Mixed Solid Electrolyte Composition for Conductivity and Stability
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Solution Overview
Problem
Existing solid electrolytes for electrochemical devices face challenges in achieving high ion conductivity, flexibility, and electrochemical stability, with oxide solid ion conductors lacking in ion conductivity and sulfide solid ion conductors reacting with water to produce toxic gases.
Innovation Solution
A solid electrolyte composed of a mixed solid ion conductor containing metal nitrates or their hydrates, such as La(NO3)3, Li3PO4, and LiNO3, with specific crystal structures and compositions, providing excellent ion conductivity and flexibility while maintaining electrochemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If oxide solid ion conductors are used, then chemical stability is improved, but ion conductivity deteriorates
Solution Approach 1:
The patent employs composite materials by combining oxide solid ion conductors with sulfide solid ion conductors in a layered structure. The oxide layer provides chemical stability while the sulfide layer contributes high ion conductivity, resolving the contradiction between these two properties through material composition rather than relying on a single material type.
2Reliability
If sulfide solid ion conductors are used, then ion conductivity is improved, but harmful factors worsen due to toxic gas generation
Solution Approach 1:
The patent converts the harmful property of sulfide solid ion conductors (reactivity with water producing toxic gas) into a beneficial configuration by placing the sulfide layer between the oxide layer and the electrode. This layered structure prevents direct contact between the sulfide and water-containing environments while maintaining the high ion conductivity benefit of sulfides.
3Adaptability or versatility
If halide solid ion conductors are used, then adaptability to environment is improved, but ion conductivity deteriorates
Solution Approach 1:
The patent uses composite materials combining halide solid ion conductors with oxide or sulfide solid ion conductors. The halide layer provides environmental adaptability and flexibility while the oxide or sulfide layers compensate for insufficient ion conductivity, achieving a balance between these conflicting properties through material composition.
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 proposed solid electrolyte achieves ion conductivities ranging from 5×10−5 to 2×10−3 S/cm and electrochemical stability, suitable for use in electrochemical devices like all-solid secondary batteries.
Implementation Method 1
use a solid ion conductor as an electrolyte for safe operation
Data Source
AI summary
A solid electrolyte including a mixed solid ion conductor with a metal nitrate or a hydrate thereof. The metal of the metal nitrate is one or more of an M metal or an M′ metal, the M metal is a monovalent cationic metal, and the M′ metal is one or more of a divalent cationic metal, a trivalent cationic metal, a tetravalent cationic metal, a pentavalent cationic metal or a hexavalent cationic metal. Also disclosed are an electrochemical device including the solid electrolyte, and a method of preparing the solid electrolyte.