Lithium Argryrodite Solid Electrolyte Phase Purity
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Solution Overview
Problem
The production of phase-pure lithium-rich solid-state compounds, particularly lithium argyrodites, is challenging due to their sensitivity to starting materials and crucible materials, leading to the formation of by-products and limited lithium ion mobility, which affects their use as solid electrolytes in electrochemical energy storage.
Innovation Solution
Development of lithium argyrodites with the general formula Li_(10-n-x)B_n+X_2-xY_x, where B_n+ includes elements like P, As, Ge, and Ga, X_2- includes S, Se, and Y includes Cl, Br, and I, allowing for phase-pure production and high lithium ion mobility, usable as solid electrolytes over a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional production methods are used for lithium-rich solid-state compounds, then production can proceed with standard materials, but phase purity is compromised and by-products form due to sensitivity to starting materials and crucible materials
Solution Approach 1:
The patent employs an intermediary substance (iodine or bromine) during the synthesis process that mediates the reaction between lithium sulfide and phosphorus pentasulfide. This intermediary enables phase-pure formation of Li6PS5X compounds by controlling the reaction pathway and preventing unwanted by-products, thereby resolving the contradiction between standard production methods and phase purity requirements.
2Temperature
If standard solid electrolyte materials are used, then electrochemical energy storage can be implemented, but temperature sensitivity limits the operational temperature range
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the solid electrolyte through substitution of halogen atoms (Cl, Br, I) at the X position in the Li6PS5X formula. This compositional parameter change fundamentally alters the material's thermal properties, enabling stable operation across an extended temperature range from -150°C to 600°C and reducing temperature sensitivity.
3Speed
If conventional lithium electrolytes are used, then electrochemical energy storage is achievable, but lithium ion mobility is limited affecting performance
Solution Approach 1:
The patent utilizes composite material design by creating Li6PS5X compounds that combine lithium sulfide, phosphorus sulfide, and halogen components in a specific crystalline structure. This composite approach optimizes the material's ionic conductivity and lithium ion mobility while maintaining structural stability, thereby improving both speed and reliability of ion transport.
Data Source
AI summary
The invention relates to lithium argyrodite of the general formula (I): Li+ (12-n-x)Bn+ X2- 6-x Y- x (I), where Bn+ is selected from the group P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, and Ta, X2 - is selected from the group S, Se, and Te, Y- is selected from the group Cl, Br, I, F, CN, OCN, SCN, N3, and where 0 = x = 2, and a method for the production thereof, and the use thereof as a lithium-ion electrolyte in primary and secondary electrochemical energy storage.