite material structure combining solid particles with a binder matrix. This composite approach allows the solid particles to maintain their dispersed state while the binder provides the necessary adhesive properties for good interface contact and low resistance.
2Stability of the object's composition
If binding properties of a binder between solid particles are weak, then dispersibility is improved, but poor contact between solid particles occurs
Solution Approach 1:
The patent optimizes the molecular weight and chemical structure parameters of the binder to achieve the right balance. By controlling the binder's physical and chemical parameters, both dispersibility and binding strength are improved simultaneously, resolving the contradiction between these two properties.
3Reliability
If poor contact occurs between active material layer and solid electrolyte layer due to expansion and contraction during charging and discharging, then battery performance decreases
Solution Approach 1:
The binder acts as a flexible matrix that can accommodate the expansion and contraction of solid particles during charging and discharging cycles. This flexibility maintains continuous contact between particles and layers, preventing poor contact and maintaining stable battery performance throughout operation.
4Reliability
If poor contact occurs between solid particles and current collector, then interface resistance increases and battery performance decreases
Solution Approach 1:
The binder serves as an intermediary adhesive layer between solid particles and the current collector, ensuring intimate contact and efficient electrical connection. This intermediary role reduces interface resistance and prevents energy loss at the interface.
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 solid electrolyte composition achieves strong binding between solid particles and current collectors, resulting in enhanced battery performance and increased energy density for all-solid state secondary batteries.
Implementation Method 1
a polymer chain PC that includes a component having at least one selected from a fluoroalkylene group or a siloxane structure
Implementation Method 2
a partial structure that has a group having adsorption to solid particles
Implementation Method 3
a partial structure that has a group having adsorption to solid particles
Implementation Method 4
binding properties between inorganic solid electrolyte particles and active material layers
Data Source
AI summary
Provided is a solid electrolyte composition including: an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 in the periodic table; and a polymer represented by a specific formula. Provided are also a sheet for an all-solid state secondary battery, an electrode sheet for an all-solid state secondary battery, and an all-solid state secondary battery that are formed of the solid electrolyte composition, a sheet for an all-solid state secondary battery, and a method of manufacturing an all-solid state secondary battery.