Composite Carbon Black Anode Material for Battery Cycle Stability
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Solution Overview
Problem
Lithium-ion batteries face challenges with high material costs and limited capacity due to lithium resource distribution, and existing alternatives like sodium ion batteries struggle with low ionic radius penetration and electrode strength issues, particularly with carbon black as a negative electrode active material, which absorbs binders and causes volume fluctuations.
Innovation Solution
A composite particle is created by granulating carbon black with a larger particle size material, such as metal oxides, to buffer volume fluctuations and enhance electrode strength, allowing for increased capacity and improved cycle characteristics in sodium ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon black is used as negative electrode active material to achieve high capacity, then capacity increases, but electrode strength decreases and cycle characteristics deteriorate due to binder adsorption and volume fluctuation
Solution Approach 1:
The invention uses a composite structure combining carbon black particles (providing high capacity) with a binder-coated particle (providing structural stability). The binder is selectively coated on the larger particles to form a protective layer, creating a composite material that simultaneously achieves high capacity and maintains electrode strength during cycling.
Solution Approach 2:
The binder is applied in advance to the surface of particles larger than carbon black before assembling the electrode structure. This pre-coating creates a cushioning layer that absorbs volume fluctuations of carbon black during charging and discharging, preventing electrode degradation before it occurs.
2Quantity of substance
If carbon black particle size is reduced to increase basis weight and capacity, then capacity increases, but binder adsorption increases causing severe shrinkage and handling difficulty
Solution Approach 1:
The invention changes the size parameter of the binder-coated particles to be larger than carbon black particles. This parameter change reduces the specific surface area, thereby reducing binder adsorption and improving handling ease while maintaining high basis weight through optimized particle size distribution.
3Quantity of substance
If carbon black is used as negative electrode active material, then high capacity is achieved, but cycle characteristics deteriorate due to volume fluctuation during charging and discharging
Solution Approach 1:
The binder-coated particle acts as an intermediary between carbon black particles and the electrode structure. This intermediary absorbs and buffers the volume fluctuations of carbon black during charging and discharging, preventing direct mechanical stress on the electrode and thereby improving cycle characteristics while maintaining high capacity.
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 composite particle effectively increases battery capacity and cycle life by stabilizing the electrode structure and reducing degradation, enabling higher capacity and improved thermal conductivity in sodium ion batteries, while also being applicable to other secondary batteries.
Implementation Method 1
the composite of carbon black particle and a particle not involved in charging and discharging acts as a buffer to reduce the effects of volume fluctuations of carbon black to maintain the electrode structure
Implementation Method 2
the degradation of active material properties resulting from the volume fluctuation of carbon black can be reduced
Data Source
AI summary
An object of the present invention is to provide a negative electrode active material that can impart both high capacity and improved cycle characteristics to secondary batteries to a high degree and a secondary battery using the same. A negative electrode active material for a secondary battery, comprising a composite particle of a carbon black particle as an active material and a deterioration reducing material particle that reduces deterioration of active material properties of the carbon black particle by charging and discharging, wherein the deterioration reducing material particle is a particle that has a larger particle size than the carbon black particle and that does not act as an active material, and wherein the composite particle is a mixture particle of the carbon black particle and the deterioration reducing material particle.