Sulfide Solid Electrolyte Composition for High Filling Rate
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Solution Overview
Problem
Sulfide solid electrolytes in secondary batteries face limitations in increasing filling rate due to high Young's modulus and potential reactivity with additional components, which can decrease ionic conductivity.
Innovation Solution
An electrolytic material comprising a sulfide solid electrolyte and an alkali metal salt with a quaternary ammonium cation, an alkali metal ion, and a bistrifluoromethanesulfonylamide (TFSA) anion, where the alkali metal salt has a low Young's modulus and low reactivity with the sulfide solid electrolyte, enhancing filling rate and maintaining ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filling rate of sulfide solid electrolyte is increased, then the performance of secondary battery is improved, but the filling rate has a limit due to high Young's modulus
Solution Approach 1:
The patent combines sulfide solid electrolyte particles with an additional component (ionic liquid or molten salt) to form a composite electrolyte layer. This composite structure allows the additional component to fill in the gaps between the rigid sulfide solid electrolyte particles, thereby increasing the overall filling rate while maintaining structural integrity and avoiding the limitations imposed by the high Young's modulus of sulfide solid electrolyte alone.
2Quantity of substance
If additional component is combined with sulfide solid electrolyte to increase filling rate, then filling rate is improved, but ionic conductivity may decrease due to reaction between components
Solution Approach 1:
The patent carefully controls the composition parameters of the additional component, specifically selecting ionic liquids or molten salts with appropriate chemical stability. The ratio of additional component is optimized (5-50 mass%) to ensure sufficient gap-filling capability while minimizing reactive interactions that could degrade ionic conductivity. This parameter optimization allows simultaneous achievement of high filling rate and maintained ionic conductivity.
Data Source
AI summary
Disclosed is a technique capable of improving the filling rate of an electrolytic material and inhibiting a decrease in ionic conductivity of the electrolytic material. The electrolytic material of the present disclosure is an electrolytic material used in secondary cells, comprising a sulfide solid electrolyte and an alkali metal salt, wherein the alkali metal salt comprises a quaternary ammonium cation, an alkali metal ion, and a bistrifluoromethanesulfonylamide anion.