Silicon Nanoparticle Coating for Battery Anode Uniformity

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Solution Overview

Problem

Existing methods for coating high surface area layers in energy devices, such as lithium ion batteries, face challenges in achieving uniform coatings and effective contact between silicon nanostructures and conductive materials, leading to poor cycling ability and rapid capacity fading due to mechanical stress and high manufacturing costs.

Innovation Solution

A stable colloidal dispersion of silicon nanoparticles functionalized with appropriate ligands is used to form a nanostructured composite with carbon nanotubes, applied via drop casting at room temperature, enabling effective contact and improved cycling stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If chemical vapor deposition (CVD) growth of silicon is used to coat carbon nanotubes, then uniform coating and effective contact are achieved, but manufacturing cost increases due to high-temperature vacuum systems

Engineering Contradiction:

Improvecoating uniformityVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the temperature parameter from high-temperature CVD processing to room-temperature liquid application, eliminating the need for vacuum systems while achieving uniform coatings through colloidal nanoparticle dispersions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical vacuum system and high-temperature heating equipment with a simple liquid deposition process, substituting complex manufacturing infrastructure with a straightforward chemical colloidal approach

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If silicon nanowires and nanotubes are grown on conductive substrates, then effective contact between silicon and conductive materials is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvecontact effectivenessVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention uses liquid colloidal dispersions as an intermediary medium to deliver silicon nanoparticles to the conductive substrate, enabling effective contact without requiring complex in-situ growth processes

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention employs liquid application methods (hydraulic approach) to deposit silicon nanoparticles, replacing gas-phase CVD processes and enabling simpler, more cost-effective manufacturing

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Quantity of substance

If silicon experiences large volume variations during battery charge/discharge, then high capacity is achieved, but mechanical stress causes pulverization and poor cycling ability

Engineering Contradiction:

Improvebattery capacityVSAvoidcycling ability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention divides bulk silicon into nanoscale particles, which segment the material into smaller units that can individually accommodate volume changes without causing catastrophic pulverization, thereby maintaining structural integrity during cycling

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The silicon nanoparticles are coated with thin film structures that provide flexible containment, allowing volume expansion and contraction during lithium insertion/extraction while preventing particle fragmentation and maintaining electrochemical performance

Inventive Principle:

Principle #30Flexible shells and thin films

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 nanostructured composite material achieves enhanced capacity and cycling stability, reducing mechanical stress and manufacturing costs while maintaining high electrical conductivity and contact area with electrolytes.

Implementation Method 1

The stable colloidal dispersion can include silicon nanoparticles functionalized using the appropriate ligand. For instance, carbon nanotube films can be coated with silicon nanoparticles

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

a stable colloidal dispersion of nanoparticles functionalized using an appropriate ligand

Methodology Applied

Scientific EffectColloidal stabilization: Colloid

Data Source

PatentUS10084184B2Conformal coating of nano-porous material with group IV semiconductor using nanoparticle ink

Publication Date: 2018.09.25 RGT UNIV OF CALIFORNIA

AI summary

A nanostructured composite material includes a substrate, a porous layer including a highly structured material, and a coating including nanoparticles. A method for forming the nanostructured composite material can include forming a porous layer on a substrate, the porous layer including a highly structured material, and applying nanoparticles to the porous layer to form the nanostructured composite material.