Carbon Black Conductive Additive for Battery Electrodes
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Solution Overview
Problem
Carbon black with small primary particle diameter and long structure in batteries faces challenges with dispersibility and aggregation, leading to poor electron conductivity and increased viscosity in electrode compositions, while existing solutions either fail to improve dispersibility sufficiently or result in oxidative decomposition at high voltages.
Innovation Solution
A carbon black with a BET specific surface area of 50 to 220 m2/g, crystallite diameter of 30 to 42 Å, and a specific number of CO2 desorption molecules per unit surface area, combined with a polymer binder and active material, forms a conductive composition that enhances dispersibility and conductivity while maintaining oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon black with small primary particle diameter and long structure is used to improve electron conductivity, then electron conductivity is improved, but dispersibility deteriorates and aggregation occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallite diameter (La) within 22-50 Å and BET specific surface area within 50-220 m2/g. This optimization balances the electron conductivity (improved by smaller particles) with dispersibility (improved by larger surface area), resolving the contradiction between these two properties
Solution Approach 2:
The patent creates a composite conductive composition containing carbon black particles dispersed in a binder material. This composite structure allows the carbon black to provide conductivity while the binder matrix prevents aggregation and maintains dispersibility, resolving the contradiction between conductivity enhancement and compositional stability
2Reliability
If carbon black with small primary particle diameter and long structure is used to improve electron conductivity, then electron conductivity is improved, but viscosity of conductive composition increases
Solution Approach 1:
The patent controls the crystallite diameter and BET specific surface area parameters to optimize the balance between conductivity and viscosity. The specific surface area range of 50-220 m2/g ensures sufficient conductivity while preventing excessive viscosity increase that would occur with much finer particles
Solution Approach 2:
The patent uses a moderate amount of carbon black (1-10 mass%) rather than maximizing the content. This partial action provides sufficient conductivity improvement while avoiding the excessive viscosity increase that would result from higher carbon black loading
3Stability of the object's composition
If dispersant is added to improve dispersibility of carbon black, then dispersibility is improved, but oxidation resistance deteriorates due to oxidative decomposition at high voltage
Solution Approach 1:
The patent removes the dispersant component from the conductive composition entirely. Instead of adding a dispersant that would compromise oxidation resistance, the patent achieves dispersibility through optimized carbon black particle characteristics (crystallite diameter and surface area) and the binder matrix, thereby eliminating the oxidation vulnerability
Solution Approach 2:
The carbon black particles themselves, through their optimized physical characteristics, provide their own dispersibility without requiring external dispersants. The binder material also contributes to maintaining particle separation, allowing the system to achieve good dispersibility through its inherent properties rather than added chemicals
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 solution achieves high dispersibility and conductivity, reducing electrode resistance and improving battery output and cycle characteristics, with the battery exhibiting low polar plate resistance and high discharge capacity retention rates.
Implementation Method 1
carbon black as a conductive agent is required to exhibit sufficient electronic conductivity even if the amount thereof is small
Implementation Method 2
a number of CO2 desorption molecules per unit surface area measured by a temperature-rising desorption gas analysis method
Data Source
AI summary
An object of the present invention is to provide a carbon black for batteries having excellent dispersibility, electron conductivity and oxidation resistance. In addition, an object of the present invention is to provide a low-viscosity conductive composition for an electrode produced using the carbon black, and a low-resistance battery electrode and a battery having excellent high-output characteristics and cycle characteristics produced using the conductive composition.A carbon black for batteries having: BET specific surface area of 50 to 220 m2/g; a crystallite diameter (La) of 30 to 42 Å; and a number of CO2 desorption molecules per unit surface area measured by a temperature-rising desorption gas analysis method (50° C. to 1200° C. of measurement temperature) of 8.0×1016 to 15.0×1016 molecules/m2 is excellent in dispersibility, electron conductivity and oxidation resistance. A conductive composition for a low-viscosity electrode produced using the carbon black, and a low-resistance battery electrode and a battery having excellent high-output characteristics and cycle characteristics produced using the conductive composition can be obtained.