Negative-Electrode Material With Solid Electrolyte for Faster Li-Ion Transport
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Solution Overview
Problem
Lithium titanium oxide-based negative-electrode materials in lithium-ion batteries face challenges with slow lithium diffusion and difficulty in high-rate charging and discharging due to their inherent properties.
Innovation Solution
A novel negative-electrode material is developed, comprising lithium, titanium, and additional metal or metalloid elements, combined with a solid electrolyte containing lithium, metal, and halogen elements, which improves ionic conductivity and charge-discharge rates in solid-state batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium titanium oxide is used as negative-electrode active material, then cycle characteristics are improved and electric potential is higher than metallic lithium, but lithium diffusion is slow and high-rate charging and discharging is difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the negative-electrode active material by introducing dopant elements (M1) such as Zr, Nb, Ta, or Mo at specific concentrations (0.01≤α≤0.20 in formula Li4Ti5-αM1αO12). This compositional modification alters the electronic and ionic properties of the material, enabling faster lithium diffusion while maintaining the stable spinel structure that provides good cycle characteristics.
Solution Approach 2:
The patent creates a composite negative-electrode material by combining lithium titanium oxide with dopant elements (M1) to form a doped spinel structure Li4Ti5-αM1αO12. This composite approach leverages the stable framework of Li4Ti5O12 while the dopant elements introduce pathways for faster lithium ion transport, resolving the contradiction between structural stability and ion diffusion speed.
2Productivity
If solid electrolyte containing halogen elements is used, then ionic conductivity and charge-discharge rates are improved, but device complexity increases
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating halogen elements (F, Cl, Br, or I) at controlled ratios (0.05≤x≤0.50 in formula Li10-a-bM2aXbO12-y/2). This parameter change optimizes the balance between ionic conductivity and structural stability, achieving high charge-discharge rates while maintaining a manageable device structure through systematic compositional control.
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 new material enhances the charge-discharge rate and efficiency of solid-state batteries by optimizing lithium ion transport, leading to improved performance and safety with reduced sulfur content.
Implementation Method 1
the solid electrolyte contains Li, M2, and X... improves ionic conductivity and charge-discharge rates
Implementation Method 2
Lithium titanium oxide has been used as a negative-electrode active material... can characteristically improve the cycle characteristics
Data Source
AI summary
A negative-electrode material includes a negative-electrode active material and a solid electrolyte. The negative-electrode active material contains Li, Ti, M1, and O, wherein M1 denotes at least one selected from the group consisting of metal elements and metalloid elements other than Li and Ti. The solid electrolyte contains Li, M2, and X, wherein M2 denotes at least one selected from the group consisting of metal elements and metalloid elements other than Li, and X denotes at least one selected from the group consisting of F, Cl, Br, and I.