Solid Electrolyte Binder Composition for Bend Resistance and Ion Conductivity
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Solution Overview
Problem
Existing solid electrolyte compositions for all-solid state secondary batteries face challenges in balancing bend resistance, scratch resistance, and ion conductivity, often requiring a trade-off between these properties due to the role of binders, which can decrease ion conductivity when increased to improve mechanical properties.
Innovation Solution
A solid electrolyte composition combining an inorganic solid electrolyte with a binder having specific functional groups, such as those described in Formulae (1) and (2), which enhances the adhesion and mobility of the binder, thereby improving bend resistance, scratch resistance, and maintaining high ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of binder is increased to improve mechanical properties (bend resistance and scratch resistance), then the mechanical strength is improved, but the ion conductivity decreases
Solution Approach 1:
The invention changes the chemical structure parameters of the binder by introducing specific functional groups (carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, or cyano groups) into the polymer backbone. This structural modification enables the binder to form strong chemical bonds with inorganic solid electrolyte particles, achieving high mechanical strength at lower binder concentrations (0.1-10 mass%), thereby maintaining high ion conductivity (≥10⁻⁵ S/cm).
Solution Approach 2:
The invention creates a composite binder structure combining a polymer backbone with specific functional groups that have high affinity for inorganic solid electrolytes. This composite approach allows the binder to simultaneously provide mechanical support and maintain good interfacial contact with electrolyte particles, resolving the trade-off between mechanical strength and ion conductivity.
2Stability of the object's composition
If the amount of binder is increased to improve adhesion, then the bonding property is improved, but the ion conductivity decreases
Solution Approach 1:
The invention modifies the chemical parameters of the binder by incorporating functional groups with high polarity and electron-withdrawing characteristics. These groups enhance the binder's ability to form strong interfacial bonds with inorganic solid electrolytes through chemical adsorption and coordination, achieving excellent adhesion at low concentrations and maintaining high ion conductivity.
Solution Approach 2:
The functional groups on the binder act as intermediaries that facilitate strong bonding between the polymer matrix and inorganic solid electrolyte particles. Groups such as carboxylic acid, sulfonic acid, phosphoric acid, and cyano groups serve as anchoring sites that improve interfacial adhesion without forming continuous binder phases that would block ion transport pathways.
3Strength
If the amount of binder is increased to improve toughness, then the mechanical robustness is improved, but the ion conductivity decreases
Solution Approach 1:
The invention optimizes the molecular weight and structural parameters of the polymer backbone to achieve adequate toughness at low binder concentrations. The combination of functional groups with appropriate polymer chain flexibility enables the solid electrolyte layer to withstand mechanical stress while maintaining porous structures that facilitate ion transport.
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 excellent bend resistance, scratch resistance, and ion conductivity, reducing the occurrence of short-circuits and improving manufacturing yield, particularly suitable for roll-to-roll production methods.
Implementation Method 1
a binder (B) having at least one of a constituent component selected from Formulae (1) and (2)
Data Source
Figure 1~3
AI summary
Provided are a solid electrolyte composition containing an inorganic solid electrolyte having a conductivity of an ion of a metal belonging to Group I or II of the periodic table and a binder having a specific constituent component, a solid electrolyte-containing sheet in which the same solid electrolyte composition is used and a manufacturing method therefor, an all-solid state secondary battery and a manufacturing method therefor, a polymer having a specific constituent component, a non-aqueous solvent dispersion thereof, and a diol compound.