Crab-Batteries, Upcycled From Waste Shells, Could Be the Eco-Friendly Power Storage of the Future

Researchers from the Shandong Academy of Medical Sciences and the Kyushu Institute of Technology have come up with an unusual ingredient to help lessen future rechargeable batteries' reliance on lithium: crabs.

"The demand for energy storage devices has increased significantly, and the sustainable development of lithium-ion batteries is limited by scarce lithium resources," the researchers explain in the abstract to their paper. "Therefore, alternative sodium-ion batteries which are rich in resource may become more competitive in the future market. In this work, we synthesized low-cost SnS₂/C and FeS₂/C anode materials of sodium-ion batteries which used waste crab shells as biomass carbon precursor."

The idea: replacing lithium-ion batteries with something less reliant on the rare metal, but not just jumping head-first into something else which will prove in limited supply or environmentally damaging to obtain. Crab shells, currently treated as a waste product of the seafood industry, are an ideal candidate for upcycling — by turning them into "hard carbon" for use in the anode of a sodium-ion battery.

The waste crab shells are first super-heated, to temperatures around 700°C (almost 1,300°F), to carbonize them. The resulting "crab carbon" is then added to a mixture of tin sulfide or iron sulfide and dried, forming a material suitable for use in the batteries. Better still, the resulting carbon was no only compatible but ideal — offering a larger surface area than rival materials.

In testing, the team's crab-battery proved able to store a reasonable amount of energy and withstand 200 repeated charge- discharge cycles. The next step, the researchers say, will be to extend the concept to other waste materials — turning the landfill of today into the batteries of tomorrow.

The team's work has been published under open-access terms in the journal ACS Omega.