Carbon Black Conductive Additive with Low Viscosity
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Solution Overview
Problem
Conductive carbon black materials with low electrical resistivity typically exhibit high surface areas, leading to increased viscosity in dispersions and processing difficulties, which is undesirable in applications like lithium-ion batteries where low surface area is beneficial for electrochemical behavior and handling.
Innovation Solution
Developing carbon black materials with a high ratio of compressed oil absorption number to uncompressed oil absorption number (cOAN/OAN) and a significant fraction of micropores, which maintains low electrical resistivity without increasing viscosity, achieved through a thermal-oxidative decomposition process using hydrocarbons with sub-stoichiometric amounts of air and steam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive carbon black materials with low electrical resistivity are used, then electrical conductivity is improved, but viscosity in dispersions increases and processing becomes difficult
Solution Approach 1:
The patent applies porous materials by creating carbon black with a specific porous structure characterized by a high cOAN/OAN ratio (at least 40%). The porous structure allows the material to maintain low electrical resistivity while the controlled pore architecture prevents excessive solvent adsorption, thereby avoiding high viscosity in dispersions and improving processing ease.
Solution Approach 2:
The patent applies parameter changes by modifying the structural parameters of carbon black, specifically the cOAN/OAN ratio and pore size distribution. By controlling these parameters through the thermal-oxidative decomposition process, the material achieves low electrical resistivity while maintaining low dispersion viscosity, resolving the contradiction between conductivity and processability.
2Reliability
If high surface area carbon black is used to achieve low electrical resistivity, then conductivity is improved, but electrode surface area wetting increases leading to charge losses
Solution Approach 1:
The patent applies porous materials by creating an internal porous structure within the carbon black aggregates (high cOAN/OAN ratio indicating retained structure after compression). This internal porosity provides conductive pathways for electricity while the external surface area remains controlled, reducing the electrode surface area wetted by electrolyte and minimizing charge losses from parasitic side reactions.
Solution Approach 2:
The patent applies the nested doll principle by creating a hierarchical structure where micropores are nested within aggregates, which are nested within agglomerates. This nested architecture provides internal conductive pathways without increasing external surface area, achieving low electrical resistivity while minimizing electrolyte contact and charge losses.
3Reliability
If high surface area carbon black is used to achieve low electrical resistivity, then conductivity is improved, but dispersion viscosity increases
Solution Approach 1:
The patent applies porous materials by creating carbon black with controlled internal porosity (cOAN/OAN ratio ≥ 40%). The internal pores provide conductive pathways for low electrical resistivity, while the controlled pore architecture and aggregate structure limit solvent adsorption, preventing excessive viscosity increase in dispersions.
Solution Approach 2:
The patent applies parameter changes by optimizing the cOAN/OAN ratio and pore size distribution parameters. By controlling these structural parameters through the thermal-oxidative decomposition process, the material achieves low electrical resistivity while maintaining low dispersion viscosity, resolving the contradiction between conductivity and viscosity.
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 resulting carbon black materials exhibit excellent electrical conductivity with low viscosity, improving processing and electrochemical performance in lithium-ion batteries by retaining structural integrity and minimizing electrode surface area wetting, thus reducing charge losses and processing challenges.
Implementation Method 1
Carbon black is generally formed in the gas phase by the thermal decomposition of hydrocarbons from various sources. The energy for the thermal decomposition can be taken by burning fuel like oil or gas, or by burning part of the feedstock used for the decomposition process with sub-stoichiometric amount of air.
Implementation Method 2
There are two principles for the thermal decomposition, the first is a thermal decomposition in the absence of oxygen, while the second is a thermal-oxidative decomposition (incomplete combustion).
Data Source
AI summary
The present disclosure relates to novel carbon black materials characterized by a good retention of their structure in the compressed state, as shown, e.g., by a relatively high ratio of compressed OAN/OAN. The materials may inter alia be characterized by a low viscosity in dispersions and by exhibiting low electrical resistivity. Such materials can be advantageously used in various applications, for example in the manufacture of electrochemical cells such as lithium ion batteries or as conductive additive in polymer composite materials. The disclosure also describes a procedure for making such a material as well as well as downstream uses and products comprising said carbon black material.