Solid-State Battery Electrolyte Pairing for Faster Charge-Discharge
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Solution Overview
Problem
Existing batteries with negative-electrode materials and solid electrolytes, such as those disclosed in International Publication No. WO 2019/146295, have room for improvement in output characteristics, specifically in charge-discharge rate performance.
Innovation Solution
A battery structure featuring a negative-electrode layer with a first solid electrolyte containing Li, Ti, and O, and a monoclinic crystal phase, and an electrolyte layer with a second solid electrolyte containing Li, M2, and X2, where M2 and X2 are metal and halogen elements, respectively, to enhance ionic conductivity and charge-discharge rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in the negative-electrode layer and electrolyte layer, then safety is improved, but output characteristics and charge-discharge rate performance deteriorate
Solution Approach 1:
The patent employs composite solid electrolyte materials with specific crystal structures (monoclinic phase in negative-electrode layer, trigonal phase in electrolyte layer) to achieve both high safety and improved charge-discharge rate performance. The composite structure combines the safety benefits of solid electrolytes with enhanced ionic conductivity through carefully selected crystal phases and compositions (Li, M1, X1 in negative-electrode layer; Li, M2, X2 in electrolyte layer).
Solution Approach 2:
The patent optimizes specific parameters including the crystal structure phases (monoclinic and trigonal), chemical composition ratios (Li, M1, X1 and Li, M2, X2), and grain boundary characteristics to simultaneously improve safety and charge-discharge rate performance. By controlling these parameters, the solid electrolyte achieves higher ionic conductivity while maintaining its safety advantages.
2Productivity
If solid electrolyte composition is optimized for ionic conductivity, then charge-discharge rate performance is improved, but grain boundary resistance increases
Solution Approach 1:
The patent applies different solid electrolyte compositions and crystal structures to different locations: the negative-electrode layer contains a monoclinic phase solid electrolyte (Li, M1, X1) optimized for local electrochemical reactions, while the electrolyte layer contains a trigonal phase solid electrolyte (Li, M2, X2) optimized for bulk ionic conduction. This local optimization minimizes grain boundary resistance while maintaining high ionic conductivity.
Solution Approach 2:
The patent carefully controls compositional parameters and crystal structure parameters to reduce grain boundary resistance. By selecting specific metal elements (M1, M2) and halogen elements (X1, X2) and optimizing their ratios, the patent achieves low grain boundary resistance while maintaining high ionic conductivity for improved charge-discharge performance.
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 battery structure improves output characteristics by optimizing the combination of solid electrolytes, achieving higher charge-discharge rate performance and safety by maintaining ionic conductivity while minimizing grain boundary resistance.
Implementation Method 1
the first solid electrolyte contains a crystalline phase assigned to a monoclinic crystal and contains Li, M1, and X1... the second solid electrolyte contains a crystalline phase assigned to a trigonal crystal and contains Li, M2, and X2
Data Source
AI summary
A battery includes a positive-electrode layer, a negative-electrode layer, and an electrolyte layer between the positive-electrode layer and the negative-electrode layer, wherein the negative-electrode layer includes a negative-electrode active material and a first solid electrolyte, the electrolyte layer contains a second solid electrolyte, the negative-electrode active material contains Li, Ti, and O, the first solid electrolyte contains a crystalline phase assigned to a monoclinic crystal and contains Li, M1, and X1, wherein M1 denotes at least one of metal elements and metalloid elements other than Li, and X1 denotes at least one of F, Cl, Br, and I, and the second solid electrolyte contains a crystalline phase assigned to a trigonal crystal and contains Li, M2, and X2, wherein M2 denotes at least one of metal elements and metalloid elements other than Li, and X2 denotes at least one of F, Cl, Br, and I.