Researchers from University of Michigan developed a structural battery prototype that integrates a cartilage-like material to offer highly durable batteries
A team of researchers from University of Michigan developed a damage-resistant rechargeable zinc battery with a cartilage-like solid electrolyte. According to the researchers, the batteries can replace the top casings of several commercial drones. The prototype cells are capable of performing over 100 cycles at 90% capacity and can sustain hard impacts and even stabbing without losing voltage or starting a fire. The research was led by Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering at University of Michigan. The findings were described in the journal ACS Nano on January 04, 2019.
The team used zinc and branched nanofibers that resemble the collagen fibers of cartilage. In a human body, cartilage combines mechanical strength and durability with the ability to let water, nutrients, and other materials move through it. These qualities are analogous to those of a good solid electrolyte that is tasked to resist damage from dendrites and to allow ions flow from one electrode to the other. Dendrites pierce the separator between the electrodes and increase the flow of electrons, thereby shorting the circuit and causing a fire. Zinc tends to short out after just a few charge/discharge cycles. The membranes made by the team shuttle zinc ions between the electrodes and halt zinc’s piercing dendrites. Similar to cartilage, the membranes are made of ultra-strong nanofibers that are interwoven with a softer ion-friendly material.
Aramid nanofibers in the batteries act as collagen and polyethylene oxide and a zinc salt replace soft components of cartilage. The team paired the zinc electrodes with manganese oxide. In rechargeable batteries, the cartilage-like membrane replaces the standard separator and alkaline electrolyte. The zinc cells can act as secondary batteries on drones and can extend the flight time by 5 to 25%, according to the researchers. This also depends on the battery size and mass of the drone and flight conditions. The research was conducted with support from Air Force Office of Scientific Research and National Science Foundation.