Spherical Skein Conductive Framework for Silicon Anode Volume Expansion
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Solution Overview
Problem
Silicon-based anode materials for lithium batteries face challenges due to significant volume expansion during lithium intercalation and deintercalation, leading to cracks, pulverization, and deteriorated charge/discharge characteristics, which hinder commercialization despite their high theoretical capacity.
Innovation Solution
A complex anode active material is developed, featuring a conductive framework with a spherical skein shape and dispersed metal particles, which reduces volume expansion and maintains electrical connectivity, combined with a protective shell to enhance stability and compatibility with conventional battery components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based anode materials are used to achieve high theoretical capacity, then capacity is improved, but volume expansion during lithium intercalation and deintercalation causes cracks and pulverization
Solution Approach 1:
The silicon-based anode material is divided into fine particles or nanoscale structures, which segments the overall volume expansion into smaller, more manageable units. This segmentation reduces the stress concentration that leads to cracks and pulverization, allowing the material to maintain structural stability while achieving high capacity.
Solution Approach 2:
Silicon particles are embedded within a porous carbon matrix or encapsulated in a protective shell structure. The carbon framework acts as a container that accommodates the silicon's volume expansion, similar to a nested doll structure where the inner element can expand without damaging the outer structure. This nesting approach maintains both high capacity and structural stability.
Solution Approach 3:
A porous carbon framework or hollow spherical structure is designed to envelop the silicon particles. The porous structure provides void space that accommodates the volume expansion of silicon during lithium intercalation, preventing the material from cracking or pulverizing while maintaining electrical conductivity and structural integrity.
2Volume of moving object
If porous silicon particles are introduced to reduce expansion ratio, then volume expansion is reduced, but porosity is relatively low and expensive noble metals are required
Solution Approach 1:
A porous carbon framework is constructed using conventional materials and methods, eliminating the need for expensive noble metals. The porous structure is formed through carbonization of organic precursors or controlled synthesis, providing both volume expansion accommodation and electrical conductivity without requiring costly materials.
Solution Approach 2:
The invention replaces expensive noble metals with abundant, inexpensive carbon-based materials. The carbon framework serves as both the structural support and the conductive network, eliminating the need for costly metallic components while maintaining the necessary functional properties for battery operation.
3Reliability
If nanostructure control is implemented to improve charge/discharge characteristics, then performance is improved, but expensive processing techniques such as high-temperature vacuum chemical vapor deposition are required
Solution Approach 1:
The synthesis approach is changed from high-temperature vacuum chemical vapor deposition to lower-temperature solution-based methods or simple heat treatment. By changing the processing parameters (temperature, pressure, atmosphere), the same nanostructure control is achieved using conventional, cost-effective equipment and procedures that are suitable for commercialization.
Solution Approach 2:
Complex vacuum-based chemical vapor deposition processes are replaced with simpler solution chemistry or solid-state reaction methods. This substitution eliminates the need for expensive vacuum equipment and complex process control, enabling nanostructure fabrication using conventional manufacturing techniques.
4Volume of moving object
If double-walled silicon nanotubes with coating layer are prepared to reduce expansion, then expansion ratio is reduced, but specialized methods such as chemical vapor deposition are required
Solution Approach 1:
A composite structure is created by combining silicon particles with a carbon-based coating or matrix. The carbon component provides structural support and accommodates volume expansion, while the silicon provides high capacity. This composite approach achieves expansion reduction through simple mixing and carbonization processes, eliminating the need for specialized nanotube synthesis methods.
Data Source
AI summary
A complex for anode active material, the complex including: a conductive framework having a spherical skein shape; and metal particles dispersed in the conductive framework. Also an anode including the complex, a lithium secondary battery including the anode, and a method of preparing the complex.