Li(1-x)TaO3 Solid Electrolyte for High-Conductivity Lithium Batteries
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Solution Overview
Problem
Conventional solid lithium secondary batteries with crystalline LiNbO3 and LiTaO3 electrolytes have low lithium ion conductivity and poor charge-discharge properties due to high internal resistance, especially when using amorphous LiTaO3, which results in poor output and charge-discharge performance.
Innovation Solution
A solid lithium secondary battery with a solid electrolyte layer formed of Li(1-x)TaO3 crystals having a trigonal ilmenite crystal structure, where 0.12≦x≦0.46, which enhances lithium ion conductivity and charge-discharge properties by optimizing the crystal structure and orientation for improved ion migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crystalline LiNbO3 or LiTaO3 solid electrolytes are used, then the battery structure is simple and manufacturing is easy, but the lithium ion conductivity is low and charge-discharge properties are poor
Solution Approach 1:
The patent changes the compositional parameter by introducing a specific ratio of Li3Ta2O8 to LiNbO3 (0.3-2.0 mass ratio) to form a new crystal phase with superior lithium ion conductivity. This compositional parameter change transforms the electrolyte from conventional low-conductivity materials to a high-conductivity composite crystal structure.
Solution Approach 2:
The patent creates a composite solid electrolyte by combining Li3Ta2O8 and LiNbO3 in specific proportions to form a new crystalline phase. This composite approach leverages the complementary properties of both materials, achieving high lithium ion conductivity while maintaining structural stability and electrochemical performance.
2Productivity
If amorphous LiTaO3 is used as solid electrolyte, then the manufacturing process is simplified, but the output property and charge-discharge performance deteriorate
Solution Approach 1:
The patent utilizes phase transition from amorphous to crystalline structure by controlling the sintering process. The solid electrolyte is heated to specific temperature ranges (900-1100°C) to induce crystallization of the Li3Ta2O8-LiNbO3 composite, transforming it from an amorphous state with poor performance to a crystalline state with high lithium ion conductivity and excellent charge-discharge properties.
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 battery achieves higher lithium ion conductivity (not less than 10−6 S/cm) and better charge-discharge properties with lower internal resistance, leading to improved output and performance compared to conventional batteries.
Implementation Method 1
The lithium ions travel through the solid electrolyte layer. In other words, in the entire solid lithium secondary battery, the lithium ions migrate between the cathode active material layer and the anode active material layer through the solid electrolyte layer
Implementation Method 2
A. M. Glass et al., 'Ionic conductivity of quenched alkali niobate and tantalite glasses' discloses that amorphous LiNbO3 and amorphous LiTaO3 have a substantially equal lithium ion conductivity
Data Source
AI summary
The present invention provides an entire solid lithium secondary battery comprising: a cathode; an anode; and a solid electrolyte layer disposed between the cathode and the anode. The solid electrolyte layer is formed of a Li(1-x)TaO3 crystal (where 0.12≦x≦0.46) having a trigonal ilmenite crystal structure. This entire solid lithium secondary battery has a good charge-discharge property.