The chitin ingredient found in shrimp shells has been used by researchers at MIT to develop new electrode components for vanadium flow batteries. (Image Credit: Arina Ertman, Unsplash)

 

Poor shrimps… about to harvested more than ever. The modern world is mostly dominated by lithium-ion batteries. Still, when it comes to renewable energy, scientists think there is a lot of potential in a novel alternative called vanadium flow batteries. Researchers at MIT have extracted chitin from shrimp shells to develop electrodes for vanadium flow batteries. The team presented their findings in ACS Sustainable Chemistry & Engineering journal.

 

"We propose to produce these vanadium flow battery electrodes from chitin, a material from shrimp shells, which, in addition to carbon, contains nitrogen," says Francisco Martin-Martinez, a chemical engineer from Swansea University.

 

Martin-Martinez, an expert in the development of bio-inspired materials, stated that carbon electrodes are commonly used to facilitate the electrons' flow from one side of the battery to the opposite. "We have produced these electrodes from chitin, a material from shrimp shells. Chitin is a polysaccharide, similar to cellulose, which is found in the exoskeleton of crustaceans and insects."

 

The team has already shown the benefits of nitrogen in the electrode's chemical structure, where it facilitates the electrons transfer between and from the vanadium ions. "Obviously, there are carbon electrodes that can yield better performance, but the key to this project is to produce such electrodes from waste material, in this case, chitin from shrimp shells," says Martín-Martínez.

 

Currently, these types of electrodes are created from carbonized polyacrylonitrile, a synthetic polymer, so creating it from a waste product like chitin makes this a more sustainable alternative.

 

The researchers placed the chitin onto felt electrodes and put it to the test using a vanadium redox flow battery, which revealed a 100 mW cm–2 improvement in peak power density. Even though the performance increase is encouraging, the researchers are also excited about the sustainable nature of the design.

 

"Its benefit does not only relies in its good performance, but also in the low cost of the starting material, which makes the electrodes more sustainable, given the reuse of waste,," says Martin-Martinez, "These electrodes from shrimp waste could also be applied in supercapacitors, electrochemical devices that provide a very high energy density, and even in desalination processes, "although we have focused on vanadium redox flow batteries,."

 

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