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.