The new low-cost device, similar to a battery, captures CO2 emissions during charging
Researchers have developed an inexpensive device that can selectively capture carbon dioxide while charging. Then, when it is discharged, CO2 can be released in a controlled manner and collected for reuse or responsible disposal.
The supercapacitor, similar to a rechargeable battery, is about a quarter the size and partly made of durable materials, including coconut shells and seawater.
“We found that by slowly changing the current between the plates, we can capture twice the amount of CO2 than before.” – Dr. Alexander Force
A supercapacitor, developed by scientists at Cambridge University, can help carbon capture and storage technologies at a much cheaper price. About 35 billion tons of CO2 are released into the atmosphere every year, and urgent solutions are needed to eliminate these emissions and eliminate the climate crisis. The most modern carbon capture technologies are quite expensive and require a lot of energy.
The supercapacitor consists of two electrodes of positive and negative charge. Working under Trevor Binford while earning a master’s degree at Cambridge, the team tried to alternate negative to positive voltage to extend the charging time in previous experiments. This has improved the ability of the supercapacitor to trap carbon.
“We found that by slowly changing the current between the plates, we could capture twice as much CO2 as before,” said Dr. Alexander Force of Cambridge Chemistry, Youssef Hamid, who led the study.
“The charging-discharging process of our supercapacitor potentially uses less energy than the amine heating process currently used in industry,” Force said. “Our next questions will include researching the exact mechanisms of CO2 capture and improving them. Then we will talk about building up. “
The results were published May 19, 2022 in the journal Nanosize.
The supercapacitor is similar to a rechargeable battery, but the main difference is how these two devices store charge. The battery uses chemical reactions to store and release the charge, while the supercapacitor is independent of chemical reactions. Instead, it depends on the movement of electrons between the electrodes, so its degradation requires more time and longevity.
“The trade-off is that supercapacitors can’t store as much charge as batteries, but for something like carbon capture, we prefer durability,” said co-author Grace Mapstone. “The best thing is that the materials used to make supercapacitors are cheap and rich. The electrodes are made of carbon obtained from coconut shell waste.
“We want to use inert materials that do not harm the environment and that we need to dispose of less often. For example, CO2 is soluble in water-based electrolyte, which is mostly seawater. ”
However, this supercapacitor does not absorb CO2 spontaneously: it must be charged to absorb CO2. When the electrodes are charged, the negative plate draws CO2 gas, ignoring other emissions such as oxygen, nitrogen and water that are not conducive to climate change. Using this method, the supercapacitor simultaneously captures carbon and stores energy.
Co-author Dr. Israel Temprano contributed to the project by developing a gas analysis technique for the device. The technique uses a pressure sensor that responds to changes in gas adsorption in the electrochemical device. The results of Temprano’s contribution help narrow down the precise mechanism that works inside a supercapacitor when CO2 is absorbed and released. An understanding of these mechanisms, possible losses, and degradation pathways is all necessary before a supercapacitor can be augmented.
“This area of research is very new, so the exact mechanism that works inside a supercapacitor is still unknown,” Temprano said.
Reference: “Enhancing the Capacity of Ultra-Capacitive CO2 Adsorption Capture by Configuring Charging Protocols” Trevor B. Binford, Grace Mapstone, Israel Temprano, and Alexander S. Force, May 19, 2022, Nanosize.
DOI: 10.1039 / D2NR00748G
The study was funded by Dr. Force’s Future Leaders Fellowship, a British research and innovation scheme that is developing the next wave of world-class research and innovation.