Composite Anode Material Manufacturing via Carbothermal Shock
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Solution Overview
Problem
The high manufacturing costs and limited competitiveness of silicon-graphite composite anode materials for lithium secondary batteries due to expensive silicon nanoparticles and the complexity of their production process, as well as the mechanical damage and shortened life caused by volume expansion during charging and discharging.
Innovation Solution
A one-step method involving carbothermal shock to disperse and attach nano-sized silicon particles to the surface of a carbonaceous material, such as graphite or carbon fibers, by rapidly heating the carbonaceous material to 1400°C or higher within 10 seconds, allowing for the adjustment of silicon particle size and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon nanoparticles are used to increase theoretical capacity to 4200 mAh/g, then energy density is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent combines the manufacturing of silicon nanoparticles and their compounding with carbonaceous material into a single carbothermal shock step. By mixing carbonaceous material and solid silicon as raw materials and heating them together, the process achieves both nanoparticle formation and composite creation simultaneously, eliminating the need for separate manufacturing and compounding steps, thereby reducing manufacturing cost while maintaining high energy density.
Solution Approach 2:
The patent uses rapid heating to 1400°C or higher within 10 seconds to change the physical state of silicon from solid to melted and dispersed form. This parameter change in temperature and heating rate enables the formation of nano-sized silicon particles directly during the carbothermal shock process, achieving high energy density without the need for expensive pre-manufactured silicon nanoparticles.
2Manufacturing precision
If a two-step process is used to manufacture silicon nanoparticles and then compound them, then particle size control is improved, but process complexity increases
Solution Approach 1:
The patent merges two separate processes (silicon nanoparticle manufacturing and compounding with carbonaceous material) into a single carbothermal shock step. By performing both operations simultaneously through rapid heating of the mixed raw materials, the process maintains particle size control while significantly reducing process complexity from two steps to one step.
3Quantity of substance
If silicon is used as anode material to achieve high capacity, then charge capacity is improved, but mechanical damage occurs due to volume expansion and contraction
Solution Approach 1:
The patent embeds silicon particles within a carbonaceous material matrix, creating a composite structure where the carbonaceous material acts as a flexible container or shell. This structure allows the silicon to expand and contract during charging and discharging cycles while being constrained by the carbonaceous material, preventing mechanical damage and maintaining electrode durability while preserving high charge capacity.
Solution Approach 2:
The patent creates a composite anode material combining silicon and carbonaceous material. The silicon provides high charge capacity (4200 mAh/g theoretical capacity) while the carbonaceous material provides structural stability and prevents mechanical damage from volume changes. This composite structure successfully combines the advantages of both materials to achieve high capacity with improved reliability.
4Reliability
If graphite is used as anode material to ensure structural stability, then reliability is improved, but interlayer diffusion rate of lithium is low
Solution Approach 1:
The patent creates a composite anode material combining silicon and carbonaceous material. The carbonaceous material provides a structure similar to graphite with good structural stability, while the dispersed silicon particles provide high capacity. The composite structure maintains the structural reliability of carbonaceous material while the nano-sized silicon particles enable faster lithium diffusion compared to bulk graphite, achieving both stability and rapid charging capability.
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
This method reduces processing and manufacturing costs while enhancing the durability and charge/discharge performance of the composite anode material by dispersing nano-sized silicon particles, which lowers interface resistance and prevents mechanical damage from volume changes, enabling rapid charging and extended battery life.
Implementation Method 1
a carbothermal shock step of heating the carbonaceous material so that the solid silicon is melted using the heated carbonaceous material
Implementation Method 2
The carbothermal shock step provides to heat the carbonaceous material to 1400°C or higher within 10 sec.
Implementation Method 3
heating the carbonaceous material so that the solid silicon is melted using the heated carbonaceous material
Implementation Method 4
is dispersed and attached in the form of particles to the surface of the carbonaceous material
Data Source
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AI summary
Disclosed is a method of manufacturing a composite anode material for a lithium secondary battery containing nano-sized silicon and a carbonaceous material through a single process, the method including mixing a carbonaceous material and solid silicon and performing carbothermal shock for rapidly heating the carbonaceous material so that the solid silicon is melted using the heated carbonaceous material and is dispersed and attached in the form of particles to the surface of the carbonaceous material, the size of the silicon particles, which grow on the surface of the carbonaceous material, being adjusted during the carbothermal shock. Accordingly, processing costs can be lower than conventional methods of manufacturing silicon nanoparticles, and manufacturing costs can be further reduced by simultaneously performing formation of the silicon nanoparticles and compounding with the carbonaceous material.