Carbon-Coated Graphite Particles for Li-Ion Cycle Capacity Retention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional graphite particles used as negative electrode materials for lithium ion secondary batteries exhibit insufficient cycle capacity maintaining characteristics.

Innovation Solution

Carbonaceous substance-coated graphite particles are produced by optimizing baking conditions, with specific crystallinity achieved through a method involving attachment of a carbonaceous precursor, followed by first and second baking steps in non-oxidizing and oxidizing atmospheres, resulting in a carbonaceous substance coating with an elastic modulus of 10 GPa or higher.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional graphite particles are used as negative electrode material, then the battery can operate with basic charging-discharging function, but the cycle capacity maintaining characteristic is insufficient

Engineering Contradiction:

Improvecycle capacity maintaining characteristicVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by coating graphite particles with a carbonaceous substance layer. This creates a composite structure where the inner graphite core provides lithium ion insertion/extraction sites while the outer carbonaceous coating layer protects the graphite surface and improves structural stability during cycling, thereby enhancing cycle capacity maintaining characteristics without fundamentally changing the manufacturing process

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs parameter changes by controlling the elastic modulus of the carbonaceous substance coating to be within a specific range (10-50 GPa). This parameter optimization ensures the coating is sufficiently rigid to maintain structural integrity during battery cycling yet flexible enough to accommodate volume changes, directly improving cycle capacity maintaining characteristics

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the carbonaceous substance coating is made thicker to improve cycle capacity maintaining characteristic, then the coating provides better protection, but the elastic modulus requirement becomes harder to maintain and manufacturing complexity increases

Engineering Contradiction:

Improvecycle capacity maintaining characteristicVSAvoidcoating thickness control and elastic modulus uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies that the carbonaceous substance coating must have an elastic modulus within 10-50 GPa, which is a critical parameter control. This modulus range ensures optimal balance between mechanical strength for protection and flexibility for volume accommodation during lithium ion insertion/extraction, improving cycle capacity maintaining characteristics while maintaining manufacturing feasibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by ensuring the carbonaceous substance coating uniformly covers the graphite particle surfaces with consistent elastic modulus properties. This uniform local quality across all particles ensures reliable cycle capacity maintaining characteristics without requiring excessive coating thickness, thereby managing manufacturing precision requirements

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

The carbonaceous substance-coated graphite particles demonstrate excellent cycle capacity maintaining characteristics when used as a negative electrode material, enhancing battery performance.

Implementation Method 1

an elastic modulus determined using a scanning probe microscope is not less than 10 GPa

Methodology Applied

Scientific EffectElastic modulus: Elasticity

Implementation Method 2

an elastic modulus determined using a scanning probe microscope

Methodology Applied

Scientific EffectScanning probe microscopy: Scanning Probe Microscopy

Data Source

PatentEP4678597A1Carbonaceous material-coated graphite particles, negative electrode for lithium ion secondary batteries, lithium ion secondary battery, and method for producing carbonaceous material-coated graphite particles

Publication Date: 2026.01.14 JFE CHEMICAL CORP

Figure 1

AI summary

There is provided carbonaceous substance-coated graphite particles that exhibit an excellent cycle capacity maintaining characteristic when used as a negative electrode material for a lithium ion secondary battery. The carbonaceous substance-coated graphite particles include: graphite particles; and a carbonaceous substance covering at least part of surfaces of the graphite particles. An elastic modulus of the carbonaceous substance-coated graphite particles determined using a scanning probe microscope is not less than 10 GPa.