Sustainabilty aspects

HiQ-CARB will change the way to produce conductive additives as carbon blacks – with high yield and low carbon footprint

A large volume of the conventionally produced carbon blacks is obtained from heavy oils in a furnace carbon-black manufacturing process. Residual oils from various industries, such as coal gasification or refineries, are used in this process. These residues contain heteroatoms (nitrogen, sulphur and heavy metals), which accumulate as SOx and NOx in the exhaust gas, thus requiring state-of-the-art waste gas treatment, or remain in the soot with heavy metals. The production of 1 mton of carbon black via a furnace process results in approximately 5 mton CO₂. The yield varies between 20 % for high surface area special blacks, e.g. super conductive grades or ultra-high jetness, and above 60 % for ASTM rubber blacks. A 20 % yield for highly conductive grades implies the amount of CO₂ is more in the range of 14.7 mtons per ton of carbon black.

Low-carbon Acetylene Blacks, the goal of the HiQ-CARB project, in contrast to furnace blacks, are obtained from acetylene gas, which is a refinery by-product of the so-called steam cracker. The yield of acetylene black is >95 % and therefore, the CO₂ production is approximately 200 kg CO₂ per 1 mton of actylene black produced. Therefore, the AB, as will be upscaled in the HiQ-CARB project, have a carbon footprint that is more than 70 times lower than a highly conductive furnace black. The overall emissions of the AB will be further reduced with the installation of the wet beading facilities.

The classical Carbon NanoTubes (CNT) synthesis uses ethylene from fossil fuel sources, which requires proximity to a petrochemical plant along with the associated transportation costs and GHG emissions.

In the HiQ-CARB project CNTs are manufactured from bio-resources via bioethanol and bio-ethylene, the specific processing minimizes the energy consumption and obtains a reproducible and homogeneous material. Starting from ethanol opens the possibility to set up CNT manufacturing units close to the battery manufacturing units, which is the best way to CO₂ emissions due to transportation. Transport costs are particularly relevant given the small bulk density of CNTs (0.1 g/mL).

And also the processing of cell electrodes benefits as an aqueous processing will be implemented through the use of waterbased conductive additive dispersions and subsequently, their testing in water-based cathodes. Sustainability is an important aspect of this project and provides specific advantages compared to the competitive materials.

To fully justify these claims of a lower footprint, less material for the same performance and greener processing, these aspects will be evaluated with a LCA in the HiQ-CARB project.