Scavenger robots that ‘eat’ metal to harvest energy

The new approach presents an attractive alternative to lithium-ion batteries, as it will allow robots to recharge on-the-go by consuming parts of nearby metal surfaces

Spotted: Researchers from the University of Pennsylvania’s School of Engineering and Applied Science have designed a Robot prototype that recharges by chowing down scrap metal as it moves around. 

Right now, the team’s prototype (which still has much to evolve) consists of a small hydrogel dragged behind a miniature motorised vehicle. The hydrogel works as an electrolyte, so that nearby metal surfaces act as the anode of a battery. This allows electrons to flow to the cathode and produce different energy densities, depending on their individual potential for oxidation. The vehicle also has a small reservoir that provides water to the hydrogel to prevent it from drying out. 

A major hurdle for present robots in real-world environments is that they rely on batteries which store energy internally and have the issue of being heavy and offering a limited supply.

James Pikul, Assistant Professor in the Department of Mechanical Engineering and Applied Mechanics, said: “This approach is similar to the way we humans get energy. We have to eat fuel, breathe oxygen and drink water. Our device enables the same capability for robots, except they ‘eat’ metal as a fuel, breathe oxygen, and drink water.”

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