Lithium Titanate Anode Preparation via Low-Temperature Sintering
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Solution Overview
Problem
Current methods for preparing lithium titanate Li4Ti5O12 are inefficient due to high-temperature calcining requirements, leading to coarse primary particles and impurities, and sol-gel processes are uneconomical due to expensive starting compounds and the need for additional calcination.
Innovation Solution
A composite oxide containing Li2TiO3, TiO2, Li2CO3, and a carbon source, optionally with transition or main group metal compounds, is used to prepare phase-pure lithium titanate through a process involving an aqueous solution reaction, spray-drying, and low-temperature sintering, avoiding extensive grinding and expensive starting materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature calcining is used to prepare lithium titanate, then phase-purity is improved, but particle size becomes coarse and manufacturing complexity increases
Solution Approach 1:
The patent changes the temperature parameter from high-temperature calcining (>800°C) to low-temperature sintering (600-750°C), achieving phase-pure lithium titanate without requiring extensive grinding and complex manufacturing processes. The composite oxide precursors enable complete reaction at lower temperatures, resolving the contradiction between phase-purity and manufacturing complexity.
Solution Approach 2:
The patent performs preliminary action by preparing composite oxide precursors containing Li2TiO3, TiO2, Li2CO3, and carbon source before the final sintering step. This pre-organization of reactants in optimal ratios and physical states enables the low-temperature synthesis to proceed efficiently, avoiding the need for post-synthesis grinding and complex processing.
2Length of moving object
If sol-gel process is used to prepare lithium titanate, then particle size is reduced, but production cost increases due to expensive starting compounds
Solution Approach 1:
The patent replaces expensive sol-gel starting compounds (organometallic precursors) with inexpensive, readily available inorganic materials (Li2CO3, TiO2, Li2TiO3) and carbon sources. These cheap precursors are processed through simple wet-mixing and spray-drying to produce fine particles, resolving the contradiction between particle size reduction and production cost.
Solution Approach 2:
The patent substitutes the complex chemical sol-gel process with a simpler physical-chemical approach involving wet-mixing of inorganic powders, spray-drying to form fine particles, and low-temperature sintering. This replacement eliminates the need for expensive organometallic reagents while achieving comparable or superior particle size control.
3Device complexity
If conventional solid-state reaction is used, then process simplicity is maintained, but energy consumption increases due to high-temperature requirements
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature calcining (>800°C) to low-temperature sintering (600-750°C) by using composite oxide precursors. This parameter change maintains process simplicity while dramatically reducing energy consumption, as the precursors are designed to react completely at lower temperatures.
Solution Approach 2:
The patent uses composite oxide precursors containing multiple components (Li2TiO3, TiO2, Li2CO3, carbon source) in specific ratios. This composite structure ensures complete reaction and phase formation at lower temperatures, reducing energy consumption while maintaining the simplicity of a single-step sintering process.
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
This method produces phase-pure lithium titanate with improved flowability and cycle stability, achieving high current density and low sintering temperatures, reducing production costs and environmental impact.
Implementation Method 1
a process for the preparation of a composition of phase-pure doped or non doped lithium titanate Li4Ti5O12 by heating a composite oxide at a temperature of ≤780° C., preferably ≤750° C. and more preferably ≤735° C.
Implementation Method 2
spray-drying
Data Source
AI summary
The present invention relates to a composite oxide with x wt.-parts Li2TiO3, preferably in its cubic modification of space group Fm-3m, t wt.-parts TiO2, z wt.-parts of Li2CO3 or LiOH, u wt.-parts of a carbon source and optionally v wt.-parts of a transition or main group metal compound and/or a sulphur containing compound, wherein x is a number between 2 and 3, y is a number between 3 and 4, z is a number between 0.001 and 1, u is a number between 0.05 and 1 and 0≤v<0.1 and the metal of the transition or main group metal compound is selected from Al, Mg, Ga, Fe, Co, Sc, Y, Mn, Ni, Cr, V or mixtures thereof. Further the present invention relates to the use of the composite oxide in a process for the preparation of a composition of a non-doped and doped lithium titianate Li4Ti5O12 comprising secondary agglomerates of primary particles and its use as anode material in secondary lithium-ion batteries.