Dense Carbon-Coated Silicon Oxide Anode for Stable Li-Ion Cycling
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Solution Overview
Problem
The existing silicon-carbon composite anode materials for lithium-ion batteries suffer from limited conductivity improvement due to a non-dense carbon coating layer and particle pulverization during lithium intercalation and deintercalation, leading to poor stability and cycling performance.
Innovation Solution
A composite anode material with a silicon-oxygen material and a carbon coating layer, where the physical adsorption-desorption isotherm of the silicon-oxygen material is of type IV or V, bonded closely with the carbon coating layer, forming a dense structure and mechanical strength, enhancing electron and ion conduction, and a method involving preheating and intermittent pulsing of aliphatic hydrocarbon gas for chemical vapor deposition to create a stable and conductive network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbon coating layer is applied to silicon-oxygen material, then conductivity is improved, but the structure becomes non-dense with pores, limiting further conductivity improvement
Solution Approach 1:
The patent changes the porosity parameter of the carbon coating layer from high (non-dense) to low (dense) by optimizing the carbonization process, thereby improving conductivity while maintaining structural integrity
Solution Approach 2:
The patent creates a composite structure where carbon coating layer and silicon-oxygen material are densely integrated, forming a new material system with superior conductivity and structural properties compared to separate components
2Quantity of substance
If silicon content is increased to improve capacity, then cycling stability deteriorates due to particle pulverization during lithium intercalation and deintercalation
Solution Approach 1:
The patent uses a dense carbon coating layer as a flexible protective shell around silicon-oxygen particles, accommodating volume changes during lithium intercalation and deintercalation while preventing particle pulverization and maintaining cycling stability
Solution Approach 2:
The carbon coating layer is applied beforehand to the silicon-oxygen material, creating a protective cushion that absorbs mechanical stress and prevents particle breakdown during subsequent cycling operations
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 solution improves the cycling stability and first efficiency of the anode material by ensuring particle integrity and reducing pulverization, resulting in enhanced performance and reduced manufacturing costs suitable for mass production.
Implementation Method 1
a physical adsorption-desorption isotherm of the silicon-oxygen material is of type IV or type V, so that the silicon-oxygen material and the carbon coating layer can be bonded more closely
Implementation Method 2
feeding a second aliphatic hydrocarbon gas by intermittent pulsing, and causing the second aliphatic hydrocarbon gas to undergo chemical vapor deposition on the preheated product, to obtain the composite anode material
Implementation Method 3
by preheating, the aliphatic hydrocarbon gas can be adsorbed in pores of particles of the silicon-oxygen material whose physical adsorption-desorption isotherm is of the type IV or type V, thereby filling pores of the silicon-oxygen material
Data Source
AI summary
The present disclosure relates to the field of anode materials, and provides a composite anode material, a method for preparating the composite anode material, and a lithium-ion battery. The composite anode material includes a silicon oxide material and a carbon coating layer, which is located on the surface of the silicon-oxygen material. A physical adsorption-desorption isotherm of the composite anode material is of a type II or type III, and a physical adsorption-desorption isotherm of the silicon-oxygen material is of a type IV or type V. The composite anode material, the method for preparating the same, and the lithium-ion battery provided in the present disclosure can effectively improve rate performance and cycling stability of a lithium battery.