As the world increasingly turns to renewable energy sources and electric vehicles, the demand for batteries is skyrocketing. However, the batteries used today are not always sustainable. 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.
On the other hand, you know that every year about 6 to 8 million tons of crabs, oysters and lobsters are produced in the world! And considering the fact that crab meat is only about 40 percent of its size, it can create a lot of food waste.
EVs, batteries, sustainability, crabs, trees…. you can’t log in directly! Well let’s find out:
Here we have two problems (1) The materials used to make batteries are non-biodegradable and (2) Crabs in our food chain produce a lot of waste.
Scientists always get clues from nature—or in this case, using it to create a more sustainable future. Researchers at the University of Maryland have created a zinc battery with a biodegradable electrolyte derived from crab shells.
Rechargeable batteries made from crab shells and zinc can store energy from renewable sources, then parts can biodegrade in a few years or be recycled.
The new battery uses an electrolyte gel made from a lead material called chitosan. Do you know the best source of chitosan? Exoskeletons of crustaceans, including crabs, shrimps, and lobsters, which can be easily obtained from seafood. Didn’t we hit two targets with one arrow?
Lithium-ion batteries are the current standard, but their production requires the mining of lithium, which can pollute the environment, and there are limited supplies of the metal.
Zinc ion batteries are another attractive option because zinc is abundant in nature, Hu said. However, zinc-ion batteries cannot be recharged many times and work efficiently because the water in the battery – which is needed as an ion conductor – corrodes the zinc and creates deposits on the anode of preventing battery operation.
Over the years, scientists have mined chitin from crustacean shells for everything from tissue engineering to making biodegradable plastic. Because it and its sister polymer chitosan are considered eco-friendly and non-toxic, there has been much interest in incorporating these chemical compounds into batteries of all kinds.
Further Hu decided to investigate chitosan because its molecules bond well with water, which means fewer water molecules should be available to react with the zinc, which might help prevent zinc corrosion. The prototype also had an energy efficiency of 99.7% after 1,000 cycles, meaning it is a viable option for storing wind or solar energy in power grids. That is a significant improvement for the world of zinc batteries.
While you’re not going to see crab-shell batteries anytime soon, the researchers hope their batteries may become commonplace, used in electronic devices like your cellphone to dedicated storage for renewable energy that release to a commercial grid.
Currently, Hu says that including chitosan as an electrolyte in a battery means about two-thirds of the battery can be biodegraded, but going forward, the team hopes to tackle that remaining one-third. “In the future, I hope all components in batteries are biodegradable,”
Who knows what the future might hold for us? Right now, it looks like our briny seafood waste could be a solution to our current energy problems.