Hydroxyl-Rich Sulfide Solid Electrolyte Powder for Better Dispersion
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Solution Overview
Problem
The existing sulfide solid electrolyte powders for lithium-ion secondary batteries face issues with low dispersibility in non-aqueous organic solvents, leading to uneven electrode layers and reduced lithium ion conductivity due to particle aggregation and surface performance degradation, which also decreases productivity.
Innovation Solution
A sulfide solid electrolyte powder with a surface rich in hydroxy groups, characterized by specific 1H-NMR intensity and BET specific surface area relationships, and a method involving pulverization and heating in a controlled moisture environment to enhance dispersibility and lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sulfide solid electrolyte powder is made finer to increase dispersibility, then the dispersibility is improved, but primary particles aggregate and lithium ion conductivity decreases
Solution Approach 1:
The invention changes the surface chemical composition of the powder particles by introducing a hydroxyl group-containing surface layer. This parameter change in surface chemistry allows finer particles to maintain both high dispersibility and high lithium ion conductivity, resolving the contradiction between particle fineness and performance.
2Ease of operation
If the sulfide solid electrolyte powder is made finer to improve dispersibility, then the dispersibility is improved, but productivity decreases
Solution Approach 1:
The invention performs preliminary surface modification by forming a hydroxyl group-containing surface layer on the powder particles before dispersal. This preliminary action of surface treatment enables the use of finer particles with improved dispersibility without the negative impact on productivity, as the surface layer prevents aggregation during handling and processing.
3Ease of operation
If a polar solvent is used as dispersion medium, then the sulfide solid electrolyte powder can be dispersed, but the powder is dissolved and cannot be used for sheet formation
Solution Approach 1:
The invention introduces a hydroxyl group-containing surface layer as an intermediary between the sulfide solid electrolyte powder and the polar solvent. This surface layer acts as a protective barrier that allows the powder to be dispersed in polar solvents without dissolving, enabling sheet formation while maintaining chemical stability.
4Stability of the object's composition
If non-aqueous organic solvent is used as dispersion medium, then the sulfide solid electrolyte powder can be dispersed, but dispersibility is low and aggregation occurs
Solution Approach 1:
The invention changes the surface chemical properties of the powder by introducing hydroxyl groups, which improve the interaction between particles and non-aqueous organic solvents. This parameter change in surface chemistry significantly enhances dispersibility in non-aqueous solvents while maintaining chemical stability, preventing aggregation and enabling effective sheet formation.
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 modified sulfide solid electrolyte powder achieves high dispersibility and homogeneity in non-aqueous organic solvents, resulting in improved battery performance and lithium ion conductivity, enhancing the overall characteristics of lithium-ion secondary batteries.
Implementation Method 1
a surface layer rich in hydroxy groups (—OH)
Implementation Method 2
a 1H-NMR intensity is 0.3 or more
Data Source
AI summary
The present invention relates to a sulfide solid electrolyte powder to be used for a lithium-ion secondary battery, and the sulfide solid electrolyte powder includes: at least one of a crystal phase including Li, P, and S, and an amorphous phase including Li, P, and S, in which a 1H-NMR intensity is 0.3 or more, and a BET specific surface area (m2/g) and the 1H-NMR intensity satisfy a relationship of 2≤(BET specific surface area×1H-NMR intensity).