Composite Cathode Material for Lithium Battery Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary battery cathode materials face challenges in achieving high energy density, long lifetime, and stable voltage characteristics due to phase transitions and manganese ion dissolution at high temperatures, leading to irreversible capacity and degradation.
Innovation Solution
A composite cathode active material is developed, comprising a lithium composite oxide and a metal phosphate, specifically vanadium, niobium, or tantalum phosphate, which is mixed with a lithium composite oxide to form a composite structure or coating layer, enhancing stability and intercalation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium manganese-excess layered structure composite oxide is used to achieve high energy density, then capacity is improved, but phase transition degradation and manganese ion dissolution occur at high temperatures leading to poor stability and short lifetime
Solution Approach 1:
The patent applies composite materials by combining lithium manganese-excess layered structure composite oxide with metal phosphate (vanadium, niobium, or tantalum phosphate) to create a composite cathode active material. The metal phosphate component forms a stable structure that prevents phase transition degradation and manganese ion dissolution, while the lithium manganese-excess component provides high capacity. This composite approach resolves the contradiction by integrating the high capacity feature with the stability feature through material composition.
2Quantity of substance
If lithium manganese-excess layered structure composite oxide is used to achieve high energy density, then capacity is improved, but lifetime is reduced due to degradation
Solution Approach 1:
The composite structure of lithium manganese-excess layered oxide and metal phosphate extends the lifetime of the cathode material. The metal phosphate component exhibits high structural stability and resistance to degradation, which maintains the integrity of the cathode during prolonged cycling and high-temperature operation, thereby extending the operational lifetime while preserving the high capacity characteristics.
3Quantity of substance
If lithium manganese-excess layered structure composite oxide is used to achieve high energy density, then capacity is improved, but voltage characteristics deteriorate due to phase transitions
Solution Approach 1:
The metal phosphate component in the composite cathode material provides structural stability that suppresses phase transitions during charge-discharge cycles. This stable framework maintains consistent voltage characteristics and electrochemical performance, preventing the voltage degradation that would otherwise occur due to phase transitions in the lithium manganese-excess layered structure.
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 cathode active material improves the lithium battery's lifetime and voltage characteristics by preventing phase transition degradation and facilitating lithium ion diffusion, resulting in improved charge and discharge performance.
Implementation Method 1
preventing phase transition degradation
Implementation Method 2
facilitating lithium ion diffusion
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A composite cathode active material including: a lithium composite oxide; a metal phosphate represented by Formula 1, preparation methods thereof, a cathode and a lithium battery. Formula 1 MxPyOz wherein, in Formula 1, M is vanadium, niobium, tantalum, or a combination thereof, 1≤y/x≤1.33, and 4≤z/y≤5.