Fluorine-Modified Graphene Negative Electrode for Battery Cycle Life

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Solution Overview

Problem

Current lithium-ion secondary batteries face challenges in maintaining the stability and performance of negative electrode active materials, leading to deterioration and reduced cycle life, especially due to irreversible reactions with the electrolyte.

Innovation Solution

A method involving a negative electrode active material with a conductive additive containing a graphene compound modified with fluorine, where the graphene compound has a two-dimensional structure and is used in conjunction with a metal or compound like silicon, tin, or gallium, and a halogen such as fluorine, to inhibit surface reactions and enhance charge/discharge efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional negative electrode active material is used, then the battery can operate, but the material deteriorates due to irreversible reactions with the electrolyte, reducing cycle life

Engineering Contradiction:

Improvecycle lifeVSAvoidirreversible reactions with electrolyte

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A coating layer comprising silicon oxide and fluorine is formed on the surface of the negative electrode active material. This coating layer acts as an intermediary between the active material and the electrolyte, preventing direct contact and irreversible reactions while allowing lithium ion transport, thereby improving cycle life without sacrificing capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface composition and chemical properties of the negative electrode active material are modified by forming a coating layer with specific composition (silicon oxide and fluorine). This changes the surface parameters to reduce reactivity with the electrolyte while maintaining electrochemical performance, addressing the deterioration issue

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the negative electrode active material surface is modified to prevent reactions, then stability improves, but charge/discharge efficiency may be reduced

Engineering Contradiction:

Improvesurface stabilityVSAvoidcharge/discharge rate

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The coating layer is designed with controlled porosity and thickness to allow lithium ion diffusion while providing surface protection. The porous structure enables efficient ion transport pathways, maintaining high charge/discharge rates even with the protective coating in place

Inventive Principle:

Principle #31Porous 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 approach results in a negative electrode active material with improved stability and performance, reducing deterioration and increasing the cycle life of lithium-ion secondary batteries by inhibiting irreversible reactions and facilitating high charge/discharge rates.

Implementation Method 1

the graphene compound contains fluorine... to inhibit surface reactions

Methodology Applied

Scientific EffectSurface passivation by fluorine:

Implementation Method 2

the conductive additive contains a graphene compound... facilitating high charge/discharge rates

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20230216051A1Electrode, negative electrode active material, vehicle, electronic device, and method for manufacturing negative electrode active material

Publication Date: 2023.07.06 SEMICON ENERGY LAB CO LTD

AI summary

A negative electrode active material particle with little deterioration is provided. Alternatively, a novel negative electrode active material particle is provided. Alternatively, a power storage device with little deterioration is provided. Alternatively, a highly safe power storage device is provided. Alternatively, a novel power storage device is provided. The electrode includes an active material and a conductive additive; the active material contains a metal or a compound including one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium; the conductive additive contains a graphene compound; and the graphene compound contains fluorine.