Unlike the carbon-fiber and lithium-ion sheets being developed by Asp and Greenhalgh, Kotov and his students created a zinc-air structural battery for their automatons. This cell chemistry is able to store much more energy than conventional Li-ion cells. It consists of a zinc anode, a carbon cloth cathode, and a semi-rigid electrolyte made from polymer-based nanofibers that is nanoengineered to mimic cartilage. The energy carriers in this type of battery are hydroxide ions that are produced when oxygen from the air interacts with the zinc.

While structural batteries for vehicles are highly rigid, the cell developed by Kotov’s team is meant to be pliable to cope with the movements of the robots. They’re also incredibly energy-dense. As Kotov and his team detailed in a paper published earlier this year, their structural batteries have 72 times the energy capacity of a conventional lithium-ion cell of the same volume. For now, their batteries are being used to power robotic toys and small drones as a proof of concept. But Kotov says he expects they’ll be used in midsize robots as well as larger hobby drones in the not-so-distant future. “Drones and medium-size robots need to have new solutions for energy storage,” Kotov says. “I can guarantee you that structural batteries will be a part of that.”

The battery has always been an addendum, a limiting factor, and a parasite. Today it’s vanishing before our eyes, melting into the fabric of our electrified world. In the future, everything will be a battery, and stand-alone energy storage will seem as quaint as landline telephones and portable CD players. It’s a disappearing act worthy of a great magician: Now you see it—and soon you won’t.

Eoin Treacy's view

Dematerialisation is the process through which many of the locations and products we have previously physically interacted with have disappeared onto the internet. The disappearance first of the record player and then the record store is a clear example of that trend.

Removing the physical presence of a battery and integrating it into the product is not strictly an iteration of that trend since it is a material science rather than a software problem.

Material sciences take more time and at present a number of big questions being addressed by innovators. One is the question of battery energy density and longevity. Another is solar cell efficiency and cost of production. The Lightyear One solar/electric vehicle with a 500-mile range is due to begin production in a year. That would not be possible without the gains in cell efficiency achieved to date. Another would be the evolution of the hydrogen economy, where significant capital is being deployed at present. 

Meanwhile the much quicker iterations of software mean artificial intelligence and deep learning would greatly enhance the application of advances in materials science.