Silicon Anode Composite With 3D Conductive Network for Cycle Stability
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Solution Overview
Problem
Current lithium-ion batteries using graphite as an anode material are limited by a theoretical specific capacity of 372 mAh/g, and silicon-based anodes suffer from volume expansion leading to poor cycling stability due to particle pulverization and exfoliation from current collectors.
Innovation Solution
A three-dimensional conductive network structure is formed by combining a silicon-based material with carbon-coated tin nanowires and carbon nanotubes, which provide flexibility, elasticity, and enhanced ionic and electronic conductivity to alleviate volume effects during lithiation/delithiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based material is used as anode material, then specific capacity is improved, but cycling stability deteriorates due to volume expansion causing particle pulverization and exfoliation
Solution Approach 1:
The silicon-based material particles are embedded within a three-dimensional conductive network formed by carbon-coated tin nanowires and carbon nanotubes. This nested structure allows the silicon particles to be contained and supported by the flexible conductive network, which accommodates volume expansion during lithiation/delithiation cycles, preventing particle pulverization and maintaining cycling stability while preserving high specific capacity
Solution Approach 2:
The carbon-coated tin nanowires and carbon nanotubes form a flexible three-dimensional conductive network that acts as a supportive framework around the silicon-based material. This flexible network can dynamically adapt to volume changes during charging and discharging, preventing mechanical failure of the silicon particles and ensuring long-term cycling stability
2Reliability
If graphite is used as anode material, then cycling stability is improved, but specific capacity is limited to 372 mAh/g
Solution Approach 1:
The anode material is designed as a composite system combining silicon-based material (providing high specific capacity) with carbon-coated tin nanowires and carbon nanotubes (providing conductive network and structural stability). This composite structure overcomes the limitations of pure graphite by incorporating silicon for higher capacity while using the carbon-based conductive network to maintain cycling stability
3Quantity of substance
If silicon particles are used, then specific capacity is improved, but electronic conductivity and ionic conductivity deteriorate
Solution Approach 1:
The carbon-coated tin nanowires and carbon nanotubes serve as intermediary conductive pathways between silicon-based material particles. This three-dimensional conductive network mediates electron and ion transport, overcoming the poor intrinsic conductivity of silicon particles while maintaining their high capacity benefits, thereby achieving both high specific capacity and excellent conductivity
Data Source
AI summary
The present disclosure relates to an anode material, an anode sheet and a lithium-ion battery, and belongs to the technical field of lithium-ion battery materials. The anode material comprises a silicon-based material, a carbon-coated tin nanowire and a carbon nanotube. The carbon-coated tin nanowire and the carbon nanotube both have a certain length, and have flexibility and elasticity to some extent. And they are mixed with the silicon-based material to form a three-dimensional conductive network structure, which can alleviate the volume effect of the anode material during the lithiation/delithiation process. Thus the lithium-ion battery has a large specific capacity and high cycling stability. At the same time, the anode material has a remarkable ionic conductivity and an excellent electronic conductivity, thereby obtaining a better conductivity.