Silicon-Graphene Electrode Structure for Stable High-Capacity Batteries
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Solution Overview
Problem
Secondary batteries used in moving vehicles and portable terminals face challenges in increasing capacity, stability, and energy density, with existing electrodes prone to collapse due to repeated charging and discharging, leading to reduced performance and safety concerns.
Innovation Solution
An electrode design featuring a particle with a sheet-like material that clings to the active material via hydrogen bonds, using silicon and graphene compounds with functional groups, which enhances adhesion and conductivity, reducing the risk of collapse and increasing energy density.
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 structural stability deteriorates due to repeated expansion and contraction during charging and discharging
Solution Approach 1:
The patent employs a composite structure where silicon particles (active material) are integrated with a three-dimensional network of conductive agents and binder. This composite architecture allows the active material to undergo volume changes during lithiation/delithiation while the network provides structural support, preventing particle collapse and maintaining electrode integrity throughout charge-discharge cycles.
Solution Approach 2:
The conductive agent forms a three-dimensional network that acts as a flexible scaffold surrounding the silicon particles. This network accommodates the expansion and contraction of silicon during charging and discharging cycles, preventing structural collapse while maintaining electrical connectivity and mechanical integrity of the electrode.
2Reliability
If conductive agent and binder are added to prevent collapse and short-circuiting, then reliability is improved, but the proportion of active material decreases, reducing capacity
Solution Approach 1:
The conductive agent is strategically distributed in a three-dimensional network throughout the electrode structure, concentrating conductivity where needed at particle interfaces and within the matrix, rather than requiring uniform distribution. This localized approach maximizes conductive function while minimizing the overall amount of non-active material required.
Solution Approach 2:
The conductive agent network serves multiple functions simultaneously: it provides electrical conductivity pathways, acts as a structural scaffold to prevent particle collapse, and maintains mechanical integrity during volume changes. This multi-functionality reduces the need for separate binder materials, thereby increasing the proportion of active material in the electrode.
3Quantity of substance
If silicon-based material is used as active material to achieve high capacity, then energy density is improved, but structural stability deteriorates due to collapse from repeated expansion and contraction
Solution Approach 1:
The silicon-based active material is divided into discrete particles rather than used as a continuous bulk material. This segmentation into individual particles allows each particle to undergo volume changes independently during lithiation/delithiation, preventing stress accumulation and structural collapse that would occur in a monolithic structure, thereby maintaining both high capacity and structural stability.
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 proposed electrode design provides a durable, high-capacity, and safe secondary battery with improved energy density and stability, capable of withstanding repeated charging and discharging cycles, thus enhancing the performance and range of electric vehicles and portable devices.
Implementation Method 1
the material having a sheet-like shape is curved so as to be close to the particle by an intermolecular force such as London dispersion force
Implementation Method 2
the particle has a region that is terminated by a functional group containing oxygen
Data Source
AI summary
An electrode with excellent characteristics is provided. An active material with excellent characteristics is provided. A novel silicon material is provided. An electrode includes a plurality of particles and a graphene compound. At least part of the surface of each of the plurality of particles is terminated by a functional group containing oxygen, the graphene compound contains the plurality of particles so as to cover the surrounding of the plurality of particles, and the graphene compound is graphene containing at least one of a carbon atom terminated by a hydrogen atom and a carbon atom terminated by a fluorine atom in a two-dimensional structure formed with a six-membered ring of carbon.