Semiconductor Nanowire Growth from Solid Particles
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Solution Overview
Problem
Current methods for producing silicon nanopowders are costly, energy-intensive, and challenging to scale for commercialization due to high-vacuum, high-temperature, and high-pressure requirements, leading to expensive products and limited capacity for high-energy density lithium-ion batteries.
Innovation Solution
A process involving the preparation of solid semiconductor materials, deposition of catalytic metals, and exposure to high temperatures to grow semiconductor nanowires with diameters from 2 nm to 100 nm, allowing for cost-effective mass production by avoiding hazardous reactions and expensive equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (PECVD, laser-induced pyrolysis, hot-wire synthesis) are used to produce silicon nanopowders, then nano-scaled anode active materials can be obtained, but the production process becomes time-consuming, energy-intensive, and requires expensive high-vacuum, high-temperature, and high-pressure equipment
Solution Approach 1:
The invention changes the key parameters of the production process by using mechanical ball-milling at ambient conditions instead of high-vacuum, high-temperature, and high-pressure conditions. This transforms the production from an energy-intensive, equipment-heavy process to a simple, scalable mechanical process that achieves the same nano-scaled particle size control
Solution Approach 2:
The invention replaces complex thermal and vacuum-based mechanical systems (PECVD, laser-induced pyrolysis, hot-wire synthesis) with a simple mechanical ball-milling system. This substitution eliminates the need for expensive equipment while maintaining particle size control through mechanical forces
2Temperature
If magnesium vapor is used to chemically reduce silica, then silicon can be produced at lower temperatures, but the process requires high pressure conditions, poses explosion dangers, and may form magnesium silicide impurities
Solution Approach 1:
The invention uses conventional silicon particles as a sacrificial reducing agent that is consumed in the reaction. This disposable approach eliminates the need for expensive and hazardous magnesium vapor, replacing it with safe, conventional materials that can be handled under ambient conditions
Solution Approach 2:
The invention converts the potentially harmful high-temperature carbothermal reduction process into a beneficial low-temperature mechanical ball-milling process. The mechanical energy of ball-milling replaces thermal energy, converting a hazardous thermal process into a safe mechanical process that achieves the same reduction
3Quantity of substance
If silicon particle size is reduced to nano-scale, then volumetric energy density improves, but the intrinsically low electric conductivity of silicon remains a challenge
Solution Approach 1:
The invention creates a composite structure where silicon nanoparticles are embedded in a conductive carbon matrix. This composite approach combines the high capacity of nano-scaled silicon with the high conductivity of carbon, simultaneously improving both volumetric energy density and electrical conductivity
Solution Approach 2:
The invention applies different materials to different locations: silicon nanoparticles provide high capacity in the core, while conductive carbon provides electrical pathways in the surrounding matrix. This local differentiation of material properties solves the conductivity problem while maintaining the high energy density of nano-scaled silicon
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 enables the production of semiconductor nanowires with high aspect ratios, enhancing lithium storage capacity and rate capability while reducing production costs, making them viable for large-scale commercialization.
Implementation Method 1
exposing the catalyst metal-coated semiconductor material to a high temperature environment, from 100° C. to 2,500° C., for a period of time sufficient to enable a catalytic metal-assisted growth of multiple semiconductor nanowires from the semiconductor material particulate
Data Source
AI summary
Disclosed is a process for producing semiconductor nanowires having a diameter or thickness from 2 nm to 100 nm, the process comprising: (A) preparing a semiconductor material particulate having a size from 50 nm to 500 μm, selected from Ga, In, Ge, Sn, Pb, P, As, Sb, Bi, Te, a combination thereof, a compound thereof, or a combination thereof with Si; (B) depositing a catalytic metal, in the form of nanoparticles having a size from 1 nm to 100 nm or a coating having a thickness from 1 nm to 100 nm, onto surfaces of the semiconductor material particulate to form a catalyst metal-coated semiconductor material; and (C) exposing the catalyst metal-coated semiconductor material to a high temperature environment, from 100° C. to 2,500° C., for a period of time sufficient to enable a catalytic metal-assisted growth of multiple semiconductor nanowires from the particulate.