Negative Electrode Material with Pre-dispersed Carbon Microparticles
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Solution Overview
Problem
Current negative electrode materials for secondary batteries face challenges in maintaining effective conductive carbon distribution and adhesion over long cycling times, leading to reduced dynamic performance and potential safety issues due to Li ion reduction on the electrode surface.
Innovation Solution
A negative electrode material comprising a kernel particle with a coated connection carbon layer and conductive carbon microparticles, where the conductive carbon microparticles are distributed on the connection carbon layer, forming a stable conductive network, eliminating the need for additional conductive carbon and dry-mixing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive carbon is added, dry-mixed and dispersed to form a conductive network, then dynamic performance of the negative electrode is improved, but the preparation time is extended due to small particle size requiring long dry-mixing
Solution Approach 1:
The conductive carbon is segmented into microparticles with specific size ranges (SuperP: 3-15 μm, acetylene black: 1-5 μm, carbon nanotubes: 0.5-2 μm) and pre-dispersed on the kernel particle surface before electrode formation, eliminating the need for extended dry-mixing while maintaining effective conductive network formation
Solution Approach 2:
The conductive carbon microparticles are pre-dispersed on the kernel particle surface during the slurry preparation stage, forming a preliminary conductive network structure that eliminates the need for subsequent long-duration dry-mixing processes to achieve uniform distribution
2Reliability
If conventional conductive carbon is used, then initial conductive network is formed, but contact between conductive carbon and active material deteriorates after long-term cycling due to adhesive failure and particle re-arrangement
Solution Approach 1:
The conductive carbon microparticles are merged with the active material through simultaneous carbonization of both components at 900-1100°C, creating a unified carbon structure where conductive carbon and active material carbonized layers are intimately interconnected, preventing particle re-arrangement and adhesive failure during cycling
Solution Approach 2:
The negative electrode material is designed as a composite structure with kernel particles (active material), connection carbon layer (from carbonized binder), and conductive carbon microparticles distributed on the surface, forming a multi-component system where each component serves specific functions and works synergistically to maintain stability during cycling
3Reliability
If additional conductive carbon and dry-mixing process are used, then conductive network is formed, but manufacturing complexity and cost increase
Solution Approach 1:
The formation of conductive network and binder carbonization are merged into a single carbonization step at 900-1100°C, where both the binder precursor and conductive carbon microparticles are carbonized simultaneously, eliminating separate processing steps and reducing manufacturing complexity
Solution Approach 2:
The carbonization process serves multiple functions simultaneously: it carbonizes the binder to form the connection carbon layer, carbonizes the conductive carbon microparticles, and creates strong adhesion between all components, replacing multiple separate processes with a single multi-functional treatment
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
This configuration enhances dynamic performance, supports fast charging capabilities, and reduces manufacturing costs while maintaining stable conductive networks during cycling, preventing Li ion reduction and capacity decay.
Implementation Method 1
the connection carbon layer is coated on a surface of the kernel particle, and the conductive carbon microparticle is distributed on a surface of the connection carbon layer
Data Source
AI summary
The present application relates to the field of secondary batteries and, particularly, relates to a negative electrode material for the secondary battery, a method for preparing the same, and a secondary battery containing the same. The negative electrode material includes a kernel particle, a connection carbon layer, a conductive carbon microparticle, the connection carbon layer is coated on a surface of the kernel particle, and the conductive carbon microparticle is distributed on a surface of the connection carbon layer. A high-molecular polymer is used as binder. A layer of conductive carbon microparticle is uniformly coated on a surface of the negative electrode active material, so that a stable and effective conductive network is formed in the electrode plate, thereby significantly improving a dynamic performance of the negative electrode material and providing a battery containing the negative electrode material with high rate performance and fast charging capability.