Pressure-Resistant Cathode Material for Low-Swelling Li-Ion Cycling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium-ion batteries face issues with particle crushing during cycling due to high nickel content, leading to deteriorated cycle performance and volume swelling, which is a bottleneck for their application in traction batteries.

Innovation Solution

A positive active material with secondary particles composed of primary particles, featuring a compact structure and high pressure-resistant strength, along with an outer and inner coating layer to enhance mechanical stability and ionic conductivity, is developed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If nickel content of high nickel ternary positive electrode material is increased to improve energy density, then energy density is improved, but cycle performance deteriorates due to aggravated side reactions between positive active material and electrolyte

Engineering Contradiction:

Improveenergy densityVSAvoidcycle performance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A coating layer comprising Li2SiO3 and Li4SiO4 is formed on the surface of the positive active material particles. This coating layer acts as an intermediary barrier between the high nickel content positive active material and the electrolyte, preventing direct contact and side reactions while allowing lithium ion transport, thus maintaining both high energy density and good cycle performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The positive electrode material is designed as a composite structure with the positive active material (high nickel content) core and a protective coating shell. The coating layer combines Li2SiO3 and Li4SiO4 in specific ratios to create a composite material that provides both protection against side reactions and efficient lithium ion conductivity, resolving the contradiction between high nickel content and cycle stability

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If high nickel content positive active material is used to improve energy density, then energy density is improved, but particle crushing occurs during cycling leading to deteriorated cycle performance

Engineering Contradiction:

Improveenergy densityVSAvoidparticle strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

A protective coating layer of Li2SiO3 and Li4SiO4 is applied beforehand to the surface of the high nickel positive active material particles. This coating layer serves as a cushioning protective layer that prevents particle crushing during cycling while maintaining the high energy density benefits of high nickel content material

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The coating layer composition parameters are precisely controlled with Li2SiO3 content at 20-80 wt% and Li4SiO4 content at 20-80 wt%. By optimizing these compositional parameters, the coating layer achieves the right balance between mechanical strength to prevent particle crushing and ionic conductivity to maintain high energy density performance

Inventive Principle:

Principle #35Parameter changes

3Reliability

If coating modification techniques are applied to improve cycle performance, then cycle performance is improved to some extent, but volume swelling rate increases and kinetic performance deteriorates

Engineering Contradiction:

Improvecycle performanceVSAvoidvolume swelling rate

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The coating layer is designed with specific local compositional quality, containing Li2SiO3 and Li4SiO4 in optimized ratios (each 20-80 wt%). This localized compositional control ensures the coating provides protection against volume swelling while maintaining good lithium ion kinetics, achieving cycle performance improvement without the trade-offs of excessive swelling or kinetic deterioration

Inventive Principle:

Principle #3Local quality

4Use of energy by moving object

If high nickel content positive active material is used, then energy density is improved, but direct side reactions with electrolyte aggravate leading to deteriorated cycle performance

Engineering Contradiction:

Improveenergy densityVSAvoidside reactions with electrolyte

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260031347A1Pressure-resistant positive active material and electrochemical energy storage apparatus

Publication Date: 2026.01.29 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

This application relates to the field of battery technologies, and in particular, to a pressure-resistant positive active material and an electrochemical energy storage apparatus. The positive active material includes secondary particles composed of primary particles, and a quantity σ of primary particles per unit sphere area in a SEM graph of the secondary particles is 5/μm2 to 30/μm2. A single-particle pressure-resistant strength of the secondary particles is 60 MPa to 300 MPa. A molecular formula of the positive active material is LixNiyCOzMkMepOrAm, where 0.95≤x≤1.05, 0≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤2, 0≤m≤2, and m+r≤2. The positive active material in this application has a compact particle structure and a high single-particle pressure-resistant strength. A lithium-ion battery using the positive active material in this application has good cycle performance, a low volume swelling rate, and good kinetic performance.