Silicon Nanoparticle Core with Carbon Shell for Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face capacity loss and shortened lifespan due to the pulverization of silicon electrodes during charge/discharge cycles, leading to irreversible capacity loss and electrolyte consumption.
Innovation Solution
A composite electrode material is developed, where silicon nanoparticles are coated with conductive carbon nanoparticles using chemical vapor deposition, facilitated by a catalyst, to enhance electrical conductivity and buffer volume changes, reducing fragmentation and electrolyte interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as electrode material to achieve high capacity, then storage capacity is improved, but volume change during charge/discharge causes pulverization and shortened lifespan
Solution Approach 1:
The patent embeds silicon nanoparticles inside a carbon nanoparticle shell, creating a nested structure where the silicon core is protected by the carbon container. This prevents direct contact between silicon and electrolyte, reducing SEI formation and pulverization while maintaining high capacity
Solution Approach 2:
The carbon nanoparticle shell acts as a flexible protective layer that can accommodate the volume expansion and contraction of silicon during lithiation and delithiation. This flexible shell prevents mechanical fracture of silicon particles, maintaining structural integrity over many cycles
2Reliability
If graphite is used as electrode material to ensure structural stability, then battery lifespan is improved, but storage capacity is limited due to SEI formation and fragmentation
Solution Approach 1:
The patent creates a composite electrode material combining silicon's high capacity properties with carbon's structural stability and conductivity. The silicon-carbon composite achieves both high storage capacity (4200 mAhg-1 theoretical) and improved cycle life by leveraging the complementary properties of both materials
3Quantity of substance
If silicon particles are used to achieve high capacity, then storage capacity is improved, but conductive contact is lost due to pulverization
Solution Approach 1:
The carbon nanoparticle shell provides continuous conductive pathways around the silicon core, ensuring electrical connectivity is maintained even when silicon undergoes volume changes. The carbon shell acts as an conductive envelope that preserves electron transport paths
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 composite electrode maintains high capacity and cycle life by minimizing silicon fragmentation and electrolyte consumption, ensuring stable charge/discharge properties and prolonged battery life.
Implementation Method 1
growing a conductive carbon nanoparticle on a surface of the core at a predetermined temperature by chemical vapor deposition
Implementation Method 2
The composite electrode material further comprises an additive promoting and accelerating a growth of the conductive carbon nanoparticle, hereinafter referred to as a catalyst
Data Source
AI summary
A novel composite electrode material and a method for manufacturing the same, a composite electrode containing the said composite electrode material, and a Li-based battery comprising the said composite electrode are disclosed. Herein, the composite electrode material of the present invention comprises: a core, wherein a material of the core is at least one selected from the group consisting of Sn, Sb, Si, Ge, C, a compound thereof and a complex thereof; and a conductive carbon nanoparticle, wherein the conductive carbon nanoparticle grows on a surface of the core.