Silicon Nanoparticles in Graphite Matrix for Battery Anodes
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Solution Overview
Problem
Current anode materials, such as carbon, suffer from low volumetric power density and mechanical stress issues due to volume changes during alloying, leading to capacity loss and rapid failure in energy storage devices.
Innovation Solution
A nano-particle composition comprising amorphous and/or nanocrystalline silicon-containing particles embedded in a graphite matrix with an amorphous carbon interface, formed through high energy mechanical milling and heat treatment, which helps maintain electrical contact and stability during alloying and de-alloying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal or metal alloy nano-composites are used as anode materials to increase discharge capacity, then gravimetric and volumetric capacitance improve, but structural stability deteriorates due to volume changes during alloying
Solution Approach 1:
The metal alloy is divided into nanoscale particles (1-100 nm) embedded in a carbon matrix, segmenting the bulk material into discrete units that can independently accommodate volume changes without compromising overall structural integrity
Solution Approach 2:
A composite structure is formed by embedding metal or metal alloy nano-particles within a carbon matrix, combining the high capacitance of metal alloys with the structural stability and flexibility of carbon to maintain electrical contact during volume changes
2Reliability
If carbon is used as anode material to ensure structural stability, then reliability improves, but volumetric power density deteriorates
Solution Approach 1:
The invention creates a composite anode material combining carbon matrix with metal or metal alloy nano-particles, achieving both the structural stability of carbon and the high volumetric power density of metal alloys through synergistic integration
Solution Approach 2:
Different regions of the anode serve different functions: the carbon matrix provides structural stability and flexibility, while the embedded metal nano-particles provide high capacitance and power density, optimizing local properties for their specific roles
3Ease of manufacture
If metal alloys are polarized to negative potential to form at room temperature, then ease of manufacture improves, but mechanical strength deteriorates due to brittle alloy formation
Solution Approach 1:
The metal alloy is processed into nanoscale particles, where the small size prevents brittle fracture and maintains mechanical integrity even after room temperature formation through polarization
Solution Approach 2:
The brittle metal alloy is embedded in a flexible carbon matrix that provides mechanical support and maintains structural integrity, allowing room temperature formation while preventing catastrophic failure
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 silicon-based nano-particle composition achieves high and reversible capacities, improved mechanical strength, and electrochemical stability, reducing capacity loss and electrode failure.
Implementation Method 1
an amorphous carbon interface formed between the amorphous and/or nanocrystalline silicon-containing nano-particles and the graphite matrix
Implementation Method 2
formed through high energy mechanical milling and heat treatment
Implementation Method 3
high energy mechanical milling and heat treatment
Data Source
AI summary
The present invention is related to nano-particle compositions, methods of their preparation and applications thereof. The nano-particle compositions include silicon-containing nano-particles, a graphite matrix, carbon nanotubes and an amorphous carbon interface formed between the silicon-containing nano-particles and the graphite matrix.