Li4Ti5O12 Negative Electrode Material for Lithium Ion Battery
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Solution Overview
Problem
Lithium ion secondary batteries using Li4Ti5O12 as the negative electrode material face challenges with low discharge capacity at high loads and low packing density, which affects energy density and safety due to small primary particle size.
Innovation Solution
Substituting a portion of the Ti element in Li4Ti5-x-y Fe x V y O12 or Li4 Ti 5-x-z Fe x B z O12 with V or B elements to increase the primary particle size, enhancing packing density and capacity density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li4Ti5O12 is used as negative electrode material, then the battery can operate with good stability, but the discharge capacity at high loads is insufficient
Solution Approach 1:
The patent changes the compositional parameters of Li4Ti5O12 by substituting Ti elements with Fe, V, and B elements in specific proportions (0 < x ≤ 0.1, 0 < y ≤ 0.05, 0 < z ≤ 0.05), thereby improving electronic conductivity and discharge capacity while maintaining storage stability
Solution Approach 2:
The patent creates a composite material system Li4Ti5-x-y-z Fe x V y B z O12 combining multiple elements with complementary properties: Fe for capacity enhancement, V for conductivity improvement, and B for particle size control, achieving synergistic effects that resolve the contradiction between stability and high-load performance
2Quantity of substance
If primary particle size is increased to improve packing density, then capacity density improves, but electronic conductivity may decrease
Solution Approach 1:
The patent optimizes the particle size parameter to 1-5 μm through controlled substitution with V and B elements, achieving optimal packing density while the simultaneous introduction of Fe and V elements maintains electronic conductivity through compositional modification
Solution Approach 2:
The multi-element composite Li4Ti5-x-y-z Fe x V y B z O12 balances the competing requirements: V and B increase particle size for better packing, while Fe and V maintain electronic conductivity, resolving the contradiction between quantity and quality
3Productivity
If Ti element is substituted with Fe element to improve capacity, then discharge capacity increases, but primary particle size decreases
Solution Approach 1:
The patent balances the substitution parameters by introducing V and B elements alongside Fe, where V and B promote particle growth while Fe enhances capacity, achieving an optimal balance through coordinated compositional adjustment
Solution Approach 2:
The composite Li4Ti5-x-y-z Fe x V y B z O12 uses synergistic element combinations: Fe provides capacity enhancement, while V and B simultaneously promote particle size growth, resolving the contradiction between capacity and particle size through multi-functional material design
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 approach results in a lithium ion secondary battery with improved capacity density and packing density, effectively addressing the limitations of existing materials by increasing the primary particle size and maintaining a single spinel crystalline structure.
Implementation Method 1
a negative electrode for a lithium ion secondary battery, comprising an active material containing a lithium titanium complex oxide having a composition expressed as Li 4 Ti 5-x-y Fe x V y O 12
Implementation Method 2
Li 4 Ti 5 O 12 is a material having a spinel crystalline structure and is capable of repeatedly occlude and release Li
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A negative electrode active material for a lithium ion secondary battery contains a lithium titanium complex oxide having a composition expressed as Li4Ti5-x-yFexVyO12 (where 0<x≤0.3, 0<y≤0.5) or Li4Ti5-x-zFexBzO12 (where 0<x≤0.3, 0<z≤0.3).