Lithium Manganese Composite Cathode Stabilization
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Solution Overview
Problem
Lithium manganese composite oxide cathodes used in electric vehicle batteries suffer from manganese elution at high temperatures, leading to deteriorated battery properties and limited capacity per battery weight, necessitating a solution for enhanced stability and lifespan.
Innovation Solution
A cathode composition combining lithium nickel-manganese-cobalt composite oxide with lithium manganese oxide, incorporating lithium carbonate and lithium hydroxide in specific amounts to stabilize the structure and minimize manganese elution, along with a 6-coordinated metal structure substitution, to improve thermal stability and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium manganese composite oxide is used as cathode material, then cost is reduced and stability is improved, but manganese is eluted at high temperature deteriorating battery properties
Solution Approach 1:
The patent uses a composite cathode material consisting of lithium manganese composite oxide (spinel structure) combined with lithium nickel cobalt manganese composite oxide (layered structure). This composite approach allows the spinel component to provide stability and low cost, while the layered component prevents manganese elution through its structural characteristics, thus resolving the contradiction between stability and manganese elution.
Solution Approach 2:
The patent optimizes the composition parameters of the composite material, specifically controlling the molar ratio of lithium manganese composite oxide to lithium nickel cobalt manganese composite oxide within 95:5 to 50:50. Additionally, aluminum substitution in the spinel structure is controlled at 0.01 to 0.5 moles per formula unit. These parameter optimizations enhance thermal stability while minimizing manganese elution.
2Quantity of substance
If lithium manganese composite oxide is used, then cost is reduced, but capacity per battery weight is limited
Solution Approach 1:
The composite structure combines lithium manganese composite oxide (providing stability and low cost) with lithium nickel cobalt manganese composite oxide (providing high capacity). This allows the battery to achieve both cost-effectiveness and high capacity per battery weight, while maintaining stability through the spinel component.
3Quantity of substance
If lithium cobalt composite oxide is used, then capacity per battery weight is high, but cost is extremely high and stability is poor
Solution Approach 1:
The patent creates a composite where lithium manganese composite oxide (low cost, stable) serves as the base material, and lithium nickel cobalt manganese composite oxide (high capacity) is added in controlled amounts (5-50 moles per 100 moles of spinel). This composite achieves a balance: cost is reduced compared to pure lithium cobalt oxide, stability is improved through the spinel structure, and capacity is maintained through the layered component.
Solution Approach 2:
The patent optimizes the compositional parameters to achieve the desired balance. Specifically, the ratio of lithium nickel cobalt manganese composite oxide is controlled at 5-50 moles per 100 moles of lithium manganese composite oxide, and aluminum substitution is optimized at 0.01-0.5 moles per formula unit. These parameter changes enable the material to simultaneously achieve low cost, high stability, and adequate capacity.
Data Source
AI summary
Provided is a cathode for lithium secondary batteries comprising a combination of one or more compounds selected from Formula 1 and one or more compounds selected from Formula 2. The cathode provides a high power lithium secondary battery composed of a non-aqueous electrolyte which exhibits long lifespan, long-period storage properties and superior stability at ambient temperature and high temperatures.