Silicon Monoxide Composite Anode for Li-Ion Batteries
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Solution Overview
Problem
Current silicon monoxide negative electrode materials for lithium ion batteries have poor conductivity and limited charge-discharge efficiency and cycling stability due to their insulating properties and phase transformations during lithium intercalation, which restricts their potential for high energy density applications.
Innovation Solution
A silicon monoxide composite negative electrode material is developed by uniformly depositing Nano-Silicon on a silicon monoxide substrate and coating it with a nanoscale conductive material layer, such as carbon nanotubes or graphene, to enhance conductivity and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon monoxide material is used as negative electrode material, then specific capacity is improved (>2000 mAh/g), but conductivity deteriorates (poor conductivity, properties close to insulator)
Solution Approach 1:
The patent uses a composite material structure consisting of silicon monoxide core particles coated with carbon material layer. This composite structure combines the high specific capacity of silicon monoxide (>2000 mAh/g) with the good conductivity of carbon material, resolving the contradiction between capacity and conductivity. The carbon coating layer acts as a conductive network that compensates for the insulating properties of silicon monoxide.
2Quantity of substance
If silicon monoxide material is used, then theory specific capacity is improved (>2000 mAh/g), but charge-discharge efficiency deteriorates (poor electrochemical reaction property)
Solution Approach 1:
The carbon-coated silicon monoxide composite structure improves charge-discharge efficiency by providing a conductive pathway that facilitates electron transport and electrochemical reactions. The carbon layer enhances the interfacial contact between the active material and electrolyte, improving reaction kinetics while maintaining high specific capacity.
3Productivity
If pre-lithiation method is used to improve charge-discharge efficiency, then efficiency is improved (from 67.7% to 72.8%), but operation complexity increases (difficult to operate, difficult to control)
Solution Approach 1:
The patent applies preliminary action by pre-coating the silicon monoxide particles with carbon material before electrode fabrication. This pre-treatment step permanently improves the conductivity and electrochemical properties of the material, eliminating the need for complex post-fabrication pre-lithiation procedures. The carbon coating is applied in advance during material preparation, making the process suitable for industrial scale-up.
4Productivity
If Fe2O3 mixed heat treatment is used to improve charge-discharge efficiency, then efficiency is improved (from 70% to 90%), but reliability deteriorates (Fe2O3 reacts incompletely, forms Fe, causing self-discharge and cycling performance decline)
Solution Approach 1:
The patent uses carbon material (such as graphite, amorphous carbon) as a coating layer that is stable and does not undergo harmful reactions during battery cycling. Unlike Fe2O3 which can react incompletely and form problematic Fe, the carbon coating remains stable throughout the battery life, preventing self-discharge and maintaining cycling performance while still improving conductivity and charge-discharge efficiency.
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 composite material achieves high specific capacity (>1600 mAh/g) and charge-discharge efficiency (>80%) with improved cycling stability, making it suitable for industrial production and future lithium ion battery requirements.
Implementation Method 1
Nano-Silicon material uniformly deposited on the silicon monoxide substrate
Implementation Method 2
nanoscale conductive material coating layer on the surface of the silicon monoxide/Nano-Silicon
Data Source
AI summary
The present invention relates to a silicon monoxide composite negative electrode material, which comprises silicon monoxide substrate. Nano-Silicon material uniformly deposited on the silicon monoxide substrate and nanoscale conductive material coating layer on the surface of the silicon monoxide/Nano-Silicon. The preparation method of the silicon monoxide composite negative electrode material includes Nano-Silicon chemistry vapor deposition, nanoscale conductive material coating modification, screening and demagnetizing. The silicon monoxide composite negative electrode material has properties of high specific capacity (>1600 mAh/g), high charge-discharge efficiency of the first cycle (>80%) and high conductivity.