Carbon-Silicon Composite Electrode for Lithium-Ion Battery Capacity and Lifespan
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Solution Overview
Problem
Lithium-ion batteries face challenges with the poor lifespan and output characteristics due to the high volume expansion and contraction of silicon anode materials, leading to instability in the surface electrolyte interface and low lithium ion diffusion rates, which affect capacity and rate capability.
Innovation Solution
A carbon-silicon composite electrode material is prepared using silicon nanoparticles and an inverse opal-structured porous carbon structure, formed by injecting a carbon precursor into a nanoparticle aggregate, cross-linking, and calcinating to create a porous carbon structure, which is then mixed with a conductive material and binder to enhance electrical conductivity and mitigate volume changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as anode material to achieve high capacity, then capacity is improved, but volume expansion and contraction causes poor lifespan and instability
Solution Approach 1:
Silicon nanoparticles are embedded within the porous structure of inverse opal carbon, creating a nested configuration where the silicon is contained within the carbon matrix. This nesting approach allows the silicon to expand and contract within the confined porous space of the carbon structure, preventing structural degradation while maintaining high capacity
Solution Approach 2:
The invention creates a composite material system combining silicon nanoparticles with inverse opal carbon structure. The composite leverages the high capacity of silicon while the carbon matrix provides structural stability and conductivity, resolving the contradiction between capacity and lifespan through material composition
2Quantity of substance
If silicon nanoparticle aggregate is used to achieve high capacity, then capacity is improved, but low electric conductivity results in poor rate capability
Solution Approach 1:
The inverse opal carbon matrix serves as a conductive network surrounding the silicon nanoparticles. This composite structure combines the high capacity of silicon with the excellent electrical conductivity of carbon, enabling both high capacity and fast charge/discharge rates by providing continuous electron transport pathways
Solution Approach 2:
The porous inverse opal carbon structure provides a three-dimensional conductive network that facilitates rapid electron and ion transport. The porous architecture increases surface area and creates multiple transport channels, improving rate capability while maintaining high capacity
3Reliability
If conventional carbon structure is used to mitigate volume change, then lifespan is improved, but complex manufacturing process increases device complexity
Solution Approach 1:
The inverse opal carbon structure provides a regular, self-assembled porous architecture that can be formed through relatively simple processes. The porous structure naturally accommodates silicon expansion while maintaining structural integrity, achieving lifespan improvement without requiring complex manufacturing steps
Solution Approach 2:
The inverse opal carbon structure is prepared in advance with a predetermined porous architecture before silicon nanoparticles are introduced. This preliminary preparation of the carbon matrix creates pre-formed channels and spaces that guide subsequent silicon incorporation, simplifying the overall manufacturing process while ensuring proper volume change accommodation
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 secondary battery with improved charge/discharge capacity and lifespan characteristics by controlling the composition and structure of the carbon-silicon composite electrode material, maintaining high capacity and stability over repeated cycles.
Implementation Method 1
injecting a carbon precursor resol in a nanoparticle aggregate and cross-linking them to form a composite
Implementation Method 2
calcinating the composite to carbonize the carbon precursor resol in the composite with removing the nanoparticle aggregate in the composite to form a porous carbon structure
Implementation Method 3
a method of mitigating a volume change by positioning silicon nanoparticle or fiber within a pore structure such as a yolk-shell structure
Implementation Method 4
a lithium ion diffusion velocity of a silicon material is low due to a low electric conductivity of silicon
Data Source
AI summary
The present disclosure relates to a method of preparing a carbon-silicon composite electrode material including silicon nanoparticles and an inverse opal-structured porous carbon structure, the carbon-silicon composite electrode material prepared by the method, and a secondary battery including the carbon-silicon composite electrode material.