Li4Ti5O12-Bi2Ti2O7 Composite Anode for High-Rate Discharge
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Solution Overview
Problem
Current anode active materials in lithium secondary batteries lack satisfactory high-rate discharge and lifetime characteristics, limiting their performance in lithium secondary batteries.
Innovation Solution
A composite of lithium titanium oxide and bismuth titanium oxide is used as an anode active material, with a specific composition and manufacturing method involving mechanical mixing and heat treatment, to enhance high-rate discharge and lifetime characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anode active materials are used, then the battery can be manufactured with existing materials, but the high-rate discharge and lifetime characteristics are not satisfactory
Solution Approach 1:
The patent uses a composite material consisting of Li4Ti5O12 and Bi2Ti2O7 in a specific molar ratio range (99:1 to 1:99). This composite structure combines the advantages of both materials to achieve satisfactory high-rate discharge and lifetime characteristics while maintaining manufacturability through established ceramic processing techniques.
Solution Approach 2:
The patent optimizes specific parameters including the molar ratio of Li4Ti5O12 to Bi2Ti2O7 (99:1 to 1:99), interplanar spacing of (111) planes (4.810-4.900 Å), and stoichiometric ranges in the chemical formulas. These parameter optimizations enable the material to achieve improved performance characteristics.
2Reliability
If graphite, high capacity silicon-based transition metal oxides, or tin-based transition metal oxides are used as anode active materials, then the battery can operate with these conventional materials, but the high-rate discharge and lifetime characteristics have not reached satisfactory levels
Solution Approach 1:
The patent employs a composite of Li4Ti5O12 and Bi2Ti2O7 that requires precise control of the molar ratio (99:1 to 1:99 range) and stoichiometry within specified ranges (−0.2≦a≦0.2, −0.3≦b≦0.3, etc.). This composite approach with controlled composition achieves the desired high-rate discharge and lifetime characteristics.
Solution Approach 2:
The patent specifies precise parameter ranges including interplanar spacing (4.810-4.900 Å), molar ratios (99:1 to 1:99), and stoichiometric deviations (−0.2≦a≦0.2, −0.3≦b≦0.3, 0≦c≦0.3, −0.3≦d≦0.3). These controlled parameter variations enable achievement of satisfactory performance characteristics.
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 composite anode active material improves high-rate discharge and lifetime characteristics of lithium secondary batteries, providing better performance compared to existing materials.
Implementation Method 1
The lithium secondary battery generates electrical energy via oxidation and reduction reactions in which lithium ions are inserted into and extracted from the cathode and the anode, respectively
Implementation Method 2
mechanically mixing a lithium salt, a titanium precursor, and a bismuth salt at the same time to form a mixture
Implementation Method 3
heat treating the mixture to form a composite including a lithium titanium oxide and a bismuth titanium oxide
Data Source
AI summary
Provided are a composite including a lithium titanium oxide and a bismuth titanium oxide, a method of manufacturing the composite, an anode active material including the composite, an anode including the anode active material, and a lithium secondary battery having improved cell performance by including the anode.