Rising demands for renewable energy and electric vehicles are currently sparking a high demand for batteries which store generated energy and power engines. However, until now, the batteries behind these sustainable solutions are not sustainable themselves. To solve this problem, a research team led by the University of Maryland has created a zinc battery with a biodegradable electrolyte from a surprising source: crab shells.
“Vast quantities of batteries are being produced and consumed, raising the possibility of environmental problems,” said study lead author Liangbing Hu, an expert in Materials Innovation at the University of Maryland. “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.”
Batteries use electrolytes to shuttle ions back and forth between electrically charged terminals. These electrolytes can be liquids, pastes, or gels, and many current batteries use highly flammable or corrosive substances for this function. However, the new battery – which can store power from large-scale solar and wind sources – uses a gel electrolyte made from a biodegradable 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,” Dr. Hu explained. “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.”
Since it contains biodegradable electrolytes, two thirds of this battery could be broken down by microbes. Under the action of these microorganisms, the chitosan electrolyte itself can vanish completely in about five months, leaving behind the metal component – zinc, rather than lead or lithium, as in the case of older batteries – which could then be recycled. “Zinc is more abundant in Earth’s crust than lithium. Generally speaking, well-developed zinc batteries are cheaper and safer,” said Dr. Hu.
Next, the scientists aim to make even more environmentally-friendly batteries. “In the future, I hope all components in batteries are biodegradable. Not only the material itself but also the fabrication process of biomaterials,” Dr. Hu concluded.
The study is published in the journal Matter.
By Andrei Ionescu, Earth.com Staff Writer