New Low-Cost Battery-Like Device Captures CO2 Emissions While It Charges

Researchers have created a low-cost gadget that can absorb carbon dioxide gas selectively while charging. The CO2 may then be discharged in a regulated manner and collected to be reused or safely disposed of as it discharges.
The supercapacitor device is roughly the size of a quarter and is manufactured partly from sustainable resources such as coconut shells and saltwater.

The supercapacitor, developed by scientists at the University of Cambridge, might help power carbon capture and storage technology at a lower cost. Around 35 billion tonnes of CO2 are emitted into the atmosphere each year, and measures to reduce these emissions and solve the climate problem are urgently needed. The most advanced carbon capture methods are currently highly costly and energy intensive.

The supercapacitor is made up of two positive and negative charge electrodes. The team attempted cycling from a negative to a positive voltage to lengthen the charging period from prior trials in work headed by Trevor Binford while finishing his Master's degree at Cambridge. The supercapacitor's capacity to collect carbon was increased as a result.

“We found that by slowly alternating the current between the plates we can capture double the amount of CO2 than before,” stated lead researcher Dr. Alexander Forse of Cambridge's Yusuf Hamied Department of Chemistry.

“The charging-discharging process of our supercapacitor potentially uses less energy than the amine heating process used in industry now,” Forse stated. “Our next questions will involve investigating the precise mechanisms of CO2 capture and improving them. Then it will be a question of scaling up.”

The findings were published in the journal Nanoscale on May 19, 2022.
A supercapacitor is comparable to a rechargeable battery, however the two devices store charge differently. A battery stores and releases charge through chemical processes, but a supercapacitor does not. Instead of relying on the flow of electrons between electrodes, it depends on the movement of electrons between electrodes, which means it takes longer to decay and has a longer lifespan.

Researchers have developed a low-cost device that can selectively capture carbon dioxide gas while it charges. Then, when it discharges, the CO2 can be released in a controlled way and collected to be reused or disposed of responsibly.

“The trade-off is that supercapacitors can’t store as much charge as batteries, but for something like carbon capture we would prioritize durability,” 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.
“We want to use materials that are inert, that don’t harm environments, and that we need to dispose of less frequently. For example, the CO2 dissolves into a water-based electrolyte which is basically seawater.” 

This supercapacitor, however, does not absorb CO2 on its own; it must be charged in order to draw in CO2. When the electrodes get charged, the negative plate sucks in CO2 gas while ignoring other emissions that do not contribute to climate change, such as oxygen, nitrogen, and water. The supercapacitor absorbs carbon while also storing energy using this way.

Dr. Israel Temprano, a co-author on the paper, helped to the effort by creating a gas analysis approach for the device. A pressure sensor responds to variations in gas adsorption in the electrochemical device in this method. The findings from Temprano's research assist to pinpoint the exact process at work inside the supercapacitor during CO2 absorption and release. Before the supercapacitor can be scaled up, it must first understand these mechanics, as well as the potential losses and deterioration paths.

“This field of research is very new so the precise mechanism working inside the supercapacitor still isn’t known,” Temprano added.

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