Carbon-Silicon Composite Anode for Lithium Battery
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Solution Overview
Problem
Silicon-based anode active materials for lithium secondary batteries face challenges with cycle life and power properties due to volume changes during charge and discharge, leading to electrical insulation and rapid deterioration, and have low initial efficiency and power performance, especially under harsh conditions.
Innovation Solution
A manufacturing method for a carbon-silicon composite involving the preparation of a slurry solution with silicon-block copolymer core-shell particles, followed by a primary and secondary carbonization process with pulverization steps, to achieve uniformly dispersed nano-sized particles that improve the anode's initial efficiency, cycle life, and power properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based anode active material is used to achieve high capacity, then theoretical capacity reaches 4200 mAh/g, but cycle property deteriorates rapidly due to volume expansion and electrical insulation
Solution Approach 1:
The patent embeds silicon particles within a carbon matrix structure, creating a nested configuration where silicon is contained within carbon. This nested arrangement allows silicon to expand and contract during lithium insertion/extraction while the carbon matrix maintains structural integrity and electrical conductivity, preventing the rapid cycle deterioration that would otherwise occur
Solution Approach 2:
The patent creates a composite material system combining silicon and carbon, where silicon provides high lithium capacity and carbon provides structural stability and electrical conductivity. This composite structure synergistically combines the advantages of both materials to achieve high capacity while maintaining good cycle properties
2Quantity of substance
If inorganic particles such as silicon are directly used as anode active material, then high capacity is achieved, but conductivity deteriorates due to volume change during charge and discharge
Solution Approach 1:
The carbon matrix acts as an intermediary between silicon particles and the electrolyte, providing a conductive pathway for electron transport while allowing lithium ions to reach the silicon. This intermediary carbon structure maintains electrical conductivity even as silicon undergoes volume changes during charge and discharge cycles
3Quantity of substance
If silicon expands 300-400% in volume during charge process, then lithium absorption capacity increases, but empty space generates between particles causing electrical insulation
Solution Approach 1:
The carbon matrix functions as a flexible shell surrounding silicon particles, accommodating the 300-400% volume expansion of silicon during lithium absorption. This flexible carbon shell maintains continuous electrical contact throughout the expansion process, preventing electrical insulation despite the significant volume changes
4Ease of operation
If existing graphite-based or silicon-based anode materials are used, then basic battery function is achieved, but high power capability is not exhibited under harsh charge and discharge conditions
Solution Approach 1:
The patent divides the anode material into segmented silicon particles dispersed within a carbon matrix, creating a fine-grained composite structure. This segmentation increases the surface area available for lithium reaction and shortens ion transport paths, enabling high power capability under harsh charge and discharge conditions while maintaining basic battery functionality
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 method results in a carbon-silicon composite with significantly improved initial efficiency, cycle life, and power properties by uniformly dispersing silicon-block copolymer core-shell carbonization particles, alleviating volume expansion issues and maintaining high capacity even under harsh conditions.
Implementation Method 1
performing a primary carbonization process on the mixed solution, followed by pulverization, to manufacture a primary carbon-silicon composite
Data Source
AI summary
Disclosed herein are a manufacturing method of a carbon-silicon composite, including: (a) preparing a slurry solution including silicon (Si)-block copolymer core-shell particles; (b) mixing the slurry solution with a carbon raw material to manufacture a mixed solution; (c) performing a primary carbonization process on the mixed solution, followed by pulverization, to manufacture a primary carbon-silicon composite; and (d) performing a secondary carbonization process on the primary carbon-silicon composite, followed by pulverization, to manufacture a secondary carbon-silicon composite, the carbon-silicon composite, an anode for a secondary battery manufactured by applying the carbon-silicon composite, and a secondary battery including the anode for a secondary battery.