“Time” magazine lists Empa paper batteries among world’s best inventions in 2022

An Empa invention, which is essentially a paper battery activated by water, has been included in the list of the 200 most important inventions of 2022 in the category of “Experimental”. This list has now been published by the world-famous New York-based magazine “Time”.

“It sounds impossible: Just add water to a piece of paper and get energy”, according to “Time” magazine. But this is exactly what a team from the Cellulose & Wood Materials Laboratory at Empa has now succeeded in doing. At the end of July, it reported on this innovation. Its disposable battery operates via a small piece of paper with salt and ink mixed with graphite, zinc and carbon applied to it.

According to a more recent Empa press release, if you add a small amount of water to this mix, the salts within the paper dissolve and charged ions are released, making the electrolyte ionically conductive in the process. This step activates the battery, with the ions then being dispersed through the paper. This results in the zinc being oxidized at the anode, thereby releasing electrons. Once the circuit is closed, an electrical device can be powered with this current. At 1.2 volts, the voltage is just under that of a conventional AA alkaline battery.

Within the space of two to five years, the technology could be used in low-power single-use electronics such as medical diagnostic devices and smart packaging, according to comments from Gustav Nyström, Head of the Cellulose & Wood Materials Laboratory at Empa, in an interview with “Time” magazine. “I see a new role for paper that could also be an answer to the growing environmental concern over electronic waste”, he concludes.