Siloxane Cured Coating for Carbon Anodes With Low Swelling

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Solution Overview

Problem

The use of carbon materials as negative electrode active materials in lithium ion secondary batteries leads to the intercalation of solvated lithium ions, which destroys the graphene structure, reducing battery durability, while additives in the electrolyte cause trade-offs and limitations, and coated carbon materials with siloxane structures have high elution and swelling rates, affecting battery efficiency and productivity.

Innovation Solution

A carbon material with a modifying component, such as boron, aluminum, silicon, phosphorus, or germanium, bonded to the carbon material, promoting desolvation of lithium ions, and a cured product containing polyoxyalkylene and siloxane structures with reduced elution and swelling rates, are used to enhance battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solvated lithium ions are intercalated into the carbon material, then the carbon material can function as a negative electrode active material, but the interlayer inside the graphene structure is destroyed and battery life is shortened

Engineering Contradiction:

Improvebattery lifeVSAvoidgraphene structure integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

A coating layer is formed on the carbon material surface before battery assembly. This coating layer promotes desolvation of lithium ions during initial charge cycles, creating a stable interface that prevents subsequent destruction of the graphene interlayer structure during normal charge-discharge operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A coating layer consisting of specific polymer materials acts as an intermediary between the carbon material and the electrolyte. This intermediate layer facilitates controlled desolvation of lithium ions while protecting the underlying graphene structure from direct contact with solvated ions, thereby maintaining structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If additives are added to the electrolyte to promote desolvation, then lithium ion intercalation is improved, but there are trade-offs and limitations in battery performance

Engineering Contradiction:

Improvedesolvation efficiencyVSAvoidelectrolyte composition flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Instead of adding multiple additives to the electrolyte, a coating layer acts as an intermediary that provides desolvation promotion functionality directly at the electrode surface. This approach achieves the desired effect while maintaining electrolyte composition simplicity and avoiding trade-offs associated with multiple additives.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical approach of adding electrolyte additives is replaced with a physical/structural approach of coating the electrode surface. The coating layer's molecular structure provides the necessary interactions for desolvation without requiring chemical modification of the bulk electrolyte, thereby expanding compositional flexibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If carbon material is coated with siloxane structures to reduce elution, then coating stability is improved, but swelling rate increases and affects productivity

Engineering Contradiction:

Improvecoating stabilityVSAvoidmanufacturing efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

A composite coating layer is formed using specific polymer materials that combine the benefits of low elution rate and controlled swelling. The composite structure achieves coating stability while maintaining appropriate swelling characteristics that do not adversely affect productivity or require excessive drying time.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The coating composition parameters are optimized to achieve the right balance between elution resistance and swelling behavior. By adjusting the specific polymer materials and their ratios, the coating provides sufficient stability while allowing controlled swelling that does not hinder manufacturing efficiency.

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 carbon material ensures stable negative electrode operation with high initial efficiency and reduced side reactions, while the cured product improves battery durability by minimizing elution and swelling, enhancing overall battery performance.

Implementation Method 1

promoting desolvation of lithium ions

Methodology Applied

Scientific EffectDesolvation:

Implementation Method 2

cured product containing polyoxyalkylene and siloxane structures with reduced elution and swelling rates

Methodology Applied

Scientific EffectSwelling:

Data Source

PatentUS20260011730A1Cured product, cured product-containing carbon material, negative electrode, and nonaqueous secondary battery

Publication Date: 2026.01.08 MITSUBISHI CHEM CORP

AI summary

A cured product contains a polyoxyalkylene structure; and a three dimensional siloxane structure containing a Q unit. The cured product has a swelling rate in ethyl methyl carbonate of 70 mass % or less.