Cartilage inspires new durable material for structural batteries

Incorporating batteries into the structure of electric vehicles and drones has long been a goal of designers and engineers, as it has the potential to reduce weight and extend range. However, placing a battery into the bumper of a car or the wing of drone has obvious safety implications. Published in the journal ACS Nano, the research describes a rechargeable zinc battery with a cartilage-like solid electrolyte that is resistant to damage.

"A battery that is also a structural component has to be light, strong, safe and have high capacity,” said research lead Nicholas Kotov, a Professor of Chemical and Materials Science Engineering at Michigan. “Unfortunately, these requirements are often mutually exclusive."

Zinc is an established structural and battery material, but the rigid dendrites it forms on repeated recharge cycles have seen the metal largely confined to single-use batteries. To overcome the dendrite problem, Kotov’s team developed a solid electrolyte from a composite of branched aramid nanofibres (BANFs) and poly(ethyleneoxide). Based on the structure of cartilage, the BANFs mimic the tissue’s tough collagen and resist penetration from dendrites, while the poly(ethyleneoxide) replicates the cartilage’s softer components and allows zinc ions to flow between the battery’s two electrodes.