Graphite Negative Electrode Material for Low-Swelling Li-Ion Cycling
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Solution Overview
Problem
Existing electrochemical devices, particularly lithium-ion batteries, face challenges in cycle performance and thickness swelling during high-temperature cycling due to the recombination of negative electrode active materials, which affects capacity and efficiency.
Innovation Solution
The use of graphite particles with specific particle size ratios and surface area adjustments, combined with a high-viscosity binder to form secondary particles, enhances the strength and stability of the negative electrode active material, reducing particle crushing and SEI film formation, thereby improving cycle performance and reducing swelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If graphite particles are used as negative electrode active material, then high capacity and long cycle life are achieved, but thickness swelling occurs during high-temperature cycling due to particle recombination
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of graphite particles (D10: 3-8 μm, D50: 9-15 μm, D90: 18-30 μm) and specific surface area (0.8-1.5 m²/g). These parameter optimizations reduce particle recombination during high-temperature cycling, thereby minimizing thickness swelling while maintaining long cycle life.
Solution Approach 2:
The patent uses composite materials by combining graphite particles with specifically controlled properties (particle size distribution and surface area) to create a negative electrode active material that resists recombination. This composite approach with optimized characteristics prevents thickness swelling during cycling while preserving high capacity and durability.
2Reliability
If particle size and surface area of graphite particles are optimized, then particle recombination is reduced and cycle performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for particle size (D10: 3-8 μm, D50: 9-15 μm, D90: 18-30 μm) and specific surface area (0.8-1.5 m²/g) that balance manufacturing feasibility with performance requirements. These optimized parameters improve cycle performance while maintaining reasonable manufacturing precision standards.
3Productivity
If graphite particles with specific properties are used, then initial coulomb efficiency and capacity are enhanced, but particle crushing may occur during electrode fabrication
Solution Approach 1:
The patent optimizes particle size parameters (D10: 3-8 μm, D50: 9-15 μm, D90: 18-30 μm) to achieve a balance between initial coulomb efficiency and particle strength. The specific surface area is controlled at 0.8-1.5 m²/g to enhance electrochemical performance while maintaining sufficient particle strength to prevent crushing during electrode fabrication processes.
Data Source
AI summary
This application relates to a negative electrode active material and an electrochemical device and an electronic device using the same. Specifically, this application provides a negative electrode active material, where the negative electrode active material has a median particle size D1v50, the negative electrode active material has a median particle size D2v50 under a pressure of 1 t, and D2v50/D1v50 is not less than 0.8. The negative electrode active material of this application helps to achieve a balance between high capacity and high cycle expansion performance of an electrochemical device.