Graphitized Carbon Anode Material Without Granulation for Li-Ion Output
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Solution Overview
Problem
Current negative electrode active materials for lithium secondary batteries face challenges in achieving high discharge capacity, high charge output, and long cycle life while minimizing volume changes, often requiring costly granulation processes that compromise performance.
Innovation Solution
A carbon raw material with a total fibrosity index (TFI) of 0.58 to 0.78, including petroleum-based or coal-based cokes, is used to manufacture a negative electrode active material through pulverization, grinding, and graphitization, without the need for granulation, resulting in a high graphitization degree and low orientation degree, and a particle diameter of 5 to 30 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If natural graphite is spheroidized through milling to increase filling density and improve output characteristics, then filling density and output characteristics are improved, but capacity decreases due to increased stress and defects inside graphite particles
Solution Approach 1:
The invention changes the processing method from mechanical milling to chemical etching using ferric chloride solution. This parameter change in the processing mechanism avoids mechanical stress and defects while achieving spheroidization, thereby maintaining capacity while improving output characteristics
Solution Approach 2:
The invention replaces the mechanical milling system with a chemical etching system using ferric chloride. This substitution eliminates mechanical stress on graphite particles while achieving the desired spheroidization effect, resolving the contradiction between output improvement and capacity maintenance
2Reliability
If artificial graphite is manufactured through carbonization and high-temperature graphitization to achieve better lifespan characteristics, then lifespan characteristics are improved, but capacity is reduced and manufacturing cost increases
Solution Approach 1:
The invention changes the graphitization temperature from high temperature (2800-3000°C) to a lower temperature (2000-2500°C) while using ferric chloride etching to achieve the desired particle morphology. This parameter change reduces manufacturing cost and prevents excessive graphitization that reduces capacity, while still achieving good lifespan characteristics
Solution Approach 2:
The invention creates a composite structure by coating graphite particles with a carbonaceous layer formed from pitch or resin. This composite approach improves lifespan characteristics and prevents capacity loss without requiring extreme graphitization temperatures, thereby reducing manufacturing costs
3Manufacturing precision
If graphitization heat treatment temperature is maintained high to increase graphitization degree for higher capacity, then graphitization degree is improved, but manufacturing cost increases and charge/discharge efficiency may be compromised
Solution Approach 1:
The invention optimizes the graphitization temperature to a lower range (2000-2500°C) combined with ferric chloride etching and carbonaceous coating. This parameter optimization achieves sufficient graphitization degree for high capacity while significantly reducing energy consumption and manufacturing cost
4Reliability
If granulation process is applied to composite negative electrode material to achieve high capacity, high output, and long lifespan, then performance characteristics are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts and eliminates the granulation process from the manufacturing sequence. By using ferric chloride etching to directly spheroidize graphite particles and carbonaceous coating to form protective layers, the invention achieves high performance without the complex granulation step, thereby reducing device complexity and manufacturing cost
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 enhances discharge capacity, charge and discharge efficiency, and reduces production costs and complexity, achieving excellent performance without the granulation process, thereby improving battery lifespan and output characteristics.
Implementation Method 1
a ferric chloride solution is used to etch a carbonaceous layer on a surface of the graphite particles
Implementation Method 2
coating each of natural graphite and artificial graphite with a pitch material, carbonizing them to form a carbonaceous layer on the surface
Implementation Method 3
adding a small amount of a material capable of a catalytic graphitization reaction for increasing a capacity to perform a graphitization heat treatment
Implementation Method 4
coal or petroleum-based residues or pitch as a processed product is manufactured by carbonization and a heat treatment at a high temperature (graphitization)
Data Source
AI summary
The present invention provides: a negative electrode active material having high discharge capacity, high charge output, and excellent discharge output characteristics; and a carbon material therefor. A carbon material for a negative electrode active material according to an embodiment of the present invention provides a carbon material having the total fibrosity index (TFI) of 0.58 to 0.78.