Silicon-Graphite Composite Anode With Polymer-Mediated Particle Distribution
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Solution Overview
Problem
The challenge of achieving uniform distribution of silicon particles on graphite surfaces in silicon-carbon composite anode materials is hindered by their similar surface potentials, leading to lower performance.
Innovation Solution
Surface modification of graphite with an organic polymer, such as PDDA or PVA, creates a positive potential on the graphite, attracting silicon particles and forming a carbon coating layer through heat treatment, ensuring uniform distribution and enhanced bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If graphite and silicon particles are mixed to form a silicon-carbon composite anode material, then the specific capacity of the anode material is improved, but the silicon particles cannot be uniformly distributed on the graphite surface due to similar surface potentials
Solution Approach 1:
The patent introduces an organic polymer as an intermediary substance between graphite and silicon particles. The polymer modifies the surface of graphite particles, creating a positive surface potential that attracts negatively charged silicon particles through electrostatic interaction. This intermediary layer enables uniform distribution of silicon particles on graphite surfaces, resolving the distribution problem while maintaining high specific capacity.
Solution Approach 2:
The patent changes the surface potential parameter of graphite by applying organic polymer modification. This parameter change transforms the originally negative surface potential of graphite into a positive surface potential, creating an electrostatic attraction force that enables uniform distribution of silicon particles. The parameter change directly addresses the distribution issue without compromising capacity.
2Manufacturing precision
If an organic polymer is used for surface modification of graphite, then uniform distribution of silicon particles is achieved, but additional process steps are required
Solution Approach 1:
The patent combines multiple functions into the organic polymer modification step: (1) surface potential modification to enable silicon particle distribution, (2) formation of a carbon coating layer through subsequent carbonization, and (3) potential binder function. By merging these functions into a single modification approach, the patent reduces overall process complexity despite adding the polymerization step.
Solution Approach 2:
The organic polymer serves multiple functions simultaneously: it acts as a surface modifier to create electrostatic attraction, serves as a precursor for carbon coating layer formation through carbonization, and potentially functions as a binder holding the composite structure together. This multi-functionality reduces the need for separate process steps for each function.
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
This method results in superior electrochemical performance by uniformly distributing silicon particles and forming a carbon coating layer, enhancing the anode material's capacity and stability.
Implementation Method 1
the graphite and an organic polymer are liquid-mixed, so that the graphite is surface-modified with the organic polymer to form a first composite particle
Implementation Method 2
positive surface potential is formed on the first composite particle. Therefore, the silicon particles having negative surface potential are attracted to the graphite
Implementation Method 3
the graphite and the organic polymer are mixed with a crosslinker, such as glutaraldehyde (GA), so that the bonding between the graphite surface and the organic polymer are strengthened through a cross-linking between the crosslinker and the organic polymer
Implementation Method 4
the second composite particle is heat-treated to form the composite anode material. The carbon coating layer is formed by carbonizing the organic polymer, which is used for surface modification on the graphite surface, through the heat treatment
Data Source
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AI summary
A composite anode material (1) is provided. The composite anode material (1) includes a graphite (10), a plurality of silicon particles (20), and a carbon coating layer (30). The graphite (10) is pretreated with surface modification through an organic polymer. The plurality of silicon particles (20) are coated on the graphite (10). The carbon coating layer (30) is coated on the graphite (10) and the plurality of silicon particles (20). The carbon coating layer (30) is formed by carbonizing the organic polymer through a heat treatment. A preparation method of the composite anode material (1) includes steps as follows. Firstly, a graphite (10) and an organic polymer are mixed to form a first composite particle. Secondly, the first composite particle and a plurality of silicon particles (20) are mixed to form a second composite particle. Finally, a heat treatment is performed on the second composite particle to form the composite anode material (1).