Artificial Graphite Anode Surface Oxidation for Higher Capacity
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Solution Overview
Problem
The specific capacity of current artificial graphite negative electrode materials for lithium-ion batteries is limited, affecting the overall energy density and cycling performance of the batteries.
Innovation Solution
A method involving heating artificial graphite in a protective atmosphere and injecting an active gas to modify the surface of the graphite material, reducing SP3 carbon and enhancing ion transport properties, thereby increasing the specific capacity without compromising bulk cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity negative electrode materials (silicon, tin) are added to increase specific capacity, then the specific capacity increases, but the cycling performance deteriorates and battery stability decreases
Solution Approach 1:
The patent extracts and removes SP3 carbon from the graphite surface through oxidation treatment. This extraction of harmful components (SP3 carbon) allows the base graphite material to achieve higher capacity without adding unstable high-capacity materials like silicon or tin, thus maintaining cycling performance while improving specific capacity.
Solution Approach 2:
The patent changes the chemical composition parameters of the graphite surface by controlling the oxidation process to selectively remove SP3 carbon while preserving the SP2 carbon structure. This parameter change (reducing SP3 carbon content) enables the material to achieve higher capacity with maintained stability.
2Quantity of substance
If SP3 carbon is removed from the graphite surface to increase specific capacity, then the specific capacity increases, but the surface structure is modified
Solution Approach 1:
The patent applies local quality change by selectively modifying only the surface layer of the graphite particles through oxidation treatment. The SP3 carbon on the surface is removed while the bulk SP2 carbon structure remains intact, achieving local purification that increases capacity without compromising overall structural stability.
Solution Approach 2:
The oxidation treatment is conducted in a controlled atmosphere environment, allowing selective removal of SP3 carbon while protecting the SP2 carbon structure. The controlled environment enables precise modification of surface composition without damaging the underlying stable structure.
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 achieves a discharge specific capacity of over 353.2 mAh/g at 0.1 C, a first cycle efficiency of over 94.9%, and a capacity retention of over 96.7% after 100 cycles, while maintaining fast charging performance.
Implementation Method 1
heating up artificial graphite in a protective atmosphere and injecting an active gas
Implementation Method 2
heating up artificial graphite in a protective atmosphere and injecting an active gas
Data Source
AI summary
An artificial graphite negative electrode material, a method for preparing the same, and a lithium-ion battery are provided. The method includes: obtaining the artificial graphite negative electrode material by heating up artificial graphite in a protective atmosphere and injecting an active gas. The artificial graphite negative electrode material is obtained by heating up artificial graphite in a protective atmosphere and injecting an active gas.