Manganese Spinel Composite Cathode for High-Power Lithium Batteries
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Solution Overview
Problem
Lithium manganese composite oxide cathodes in lithium secondary batteries suffer from manganese ion dissolution at high temperatures and large currents, leading to degradation and limited cycle life, and have low charge density, making them unsuitable for electric vehicles requiring long-term high-power output and safety.
Innovation Solution
A cathode active material comprising a mixture of lithium/nickel/cobalt/manganese composite oxide and manganese spinel oxide with specific anion substitution, enhancing binding ability and structural stability to improve lifespan and safety at both room and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium manganese composite oxide is used as cathode material, then safety and cost are improved, but manganese ion dissolution occurs at high temperature and large current leading to degradation
Solution Approach 1:
The patent uses a composite cathode material consisting of lithium manganese composite oxide with spinel structure combined with lithium nickel composite oxide or lithium cobalt composite oxide. This composite structure prevents manganese ion dissolution while maintaining safety and cost benefits, resolving the contradiction between reliability and compositional stability.
Solution Approach 2:
The patent modifies the chemical composition parameters of the lithium manganese composite oxide by controlling the ratios of Mn, Ni, and Co elements, and adjusting the oxygen content. These parameter changes enhance structural stability at high temperatures and prevent manganese ion dissolution, while maintaining the safety advantages of manganese-based materials.
2Reliability
If lithium manganese composite oxide is used as cathode material, then cost and safety are improved, but charge density decreases compared to lithium cobalt or lithium nickel composite oxides
Solution Approach 1:
The patent creates a composite cathode material that combines lithium manganese composite oxide (providing safety and cost benefits) with lithium nickel composite oxide or lithium cobalt composite oxide (providing high charge density). This composite structure achieves both safety and high charge density simultaneously.
Solution Approach 2:
The patent applies different material compositions to different regions or phases of the cathode structure, allowing the lithium manganese component to provide safety while the lithium nickel or cobalt components provide high charge density in specific active regions, achieving local optimization of both properties.
3Power
If high-current charge and discharge cycles are repeated, then power output is improved, but lifespan decreases even under severe conditions
Solution Approach 1:
The patent employs a composite cathode material structure that preemptively protects against degradation during high-current cycling. The stable spinel structure of lithium manganese composite oxide acts as a protective framework that prevents structural collapse and material dissolution during severe charge/discharge cycles, cushioning the impact on lifespan.
Solution Approach 2:
The composite cathode material combines the high power output capability of lithium nickel or cobalt composite oxides with the structural stability of lithium manganese composite oxide. This composite structure enables sustained high-power operation while maintaining long lifespan even under severe cycling conditions.
Data Source
AI summary
Provided is a high-power, non-aqueous electrolyte lithium secondary battery having a long lifespan and superior safety at both room temperature and high temperatures, even after repeated high-current charging and discharging. The battery comprises a mixture of a manganese spinel oxide and a lithium/nickel/cobalt/manganese composite oxide, as a cathode active material.