Carbon dioxide (CO2) is a chief component of smokestack emissions, and is considered to be the most vital greenhouse gas involved in climate change. Recently ACS Central Science featured a report highlighting how the pollutant can be converted into a useful material, increasingly used in high-tech batteries that store "green" energy like solar power, while simultaneously controlling the environmental impact of existing power plants.
A process called STEP turns carbon dioxide from smokestacks into multi-walled carbon nanotubes that can be used in various types of batteries. Credit: American Chemical Society
A wide range of materials have been analyzed as potential Earth-abundant battery components, ranging from banana peels to peat moss. Currently researchers from all over the world are focusing on the capture and conversion of CO2 into a number of products. Previously researchers concentrated on developing an increasing amount of chemicals, such as methanol, instead of developing high-value materials, such as those required for sodium and lithium batteries.
Stuart Licht, Cary Pint and team have introduced a technique where gas was bubbled through molten lithium carbonate and then electrified, in order to form products including different forms of carbon, such as carbon nanofibers and carbon nanotubes (CNTs). The researchers demonstrated that CNTs are capable of being used as anodes, which are the negative electrodes utilized in batteries. Stable performance and almost 100% columbic efficiency was delivered by two different types of CNTs. The work demonstrates that an enhanced flue system for combustion plants that integrate this process could be self-sustaining to a certain degree. This is due to the fact that oxygen is used as a side product for the entire process, and plants can use this side product for additional combustion. The estimated cost for a single metric tonne of CNTs is estimated to be extremely less expensive, compared to the currently used synthetic methods.