Nitrogen-Doped Sulfide Solid Electrolyte for Reduction Stability
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Solution Overview
Problem
Sulfide solid electrolytes used in all-solid-state batteries have low oxidation and reduction resistance, which affects their performance and safety.
Innovation Solution
A sulfide solid electrolyte containing at least one element M selected from Al, Si, B, Mg, Zr, Ti, Hf, Ca, Sr, Sc, Ce, Ta, Nb, W, Mo, and V, and N, with a crystalline structure, is developed to improve reduction resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte is used as nonaqueous electrolyte in all-solid-state battery, then safety is improved, but reduction resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the sulfide solid electrolyte. Specifically, it controls the ratio of Li2S to P2S5 within 70:30 to 85:15 and adds Li3N at 5-20 mass%, which changes the electrochemical stability parameters and improves reduction resistance while maintaining safety
Solution Approach 2:
The patent uses composite materials by combining multiple components: Li2S, P2S5, and Li3N in specific proportions to form a composite sulfide solid electrolyte. This composite structure leverages the complementary properties of each component to achieve both high safety and improved reduction resistance
2Reliability
If sulfide solid electrolyte is used as nonaqueous electrolyte in all-solid-state battery, then safety is improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the Li2S:P2S5 ratio and Li3N content to alter the electrochemical window and oxidation stability parameters of the electrolyte, achieving improved oxidation resistance while maintaining the safety benefits of solid electrolyte
3Reliability
If Li2S-P2S5 glass ceramic is used as sulfide solid electrolyte, then ion conductivity is improved, but reduction resistance deteriorates
Solution Approach 1:
The patent uses composite materials by incorporating Li3N into the Li2S-P2S5 glass ceramic matrix. This composite structure maintains the high ion conductivity of the glass ceramic while the Li3N component provides improved reduction resistance through its electrochemical stability
4Reliability
If Li2S-P2S5-Li3N glass ceramic is used as sulfide solid electrolyte, then ion conductivity is improved, but reduction resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios within the Li2S-P2S5-Li3N system, optimizing the balance between ion conductivity and reduction resistance through systematic variation of compositional parameters
Data Source
AI summary
An aspect of the present invention is a sulfide solid electrolyte that contains at least one element M selected from the group consisting of Al, Si, B, Mg, Zr, Ti, Hf, Ca, Sr, Sc, Ce, Ta, Nb, W, Mo, and V, and N and has a crystalline structure. Another aspect of the present invention is a sulfide solid electrolyte that contains Al and N and that has a crystalline structure.