Modified Green Coke Microstructure for Non-Agglomerating Graphitization
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Solution Overview
Problem
Conventional raw green coke materials have a structure that is not fully developed, with high volatile components and residual light components, leading to low graphitization degree, low gram capacity, and low compaction density, and are prone to agglomeration during heat treatment, which affects the performance of graphite negative electrode materials.
Innovation Solution
A modified green coke material is prepared by increasing the long fibrous structure and broad-domain structure while reducing volatile components to below 5%, achieved through low-temperature heat treatment of green coke particles with controlled size and oxygen content, eliminating self-bonding properties and agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional raw green coke material is used, then the material is readily available and easy to process, but the graphitization degree is low and the structure is not fully developed
Solution Approach 1:
The patent applies preliminary action by performing a low-temperature heat treatment (calcination) on the green coke material before the main graphitization process. This pre-treatment develops the microstructure and removes volatile components in advance, creating a more favorable starting condition for subsequent high-temperature graphitization, thereby improving the final graphitization degree without significantly increasing overall process complexity
Solution Approach 2:
The patent utilizes parameter changes by controlling the low-temperature heat treatment conditions (temperature range of 200-400°C, holding time of 1-6 hours) to optimize the removal of volatile components and development of microstructure. By adjusting these parameters, the material achieves better graphitization characteristics while maintaining process feasibility
2Ease of manufacture
If conventional raw green coke material with high volatile components is used, then the material is easier to obtain, but agglomeration and caking occur during heat treatment increasing subsequent process costs
Solution Approach 1:
The patent applies preliminary action by conducting a low-temperature heat treatment step before main processing. This pre-treatment removes volatile components and prevents self-bonding properties from developing, thereby eliminating the root cause of agglomeration and caking that would otherwise occur during subsequent heat treatment processes
Solution Approach 2:
The patent converts the potentially harmful effect of volatile components (which cause agglomeration) into a benefit by using controlled low-temperature heat treatment to selectively remove these volatiles. The process transforms the problematic high-volatile material into a stable, non-agglomerating material suitable for high-quality graphite production
3Manufacturing precision
If conventional raw green coke material is used, then the processing is simpler, but the gram capacity and compaction density are low无法满足 high energy density requirements
Solution Approach 1:
The patent applies preliminary action by implementing a low-temperature heat treatment step that develops the microstructure and removes volatile components before the main graphitization process. This pre-treatment creates a more favorable starting condition for achieving high gram capacity and compaction density, as the material structure is pre-optimized for dense packing and high lithium insertion capacity
Solution Approach 2:
The patent utilizes parameter changes by controlling the low-temperature heat treatment conditions (temperature, time, atmosphere) to optimize the material properties. By adjusting these parameters, the material achieves enhanced gram capacity and compaction density characteristics that meet high energy density requirements while keeping the overall process manageable
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 modified green coke material improves graphitization degree, gram capacity, and compaction density, maintaining low-expansion performance and good fast charge performance, resulting in a graphite negative electrode material with enhanced electrochemical properties.
Implementation Method 1
the composite granular graphite material is put into a graphitization furnace to perform a graphitization treatment
Implementation Method 2
a low-temperature heat treatment is performed to obtain the modified green coke material
Data Source
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AI summary
The disclosure provides a modified green coke material, a method for preparing the modified green coke material, and an application of the modified green coke material. A sum of percentages of a long fibrous structure and a broad-domain structure in a polarized microstructure of the modified green coke material is in a range of 55 ~ 99%, and a percentage of volatile components in the modified green coke material is in a range of 1% ≤ volatile components matter < 5%. In regard to the modified green coke material provided in the disclosure, the long fibrous structure and the broad-domain structure are increased, the volatile components are effectively reduced, and light components are further excluded, thereby eliminating a self-bonding property of raw materials. In this case, further agglomeration will not occur during a subsequent heat treatment for preparing a graphite negative electrode material. Using the modified green coke material to prepare the graphite negative electrode material can effectively improve a graphitization degree, a gram capacity, and a compaction density of the graphite negative electrode material, thus comprehensively improving the performance of the graphite negative electrode material.