In a recent study published in Matter, a team of researchers led by the University of Maryland have developed a zinc battery with a biodegradable electrolyte made from crab shells. This study holds the potential to expand sustainable batteries, which are in high demand due to renewable energy and electric vehicles and was in collaboration with scientists from the University of Houston.
"Vast quantities of batteries are being produced and consumed, raising the possibility of environmental problems," says Dr. Liangbing Hu, director of the University of Maryland's Center for Materials Innovation, and a co-author on the study. "For example, polypropylene and polycarbonate separators, which are widely used in Lithium-ion batteries, take hundreds or thousands of years to degrade and add to environmental burden."
Traditional batteries utilize an electrolyte to carry ions back and forth between the positively and negatively charged terminals. While the electrolyte can be a gel, paste, or liquid, many batteries use corrosive or flammable chemicals for this purpose. This new battery, which has the potential of storing power from sources such as large-scale wind and solar, uses a gel electrolyte created from a biological material called chitosan.
"Chitosan is a derivative product of chitin. Chitin has a lot of sources, including the cell walls of fungi, the exoskeletons of crustaceans, and squid pens," says Hu. "The most abundant source of chitosan is the exoskeletons of crustaceans, including crabs, shrimps and lobsters, which can be easily obtained from seafood waste. You can find it on your table."
With a biodegradable electrolyte, two thirds of the battery could be decayed by microbes, and this study’s chitosan electrolyte was completely broken down with five months. Once broken down, only the metal component remains, in this case recyclable zinc, as opposed to lead or lithium.
"Zinc is more abundant in earth's crust than lithium," says Hu. "Generally speaking, well-developed zinc batteries are cheaper and safer." With an energy efficiency of 99.7% after 1000 cycles, this new battery makes it a suitable option for energy storage generated by solar and wind for transfer to power grids.
Sources: Matter
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