Lithium Battery Design for Quick Charging and Longevity
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Summary
Problems
Existing lithium secondary batteries face challenges in achieving excellent quick charging performance, lifespan characteristics, and energy density, particularly due to issues like structural collapse of positive electrode active materials, transition metal elution, gas generation, and non-uniform reactions between silicon-based negative electrode active materials.
Innovation solutions
The use of an overlithiated manganese-based oxide with a low cobalt content as the positive electrode active material and a silicon-based negative electrode active material, which compensates for irreversible capacity and reduces oxygen-redox reactions, thereby stabilizing the battery performance.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If silicon-based negative electrode active material is used to increase capacity, then energy density is improved, but irreversible capacity increases causing lifespan deterioration
Why choose this principle:
The patent applies pre-lithiation technology by forming a lithium-rich compound layer on the silicon-based negative electrode active material surface before battery assembly. This preliminary action compensates for the irreversible capacity loss that occurs during initial charging cycles, ensuring that sufficient lithium ions are available for subsequent cycles and maintaining both high energy density and extended lifespan.
Principle concept:
If high voltage is applied to increase energy density, then capacity is improved, but structural collapse and transition metal elution occur
Why choose this principle:
The patent employs a composite positive electrode active material consisting of layered oxide and spinel oxide components. The layered oxide provides high capacity at high voltage, while the spinel oxide component enhances structural stability and suppresses transition metal elution. This composite structure enables the battery to achieve high energy density while maintaining structural integrity and reliability during cycling.
Application Domain
Data Source
AI summary:
The use of an overlithiated manganese-based oxide with a low cobalt content as the positive electrode active material and a silicon-based negative electrode active material, which compensates for irreversible capacity and reduces oxygen-redox reactions, thereby stabilizing the battery performance.
Abstract
A lithium secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode includes a positive electrode active material layer having a positive electrode active material containing an overlithiated manganese-based oxide represented by Formula 1 below, and the negative electrode includes a negative electrode active material layer having a silicon-based negative electrode active material. [Formula 1] LiaNibCocMndMeO2 In Formula 1 above, 1<a, 0≤b≤0.5, 0≤c≤0.1, 0.5≤d<1.0, and 0≤e≤0.2 are satisfied, and M is at least one selected from the group consisting of Al, B, Co, W, Mg, V, Ti, Zn, Ga, In, Ru, Nb, Sn, Sr, and Zr. Preferably, in Formula 1 above, 1.1≤a≤1.5, 0.1≤b≤0.4, 0≤c≤0.05, 0.5≤d≤0.80, and 0≤e≤0.1 may be satisfied.