User:Mwongz/Carbon black

Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal and coal tar, vegetable matter, or petroleum products, including fuel oil, fluid catalytic cracking tar, and ethylene cracking. Carbon black is a form of paracrystalline carbon that has a high surface-area-to-volume ratio, albeit lower than that of activated carbon. It is dissimilar to soot in its much higher surface-area-to-volume ratio and significantly lower (negligible and non-bioavailable) polycyclic aromatic hydrocarbon (PAH) content. However, carbon black can be used as a model compound for diesel soot to better understand how diesel soot behaves under various reaction conditions as carbon black and diesel soot have some similar properties such as particle sizes, densities, and copolymer adsorption abilities that contribute to them having similar behaviours under various reactions such as oxidation experiments. Carbon black is used as a colorant and reinforcing filler in tires and other rubber products; pigment and wear protection additive in plastics, paints, and ink pigment. It is used in the EU as a food colorant when produced from vegetable matter (E153).

Common uses

The most common use (70%) of carbon black is as a pigment and reinforcing phase in automobile tires. The structure and arrangement of carbon black contribute to its increased conductive properties that are useful in lithium-ion batteries. Its low cost makes it a common addition to cathodes and anodes and is considered a safe replacement to lithium metal in lithium-ion batteries. Carbon black also helps conduct heat away from the tread and belt area of the tire, reducing thermal damage and increasing tire life. About 20% of world production goes into belts, hoses, and other non-tire rubber goods. The remaining 10% use of carbon black comes from pigment in inks, coatings, and plastics, as well as being used as a conductive additive in lithium-ion batteries.

Use in lithium-ion batteries

Carbon black is a common conductive additive for lithium ion batteries as they have small particle sizes and large specific surface areas (SSA) which allow for the additive to be well distributed throughout the cathode or anode in addition to being cheap and long-lasting. Unlike graphite, which is one of the other common materials used in chargeable batteries, carbon black consists of crystal lattices that are further apart and promotes Li⁺ intercalation because it allows more pathways for lithium storage.

Carbon black has a low density that allows for a large volume of it to be dispersed so that its conductive effects are applied evenly throughout the battery. Furthermore, its arrangement of randomly distributed graphite-like crystals improves battery stability because of the decrease in the potential barrier of lithium intercalation into graphite, which ultimately affects the performance of cathodes.

While carbon black is lightweight and well dispersed throughout the battery and increases the conductive performance of batteries, it also contains oxygen containing hydrophilic functional groups that can cause side reactions to occur in the battery and lead to the decomposition of electrolyte. Graphitization (heating) of carbon black can thermally decompose the hydrophilic functional groups and thus increase the cycle life of the battery which maintains the conductive abilities of carbon black while mitigating the damage that can be caused to batteries by carbon black.

Half cells created with heavy graphitization, light graphitization, and no graphitization showed that the cell created with heavy graphitization had a stable cycle life of 320 cycles, the cell with light graphitization showed a stable cycle life of 200 cycles, and the cell with no graphitization showed a stable cycle life of 160 cycles.