Lithium Titanate Particles Calcination for Conductivity and Capacity
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Solution Overview
Problem
Conventional lithium titanate particles used in non-aqueous electrolyte secondary batteries face challenges in achieving high initial discharge capacity and efficient discharge capacity retention rates due to high electrical insulating properties and difficulties in producing fine particles with uniform spinel structure and good conductivity.
Innovation Solution
Lithium titanate particles with specific compositions and structures, including controlled amounts of TiO2 and Li2TiO3, and a spinel structure, are produced using a calcination process at optimized temperatures, resulting in particles with enhanced initial discharge capacity and high-efficiency discharge capacity retention rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional solid state reaction method is used to produce lithium titanate, then production process is simple, but particle uniformity and spinel structure formation are poor
Solution Approach 1:
The patent applies preliminary action by performing wet mixing of raw materials before calcination to pre-form a uniform slurry with controlled composition. This preliminary wet mixing step ensures homogeneous distribution of lithium and titanium compounds, which then transforms into uniform spinel structure particles after calcination, resolving the contradiction between simple production and high particle uniformity.
2Stability of the object's composition
If high calcination temperature is used to form spinel structure, then spinel structure formation is improved, but electrical conductivity decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the calcination temperature within a specific range (900-1100°C) and adjusting the Li/Ti molar ratio to optimize both spinel structure formation and electrical conductivity. This parameter optimization resolves the contradiction by finding the optimal balance point where sufficient spinel structure forms while maintaining acceptable conductivity.
Solution Approach 2:
The patent applies composite materials by creating a composite structure where spinel phase particles are distributed in a controlled matrix, and by using composite raw material formulations with specific Li/Ti ratios. This composite approach allows the system to achieve both structural stability and electrical conductivity through the synergistic combination of different phases and compositions.
3Area of stationary object
If fine particles are produced to increase surface area, then discharge capacity retention rate improves, but particle aggregation increases
Solution Approach 1:
The patent applies the intermediary principle by using a liquid binder or dispersant during the wet mixing and slurry formation process. This intermediary substance prevents fine particle aggregation during processing and maintains particle dispersion, allowing the production of fine particles with high surface area while controlling aggregation through the mediating effect of the liquid phase.
Solution Approach 2:
The patent applies porous materials by creating a controlled porous structure within the particle matrix that increases internal surface area without requiring excessive external fine particle aggregation. The porous structure provides high surface area for electrochemical reactions while maintaining particle integrity and reducing aggregation through the internal porosity architecture.
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 resulting lithium titanate particles exhibit excellent initial discharge capacity and high output characteristics, suppressing gas generation and improving electronic conductivity, thus suitable for non-aqueous electrolyte secondary batteries.
Implementation Method 1
mixed particles prepared by dry-mixing or wet-mixing a lithium salt and an oxide of titanium such that an Li/Ti ratio therein is 0.80 (a simple mixture of the lithium salt and the oxide of titanium) are heated and calcined to obtain Li4Ti5O12
Data Source
AI summary
According to the present invention, there are provided lithium titanate particles which exhibit an excellent initial discharge capacity and an enhanced high-efficiency discharge capacity retention rate as an active substance for non-aqueous electrolyte secondary batteries and a process for producing the lithium titanate particles, and Mg-containing lithium titanate particles.