Tungsten-Penetrated High-Nickel Cathode Material for Cycle Stability
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Solution Overview
Problem
Lithium secondary batteries with high nickel content in their cathode active materials face challenges in structural stability and lifespan due to increased resistance and surface reactions during repeated charging and discharging.
Innovation Solution
A cathode active material for lithium secondary batteries is developed, comprising lithium-nickel metal oxide particles with a tungsten compound penetration region between primary particles, enhancing lithium ion conductivity and structural stability, and formulated with specific chemical compositions and processing methods to maintain stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel content is increased to increase battery capacity, then battery capacity is improved, but structural stability and lifespan properties are lowered
Solution Approach 1:
The patent applies local quality by creating a penetration region with tungsten compound that extends from the surface to 70% or less of the particle radius, concentrating the stabilizing effect in specific internal regions where primary particles aggregate, rather than uniformly distributing additives throughout the entire particle structure
Solution Approach 2:
The patent uses composite materials by combining lithium-nickel metal oxide with tungsten compound to form a multi-component cathode active material. The tungsten compound penetrates into the particle interior to form a penetration region that stabilizes the high-nickel structure, creating a composite system that maintains both high capacity and structural stability
2Quantity of substance
If nickel content is increased to increase battery capacity, then battery capacity is improved, but lifespan properties are lowered
Solution Approach 1:
The penetration region with tungsten compound is localized to extend from the surface to 70% or less of the particle radius, providing targeted stabilization at critical interfaces between primary particles where degradation typically initiates, thereby extending battery lifespan without compromising overall capacity
Solution Approach 2:
The composite of lithium-nickel metal oxide and tungsten compound creates a stabilized structure that resists degradation during repeated charging-discharging cycles. The tungsten compound forms a protective penetration region that prevents structural collapse, thereby extending the operational lifespan of high-capacity batteries
3Quantity of substance
If nickel content is increased, then battery capacity is improved, but resistance increases during repeated charging and discharging
Solution Approach 1:
The tungsten compound penetration region is strategically positioned from the surface to 70% or less of the particle radius, targeting the internal aggregation zones where resistance typically increases during cycling. This localized treatment maintains low resistance at critical interfaces while preserving high nickel content for capacity
Solution Approach 2:
The composite material system combines high-nickel lithium metal oxide with tungsten compound to create a stable conductive network. The tungsten compound in the penetration region maintains electrical connectivity and reduces resistance growth during repeated charging-discharging cycles, ensuring reliable performance
Data Source
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AI summary
A cathode active material for a lithium secondary battery includes a lithium-nickel metal oxide particle having a form of a secondary particle in which a plurality of primary particles are aggregated therein. The lithium-nickel metal oxide particle includes a penetration region formed in an area extending from a surface to a point 70% or less of a radius of the particle in a direction to a center of the particle. The penetration region includes a tungsten compound at an interface between the primary particles. A relative standard deviation (RSD) value calculated from results of measuring a tungsten content from the surface of the secondary particle to a depth of 10 nm 10 times at different points using an X-ray Photoelectron Spectroscopy (XPS) is in a range from 10% to 40%.