Porous Carbon-Silicon Anode Scaffold for Swelling-Stable Capacity
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Solution Overview
Problem
Conventional lithium-ion battery anodes, primarily made of graphite, suffer from low power performance and limited capacity due to swelling issues when intercalated with lithium, limiting the cycle life and capacity of lithium-ion batteries, and existing solutions fail to scale effectively while maintaining cycle stability.
Innovation Solution
A carbon-silicon composition is developed by infiltrating the pore structure of carbon-based scaffolds with a silicon-containing gas and depositing silicon-based material within the fibrillar structure of nanoporous carbon-based scaffolds, creating a composite with optimal pore structure and morphology to enhance lithium storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon content in anode is increased to improve lithium storage capacity, then capacity increases, but swelling during lithiation causes limited cycle life
Solution Approach 1:
The patent employs a nanoporous carbon scaffold with controlled pore size (2-50 nm) and high porosity (50-90%) to accommodate silicon particles. The porous structure allows silicon to expand and contract during lithiation/delithiation cycles without compromising the structural integrity of the electrode, thereby maintaining cycle life while enabling high silicon content (up to 95 wt%) for increased lithium storage capacity.
Solution Approach 2:
The patent creates a composite material system consisting of silicon particles embedded within a carbon scaffold. This composite structure combines the high capacity advantage of silicon with the structural stability and conductivity of carbon, resolving the contradiction between capacity enhancement and cycle life maintenance.
2Reliability
If conventional carbon anodes are used to maintain cycle stability, then reliability is maintained, but lithium storage capacity is limited
Solution Approach 1:
The patent applies local quality by distributing silicon particles throughout the carbon scaffold structure. Different regions of the composite anode have different compositions - silicon-rich zones for high capacity and carbon-rich zones for structural stability and conductivity. This spatial differentiation allows the anode to achieve both high capacity and good cycle stability.
Solution Approach 2:
The patent changes the physical and chemical parameters of the carbon scaffold, including pore size (2-50 nm), porosity (50-90%), and surface area, to optimize the accommodation of silicon particles. These parameter adjustments enable the carbon scaffold to support high silicon content while maintaining structural integrity and electrochemical performance.
3Quantity of substance
If nanoporous carbon scaffold with high porosity is used to accommodate silicon expansion, then capacity increases, but mechanical strength decreases
Solution Approach 1:
The patent utilizes the carbon scaffold as a flexible, porous matrix that can deform elastically during silicon expansion and contraction. The scaffold's flexibility allows it to accommodate volume changes without fracturing, maintaining mechanical integrity while enabling high silicon content for increased capacity.
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 carbon-silicon composition significantly increases the lithium storage capacity and maintains cycle stability by effectively accommodating silicon expansion within the nanoporous structure, enhancing both power performance and energy storage capabilities.
Implementation Method 1
The methods generally include infiltrating the pore structure of the carbon-based scaffolds with a silicon-containing gas and depositing silicon-based material onto surfaces within the pore structure
Data Source
AI summary
Carbon-silicon compositions including nanofibrillar carbon networks coated with porous interconnected silicon and their manufacture and use thereof are provided. Embodiments include a composite material including a nanoporous carbon-based scaffold and a silicon-based material. The nanoporous carbon-based scaffold includes a pore structure that includes a fibrillar morphology, where the silicon-based material is contained in the pore structure. The compositions find utility in various applications, including electrical energy storage electrodes and devices comprising the same.