Cathode Active Material Composition for Uniform Li-Ion Battery Cycling

Solution Overview

Problem

The cycling stability of ternary positive electrode active materials in lithium-ion batteries, such as lithium nickel cobalt manganese oxide (NCM) and lithium nickel cobalt aluminum oxide (NCA), needs improvement due to non-uniform degradation of secondary particles of different sizes during battery cycling.

Innovation Solution

A positive electrode active material with a controlled chemical composition and particle size distribution is developed, where the Ni content is higher in smaller particles and balanced with other elements to ensure uniform structural stability across different particle sizes, enhancing cycling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If ternary positive electrode active materials are used to achieve high capacity, then the energy density is improved, but the cycling stability deteriorates due to non-uniform degradation of secondary particles of different sizes

Engineering Contradiction:

Improveenergy densityVSAvoidcycling stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform distribution of Ni content across particles of different sizes. Specifically, smaller secondary particles (D10) have higher Ni content (X1) while larger secondary particles (D90) have lower Ni content (X2), with the difference (X1-X2) controlled within 0.005-0.07. This local compositional variation compensates for the size-dependent degradation behavior, improving overall cycling stability while maintaining high energy density

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by systematically adjusting the Ni content parameter (X value) as a function of particle size. The chemical composition is optimized with Li1+a[NixCo yM1zM2b]O2±cAd where the Ni content varies between particles: X1 for smaller particles and X2 for larger particles. This parameter optimization balances structural stability across the particle size distribution, resolving the cycling stability issue while preserving high capacity

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If the Ni content is increased to improve capacity, then the specific capacity is improved, but the structural stability of particles deteriorates leading to non-uniform degradation

Engineering Contradiction:

Improvespecific capacityVSAvoidstructural stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a non-uniform distribution of Ni content across particles of different sizes. Specifically, smaller secondary particles (D10) have higher Ni content (X1) while larger secondary particles (D90) have lower Ni content (X2), with the difference (X1-X2) controlled within 0.005-0.07. This local compositional variation compensates for the size-dependent degradation behavior, improving overall cycling stability while maintaining high energy density

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by systematically adjusting the Ni content parameter (X value) as a function of particle size. The chemical composition is optimized with Li1+a[NixCo yM1zM2b]O2±cAd where the Ni content varies between particles: X1 for smaller particles and X2 for larger particles. This parameter optimization balances structural stability across the particle size distribution, resolving the cycling stability issue while preserving high capacity

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach improves the cycling stability and capacity retention of lithium-ion batteries by maintaining balanced structural stability among secondary particles, thereby extending battery life and maintaining capacity.

Implementation Method 1

improving the structural stability of ternary positive electrode active materials and improving the cycling performance of lithium-ion batteries

Methodology Applied

Scientific EffectStructural stability:

Implementation Method 2

sintering the mixed material in an oxygen or air atmosphere to obtain the positive electrode active material

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentEP4718535A1Positive electrode active material and preparation method therefor, and lithium ion battery

Publication Date: 2026.04.01 NINGBO RONBAY LITHIUM BATTERY MATERIAL CO LTD

AI summary

A positive electrode material, a preparation method thereof and a lithium-ion battery are provided. A first aspect provides a positive electrode active material, where a chemical composition of the positive electrode active material is Li1+a[NixCoyMlzM2b]O2±cAd, M1 is one or two of Mn or Al, M2 is one or more of Zr, Mg, Ti, Te, Al, Ca, Sr, Sb, Nb, Pb, V, Ge, Se, W, Mo, Zn, Ce, or Y; and A is one of F, Cl, or S. By controlling the Ni content in secondary particles of different particle sizes, the problem of non-uniform degradation of the secondary particles of different particle sizes during battery cycling can be avoided, thereby improving the cycling stability of lithium-ion batteries.