From cell phones to children’s toys most of life is powered by batteries. Batteries have long been known to leech into the soil and pollute the ground table. The chemicals contained in batteries contaminate the groundwater and surface water, polluting the ecosystem and all those who come in contact with it. But scientists have now come with a battery made from zinc and crab shells that will be fully recyclable.
The eco-friendly battery can be charged at least 1,000 times and is biodegradable. It was created by the researchers at the University of Maryland and University of Houston. Their findings were published in the journal Matter. Another renewable battery that made news recently is the sand battery made by Finnish researchers.
A case of battery
Non-biodegradable batteries often end up in landfills as it can be expensive to recycle them. The process is neither easy nor cheap. When not disposed of properly, it can affect human health and the environment. Different batteries contain different compositions of metals and chemicals, including cadmium, lead, mercury, nickel, lithium, and electrolytes. According to Battery University, lithium batteries can cause landfill fires that can burn underground for years. This releases toxins into the atmosphere affecting all those who breathe in the polluted air.
Rechargeable batteries consume less nonrenewable natural resources than disposable batteries. But even they can be dangerous and must be disposed of properly.
Improper and careless handling of batteries releases corrosive liquids into the soil. Recycling allows for the metal components in batteries to be reused in new products, reducing waste and keeping landfills safer.
The researchers wanted to develop batteries that are sustainable and affordable to put an end to these pollutants. By 2030, it is estimated that around 15 million metric tons of discarded batteries will make their way into landfills. Metals that can be recovered from batteries include mercury, silver, lead, manganese, nickel, cadmium, and lithium.
Biodegradable crab shell batteries
Researchers at the University of Maryland and University of Houston started working on zinc battery chemistry, as the metal is much more readily available than lithium.
“Vast quantities of batteries are being produced and consumed, raising the possibility of environmental problems,” says lead author Liangbing Hu, director of the University of Maryland’s Center for Materials Innovation. “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.”
However, traditionally made zinc batteries can have an uneven disposition of zinc on the electrode surface. The researchers were able to combat this by making a biodegradable electrolyte from crab shells. Chitosan is derived from chitin, a protein that is found in the shells of crustaceans like crabs, lobsters, and shrimps, which can be easily obtained from seafood waste. Having these materials readily available also translates to lower production costs.
Electrolytes can be in liquid, gel, or paste form and many batteries tend to use chemicals for this. The researchers made a gel electrolyte from chitosan for the eco-friendly battery.
In their study, the chitosan electrolyte broke down completely within five months. The process left behind zinc, which is easily recyclable. The researchers used zinc for the anode but replaced the cathode with biodegradable material. “Generally speaking, well-developed zinc batteries are cheaper and safer,” says Hu. The zinc and chitosan batteries have an energy efficiency of 99.7% after 1,000 battery cycles and can be used in renewable energy power grids. Additionally, renewable energy investments can be recovered in under six years.
Hu said he and his team will continue working on making batteries that are even more environmentally friendly, including throughout the manufacturing process. “In the future, I hope all components in batteries are biodegradable,” says Hu. “Not only the material itself but also the fabrication process of biomaterials.”
