Zirconium-Coated Cathode Particles for Crack-Resistant Capacity Retention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional positive electrode active materials for lithium secondary batteries suffer from cracks and fine powder generation due to volume changes during lithium ion intercalation and deintercalation, leading to reduced conductivity and capacity, and existing coatings do not adequately prevent these issues while maintaining capacity.

Innovation Solution

A method of forming a zirconium-containing coating film on the surface and inner interfaces of lithium transition metal oxide particles by mixing the oxide with a zirconium-containing raw material and a sintering aid, followed by heat treatment to create a zirconium coating at both the outer and inner interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional doping or coating with non-transition metal elements is performed to improve physical properties, then thermal stability is improved, but capacity properties are deteriorated due to substitution at transition metal sites

Engineering Contradiction:

Improvethermal stabilityVSAvoidcapacity properties

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by using silane coupling agents specifically at the particle surfaces and interfaces of lithium transition metal oxides, rather than uniform doping throughout the bulk material. This localized approach allows the coating to provide thermal stability at critical stress points without substituting transition metal sites in the crystal lattice, thereby preserving capacity properties.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The silane coupling agent acts as an intermediary substance that forms a protective coating layer between the lithium transition metal oxide particles and the external environment. This intermediary layer prevents direct contact and stress concentration at particle interfaces, improving thermal stability while not interfering with the electrochemical active sites within the bulk material.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional coating is performed to prevent cracks, then thermal stability is improved, but the coating is not capable enough to prevent the generation of cracks and fine powder

Engineering Contradiction:

Improvecrack preventionVSAvoidcoating effectiveness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs silane coupling agents that form dynamic, flexible coating layers adapted to the surface topology of lithium transition metal oxide particles. These coatings can dynamically respond to volume changes during lithium insertion/extraction cycles, maintaining adhesion and preventing crack formation without requiring excessive thickness that would impede lithium ion diffusion.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention creates a composite structure where silane coupling agents form a protective matrix around lithium transition metal oxide particles. This composite coating combines the mechanical strength of the inorganic oxide core with the flexible, adhesive properties of the silane-based organic-inorganic hybrid coating, providing superior crack prevention compared to conventional single-material coatings.

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If volume change is accommodated during charging/discharging, then lithium ion intercalation is enabled, but cracks occur along the interface between primary particles

Engineering Contradiction:

Improvelithium ion intercalationVSAvoidparticle integrity

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The silane coupling agent coating is applied beforehand to the particle surfaces and interfaces, creating a cushioning layer that absorbs and distributes the mechanical stress generated during volume changes. This pre-applied protective layer prevents stress concentration at particle interfaces during lithium insertion and extraction cycles, maintaining particle integrity while enabling full lithium ion intercalation capacity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The zirconium coating effectively prevents cracks and fine powder formation, maintaining the capacity and lifespan of the positive electrode active material, while minimizing capacity reduction.

Implementation Method 1

heat treating the mixture to form a zirconium-containing coating film on the surface of the lithium transition metal oxide secondary particle and at the interface between the primary particles

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

heat treating the mixture to form a zirconium-containing coating film

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS12451481B2Method of producing positive electrode active material for lithium secondary battery and positive electrode active material for lithium secondary battery produced thereby

Publication Date: 2025.10.21 LG CHEM LTD

AI summary

A positive electrode active material contains a lithium transition metal oxide in the form of a secondary particle in which primary particles are aggregated, wherein a zirconium-containing coating film is formed on the surface of the lithium transition metal oxide secondary particle and at the interface between the primary particles present inside the secondary particle. A method of making the positive electrode active material is also provided.