Graphite-Amorphous Carbon Composite Negative Electrode
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Solution Overview
Problem
Lithium ion batteries face challenges in balancing dynamic performance and cycle storage performance, with carbon-based materials exhibiting either poor cycle life or high cost, and existing solutions like lithium titanate having limited capacity and high cost.
Innovation Solution
A negative electrode material comprising a combination of graphite with a graphitization degree of 90-96% and amorphous carbon with a graphitization degree of 65-80%, along with surface treatment using mechanical fusion and spray drying, to enhance lithium intercalation and diffusion channels, improving both dynamic and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If graphite material with high graphitization degree is used, then capacity and dynamic performance are improved, but cycle performance and storage performance deteriorate
Solution Approach 1:
The patent uses a composite negative electrode material consisting of graphite particles coated with amorphous carbon. The graphite core provides high capacity and good dynamic performance, while the amorphous carbon coating layer provides stable structure for long cycle life. This composite structure resolves the contradiction between high capacity and long cycle performance.
Solution Approach 2:
The patent controls the graphitization degree of the amorphous carbon coating layer within a specific range (40-80%) to optimize both dynamic performance and cycle performance. By adjusting this parameter, the material achieves a balance between lithium insertion/extraction kinetics and structural stability.
2Use of energy by moving object
If natural graphite is used, then energy density is improved, but cycle life and large rate charge-discharge capacity deteriorate
Solution Approach 1:
The patent takes natural graphite as the core material to maintain high energy density, then coats it with amorphous carbon to improve cycle life and large rate charge-discharge capacity. This composite approach preserves the advantages of natural graphite while compensating for its deficiencies.
Solution Approach 2:
The patent applies amorphous carbon coating specifically on the surface of graphite particles, creating different properties in different regions. The core maintains high energy density characteristics while the surface coating provides improved cycle stability and rate performance.
3Reliability
If artificial graphite is used, then cycle life is improved, but preparation complexity and cost increase
Solution Approach 1:
The patent uses natural graphite as the core material instead of expensive artificial graphite, significantly reducing material cost. The natural graphite, while having shorter inherent cycle life, is extended through the amorphous carbon coating, achieving a cost-effective solution with improved cycle performance.
Solution Approach 2:
The patent combines inexpensive natural graphite with amorphous carbon coating to achieve cycle life comparable to or better than artificial graphite, while maintaining lower preparation complexity and cost. The composite structure simplifies the overall preparation process compared to fully synthetic 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 proposed solution achieves desirable dynamic and cycle performance, long lifetime, low production cost, and good application prospects for lithium ion batteries, while maintaining high practicality and cost-effectiveness.
Implementation Method 1
expand the diffusion channel of lithium ion in the carbon atom layer
Implementation Method 2
expand the diffusion channel of lithium ion in the carbon atom layer
Implementation Method 3
surface treatment using mechanical fusion and spray drying
Implementation Method 4
surface treatment using mechanical fusion and spray drying
Data Source
Figure 1~2
AI summary
The present invention provides a lithium ion battery and a negative electrode material thereof. The negative electrode material includes a graphite and an amorphous carbon, wherein the graphite has a graphitization degree of 90∼96% and an average particle diameter D50 of 2∼25µm, and the amorphous carbon has a graphitization degree of 65∼80% and an average particle diameter D50 of 2∼25µm. Compared with the prior art, by mixing graphite having a small particle diameter with amorphous carbon, the negative electrode material of the present invention has excellent dynamic performance, cycle performance and storage performance. The present invention also provides a lithium ion battery.