Lithium Metal Oxide Cathode Coated with Water-Soluble Polymer

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving long life-span and high capacity due to non-uniform chemical structures in lithium metal oxide cathode active materials, which are prone to damage during charging and discharging, and existing methods for removing lithium salt impurities are insufficient.

Innovation Solution

A cathode active material for lithium secondary batteries is developed, comprising a lithium metal oxide particle core with a water-soluble polymer coating layer, including cationic or anionic polymers, which forms bonds between particles to enhance structural stability and remove impurities, thereby improving capacity and life-span retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If water washing is used to remove lithium salt impurities, then impurity removal is attempted, but surface damage to particles occurs and impurity removal is insufficient

Engineering Contradiction:

Improvelithium salt impurity removalVSAvoidparticle surface damage

Core Design Contradiction:

Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the washing solution by introducing organic acids (acetic acid, formic acid, propionic acid) and their derivatives. This chemical parameter modification enables effective removal of lithium salt impurities while preventing particle surface damage, resolving the contradiction between impurity removal efficiency and particle integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses organic acids as intermediary substances in the washing process. These acids act as mediators that selectively react with lithium salt impurities to form soluble complexes, enabling impurity removal without direct mechanical or chemical damage to the particle surface

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If lithium metal oxide structure is maintained during charging and discharging, then capacity retention is improved, but structural deformation and damage occur reducing life-span stability

Engineering Contradiction:

Improvebattery life-spanVSAvoidlithium metal oxide structure stability

Core Design Contradiction:

Duration of action of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies organic acid treatment before battery operation to pre-protect the lithium metal oxide surface. This beforehand treatment creates a protective effect that cushions against structural deformation during subsequent charging and discharging cycles, improving both life-span and structural stability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent modifies the chemical parameters of the lithium metal oxide surface through organic acid treatment, changing surface chemistry to reduce susceptibility to degradation. This parameter change enhances structural stability during electrochemical cycling while maintaining long-term durability

Inventive Principle:

Principle #35Parameter changes

3Reliability

If non-uniform chemical structure is prevented in lithium metal oxide, then desired capacity and life-span are achieved, but precipitation of lithium occurs causing structural issues

Engineering Contradiction:

Improvebattery operational stabilityVSAvoidlithium metal oxide chemical uniformity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses organic acid treatment to modify chemical parameters at the particle surface and interface regions. This treatment prevents lithium precipitation by altering local chemical environment, maintaining compositional uniformity and preventing non-uniform chemical structure formation that would compromise reliability

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

The use of a water-soluble polymer coating significantly improves the structural stability and capacity retention of lithium metal oxide particles, reducing surface damage and maintaining high electrical properties, leading to enhanced performance in lithium secondary batteries.

Implementation Method 1

a water-soluble polymer coating layer configured to cover at least a portion of the core part

Methodology Applied

Scientific EffectCoating: Coatings

Implementation Method 2

washing the lithium metal oxide particle with a cleaning solution including a water-soluble polymer

Methodology Applied

Scientific EffectWashing:

Data Source

PatentUS20220293936A1Cathode Active Material for Lithium Secondary Battery and Method of Manufacturing the Same

Publication Date: 2022.09.15 SK ON CO LTD

AI summary

Provided is a cathode active material for a lithium secondary battery and a method of manufacturing the same. The cathode active material for a lithium secondary battery includes a lithium metal oxide particle and a water-soluble polymer, and may have a secondary particle structure in which the lithium metal oxide particle and the water-soluble polymer are aggregated.