A new, “just-add-water” disposable paper battery could power small-scale electronics such as smart labels to track parcels and medical diagnostic devices.
Because it’s made from paper and contains zinc, both of which are biodegradable, scientists say it could help reduce the environmental impact of this type of battery.
Designed by Gustav Nystrom and colleagues at the Swiss Federal Laboratories for Materials Science and Technology, the battery is made up of at least one cell that measures one square centimeter, or about 0.15 square inches. The team published its findings scientific report Magazine 28 July.
Three ink marks cover a rectangular piece of paper with sodium chloride (table salt) on it, while one end of the paper is dipped in wax.
The first ink mark is on one side of the paper, which contains flakes of graphite and serves as the positive end of the battery.
On the other hand there is another ink marking containing zinc powder and it acts as the negative end of the battery.
A third ink marking printed on both sides contains graphite flakes and carbon black and connects the positive and negative ends of the battery to two wires that sit on the wax-dipped ends of the paper.
When a few drops of water are added, the salt dissolves in the paper and the charged ions are released.
These ions activate the battery by spreading through the paper and cause the zinc to release electrons at the negative end.
The electrons are transferred from there through the graphite and carbon black ink to the positive end and wires where they become oxygen and are released into the air.
All these reactions create an electric current which is used to power the device.
Presenting their work in the journal Scientific Reports, the researchers demonstrated their battery’s capabilities by combining two cells into a single battery and using it to power an alarm clock with a digital display.
Two drops of water energized the battery after 20 seconds, and when one did not power the device, it reached a voltage of 1.2 volts.
In comparison, the standard AA battery used for TV remote controls and toys has a voltage of 1.5 volts.
After an hour the battery’s performance dropped significantly as the paper dried up but when two more water drops were added, it held a steady voltage of 0.5 volts for an additional hour or more.
Nystrom and his colleagues say that the biodegradability of paper and zinc means that their batteries can reduce the environmental impact of low-power electronics.
The researchers say this could be further increased by reducing the amount of zinc used in the ink, which would also mean that the electricity generated from the battery could be controlled more precisely.
produced in collaboration with SWNS,
This story was provided to Newsweek zenger news,