Silicon-Graphene Electrode Structure for Stable Li-Ion Battery Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary batteries, particularly those used in electric vehicles and portable terminals, face challenges in increasing capacity, stability, and energy density while maintaining mechanical integrity and preventing deterioration.
Innovation Solution
The development of an electrode comprising particles terminated with functional groups and a sheet-like graphene compound that cling through hydrogen bonds, enhancing conductivity and mechanical stability, and a manufacturing method involving silicon and lithium fluoride with a nitrogen atmosphere to form a high-capacity active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the proportion of active material in the electrode is increased to enhance capacity, then the capacity of the secondary battery is improved, but the mechanical integrity and stability of the electrode deteriorate due to detachment of active material and blocking of conductive paths
Solution Approach 1:
The patent introduces a binder as an intermediary substance that mediates between the active material particles and the conductive agent. This binder holds the active material together and maintains contact with the conductive network, preventing detachment while allowing high active material content. The binder acts as a binding agent that secures the structural integrity of the electrode throughout charge-discharge cycles.
Solution Approach 2:
The electrode is designed as a composite material system consisting of multiple components: active material (silicon-based), conductive agent, and binder. This composite structure allows each component to fulfill its specific function - the active material provides capacity, the conductive agent ensures electron transport, and the binder maintains structural integrity. The synergistic combination resolves the contradiction between high capacity and stability.
2Reliability
If conductive agent and binder are included in the electrode to prevent detachment and maintain conductivity, then the mechanical integrity and conductivity are improved, but the proportion of active material decreases resulting in reduced capacity
Solution Approach 1:
The patent applies local quality by concentrating the conductive agent and binder only where needed - at the interfaces between active material particles and within the conductive network pathways. Rather than uniformly distributing these non-active components throughout the entire electrode, the formulation optimizes their local placement to maintain conductivity and structural integrity while minimizing their overall proportion, thereby maximizing active material content.
Solution Approach 2:
The patent optimizes the quantitative parameters of electrode components, specifically formulating the electrode to contain 70-90 wt% active material, 1-10 wt% conductive agent, and 1-10 wt% binder. This parameter optimization allows the electrode to achieve both high capacity and adequate conductivity by precisely controlling the proportions of each component, resolving the trade-off between capacity and conductivity.
3Quantity of substance
If silicon-based material is used as active material to achieve high capacity, then the capacity of the secondary battery is improved, but the electrode structure becomes less stable due to repeated expansion and contraction during charging and discharging
Solution Approach 1:
The patent employs segmentation by dividing the silicon-based active material into particles of controlled size and distribution. This segmentation allows the silicon to accommodate volume changes during lithium insertion/extraction without causing macroscopic structural failure. The particulate form with appropriate size distribution enables local expansion and contraction while maintaining overall electrode integrity through the binder network.
Solution Approach 2:
The electrode uses a composite material system where silicon-based active material is combined with conductive agent and binder in specific proportions. This composite structure allows the silicon particles to undergo volume changes while the conductive agent maintains electrical pathways and the binder holds the structure together, resolving the contradiction between high capacity from silicon and structural stability during cycling.
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 results in a mechanically sturdy, high-capacity electrode with improved conductivity and reduced deterioration, enabling secondary batteries with enhanced energy density and stability for extended driving ranges and efficient charging.
Implementation Method 1
a sheet-like material... which is curved so as to be close to the particle by an intermolecular force
Implementation Method 2
a region that is terminated with a functional group containing oxygen and carbon, a functional group containing oxygen, or a fluorine atom
Data Source
AI summary
An electrode with little deterioration or a secondary battery with little deterioration is provided. An electrode includes a first region and a second region. The first region includes a particle containing silicon. The second region includes a particle containing silicon and a graphene compound. The second region is in contact with the first region to cover at least part thereof. Alternatively, an electrode includes a plurality of particles containing silicon and a graphene compound. Each of the plurality of particles containing silicon includes a functional group containing oxygen and carbon, a functional group containing oxygen, or a fluorine atom in at least part of the surface. The graphene compound includes at least one of carbon terminated with hydrogen and carbon terminated with fluorine in a plane of the graphene compound. The graphene compound is in contact with the plurality of particles containing silicon to closely cling thereto. The particle containing silicon preferably contains amorphous silicon or polycrystalline silicon.