Bronze-Type Titanium Oxide Negative Electrode for Lithium-Ion Batteries
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Solution Overview
Problem
Conventional titanium oxide compounds used as negative electrodes in lithium-ion secondary batteries have lower actual capacity than theoretical values, and there is a risk of internal short-circuits due to metal lithium crystal precipitation, which can lead to thermal runaway.
Innovation Solution
A titanium oxide compound is synthesized using a method that involves forming a layer structure with chain-linked TiO6 octahedrons, obtained by processing potassium tetratitanate, which enhances alkali metal ion holding and insertion/removal capabilities, and is used in a lithium-ion secondary battery with a specific crystal structure configuration to increase capacity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon-based raw material is used as negative electrode, then theoretical capacity is high (372 mAh/g), but metal lithium crystal precipitates causing internal short-circuit and thermal runaway
Solution Approach 1:
The invention changes the electrochemical potential parameter of the negative electrode from 0.08V (carbon-based) to 1.5-1.6V (titanium oxide compound). This parameter change prevents metal lithium crystal precipitation while maintaining high capacity through the bronze-type crystal structure with formula Li1+yTi2O3 (0.6≤y≤1.0), resolving the contradiction between capacity and safety
2Reliability
If spinel-type lithium titanate (S-LTO) is used as negative electrode, then safety is improved (potential 1.55V prevents lithium crystal precipitation), but theoretical capacity decreases to about 175 mAh/g
Solution Approach 1:
The invention uses a composite bronze-type titanium oxide compound with formula Li1+yTi2O3 (0.6≤y≤1.0) that combines the safety advantages of high-potential titanium oxide (1.5-1.6V) with enhanced capacity (335 mAh/g theoretical). The specific crystal structure with chain-linked TiO6 octahedrons and controlled lithium ion distribution creates a material that outperforms conventional S-LTO in both safety and capacity
3Ease of manufacture
If conventional manufacturing method is used for titanium oxide compound, then production is simpler, but actual capacity is lower than theoretical value
Solution Approach 1:
The invention performs preliminary action by precisely controlling the crystal structure formation during manufacturing. By using specific raw material ratios (TiO2:K2CO3 = 4:1 mole ratio), controlled heating rates (5-10°C/min), and specific temperature ranges (900-1000°C), the method ensures the bronze-type crystal structure forms correctly from the start, achieving both high actual capacity (335 mAh/g) and manufacturing feasibility
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 synthesized titanium oxide compound achieves higher capacity and safety by reducing the risk of internal short-circuits and thermal runaway, while maintaining high thermal stability and efficient lithium ion movement.
Implementation Method 1
a titanium oxide compound which is obtained by eluating potassium of potassium tetratitanate (4T) expressed by a general formula K2Ti4O9 and performing thermal processing
Implementation Method 2
the insertion and removal of them are enhanced
Data Source
AI summary
In a titanium oxide compound according to the present invention, the titanium oxide compound is obtained by eluating potassium of potassium tetratitanate expressed by a general formula K2Ti4O9 and performing thermal processing, and, in an X-ray diffraction spectrum of the potassium tetratitanate obtained by using a Cu—Kα ray source, between a peak intensity Ia of a (200) plane, a peak intensity Ic of a (004) plane and a peak intensity Ib of a (31-3) plane, a relationship of Ia>Ib>Ic is satisfied.