Solid Electrolyte Composition for High-Solids Battery Sheet Coating
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Solution Overview
Problem
Existing inorganic solid electrolyte compositions for all-solid state secondary batteries face challenges in achieving both high dispersibility and application suitability, particularly at high solid content concentrations, leading to aggregation and poor surface properties, which hinder the realization of excellent cycle characteristics.
Innovation Solution
An inorganic solid electrolyte-containing composition is developed, comprising an inorganic solid electrolyte with specific SP value, molecular weight, and adsorption rate, combined with a dispersion medium of 120°C or higher, to enhance dispersibility and adhesiveness, forming a flat surface and improving cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high solid content concentration is used in inorganic solid electrolyte composition, then productivity and energy density are improved, but aggregation occurs and dispersibility deteriorates
Solution Approach 1:
A dispersing agent comprising a polymer and a surfactant is introduced as an intermediary substance between the inorganic solid electrolyte particles and the dispersion medium. The polymer provides steric stabilization while the surfactant provides electrostatic stabilization, working synergistically to prevent aggregation even at high solid content concentrations of 50 wt% or more, thereby maintaining both productivity and dispersibility
Solution Approach 2:
The dispersing agent itself is designed as a composite material combining polymer and surfactant components. This composite dispersing system provides dual stabilization mechanisms that are more effective than single-component dispersants, enabling stable dispersion at high solid content concentrations without aggregation
2Productivity
If high solid content concentration is used in inorganic solid electrolyte composition, then productivity is improved, but surface properties deteriorate
Solution Approach 1:
The dispersing agent acts as a mediator that modifies the surface of inorganic solid electrolyte particles, preventing direct particle-to-particle contact that would cause aggregation. This surface modification ensures uniform distribution and flat surface formation even at high solid content concentrations, thereby improving both productivity and manufacturing precision of surface properties
Solution Approach 2:
The invention changes the chemical and physical parameters of the particle surface by introducing polymer and surfactant components. This alters surface energy, steric hindrance, and electrostatic repulsion parameters, enabling high solid content concentration to be achieved without sacrificing surface quality
3Productivity
If high solid content concentration is used in inorganic solid electrolyte composition, then productivity is improved, but adhesiveness deteriorates
Solution Approach 1:
The polymer component of the dispersing agent serves as an adhesive intermediary between inorganic solid electrolyte particles and the electrode structure. It forms a binding matrix that maintains strong adhesiveness even when solid content concentration is increased to 50 wt% or more, thereby resolving the contradiction between productivity and strength
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 dispersion characteristics and application suitability, resulting in a sheet and battery with a flat coated surface, strong adhesiveness, and improved cycle performance, even at high solid content concentrations.
Implementation Method 1
a dispersing agent with controlled SP value, molecular weight, and adsorption rate
Implementation Method 2
a dispersion medium with a boiling point of 120°C or higher, which suppresses aggregation and enhances adhesiveness and surface properties
Data Source
AI summary
There is provided an inorganic solid electrolyte-containing composition for an all-solid state secondary battery, containing an inorganic solid electrolyte, a dispersing agent, and a dispersion medium, in which the dispersing agent satisfies the following definitions of (1) to (3), and the dispersion medium includes a dispersion medium having a boiling point of 120° C. or higher. There are also provided an inorganic solid electrolyte-containing composition, 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, as well as manufacturing methods for a sheet for an all-solid state secondary battery, and an all-solid state secondary battery.(1) An SP value is 17.0 to 22.0 MPa1/2.(2) A molecular weight is 10,000 or less.(3) An adsorption rate with respect to the inorganic solid electrolyte in the dispersion medium is 2% or more.