Carbon Anode Composition for High-Density Pressing Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing negative electrode materials for lithium-ion secondary batteries face issues with destruction during high-density pressing and electrode plate expansion, leading to decreased initial efficiency.
Innovation Solution
A carbon material composition comprising two types of carbon materials, where one has amorphous carbon and multiple peaks in its pore size distribution, and the other has a high pellet density, is used to maintain efficiency and reduce expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If common negative electrode materials are used to achieve high density, then the energy density of the battery is improved, but the electrode material is destroyed during pressing, resulting in decreased initial efficiency
Solution Approach 1:
The patent uses a composite carbon material comprising natural graphite particles and artificial graphite particles. The natural graphite provides high density and capacity, while the artificial graphite with amorphous carbon coating and controlled pore structure prevents destruction during pressing. This composite structure resolves the contradiction by combining the advantages of both material types to achieve high energy density while maintaining structural integrity and initial efficiency.
Solution Approach 2:
The artificial graphite particles are designed with specific local characteristics: an amorphous carbonaceous material coating on the surface and a controlled pore size distribution with two or more peaks. The coating provides structural reinforcement at the particle surface to prevent destruction during pressing, while the pore structure maintains overall particle integrity. This local quality modification allows the material to withstand high-density pressing while preserving initial efficiency.
2Quantity of substance
If common negative electrode materials are used to achieve high density, then the energy density of the battery is improved, but the electrode plate expansion increases, leading to performance degradation
Solution Approach 1:
The composite structure of natural graphite and artificial graphite particles creates a synergistic effect where the artificial graphite particles with controlled pore structures and amorphous carbon coatings act as structural stabilizers. These particles resist expansion during lithium insertion/extraction cycles, thereby preventing overall electrode plate expansion while maintaining high energy density through the high-capacity natural graphite component.
Solution Approach 2:
The artificial graphite particles are designed with a specific pore size distribution featuring two or more peaks, including micropores (2 nm to 2 μm) and mesopores (2 μm to 50 μm). This porous structure accommodates volume changes during lithium insertion and extraction, absorbing expansion stresses internally and preventing macroscopic electrode plate expansion, thus maintaining structural stability while enabling high energy density.
3Reliability
If the pore volume in particles is increased to improve initial efficiency, then the initial efficiency is improved, but the particle structure becomes more vulnerable to destruction during pressing
Solution Approach 1:
The artificial graphite particles are designed with localized amorphous carbonaceous material coatings on their surfaces and controlled internal pore structures. The coating provides structural reinforcement at critical surfaces to prevent particle destruction during pressing, while the controlled pore volume (with two or more peaks in size distribution) maintains pathways for lithium ion transport. This local quality differentiation allows the particles to have both high initial efficiency and structural integrity under pressure.
Data Source
AI summary
The present invention provides a carbon material composition containing a carbon material (A) and a carbon material (B), in which the carbon material (A) contains graphite containing an amorphous carbonaceous material or a graphite material, has two or more peaks in a pore size distribution measured by a mercury porosimetry, and satisfies y≤−0.0084x+0.13 wherein a cumulative pore volume in a range where a pore diameter is equal to or smaller than a pore diameter at a local minimum value between a peak of a smallest pore diameter and a peak of a second smallest pore diameter in the pore size distribution is defined as y (mL/g) and a coating rate of the amorphous carbonaceous material or the graphite material in the graphite is defined as x (%), and the carbon material (B) has a pellet density of 1.80/cm3 or more.