Carbonaceous Electrode Material Balancing Density and Irreversible Capacity
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Solution Overview
Problem
Existing carbonaceous materials for non-aqueous electrolyte secondary batteries, such as lithium-ion batteries, suffer from increased irreversible capacity and decreased charge-discharge efficiency due to smaller particle sizes, which hinder the enhancement of energy density.
Innovation Solution
A carbonaceous material with controlled particle size distribution, shape, cohesion, and fluidity, characterized by a specific surface area of 23 m2/g or less, aerated energy of 40 mJ or more and 210 mJ or less, and average particle size D50 between 1 μm and 50 μm, produced through primary and secondary pulverization and classification steps, along with calcination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the particle size of carbonaceous material is reduced to increase electrode density, then the specific surface area increases, but the irreversible capacity increases and charge-discharge efficiency decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling multiple parameters of the carbonaceous material: specific surface area (23 m²/g or less), aerated energy (40-210 mJ), and particle size distribution (D50/D10 ratio of 1.9 or more). This multi-parameter optimization resolves the contradiction by finding the optimal balance point where electrode density is sufficiently high while irreversible capacity is suppressed.
Solution Approach 2:
The patent uses composite control of multiple material properties rather than focusing on a single parameter. By combining control of specific surface area, aerated energy, particle size distribution, and shape factors, the invention creates a composite material specification that simultaneously achieves high electrode density and low irreversible capacity.
2Volume of stationary object
If the particle size of carbonaceous material is reduced to increase electrode density, then the specific surface area increases, but the charge-discharge efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by changing multiple parameters simultaneously: controlling specific surface area to 23 m²/g or less, aerated energy to 40-210 mJ, and D50/D10 ratio to 1.9 or more. This multi-parameter approach ensures that electrode density is optimized while charge-discharge efficiency is maintained.
Solution Approach 2:
The patent employs feedback control through the aerated energy parameter, which reflects the cohesive properties and flow characteristics of the carbonaceous material. By measuring and controlling aerated energy within the specific range, the invention ensures optimal packing density while maintaining charge-discharge efficiency.
3Loss of energy
If the specific surface area is reduced to suppress irreversible capacity, then the particle size increases, but the electrode density decreases
Solution Approach 1:
The patent resolves this contradiction through composite control of multiple parameters: specific surface area (23 m²/g or less), aerated energy (40-210 mJ), and particle size distribution (D50/D10 ratio of 1.9 or more). This multi-parameter composite approach allows the material to achieve both low irreversible capacity and high electrode density by optimizing the overall material characteristics rather than relying on a single parameter.
Solution Approach 2:
The patent applies local quality by controlling the particle size distribution shape (D50/D10 ratio) to create a specific distribution pattern. This ensures that while the overall specific surface area is controlled to suppress irreversible capacity, the particle size distribution is optimized to maintain high electrode density through proper packing characteristics.
Data Source
AI summary
An object of the present invention is to provide a carbonaceous material suitable as an electrode material of an electrochemical device which is increased in capacity with not only suppression of an increase in irreversible capacity, but also securement of a high electrode density, as well as a method for producing the carbonaceous material The present invention relates to a carbonaceous material for an electrochemical device, having a specific surface area of 23 m2/g or less as measured according to a BET method and an aerated energy (AE) of 40 mJ or more and 210 mJ or less as measured with a powder rheometer.