Coconut shell-based supercapacitor can capture carbon during charging


Coconut shell-based supercapacitor can capture carbon during charging


Researchers at the University of Cambridge have developed a low-cost gadget which is capable of capturing carbon dioxide gas while charging. When it discharges, the carbon dioxide can be released in a controlled way and be collected to be reused.

The supercapacitor gadget is the size of a two-pence coin and is manufactured in part from renewable resources such as coconut shells and seawater.

Every year, around 35 billion tonnes of carbon dioxide are released into the atmosphere, and methods to decrease these emissions and address the climate problem are urgently needed. Currently, the most advanced carbon capture methods are energy-intensive and costly. The supercapacitor might thus help power carbon capture and storage technology at a far cheaper cost.

The supercapacitor is made up of two electrodes, one positive and one negative in charge. The team tried altering from a negative to a positive voltage to lengthen the charging period from previous trials. This increased the ability of the supercapacitor to capture carbon.

By slowly changing the current across the plates, the gadget can capture twice as much carbon as before, said Alexander Forse, who led the research at Cambridge.

Compared to current amine-based process for extracting carbon dioxide in industry which is costly and energy-intensive, the charging-discharging procedure of the supercapacitor may utilize less energy, Forse added. The next questions for the research team will involve investigating and optimizing the particular mechanics of carbon capture.

The fundamental difference between a supercapacitor and a rechargeable battery is how the two devices store charge. A battery relies on chemical reactions to store and release charge, whereas a supercapacitor does not. It instead relies on the movement of electrons between electrodes.

The supercapacitors cannot retain as much charge as batterie but has better durability, which is a key ability for carbon capture, said co-author 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.”

Yet, this supercapacitor does not absorb carbon dioxide on its own. It must be charged to draw in carbon. When the electrodes become charged, the negative plate absorbs carbon dioxide while ignoring other emissions that do not contribute to climate change, such as oxygen, nitrogen, and water. By using this approach, the supercapacitor can store energy while absorbing carbon dioxide.

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