University of Maryland Hu Liangbing's team: Zinc battery using crab shell as biodegradable electrolyte
The surge in demand for renewable energy and electric vehicles has sparked high demand for batteries for energy storage, but batteries themselves are not always sustainable. Using an unexpected source—crab shells—scientists have created a zinc battery with a biodegradable electrolyte, according to a paper published Sept. 1 in Matter, a journal of Cell Press. .
Hu Liangbing, director of the Center for Materials Innovation at the University of Maryland, said: "A large number of batteries are being produced and consumed, which may cause a series of environmental problems. For example, polypropylene and polycarbonate separators widely used in lithium-ion batteries, It takes hundreds or thousands of years to degrade, increasing the burden on the environment."
Batteries use electrolytes to shuttle ions back and forth between the positive and negative electrodes. The electrolyte can be a liquid, paste or gel, and many batteries use flammable or corrosive chemicals for this function. The new battery can store electricity from large-scale wind and solar energy and uses a gel electrolyte made from a biomaterial called chitosan.
Chitosan is a derivative of chitin. Chitin comes from many sources, including the cell walls of fungi, the exoskeletons of crustaceans, and the shells of squid. "The richest source of chitosan is the exoskeletons of crustaceans, including crabs, shrimps and lobsters, which can be easily obtained from seafood waste, even on your dinner table." "
The biodegradable electrolyte means that about 2/3 of the battery can be broken down by microorganisms - this chitosan electrolyte breaks down completely within 5 months. This leaves behind a metallic component, usually zinc that can be recycled. "Zinc is more abundant in the earth's crust than lithium," said Hu Liangbing. "In general, mature zinc batteries are cheaper and safer." This zinc-chitosan battery has an energy efficiency of 99.7 percent after 1,000 discharge cycles , making it a viable option for storing energy generated by wind and solar energy and transferring it to the grid.
