Inorganic Solid Electrolyte Composition for Battery Interface Stability
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Solution Overview
Problem
All-solid state secondary batteries face issues with increased interface resistance and deteriorated cycle characteristics due to insufficient adhesive force and non-uniform particle arrangement in their constitutional layers, which affects ion conductivity and battery performance.
Innovation Solution
An inorganic solid electrolyte-containing composition is developed, comprising an inorganic solid electrolyte with a polymer binder that exhibits low adsorption rates and high tensile permanent strain, along with a dispersion medium, to enhance dispersion stability and handleability, thereby forming a constitutional layer with reduced interface resistance and improved cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constitutional layers are formed of solid particles (inorganic solid electrolyte, active material), then ion conductivity is improved, but interface resistance increases and adhesive force becomes insufficient
Solution Approach 1:
A polymer binder is introduced as an intermediary substance between solid particles (inorganic solid electrolyte and active material) to provide adhesive force while maintaining ion conductivity. The polymer binder mediates the interaction between solid particles, ensuring both mechanical strength and ionic transport pathways are preserved in the constitutional layers.
2Device complexity
If solid particles are used to form constitutional layers, then battery structure is simplified, but interface resistance increases and cycle characteristics deteriorate
Solution Approach 1:
The polymer binder serves as a mediator that enhances cycle characteristics by providing flexible adhesion between solid particles, accommodating volume changes during charging and discharging cycles while maintaining electrical and ionic contact.
Solution Approach 2:
The constitutional layers are formed as composite materials combining solid particles (inorganic solid electrolyte and active material) with polymer binder, creating a hybrid structure that leverages the high ion conductivity of solid particles while the polymer provides mechanical integrity and cycle stability.
3Strength
If polymer binder with high adsorption rate is used, then adhesive force is improved, but dispersion stability and handleability deteriorate
Solution Approach 1:
The adsorption rate of the polymer binder to inorganic solid electrolyte is precisely controlled within the range of 40-80%, optimizing the balance between adhesive force and dispersion stability. This parameter control ensures sufficient bonding between particles while preventing excessive aggregation that would compromise handleability and processing.
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 effectively suppresses the increase in battery resistance and enhances cycle characteristics by ensuring firm adhesion and uniform particle arrangement, maintaining high conductivity and adhesiveness even after repeated charging and discharging.
Implementation Method 1
a polymer binder PB1 having an adsorption rate of less than 60% with respect to the inorganic solid electrolyte in the dispersion medium
Data Source
AI summary
There is provided an inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte, a polymer binder, and a dispersion medium, in which the polymer binder includes a polymer having a tensile permanent strain of less than 50% in a stress-strain curve obtained by repeating pulling and restoration once and includes a polymer binder in which the adsorption rate with respect to the inorganic solid electrolyte in the dispersion medium is less than 60%. 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.