This Eco-Friendly Biodegradable Battery Is Made From Crab Shells and Zinc
Designed to biodegrade five months after disposal, leaving the zinc behind for recycling, this battery targets renewable energy storage.
Scientists have come up with what they claim is a considerably more sustainable type of battery — made using crab and shrimp shells as the base material for an eco-friendly electrolyte.
"Vast quantities of batteries are being produced and consumed, raising the possibility of environmental problems," says Liangbing Hu, director of University of Maryland’s Center for Materials Innovation and lead author on the paper. "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."
The battery the team has developed is different: its gel electrolyte, which sits between zinc electrodes, is made from chitosan that can be harvested from the shells of crabs and shrimp. "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," Hu explains. "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."
Using the chitosan-based gel, the materials of the battery biodegrade within five months after disposal — leaving behind the zinc metal for retrieval and recycling. "Zinc is more abundant in earth’s crust than lithium," Hu adds. "Generally speaking, well-developed zinc batteries are cheaper and safer."
The battery, then, has the potential to be more eco-friendly, cheaper, and safer than today's lithium-ion batteries — and has proven its longevity, too, with a prototype retaining 99.7 percent of its energy storage efficiency after 1,000 full charge-discharge cycles, which the team says makes it viable for large-scale energy storage from wind, solar, and other renewable sources.
The team's work has been published in the journal Matter under closed-access terms, with Hu revealing further work on producing batteries where all components would be biodegradable — but not yet sharing a timescale for the technology to go from the lab to the fab.
Main article image courtesy of Liangbing Hu, Creative Commons Attribution-ShareAlike.