Amorphous Carbon Particles for Lithium Ion Battery Anodes
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Solution Overview
Problem
Amorphous carbon particles used in lithium ion secondary batteries face challenges with poor pressability and significant expansion and shrinkage during charging and discharging, affecting electrode density and cycle life.
Innovation Solution
Incorporating mesophase particles within the amorphous carbon particles through a crosslinking and infusibilization treatment process, which enhances electrode density and suppresses expansion and shrinkage by maintaining a mesophase structure within the particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hard carbons are used as negative electrode materials, then expansion and shrinkage during charging and discharging are reduced, but electrode density and pressability deteriorate
Solution Approach 1:
The invention creates a composite carbon particle structure where hard carbon forms the base matrix and soft carbon is embedded within it. This composite structure combines the low expansion/shrinkage特性 of hard carbon with the high density and good pressability of soft carbon, resolving the technical contradiction between these two properties.
Solution Approach 2:
The invention applies local quality by creating regions with different carbon characteristics within the same particle. The soft carbon regions provide high density and pressability, while the hard carbon matrix provides low expansion and shrinkage, allowing each region to fulfill its specific function.
2Manufacturing precision
If soft carbons are used as negative electrode materials, then electrode density and pressability are improved, but expansion and shrinkage during charging and discharging increase
Solution Approach 1:
By embedding soft carbon within a hard carbon matrix, the composite structure allows the soft carbon to contribute high density and pressability while the surrounding hard carbon matrix constrains and suppresses the expansion and shrinkage that would otherwise occur in soft carbon during battery cycling.
Solution Approach 2:
The soft carbon regions are distributed locally within the hard carbon matrix, allowing high density in specific regions while the overall particle structure maintains low expansion characteristics through the hard carbon framework.
3Manufacturing precision
If mesophase particles are incorporated into amorphous carbon particles, then electrode density and pressability are improved, but the complexity of the production process increases
Solution Approach 1:
The invention uses preliminary action by forming the mesophase structure during the carbonization process itself, rather than requiring separate post-processing steps. The mesophase particles are incorporated into the amorphous carbon precursor before carbonization, and the thermal treatment naturally develops the mesophase structure, simplifying the overall process despite the added material step.
Solution Approach 2:
The invention controls the carbonization temperature parameters to promote mesophase formation. By optimizing the temperature range and holding time during carbonization, the mesophase structure develops naturally from the precursor materials, achieving the desired structural transformation through parameter control rather than additional process steps.
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 amorphous carbon particles with improved pressability and reduced expansion and shrinkage, leading to increased electrode density and extended battery cycle life.
Implementation Method 1
obtaining a first crosslinked product by admixing mesophase particles with an amorphous carbon precursor and thereafter subjecting the mixture to a crosslinking treatment
Implementation Method 2
subjecting the first or second crosslinked product to a infusibilization treatment
Implementation Method 3
firing the product to produce amorphous carbon particles including the mesophase particles within the particles
Data Source
AI summary
A method for producing an amorphous carbon particle includes the steps of: obtaining a first crosslinked product by admixing mesophase particles with an amorphous carbon precursor and thereafter subjecting the mixture to a crosslinking treatment, or obtaining a second crosslinked product by crosslinking the amorphous carbon precursor and thereafter admixing the mesophase particles with the crosslinked precursor; and subjecting the first or second crosslinked product to an infusibilization treatment and thereafter firing the product to produce amorphous carbon particles including the mesophase particles within the particles.