Lithium Titanium Oxide Negative Electrode for High-Output Batteries
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Solution Overview
Problem
Current lithium titanium oxide materials used in negative electrodes of lithium secondary batteries fail to meet the high output requirements for hybrid vehicles due to limitations in charge/discharge efficiency and crystallite size, leading to inadequate performance in high-rate applications.
Innovation Solution
A negative electrode active material comprising lithium titanium oxide particles with controlled Na and K content (50 ppm-300 ppm and 500 ppm-2400 ppm, respectively) and crystallite size (100-200 nm), combined with specific surface area and particle diameter, is developed to enhance ion conductivity and structural stability, allowing for improved high-output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium titanium oxide is used as negative electrode material, then initial charge/discharge cycle efficiency reaches approximately 100% and no surface film is formed, but output characteristics are insufficient for high-rate applications
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallite size (100-200 nm) and particle diameter (0.5-5 μm) of lithium titanium oxide, and by controlling the content of Na (50-300 ppm) and K (500-2400 ppm) impurities. These parameter optimizations resolve the contradiction by maintaining the structural stability needed for 100% cycle efficiency while achieving the fine particle characteristics required for high output performance.
Solution Approach 2:
The patent creates a composite material system by combining lithium titanium oxide with specific amounts of Na and K impurities that act as dopants. This composite approach allows the base material to maintain its excellent cycle efficiency while the controlled impurity content enhances ion conductivity and output characteristics, resolving the power-efficiency contradiction.
2Power
If crystallite size is reduced to improve ion conductivity, then output characteristics improve, but manufacturing precision and structural stability become more difficult to control
Solution Approach 1:
The patent resolves this contradiction by establishing a specific crystallite size range (100-200 nm) that balances ion conductivity with manufacturability. This parameter optimization ensures that the material achieves sufficient ion transport while remaining controllable through standard manufacturing processes, avoiding the difficulties of producing ultra-fine crystallites.
Solution Approach 2:
The patent employs feedback control in the manufacturing process by monitoring and adjusting crystallite size, Na content, and K content to within specific ranges. This feedback mechanism ensures consistent production of lithium titanium oxide with the desired properties, maintaining both ion conductivity and structural stability.
3Power
If Na and K content is increased to improve output characteristics, then electric resistance decreases, but material purity and structural stability may be compromised
Solution Approach 1:
The patent resolves this contradiction by optimizing the Na and K content to specific ranges (Na: 50-300 ppm, K: 500-2400 ppm). These parameter settings provide sufficient dopant concentration to reduce electric resistance and improve output, while remaining low enough to maintain material purity and structural stability of the lithium titanium oxide lattice.
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 optimized lithium titanium oxide material reduces electric resistance and enables high-output performance in batteries, specifically suitable for micro-hybrid vehicles by maintaining structural integrity and ion conductivity during charging/discharging.
Implementation Method 1
the lithium titanium oxide particles have a Na content of 50 ppm-300 ppm, a K content of 500 ppm-2400 ppm and a crystallite size of 100-200 nm... ion conductivity and structural stability, allowing for improved high-output characteristics
Data Source
AI summary
A negative electrode active material including lithium titanium oxide particles, wherein the lithium titanium oxide particles have a Na content of 50 ppm-300 ppm, a K content of 500 ppm-2400 ppm and a crystallite size of 100-200 nm, and a lithium secondary battery including the same.