High-Nickel Cathode Material with Grain Control for Stable Capacity
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Solution Overview
Problem
High-nickel cathode active materials for lithium secondary batteries face issues with structural stability and conductivity due to cation mixing, leading to reduced battery life and capacity, especially in applications requiring high energy density.
Innovation Solution
A cathode active material comprising lithium metal oxide particles with a specific nickel and cobalt content, along with doping elements like Mg, Al, and Y, is developed, featuring a controlled grain size and concentration gradient, enhancing stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel content in cathode active material is increased to secure high capacity, then energy density is improved, but structural stability deteriorates due to cation mixing
Solution Approach 1:
The patent applies local quality by creating a concentration gradient of nickel and cobalt within the particle structure. The surface region has different composition than the core, with controlled nickel content distribution that prevents cation mixing at critical interfaces while maintaining high overall nickel content for energy density. This localized compositional variation resolves the contradiction between high energy density and structural stability.
Solution Approach 2:
The patent uses composite material strategy by combining nickel-rich and cobalt-rich regions within a single particle structure. This internal composite design allows different regions to fulfill different functions: nickel-rich zones provide high capacity while cobalt-rich zones maintain structural stability, effectively resolving the contradiction through material composition design.
2Quantity of substance
If nickel content is increased to achieve high capacity, then battery capacity is improved, but conductivity deteriorates
Solution Approach 1:
The patent implements local quality by creating regions with optimized nickel and cobalt concentrations throughout the particle. Certain zones maintain higher cobalt content to ensure adequate electronic conductivity, while other zones maximize nickel content for capacity. This spatially varying composition resolves the contradiction between high capacity and conductivity by allowing both properties to coexist in different locations within the same material.
3Ease of manufacture
If cobalt content is reduced for economic feasibility, then production cost is improved, but stability and life characteristics deteriorate
Solution Approach 1:
The patent applies local quality by strategically distributing cobalt only in specific regions where it provides maximum stabilizing effect, rather than uniformly throughout the entire particle. This localized cobalt placement maintains battery life and stability characteristics while minimizing overall cobalt content, thereby reducing production cost. The concentration gradient ensures cobalt is present where most needed for structural integrity.
Solution Approach 2:
The patent uses parameter changes by precisely controlling the concentration gradient profile of nickel and cobalt within the particle structure. By adjusting the spatial distribution parameters of these elements, the patent achieves optimal balance between cost (reduced total cobalt) and performance (maintained stability through strategic cobalt placement). The concentration gradient serves as a controllable parameter that resolves the contradiction.
Data Source
AI summary
A cathode active material for secondary battery according to the present disclosure includes lithium metal oxide particles. The lithium metal oxide particles include nickel, include or do not include cobalt, and have a single particle structure. Based on a total number of moles of elements excluding lithium and oxygen in the lithium metal oxide particles, a content of nickel is 70 mol % to 85 mol %, and a content of cobalt is 0.1 times or less than the content of nickel. A (104) plane grain size of the lithium metal oxide particles calculated through X-ray diffraction (XRD) analysis is 400 nm to 700 nm.