Liquid Silane Electrospinning for Scalable Silicon Nanowires
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Solution Overview
Problem
Current methods for producing silicon-based nanowires are limited by high process temperatures, formation of carbide and oxide phases, and poor scalability, which affect the electrochemical capacity and mechanical stability of silicon-based anodes in lithium ion batteries.
Innovation Solution
The use of liquid silane monomers in electrospinning processes to form silicon-based nanowires and composites, which reduces lateral cohesive stresses and allows for continuous roll-to-roll manufacturing, enabling the production of stable and conductive silicon nanowires with tailored electrical, thermal, and ionic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical vapor deposition or wafer etching is used to produce silicon-based materials, then the electrical and electrochemical properties are improved, but the process is not amendable to continuous manufacturing
Solution Approach 1:
The patent replaces traditional mechanical/thermal processing methods (chemical vapor deposition, wafer etching) with an electrospinning-based liquid precursor approach. This substitution enables continuous roll-to-roll manufacturing while maintaining the electrical and electrochemical properties of silicon-based materials through controlled decomposition of liquid silane precursors in the electrospun fibers.
Solution Approach 2:
The patent changes the physical state of silicon precursors from gaseous (CVD) or solid (wafer etching) to liquid form in electrospinning inks. This parameter change allows the precursor to be delivered continuously through liquid handling systems, enabling continuous manufacturing while the subsequent thermal or catalytic conversion maintains the desired electrical and electrochemical properties.
2Manufacturing precision
If high process temperatures are used to produce silicon nanowires, then the nanowire formation is achieved, but carbide and oxide phases form that limit electrochemical capacity
Solution Approach 1:
The patent changes the processing temperature parameter from high temperatures (>1000°C) to low temperatures (<400°C) by using liquid silane precursors that decompose at lower temperatures. This parameter change enables nanowire formation while avoiding the formation of carbide and oxide phases, thereby maintaining high electrochemical capacity.
Solution Approach 2:
The patent introduces liquid silane precursors as intermediary compounds that serve as silicon sources. These intermediaries decompose at low temperatures to form silicon nanowires, replacing the need for high-temperature direct silicon deposition and subsequent processing that would otherwise form detrimental carbide and oxide phases.
3Productivity
If bulk silicon powders are used in VI-SLS process, then scalable mass manufacture is possible, but high process temperatures lead to carbide and oxide phase formation
Solution Approach 1:
The patent changes the temperature parameter from high to low and the precursor form from bulk solid to liquid solution, enabling scalable manufacturing through continuous electrospinning while avoiding carbide and oxide phase formation. The liquid precursor approach maintains scalability through continuous processing while improving product quality.
Solution Approach 2:
The patent uses liquid silane precursors as intermediaries that enable scalable manufacturing through continuous liquid delivery and electrospinning, replacing bulk silicon powder processing. This intermediary approach maintains the scalability benefit while eliminating the high-temperature requirement that causes carbide and oxide formation.
4Shape
If hot-wire CVD or PECVD is used for silicon coating growth, then a-Si nanowires with hollow cores are formed, but precursor utilization is poor and growth rates are slow
Solution Approach 1:
The patent changes the precursor delivery method from gaseous (CVD) to liquid form in electrospinning fibers, dramatically improving precursor utilization efficiency. The liquid precursor is delivered directly to the fiber structure, enabling faster growth rates while maintaining the desired nanowire morphology and hollow core structure.
Solution Approach 2:
The patent uses electrospun polymer fibers as intermediary templates that guide silicon nanowire formation. These fiber intermediaries provide a structured scaffold that enables efficient precursor utilization and fast growth rates while maintaining the hollow core nanowire structure, replacing the less efficient gaseous precursor delivery of CVD methods.
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 approach enables the production of silicon nanowires with improved structural stability and electrochemical performance, avoiding the formation of detrimental surface oxides and carbides, thus enhancing the capacity and rate capabilities of silicon-based anodes.
Implementation Method 1
liquid silane monomers in electrospinning processes to form silicon-based nanowires and composites
Implementation Method 2
expel a viscous solution into the presence of a high electric field where continuous fibers are formed
Data Source
AI summary
Described herein are synthesis schemes and methods for producing silicon based nanostructures and materials, including compositions and methods for synthesis of silicon-based nanowires and composites from three-component and four-component liquid silane/polymer inks. Materials and methods for producing silicon based micro and nanofibers that can be used in a variety of applications including material composites, electronic devices, sensors, photodetectors, batteries, ultracapacitors, and photosensitive substrates, and the like.