Amorphous Silicon Composite Colloids via Acoustic Cavitation Encapsulation

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Solution Overview

Problem

Current methods for producing hydrogenated amorphous silicon-containing colloids and composite colloids with a silicon-containing shell are limited by high temperatures, high pressures, and complexity, often resulting in crystalline or non-hydrogenated nanoparticles, making it difficult to encapsulate substances with hydrogenated amorphous silicon-containing coatings.

Innovation Solution

A method using acoustic cavitation at room temperature and atmospheric pressure to produce hydrogenated amorphous silicon-containing colloids with a silicon-containing shell, allowing for the encapsulation of substances by dissolving hydridosilanes in solvents and subjecting them to ultrasound, creating microbubbles that implode and form colloids with a spherical geometry and cavity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vacuum processes such as PECVD, hot-wire CVD or hot-wall reactors are used to produce silicon-containing nanoparticles, then the production process is established and reliable, but the process requires high temperatures, high vacuum conditions, and complex equipment

Engineering Contradiction:
Improveproduction process reliabilityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex vacuum-based thermal CVD equipment with a simple ultrasonic liquid-phase processing system. The mechanical ultrasonic field substitutes for the thermal and vacuum fields, enabling colloid production in ambient conditions without requiring PECVD, hot-wire CVD, or hot-wall reactor equipment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent fundamentally changes the processing parameters from high temperature (typically >700°C) and high vacuum to room temperature and atmospheric pressure. This parameter transformation is achieved by using liquid-phase precursors and ultrasonic cavitation, which enables the same nanoparticle synthesis without the need for complex thermal and vacuum control systems.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If gas-phase high-temperature processes are used to produce amorphous silicon nanoparticles, then the production is efficient, but the resulting particles are non-hydrogenated and crystalline rather than amorphous and hydrogenated

Engineering Contradiction:
Improveproduction efficiencyVSAvoidnanoparticle composition
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical environment from gas-phase to liquid-phase processing, which fundamentally alters the reaction chemistry. The liquid-phase ultrasonic process enables hydrogen incorporation into the silicon nanoparticle structure, producing hydrogenated amorphous silicon (a-Si:H) colloids with the desired composition and amorphous structure, while maintaining efficient production through direct ultrasonic activation of liquid precursors.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If high pressure autoclave processes are used to produce amorphous silicon colloids, then hydrogenated amorphous colloids can be produced, but the process requires temperatures between 400-500°C and pressures between 200-400 bar

Engineering Contradiction:
Improvecolloid compositionVSAvoidprocess pressure
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The patent replaces the high-pressure thermal autoclave system with a low-pressure ultrasonic liquid-phase system. The mechanical energy of ultrasonic cavitation substitutes for the high thermal and pressure conditions, enabling the same hydrogenated amorphous colloid formation at atmospheric pressure and room temperature by directly activating the liquid precursor through cavitation bubbles.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If cyclohexasilane gas-phase pyrolysis is used to produce amorphous nanoparticles, then production is achieved, but temperatures between 900-1100°C are required

Engineering Contradiction:
Improvenanoparticle productionVSAvoidprocess temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent replaces thermal pyrolysis with ultrasonic cavitation as the activation mechanism. Instead of using 900-1100°C thermal energy to decompose cyclohexasilane, the patent uses mechanical ultrasonic energy to create cavitation bubbles that implode and provide localized energy for nanoparticle formation at room temperature, dramatically reducing the required process temperature.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

5Productivity

If conventional processes are used to produce silicon nanoparticles, then production is achieved, but direct encapsulation of materials or foreign substances with hydrogenated amorphous silicon-containing coatings is not possible

Engineering Contradiction:
Improvenanoparticle productionVSAvoidencapsulation capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent combines the nanoparticle synthesis and the encapsulation process into a single integrated liquid-phase ultrasonic treatment step. By dissolving the precursor in a liquid medium and performing ultrasonic cavitation, the process simultaneously produces the hydrogenated amorphous silicon colloids and allows co-dissolved or suspended materials to be encapsulated within the forming nanoparticle shells, eliminating the need for separate encapsulation steps.

Inventive Principle:
Principle #5Merging (Combining)

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 colloids with a silicon-containing shell and spherical geometry, facilitating the encapsulation of substances with hydrogenated amorphous silicon-containing coatings, offering advantages in simplicity, equipment requirements, and the ability to produce nano- or mesoporous layers with high specific capacities and long stabilities for lithium-ion half-cells.

Implementation Method 1

A method using acoustic cavitation at room temperature and atmospheric pressure to produce hydrogenated amorphous silicon-containing colloids with a silicon-containing shell, allowing for the encapsulation of substances by dissolving hydridosilanes in solvents and subjecting them to ultrasound, creating microbubbles that implode and form colloids with a spherical geometry and cavity

Methodology Applied
Scientific EffectAcoustic cavitation: Acoustic Cavitation

Data Source

PatentEP3707099B1Method for producing hydrogenated amorphous silicon-containing colloids and/or composite colloids and for encapsulating substances with hydrogenated amorphous silicon-containing composite colloids, hydrogenated amorphous silicon-containing colloids and/or composite colloids, substances encapsulated with silicon-containing composite layers, and use thereof
Publication Date: 2024.10.16 FORSCHUNGSZENTRUM JULICH GMBH
  • EP3707099B1 patent drawingFigure 1
  • EP3707099B1 patent drawingFigure 2
  • EP3707099B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing hydrogenated amorphous silicon-containing composite colloids and for encapsulating substances with hydrogenated amorphous silicon-containing composite layers, and to silicon-containing composite colloids and substances encapsulated with silicon-containing composite layers, and to the use thereof. According to the invention a hydridosilane, or a hydridosilane derivative, or a mixture of various hydridosilanes and/or hydridosilane derivatives, which are dissolved in at least one organic and/or inorganic solvent, or at least one hydridosilane, or a hydridosilane derivative, or a mixture of various hydridosilanes and/or hydridosilane derivatives, which, without a solvent are already in liquid form, is subjected to cavitation. Hydrogenated amorphous silicon-containing composite colloids are thus produced.