Petcoke Artificial Graphite Anodes With Acid Leaching and Graphitization
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Solution Overview
Problem
The challenge is to develop an inexpensive artificial graphite negative electrode material for rechargeable lithium batteries that matches the performance of needle coke-based materials while addressing the high impurity content and low graphitization of petcoke, which is typically used as a cheap but inefficient energy source due to environmental concerns.
Innovation Solution
A method involving drying, comminuting, and leaching petcoke in an acid solution to remove inorganic impurities, followed by primary and secondary carbonization heat treatments, and graphitization at 2500° C. to 3500° C. to produce artificial graphite with controlled impurity levels and enhanced crystallinity, using boron as a graphitization accelerant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If petcoke is used as a raw material for artificial graphite negative electrode material, then material cost is reduced, but the degree of graphitization and purity deteriorate due to high impurity content
Solution Approach 1:
The patent applies preliminary acid treatment to petcoke before carbonization to remove inorganic impurities. This preliminary action prevents impurities from interfering with the graphitization process, enabling high-degree graphitization to be achieved from low-cost petcoke raw material
Solution Approach 2:
The patent employs extreme parameter changes by conducting graphitization heat treatment at very high temperatures (2500-3500°C) to transform the crystalline structure of petcoke into highly graphitized artificial graphite, overcoming the initial low crystallizability of petcoke
2Quantity of substance
If petcoke is used as a raw material for artificial graphite negative electrode material, then material cost is reduced, but purity deteriorates due to high inorganic impurity content
Solution Approach 1:
The patent extracts inorganic impurities from petcoke through acid leaching treatment before carbonization. This extraction process removes harmful impurities while retaining the carbon structure, enabling production of high-purity artificial graphite from impure petcoke raw material
Solution Approach 2:
The patent uses acid solution as an intermediary substance to selectively remove inorganic impurities from petcoke. The acid acts as a mediator that separates desirable carbon components from harmful impurities, facilitating production of pure artificial graphite at low cost
3Ease of manufacture
If natural graphite is spherodized to improve processing and packing density, then ease of manufacture and packing density are improved, but lifespan characteristic deteriorates due to structural defects and internal stress
Solution Approach 1:
Instead of spherodizing natural graphite (which creates structural defects), the patent inverts the approach by producing artificial graphite with inherently spherical morphology through controlled carbonization of petcoke. This inversion eliminates the need for mechanical spherodization while maintaining processing advantages and avoiding structural damage
Solution Approach 2:
The patent creates artificial graphite with optimized composite structure through controlled carbonization and graphitization processes, achieving both spherical morphology for easy processing and intact crystalline structure for long lifespan, avoiding the defects associated with spherodizing natural graphite
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 approach results in a cost-effective artificial graphite negative electrode material with improved performance and lifespan, comparable to needle coke-based materials, while minimizing environmental impact and reducing material costs.
Implementation Method 1
leaching acidifying the inferior petcoke, which has been comminuted and classified, in an acid solution
Implementation Method 2
performing carbonization and graphitization
Implementation Method 3
performing carbonization and graphitization
Data Source
AI summary
The present invention provides: a method for preparing a petcoke-based artificial graphite negative electrode material for a lithium secondary battery, in which low-grade petcoke is used as a raw material, and artificial graphite having a high degree of graphitization is prepared through leaching and acid treatment of pulverized/classified low-grade petcoke in an acidic solution, followed by carbonization and graphitization; an artificial graphite negative electrode material for a lithium secondary battery, prepared thereby; and a lithium secondary battery.