Graphite Anode Carbon Layer for Fast Li-Ion Transport
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Solution Overview
Problem
Traditional graphite-based anode materials for lithium-ion batteries suffer from surface defects and poor compatibility with electrolytes, leading to irreversible side reactions, low initial Coulombic efficiency, and continuous capacity degradation due to uncontrolled surface and interface structure.
Innovation Solution
An anode material comprising graphite with a carbon layer on its surface, characterized by specific Raman ratio (A-B) and surface roughness (S) within defined ranges, ensuring a uniform carbon layer distribution and proper interface structure, enhancing electrolyte infiltration and kinetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface coating methods are employed to modify graphite, then side reactions between electrolyte and graphite are reduced, but lithium-ion transport kinetics deteriorate due to poor control of surface and internal interface characteristics
Solution Approach 1:
The patent applies local quality by creating distinct carbon layers with different structures at different locations: an outer amorphous carbon layer for electrolyte compatibility and an inner graphitic carbon layer for fast lithium-ion transport. This spatial differentiation of material properties resolves the contradiction between reducing side reactions and maintaining transport kinetics.
Solution Approach 2:
The patent uses composite materials by combining amorphous carbon and graphitic carbon in a core-shell structure. The amorphous outer layer provides electrolyte compatibility while the graphitic inner layer ensures fast lithium-ion diffusion, achieving both improved reliability and maintained speed through material composition optimization.
2Ease of manufacture
If traditional graphite-based materials are used, then cost-effectiveness is maintained, but initial Coulombic efficiency is low due to numerous surface defects and poor electrolyte compatibility
Solution Approach 1:
The patent applies preliminary action by pre-coating graphite particles with carbon material before battery assembly. This pre-treatment modifies the surface structure to reduce defects and improve electrolyte compatibility, preventing irreversible side reactions during initial charging and thereby improving initial Coulombic efficiency while maintaining cost-effectiveness.
Solution Approach 2:
The patent uses parameter changes by controlling the carbonization temperature (800-2000°C) and atmosphere to optimize the carbon layer structure. By adjusting these parameters, the surface defects are reduced and the carbon layer achieves optimal properties for both electrolyte compatibility and lithium-ion transport, resolving the contradiction between manufacturing ease and electrochemical performance.
3Device complexity
If existing coating processes are used, then manufacturing simplicity is maintained, but capacity and initial efficiency remain low due to inability to precisely control surface and internal interface characteristics
Solution Approach 1:
The patent applies parameter changes by optimizing carbonization temperature (800-2000°C), heating rate (5-20°C/min), and carbonizing atmosphere to precisely control the carbon layer structure. These parameter adjustments enable precise control over surface and internal interface characteristics, achieving high capacity and initial efficiency while maintaining relatively simple coating processes.
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 anode material exhibits high capacity, low impedance, and high initial efficiency by optimizing the carbon layer's disorder and crystallinity, improving electrolyte infiltration and interface transport kinetics.
Implementation Method 1
The anode material exhibits high capacity, low impedance, and high initial efficiency by optimizing the carbon layer's disorder and crystallinity, improving electrolyte infiltration and interface transport kinetics
Data Source
AI summary
Anode material, and battery. Anode material includes graphite and carbon layer located on at least part of surface of graphite. Particle surface and particle section of anode material are respectively tested by Raman spectroscopy, peak area ratio of D characteristic peak within range of 1300 cm−1 to 1350 cm−1 to G characteristic peak within range of 1500 cm−1 to 1580 cm−1 is ID/IG, ratio of ID/IG measured on the particle surface is A, and ratio of ID/IG measured on particle section is B, and 1.22<A-B≤2.10. Anode material improves lithium-ion transport kinetics, initial Coulombic efficiency, and cycle performance.