Lithium Nickel Composite Oxide Battery High-Temperature Cycle Stability
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Solution Overview
Problem
Lithium ion secondary batteries with high Ni content in the positive electrode material suffer from inadequate cycle characteristics and capacity reduction over repeated charge and discharge cycles, especially at high temperatures, limiting their long-term reliability and versatility across various temperature conditions.
Innovation Solution
A lithium ion secondary battery design featuring a positive electrode with lithium nickel composite oxide (LiNixCoyMnzO2) where x, y, and z are within specific ranges (0.75≤x≤0.85, 0.05≤y≤0.15, and 0.10≤z≤0.20), combined with artificial graphite and hardly graphitizable carbon in the negative electrode, and an optimized electrolyte solution, including halogenated cyclic carbonates and disulfonic acid esters, to enhance cycle stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high Ni content lithium nickel composite oxide is used in the positive electrode, then initial discharge capacity and energy density are improved, but cycle characteristics deteriorate and discharge capacity reduces during repeated charge and discharge
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters x, y, and z in the formula LiNixCoyMnzO2 within specific ranges (0.75≤x≤0.85, 0.05≤y≤0.15, 0.10≤z≤0.20). This optimization of chemical composition parameters achieves a balance between high initial discharge capacity and excellent cycle characteristics, resolving the contradiction between capacity and reliability.
Solution Approach 2:
The patent uses composite materials by combining multiple metal elements (Ni, Co, Mn) in specific proportions within the lithium nickel composite oxide structure. This multi-element composite approach leverages the high capacity of Ni while Co and Mn provide structural stability, thereby maintaining both high discharge capacity and good cycle characteristics over repeated charge-discharge cycles.
2Quantity of substance
If high Ni content lithium nickel composite oxide is used in the positive electrode, then energy density is improved, but capacity retention at high temperature deteriorates
Solution Approach 1:
The patent optimizes the compositional parameters within specific ranges to achieve high energy density while maintaining stability at high temperatures. The controlled proportions of Ni (0.75-0.85), Co (0.05-0.15), and Mn (0.10-0.20) create a composition that balances high capacity with thermal stability, preventing excessive capacity degradation at elevated temperatures.
Solution Approach 2:
The multi-element composite oxide structure combines the high energy density contribution from Ni with the thermal stability provided by Co and Mn. This composite material approach enables the battery to maintain high energy density while achieving improved capacity retention under high temperature conditions.
3Quantity of substance
If high Ni content lithium nickel composite oxide is used in the positive electrode, then initial discharge capacity is improved, but long-term reliability deteriorates
Solution Approach 1:
The patent employs parameter changes by defining specific ranges for the compositional parameters (x: 0.75-0.85, y: 0.05-0.15, z: 0.10-0.20) to optimize both initial discharge capacity and long-term reliability. This precise parameter control ensures that the battery maintains high capacity from the start while preserving reliability over extended operational periods.
Solution Approach 2:
The composite lithium nickel cobalt manganese oxide material combines the high capacity advantage of nickel-rich compositions with the stability benefits of cobalt and manganese. This composite structure delivers high initial discharge capacity while ensuring long-term reliability through repeated charge-discharge cycles.
Data Source
AI summary
There is provided a lithium ion secondary battery having excellent cycle characteristics at a high temperature and comprising lithium nickel composite oxides, in which the Ni content is high, in a positive electrode. The present invention relates to a lithium ion secondary battery having a positive electrode, a negative electrode and an electrolyte solution, wherein the positive electrode comprises a lithium nickel complex oxide denoted by the general formula, LiNixCoyMnzO2, wherein x, y, and z are respectively 0.75≤x≤0.85, 0.05≤y≤0.15, and 0.10≤z≤0.20.