Lithium Boron Oxide Coating for Cathode Impurity Removal

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium secondary batteries face rapid lifetime degradation and electrolyte decomposition issues due to impurities and moisture, leading to increased internal resistance, which existing surface coating methods like H3BO3 application do not fully address.

Innovation Solution

A method involving dry mixing of lithium transition metal oxide with a boron-containing compound followed by heat treatment near the melting point of the compound to form a structurally stable lithium boron oxide coating, which transforms lithium impurities and provides a uniform coating layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the surface of cathode active material is coated with H3BO3 by mixing with shaker, then coating is applied, but H3BO3 particles agglomerate on the surface

Engineering Contradiction:

Improvecoating uniformityVSAvoidparticle distribution

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The invention changes the physical state parameter of H3BO3 from solid particles to aqueous solution form, and changes the application method from dry mixing to wet coating followed by drying. This parameter transformation prevents particle agglomeration and achieves uniform coating distribution on the cathode active material surface.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces water as an intermediary medium to dissolve H3BO3, creating an aqueous coating solution. This intermediary enables uniform distribution of boron compounds on the cathode surface without direct particle-particle contact, thereby preventing agglomeration while achieving complete surface coverage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If H3BO3 is added in predetermined amount or more for coating, then coating coverage increases, but amount of coating layer does not increase

Engineering Contradiction:

Improvecoating coverageVSAvoidcoating layer amount

Core Design Contradiction:

Area of stationary objectVSQuantity of substance

Solution Approach 1:

The invention replaces mechanical mixing and coating methods with a chemical dissolution and evaporation process. By dissolving H3BO3 in water to form a uniform solution and then applying it, the coating amount can be precisely controlled through solution concentration and volume, rather than relying on mechanical distribution of solid particles.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If surface coating is applied to address impurity issues, then battery lifetime improves, but electrolyte decomposition and gas generation are not fully resolved

Engineering Contradiction:

Improvebattery lifetimeVSAvoidelectrolyte decomposition

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention applies coating with specific compositional quality (boron-containing compounds in aqueous solution) to the surface of cathode active material to create a protective layer with specific functional properties. This localized treatment addresses surface-related issues such as impurity reactions and electrolyte decomposition at the cathode-electrolyte interface, thereby improving battery reliability and reducing harmful effects.

Inventive Principle:

Principle #3Local quality

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 method effectively reduces lithium impurities by 30-70% and enhances the electrochemical properties of lithium secondary batteries by forming a uniform lithium boron oxide coating that suppresses side reactions and improves high-temperature storage and cycle characteristics.

Implementation Method 1

performing a heat treatment near the melting point of the compound

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

transform lithium impurities present in a lithium transition metal oxide into a structurally stable lithium boron oxide

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS10529985B2Cathode active material for lithium secondary battery

Publication Date: 2020.01.07 LG ENERGY SOLUTION LTD

AI summary

Provided are a method of preparing a cathode active material including coating a surface of a lithium transition metal oxide with a lithium boron oxide by dry mixing the lithium transition metal oxide and a boron-containing compound and performing a heat treatment, and a cathode active material prepared thereby.A method of preparing a cathode active material according to an embodiment of the present invention may easily transform lithium impurities present in a lithium transition metal oxide into a structurally stable lithium boron oxide by performing a heat treatment near the melting point of a boron-containing compound.Also, a coating layer may be formed in which the lithium boron oxide is uniformly coated in an amount proportional to the used amount of the boron-containing compound even at a low heat treatment temperature.