Lithium-ion batteries are currently uncontroversially dominated in the commercial market, but renewable energy, represented by liquid-flow batteries, has shown great potential and is expected to be a replacement in the future. Thanks to an ingredient found in shrimp shells, the researchers developed new electrode components for liquid-flow batteries that perform better than the current solution.
Liquid flow batteries (redox liquid-flow batteries) have long been seen as the power candidates to extract energy from intermittent energy sources such as wind and solar energy because they can store large amounts of energy at a relatively low cost. The liquid-flow cell stores energy in a liquid electrolyte in a huge external tank, which moves back and forth through the membrane to exchange ions and charge and discharge the device.
This means that, unlike existing lithium batteries, where energy is stored in electrode materials, the storage capacity of these fluid-flow batteries can be expanded by simply increasing the size of the tank. This type of battery architecture is ideal for renewable energy storage, because in this case, energy may not be generated on demand and often needs to be saved for later use.
In today’s liquid flow battery solutions, the potential is to use metal palladium as an electrolyte, a material that is popular because of its reliability during charging and discharging. During the transfer between niobium ions, the electrodes of the battery facilitate this process, which is usually made of carbonized polyacrylonitrile, a synthetic polymer.
But a mIT project is focused on finding other natural materials to provide more sustainable solutions and hopes to find better alternatives to performance. Researchers have found chitin, a cellulose-like polysaccharide common in shrimp shells, which we have seen used to develop everything from compostable food packaging to advanced body armor to cheaper drugs.
The lead author of the study, Francisco Martin-Martinez of Swansea University, said: “We proposed the production of these palladium cell electrodes from chitin, a material from the shrimp shell that contains nitrogen in addition to carbon.”
The team deposited chitin on a felt electrode and tested it as part of a radon redox stream battery. The test results showed an improvement in the peak power density by up to 100 mW cm-2. While the performance improvement is welcome, the team is also excited about the sustainable nature of the design.
“The benefits are not only in its good performance, but also in the low cost of the starting material, which makes the electrodes more sustainable due to the reuse of waste,” says Mr Martinez. These electrodes from shrimp waste can also be used in supercapacitors, electrochemical devices that provide very high energy density, and even in desalination, but our research focuses on radon redox stream batteries. “