During use, when discharged, CO2 can be released in a controlled manner from this device and collected for reuse or responsible disposal.
A more sustainable alternative to traditional batteries
The device developed in Cambridge is not a battery, technically speaking, even though it works similarly to a rechargeable battery. It is a supercapacitor, a small device, the size of a coin and made from sustainable materials, such as seawater and coconut shells.
This supercapacitor could help drive carbon capture and storage technologies at much lower cost, a purpose pursued in the industry, but which until now has depended on large energy consumption and high associated costs.
A supercapacitor is a device similar to a rechargeable battery, whose differences are marked in how both devices store charge. While a conventional battery uses chemical reactions to store and release charge, a supercapacitor does not rely on these reactions. Instead, it bases its operation on the movement of electrons between electrodes, which slows down its degradation, ensuring a longer life cycle.
“The tradeoff is that supercapacitors can’t store as much charge as batteries, but for something like carbon capture we’d prioritize durability.”said the co-author of this project, Grace Mapstone. “The best part is that the materials used to make supercapacitors are cheap and abundant. The electrodes are made of carbon, which comes from waste coconut shells.”he added.
Considering that around 35 billion tons of CO2 are released into the atmosphere every year, solutions are urgently needed to eliminate these emissions and tackle the climate crisis. “We want to use materials that are inert, that do not harm the environment and that we need to dispose of less frequently. For example, CO2 dissolves in a water-based electrolyte that is basically seawater.”Mapstone pointed out in this regard.
A peculiarity of this supercapacitor is that it does not absorb CO2 spontaneously. To achieve this, it must be charging. As the electrodes charge, the negative plate attracts CO2 gas, while ignoring other emissions, such as oxygen, nitrogen, and water, which are not factors that negatively impact the environment. Under this method, the supercapacitor captures carbon and stores energy.
“The charging and discharging process of our supercapacitor potentially uses less energy than the amine heating process currently used in industry”commented Dr. Alexander Forse. “Our next questions will involve investigating the precise CO2 capture mechanisms and improving them. So it will be a matter of scaling.”added the director of the investigation, belonging to the Department of Chemistry of Cambridge.
This field of research is relatively new within the area. Small advances like this pave the way for supercapacitors to emerge as alternatives to conventional batteries in the future, for the uses that are most suitable.