Composite Cathode Particles with Lithium Alloy for Cycle Capacity Retention
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Solution Overview
Problem
Lithium ion batteries experience a significant decrease in capacity after initial charging and during repeated charging and discharging, which affects their cycle characteristics.
Innovation Solution
A composite cathode active material particle is developed, comprising a cathode active material and lithium alloy particles or metal particles with a lithium alloying potential of 0.5 V (vs Li/Li+) or more, dispersed within the cathode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional cathode active materials are used to increase capacity, then the battery capacity increases, but the capacity decreases significantly after initial charging and during repeated cycles
Solution Approach 1:
Lithium alloy particles are incorporated into the cathode active material before battery assembly and initial charging. During initial charging, these particles release lithium ions in advance, which then participate in SEI formation at the anode. This preliminary lithium release prevents the cathode material from losing its own lithium, thereby maintaining capacity and improving cycle characteristics
Solution Approach 2:
Lithium alloy particles act as an intermediary substance between the cathode and anode. They serve as a lithium source that releases lithium ions during initial charging, mediating the lithium transfer process and ensuring that the cathode material retains its lithium content for subsequent cycles
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 particle effectively suppresses the decrease in capacity after initial charging and during repeated cycles, improving the battery's cycle characteristics and maintaining capacity retention.
Implementation Method 1
metal particles generated by desorption of lithium from the lithium alloy particles
Data Source
AI summary
The composite cathode active material particles for a lithium ion battery of the present disclosure have a cathode active material and lithium alloy particles having a lithium alloying potential of 0.5 V (vs Li/Li+) or more and/or metal particles generated by desorption of lithium from the lithium alloy particles, and the lithium alloy particles or the metal particles are dispersed in the cathode active material.