Artificial Graphite Anode Composition Against Surface Exfoliation

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Solution Overview

Problem

The surface exfoliation of artificial graphite-based negative electrode active materials in lithium-ion batteries leads to electrolyte side reactions, reducing discharge capacity and initial efficiency due to contact with organic solvents in non-aqueous electrolytes.

Innovation Solution

Incorporating specific amounts of nitrogen, oxygen, and hydrogen elements on the surface and inside artificial graphite particles, adjusting the graphitization degree to prevent exfoliation and enhance discharge capacity while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the graphitization degree of artificial graphite is increased to improve discharge capacity, then discharge capacity is improved, but surface exfoliation occurs due to contact with organic solvents

Engineering Contradiction:

Improvedischarge capacityVSAvoidsurface stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a coating layer comprising oxygen-containing groups and nitrogen-containing groups as an intermediary between the artificial graphite surface and the organic solvent. This coating layer acts as a protective barrier that prevents direct contact between the high-graphitization-degree surface and the solvent, thereby preventing exfoliation while preserving the high discharge capacity enabled by high graphitization degree.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the graphite surface by controlling the content of oxygen-containing groups (3.0-7.0 at%) and nitrogen-containing groups (1.0-5.0 at%). By adjusting these compositional parameters, the surface resistance to organic solvents is enhanced without significantly compromising the discharge capacity, thus resolving the contradiction between capacity and stability.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the graphitization degree is increased to improve initial efficiency, then initial efficiency is improved, but electrolyte side reactions increase due to surface exfoliation

Engineering Contradiction:

Improveinitial efficiencyVSAvoidelectrolyte side reactions

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The coating layer with specific oxygen and nitrogen group contents serves as an intermediary that prevents the high-graphitization-degree surface from directly reacting with the electrolyte. This intermediary layer suppresses electrolyte side reactions that would otherwise occur due to surface exfoliation, while allowing the high initial efficiency to be maintained through efficient lithium ion insertion/extraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potential harm of high graphitization degree (which causes surface exfoliation and electrolyte side reactions) into a benefit by applying a controlled coating. The high graphitization degree provides excellent lithium ion conductivity for high initial efficiency, while the coating layer compensates for the exfoliation tendency, effectively converting the harmful effect into a beneficial structure.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Use of energy by moving object

If artificial graphite is used as negative electrode active material, then high energy density is achieved, but surface exfoliation and electrolyte side reactions occur

Engineering Contradiction:

Improveenergy densityVSAvoidsurface stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The coating layer comprising oxygen-containing and nitrogen-containing groups acts as an intermediary protective layer on the artificial graphite surface. This layer maintains the high energy density characteristics of artificial graphite while preventing surface exfoliation and reducing electrolyte side reactions, thus resolving the contradiction between energy density and surface stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure by combining artificial graphite with a coating layer containing oxygen and nitrogen functional groups. This composite material retains the high energy density of artificial graphite while the coating provides enhanced surface stability and resistance to electrolyte degradation, effectively combining the advantages of both components.

Inventive Principle:

Principle #40Composite materials

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 solution effectively prevents surface exfoliation, reduces electrolyte side reactions, and enhances discharge capacity and initial efficiency of lithium-ion batteries.

Implementation Method 1

The nitrogen element, the oxygen element, and the hydrogen element may be doped in the artificial graphite particles

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS20250210657A1Negative electrode active material, negative electrode, and secondary battery including the same

Publication Date: 2025.06.26 LG ENERGY SOLUTION LTD

AI summary

A negative electrode active material includes artificial graphite particles; and a nitrogen element, an oxygen element, and a hydrogen element present on a surface, on an inside, or on the surface and the inside of the artificial graphite particle. The nitrogen element is included in an amount of about 80 mg to 180 mg per 1 kg of the negative electrode active material.