Spinel Lithium Titanium Oxide Coating for Battery Cycle Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium rechargeable batteries face challenges in maintaining cycle-life characteristics due to the instability of positive active materials during charge and discharge, particularly when using lithium titanium oxide compounds with layered structures.
Innovation Solution
A positive active material for lithium rechargeable batteries is developed, comprising a lithium intercalation compound with a spinel structured lithium titanium oxide (Li4-xMxTi5O12-z) on its surface, where M is an element like Mg, Al, or Ga, doped in specific amounts, enhancing ion and electric conductivity, and a method involving mixing titanium compounds with lithium intercalation compounds, drying, and heat-treating to form a stable coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium titanium oxide with layered structure is used as positive active material, then ion conductivity is improved, but structural stability during charge and discharge deteriorates
Solution Approach 1:
The patent applies composite materials by combining lithium intercalation compound (such as LiCoO2, LiMn2O4, or LiNi1-xCoxO2) with spinel structured lithium titanium oxide (Li4-xMxTi5O12-z) to form a composite positive active material. The spinel structured lithium titanium oxide coating layer provides structural stability while maintaining ion conductivity, resolving the contradiction between reliability and structural stability during charge and discharge cycles.
2Reliability
If surface coating layer is added to improve cycle-life, then capacity per gram of active material decreases
Solution Approach 1:
The patent applies local quality by forming a thin surface coating layer of spinel structured lithium titanium oxide (with thickness controlled by parameters x, y, z in the formula Li4-xMxTi5O12-z) on the surface of the lithium intercalation compound particles. This localized coating provides protective functionality while minimizing the amount of coating material, thereby maintaining high capacity per gram of active material while improving cycle-life 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 solution results in improved cycle-life characteristics and rate capability of lithium rechargeable batteries by maintaining structural stability during charge and discharge, while maintaining capacity per gram of the active material.
Implementation Method 1
a lithium intercalation compound; and a lithium titanium oxide represented by Chemical Formula 1 on a surface of the lithium intercalation compound
Implementation Method 2
enhancing ion and electric conductivity
Implementation Method 3
heat-treating the dried product. The heat-treating the dried product may be performed at about 700° C. to about 950° C. for about 3 hours to about 20 hours
Data Source
AI summary
A positive active material for a rechargeable lithium battery includes a lithium intercalation compound; and lithium titanium oxide represented by Chemical Formula 1 on the surface of the lithium intercalation compound surface.Li4-xMxTiyO12-z. Chemical Formula 1In the Chemical Formula 1,0<x≤3,1≤y≤5,−0.3≤z≤0.3, andM is an element selected from Mg, Al, Ga, La, Tb, Gd, Ce, Pr, Nd, Sm, Ba, Sr, Ca, and combinations thereof.