Coated Natural Graphite for Battery Electrodes
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Solution Overview
Problem
Current carbon materials for lithium ion secondary batteries face challenges in achieving high energy density, long cycle life, and large current load characteristics, particularly for applications requiring ultralong-term cycle characteristics and high power output, such as electric vehicles.
Innovation Solution
A carbon material with specific structural and chemical properties, including a Raman spectroscopy ratio of 0.38 to 1.2, an average interplanar spacing of 0.335 to 0.338 nm, and a BET specific surface area of 2 to 25 m^2/g, produced through a process involving calcined coke heat treatment and mixing with petroleum pitch, is used to enhance lithium ion diffusion and electrode density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If natural graphite is used as negative electrode active material, then cost is reduced, but alignment occurs during electrode production which degrades electrode performance
Solution Approach 1:
The patent uses composite materials by coating artificial carbon on the surface of natural graphite particles. This composite structure combines the cost advantage of natural graphite with the performance benefits of artificial carbon, preventing alignment and maintaining electrode performance while keeping costs low.
Solution Approach 2:
The patent changes the surface properties of natural graphite by coating it with artificial carbon, modifying parameters such as surface roughness, conductivity, and structural stability. This prevents the alignment issue during electrode production while maintaining the cost benefits of natural graphite.
2Reliability
If natural graphite is granulated and formed into spherical shape, then alignment is reduced, but surface activity increases causing gas generation and decreased initial efficiency
Solution Approach 1:
The patent modifies the surface parameters of spherical natural graphite by coating it with artificial carbon. This reduces surface activity and prevents gas generation during initial charging, while maintaining the alignment resistance provided by the spherical shape.
Solution Approach 2:
The patent converts the harmful surface activity of natural graphite into a benefit by coating it with artificial carbon. The coating material reacts with the surface to form a stable structure that prevents gas generation, turning the initially harmful surface activity into a controlled process that improves overall battery performance.
3Productivity
If artificial graphite with highly-developed fine pores is used, then high-rate discharge is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses porous artificial carbon material to coat the natural graphite particles. The porous structure provides highly-developed fine pores that enable high-rate discharge, while the coating process itself is a relatively simple manufacturing step that can be integrated into existing production lines.
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 carbon material improves lithium ion diffusion, leading to high energy density, high-speed charge and discharge capabilities, while maintaining high capacity and cycle characteristics, and is produced with economic efficiency and improved safety.
Implementation Method 1
the carbon material improves lithium ion diffusion, leading to high energy density, high-speed charge and discharge capabilities
Implementation Method 2
produced through a process involving calcined coke heat treatment and mixing with petroleum pitch
Data Source
AI summary
A carbon material and a material for a battery electrode which is suitable for use as an electrode material for an aqueous-electrolyte secondary battery, which material includes optical structures having a specific shape, and in which material the ratio IG/ID (R value) between the peak intensity (ID) of a peak in a range of 1300 to 1400 cm−1 and the peak intensity (IG) of a peak in a range of 1580 to 1620 cm−1 measured by Raman spectroscopy spectra when particles of the carbon material are measured with Raman microspectrometer is 0.38 or more and 1.2 or less and the average interplanar spacing d002 of plane (002) by the X-ray diffraction method is 0.335 nm or more and 0.338 nm or less; and a secondary battery excellent in charge/discharge cycle characteristics and large current load characteristics.