Vacuum-Treated Carbide-Derived Carbon for Battery Anodes
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Solution Overview
Problem
Lithium ion secondary batteries face issues with lithium metal anodes, including internal short circuits, uneven crystallization, and poor cycle properties due to lithium metal deposition, and carbon nanotubes have shape uniformity and cost limitations, while carbide-derived carbon lacks stable performance due to coexistence of crystalline and amorphous carbon and pore formation.
Innovation Solution
Thermal treatment of a carbide compound in a vacuum followed by thermochemical reaction with a halogen element-containing gas and annealing to produce carbide-derived carbon with dense graphite crystallinity and high ion mobility, suitable for lithium battery anodes, air battery electrodes, and supercapacitor electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as anode material, then high energy density is achieved, but internal short circuit and poor cycle properties occur due to uneven lithium deposition
Solution Approach 1:
The patent uses carbide-derived carbon as an intermediary layer between the lithium metal anode and electrolyte. This intermediate carbon layer provides a stable platform for lithium deposition, preventing direct contact between lithium metal and electrolyte that causes short circuits, while still enabling high energy density through lithium intercalation
Solution Approach 2:
The patent changes the physical and chemical parameters of the anode material by using carbide-derived carbon with specific properties (graphite crystallinity, controlled porosity, high surface area) instead of pure lithium metal. This parameter change maintains high energy density while improving cycle stability through reversible lithium insertion/extraction
2Reliability
If carbon nanotubes are used as anode material, then high conductivity and field emission properties are achieved, but high cost and poor shape uniformity occur
Solution Approach 1:
The patent creates carbide-derived carbon that copies the desirable electrical conductivity properties of carbon nanotubes but through a different, more manufacturable approach. The carbide-derived carbon achieves similar conductivity through its graphite crystalline structure without requiring expensive nanotube synthesis and processing
Solution Approach 2:
The patent replaces expensive carbon nanotubes with carbide-derived carbon obtained from more economical carbide precursors. The carbide-derived carbon provides comparable performance at lower cost, making it economically viable for commercial battery production
3Ease of manufacture
If carbide-derived carbon is produced by simple thermochemical reaction, then carbon material is obtained, but poor performance stability occurs due to coexistence of crystalline and amorphous carbon
Solution Approach 1:
The patent applies preliminary vacuum thermal treatment to the carbide compound before the main thermochemical reaction. This preliminary action ensures uniform particle structure and removes impurities, leading to more consistent graphite crystallinity in the final carbide-derived carbon product
Solution Approach 2:
The patent changes the thermal treatment parameters by conducting vacuum thermal treatment at specific temperatures and durations before carbide formation. This parameter control promotes uniform graphite crystalline structure development, reducing amorphous carbon content and improving performance stability
4Temperature
If high temperature treatment is applied to carbide compound, then carbon material is formed, but pore formation occurs reducing density
Solution Approach 1:
The patent applies preliminary vacuum thermal treatment at moderate temperatures before high-temperature carbide formation. This preliminary treatment densifies the carbide particle structure, creating a more compact framework that resists pore formation during subsequent high-temperature processing
Solution Approach 2:
The patent uses vacuum environment during thermal treatment to prevent oxidation and unwanted chemical reactions that could create pores. The inert vacuum atmosphere allows controlled densification without introducing voids or compromising material integrity
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 carbide-derived carbon with reduced amorphous carbon, uniform graphite distribution, and high ion mobility, enhancing charge/discharge efficiency and stability, suitable for various energy storage applications.
Implementation Method 1
a carbide compound is thermally treated in a vacuum so that carbide particles are pretreated into a high-density agglomerate
Implementation Method 2
thermally treated in a vacuum
Implementation Method 3
thermochemically reacted with a halogen element-containing gas so as to extract the element other than carbon
Implementation Method 4
halogen element-containing gas
Implementation Method 5
carbon material able to form an interlayer compound may result in only movement of lithium during charge/discharge
Implementation Method 6
dense graphite crystallinity
Data Source
AI summary
Disclosed is a method of preparing a carbide-derived carbon having high ion mobility for use in a lithium battery anode material, a lithium air battery electrode, a supercapacitor electrode, and a flow capacitor electrode, including thermally treating a carbide compound in a vacuum, thus obtaining a vacuum-treated carbide compound; and thermochemically reacting the vacuum-treated carbide compound with a halogen element-containing gas, thus extracting the element other than carbon from the vacuum-treated carbide compound, wherein annealing can be further performed after thermochemical reaction. This carbide-derived carbon has a small pore distribution, dense graphite fringe, and a large lattice spacing and thus high ion mobility, compared to conventional carbide-derived carbon obtained only by thermochemical reaction with a halogen element-containing gas.