Silicon Negative Electrode Material with Composite Layer
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Solution Overview
Problem
Lithium batteries using lithium metal as a negative electrode face issues of high manufacturing cost, safety concerns due to dendritic structure formation, and limited effectiveness and lifetime when using non-metal compounds, which are not cost-effective or efficient.
Innovation Solution
A negative electrode material for lithium batteries is developed, comprising a silicon composite material with a composite layer of metal silicide, metal oxide, silicon carbide, and silicon oxide, and multi-layer graphene units, formed through a thermal process and high-pressure channel treatment, enhancing charge-discharge efficiency and reducing volume expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium metal is used as negative electrode active material, then high activity and high electromotive force are achieved, but manufacturing cost is too high and safety issues arise due to dendritic structure formation
Solution Approach 1:
The patent replaces expensive lithium metal with silicon-based materials that are more cost-effective and safer. The silicon material serves as a disposable alternative that avoids the dendritic structure formation problem inherent to lithium metal, thereby improving safety while maintaining cost-effectiveness.
Solution Approach 2:
The patent employs composite materials consisting of silicon base material combined with carbon materials and metal materials. This composite structure addresses the limitations of pure lithium metal by creating a more stable, safer negative electrode that maintains high electromotive force while preventing dendritic growth through the composite architecture.
2Ease of manufacture
If non-metal compound such as carbon is used to replace lithium metal, then manufacturing cost is reduced, but effectiveness and lifetime are low
Solution Approach 1:
The patent creates a composite material system combining silicon base material with carbon materials and metal materials. This composite structure maintains the cost-effectiveness of non-metal compounds while significantly improving lifetime and effectiveness through the synergistic properties of the combined materials, particularly the silicon-carbon-metal composite layer.
Solution Approach 2:
The patent changes the material parameters by introducing silicon-based materials with specific physical and chemical properties that differ from traditional carbon materials. These parameter changes include enhanced capacity, improved charge-discharge efficiency, and extended lifetime while maintaining cost-effectiveness.
3Productivity
If silicon material is used as negative electrode material, then capacity and charge-discharge efficiency are increased, but volume expansion occurs during charge-discharge cycles
Solution Approach 1:
The patent employs a carbon material layer that acts as a flexible shell or coating around the silicon base material. This carbon layer accommodates the volume expansion of silicon during charge-discharge cycles while maintaining structural integrity, thereby preventing material degradation and extending battery lifetime.
Solution Approach 2:
The patent creates a composite structure where silicon base material is combined with carbon materials and metal materials in specific ratios and configurations. This composite architecture allows the silicon to expand and contract during cycling while the carbon and metal components provide structural support and prevent degradation, thereby maintaining high charge-discharge efficiency over extended periods.
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 increases the capacity and charge-discharge efficiency of lithium batteries, reduces manufacturing costs, and extends the battery's usage life by suppressing volume expansion and improving electric conductivity.
Implementation Method 1
performing a thermal process to make the metal material and the carbon material react on the surface of the silicon material
Implementation Method 2
make the metal material and the carbon material react on the surface of the silicon material thereby forming a silicon composite material
Implementation Method 3
passing a graphite material through a high pressure channel to strip a plurality of graphene units
Data Source
AI summary
A method for manufacturing a negative electrode material of a lithium battery is provided. The method includes: covering a metal material and a carbon material on a surface of a silicon material; performing a thermal process for reacting the metal material with the carbon material on the surface of the silicon material thereby forming a silicon composite material and at least one projection on the surface of the silicon material, wherein a free end of the projection is extended to form a head, the silicon composite material is used as the negative electrode material of the lithium battery, the silicon composite material comprises a composite layer forming on the surface of the silicon material, and the composite layer comprises a metal silicide, a metal oxide, a silicon carbide and a silicon oxide.