Graphene-Coated Battery Active Material for Durable High Output

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Solution Overview

Problem

Current electrode active materials for non-aqueous secondary batteries face challenges in achieving sufficient electrical conductivity and durability, particularly in large power devices like electric vehicles, due to uneven graphene adhesion and metal elution during charge and discharge.

Innovation Solution

A method involving the use of a dispersion with a dispersibility index of 0.25 or more, containing graphene and a dispersion medium, is contacted with alkali-metal-transition-metal composite oxide particles to reduce uneven adhesion and improve electrical conductivity, thereby enhancing the durability and output characteristics of the battery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrode active materials with conductive aids are used, then electrical conductivity is improved, but durability deteriorates due to metal elution during charge and discharge

Engineering Contradiction:

ImprovedurabilityVSAvoidmetal elution

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Graphene serves as an intermediary substance that coats the surface of alkali-metal-transition-metal composite oxide particles, preventing direct contact between the metal oxide and electrolyte, thereby eliminating metal elution while maintaining electrical conductivity through the conductive graphene network

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses composite oxide particles consisting of multiple metal elements (alkali metal + transition metal) in specific ratios, creating a composite material structure that inherently reduces metal elution while the graphene coating further enhances both durability and conductivity

Inventive Principle:

Principle #40Composite materials

2Reliability

If graphene is added to improve electrical conductivity, then output characteristics are improved, but manufacturing precision deteriorates due to uneven graphene adhesion

Engineering Contradiction:

Improveelectrical conductivityVSAvoidgraphene adhesion uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention controls specific parameters including graphene concentration (0.1-5 mass%), dispersibility index (0.25 or more), and mixing conditions to achieve uniform graphene distribution and adhesion on particle surfaces, transforming the manufacturing process from imprecise to controlled

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A dispersion medium acts as an intermediary to facilitate uniform distribution of graphene sheets during the coating process, ensuring even adhesion across all particle surfaces and eliminating clumping or uneven coverage

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If high concentration of graphene is used to improve conductivity, then electrical conductivity is improved, but loss of substance increases due to poor dispersibility

Engineering Contradiction:

Improveelectrical conductivityVSAvoidgraphene waste

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The dispersion medium serves as a mediator that maintains graphene sheets in a separated, stable state during mixing and coating, preventing aggregation and ensuring that graphene is utilized efficiently at low concentrations without waste from clumping or precipitation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By optimizing the dispersibility index to 0.25 or more and controlling graphene concentration within 0.1-5 mass%, the invention achieves maximum conductivity enhancement with minimum graphene usage, eliminating the need for high concentrations that would cause aggregation and waste

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 results in improved durability and output characteristics of non-aqueous secondary batteries by ensuring better dispersibility and stability of graphene on the composite oxide particles, reducing metal elution and enhancing electrical conductivity.

Implementation Method 1

contacting a dispersion containing graphene and a dispersion medium with alkali-metal-transition-metal composite oxide particles

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

a dispersion containing graphene and a dispersion medium, wherein the dispersion has a dispersibility index of 0.25 or more

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS12107250B2Method for producing electrode active material for non-aqueous secondary battery

Publication Date: 2024.10.01 NICHIA CORP

AI summary

Provided is a method for producing an electrode active material capable of forming a non-aqueous secondary battery with superior durability and output characteristics. The method for producing an electrode active material for a non-aqueous secondary battery includes contacting a dispersion containing graphene and a dispersion medium with alkali-metal-transition-metal composite oxide particles, and the dispersion has a dispersibility index of 0.25 or more.