Coal-Based Negative Electrode Material for High-Rate Cycle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing negative electrode materials for lithium ion batteries have complex structures, high costs, and insufficient continuous high-rate cycle performance, which do not meet market demands despite providing higher battery capacity and initial coulombic efficiency.
Innovation Solution
A coal-based negative electrode material with a compact structure and small crystal particle size is developed through a process involving crushing coal, graphitization, mixing with a modifier, pre-oxidation, and carbonization, resulting in a material with reduced pore volume and improved structural compactness, enabling efficient lithium ion intercalation and desorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex multi-layer structure with multiple processing steps is used, then battery capacity and initial coulombic efficiency are improved, but continuous high-rate cycle performance remains insufficient and production cost increases
Solution Approach 1:
The patent extracts and eliminates the complex multi-layer structure (inner layer, intermediate layer, outer layer) and complex processing steps (crushing, mixing, compression, graphitization, filling) from the prior art. Instead, it uses a simplified single-step graphitization process that directly transforms coal-based material into the desired negative electrode material, achieving excellent continuous high-rate cycle performance without the need for complex structural design
Solution Approach 2:
The patent changes the key parameter of pore volume to less than 0.02 cm³/g through controlled graphitization processing. This parameter change transforms the material structure to achieve both high battery capacity and excellent continuous high-rate cycle performance, while eliminating the need for complex multi-layer structures
2Reliability
If a complex multi-layer structure with multiple processing steps is used, then battery capacity and initial coulombic efficiency are improved, but the preparation process becomes complex and cost increases
Solution Approach 1:
The patent removes the complex multi-step preparation process (crushing, mixing with binders, compression, graphitization, filling) and replaces it with a simplified process that involves only graphitization of coal-based material. This extraction of unnecessary steps significantly simplifies manufacturing while maintaining excellent continuous high-rate cycle performance
Solution Approach 2:
The patent merges multiple separate processing steps into a single graphitization process. Instead of performing crushing, mixing, compression, graphitization, and filling as separate operations, the invention combines these functions into one integrated graphitization step that directly produces the final negative electrode material with the desired properties
3Quantity of substance
If graphite with large crystal particle size is used, then capacity is improved, but rate capability and continuous high-rate cycle performance deteriorate
Solution Approach 1:
The patent precisely controls the crystal particle size parameter through graphitization processing, achieving a pore volume of less than 0.02 cm³/g. This parameter optimization enables the material to simultaneously achieve high battery capacity and excellent rate capability, resolving the trade-off between quantity and speed
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 resulting negative electrode material achieves high charge-discharge capacity, initial coulombic efficiency, and excellent continuous high-rate cycle performance, with a capacity retention rate of over 80% after 1,500 cycles at 5 C, while reducing production costs and simplifying the preparation process.
Implementation Method 1
pre-oxidizing the mixed material in air atmosphere to obtain a pre-oxidized sample
Implementation Method 2
carbonizing the pre-oxidized sample in an inert atmosphere to obtain the negative electrode material
Data Source
AI summary
The present invention relates to the field of carbon materials, and discloses a negative electrode material, a preparation method and application thereof, and a negative electrode plate and application thereof. The negative electrode material has the following features: (1) a total pore volume of the negative electrode material is less than or equal to 0.02 cm3/g, and a volume of mesopores having a pore diameter of 2 nm to 50 nm is 0.0001 cm3/g to 0.02 cm3/g; and (2) a height ratio of a D peak to a G peak, obtained by Raman spectroscopy, of the negative electrode material meets the following condition: 0.20≤ID/IG≤1. The negative electrode material has high structural compactness and small crystal particle size, so that a battery containing the negative electrode material not only has high charge-discharge capacity, high initial coulombic efficiency and excellent rate capability, but also has excellent continuous high-rate cycle performance, and the preparation method is simple in process and low in cost.