Low-Swelling Graphite Anode Material for Better Cycle Stability
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Solution Overview
Problem
Natural graphite anode materials exhibit high swelling rates during lithium-ion battery cycling, leading to poor cycle performance and high costs due to inefficient processing methods, which hinder the widespread adoption of lithium-ion batteries in electric vehicles.
Innovation Solution
A method involving the pretreatment of flake graphite with a modifier and a pore-forming agent, followed by heat treatment under a protective atmosphere, to optimize particle size, structure, and pore structure, resulting in a low-swelling graphite anode material with enhanced electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If natural graphite is used as anode material to reduce cost, then cost is reduced, but swelling rate increases leading to poor cycle performance
Solution Approach 1:
The patent applies preliminary action by performing surface treatment and pore structure construction on natural graphite particles before they are used as anode material. The flake graphite undergoes acid treatment, oxidation, and pore-forming processes that modify its surface chemistry and internal structure in advance, preventing swelling during subsequent battery cycling while maintaining the cost advantage of natural graphite
2Shape
If flake graphite is mechanically crushed to form spherical graphite, then particle shape is improved, but yield decreases due to material waste
Solution Approach 1:
The patent extracts and removes the harmful edges and corners of flake graphite particles through selective mechanical crushing and classification processes. By taking out only the problematic portions that cause swelling and poor electrochemical performance, the method preserves most of the original graphite material while achieving the desired spherical shape and high yield
3Shape
If multiple crushing operations are performed to spheroidize graphite, then particle morphology is improved, but processing complexity increases
Solution Approach 1:
The patent merges multiple processing functions into a integrated flow: acid treatment for surface cleaning, oxidation for pore formation, controlled mechanical crushing for spheroidization, and classification for size separation. By combining these operations in a systematic sequence with optimized parameters, the method achieves excellent particle morphology while reducing overall processing complexity compared to traditional multi-step approaches
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 significantly reduces the swelling rate of graphite anode materials by 20% compared to conventional natural graphite, achieving excellent cycle and rate performance, making lithium-ion batteries more cost-effective and suitable for electric vehicles.
Implementation Method 1
followed by heat treatment under a protective atmosphere
Implementation Method 2
the heat treatment in step 2 is a carbonization treatment
Data Source
AI summary
A low-swelling graphite anode material, a preparation method thereof, and a lithium ion battery including the graphite anode material. The preparation method of the graphite anode material includes: (1) mixing a graphite raw material with a modifier, and then performing heating modification; (2) performing heat treatment on the modified graphite under a protective atmosphere; and (3) performing post-treatment on the heat-treated graphite to obtain the graphite anode material. The graphite anode material has an extremely low swelling rate, excellent cycle performance, and outstanding rate performance, an swelling rate being 24.3% or lower, a normal temperature 10C/1C discharge capacity retention rate being greater than 90%, and a capacity retention rate after charging and discharging for 300 times being 91% or greater.