This new paper battery has a stable voltage of 1.2 volts, close to the level of a standard 1.5 volt AA alkaline battery. This biodegradable battery would be used to power temporary devices used in the medical and industrial fields, where electronic waste is generated in quantity.
A team of scientists has developed a paper battery that is activated by water and generates a voltage of 1.2 volts, very close to the 1.5 volts offered by conventional batteries.
Made with biodegradable and sustainable materials, this battery would be of great importance in addressing the environmental impact generated by single-use electronics. These batteries would be essential for the medical and industrial field which generates large volumes of daily waste.
Other advantages of this eco-friendly battery are that it is very inexpensive to manufacture and its shape and size can be adapted to every need.
For example, to better understand the power of this battery, manufacturers report that a two-cell battery made with this technology was enough to power an LCD alarm clock. But it does not have enough power, for example, to charge a laptop. These batteries are ideal for low power sensors and trackers.
“Introducing a printed paper battery developed to power single-use disposable electronic devices while minimizing their impact on the environment“, write the researchers in the article published in Scientific reports. “The battery is based on a metal-air electrochemical cell which uses zinc as a biodegradable metal in the anode, graphite in the cathode, paper as a separator between the electrodes and a water-based electrolyte.“.
How is the paper stack made?
The battery, made from paper coated with sodium chloride salt, can measure as little as one square centimeter and is based on printed inks: one ink contains flakes of graphite and acts as the cathode (positive end), while the other, on the other side of the paper, contains zinc powder and serves as the anode (negative end). A third ink, consisting of carbon black and graphite flakes, is printed on both sides, above the other two inks, connecting the positive and negative ends to two wires. These are attached to one end of the paper, dipped in wax.
How does this new battery work?
To activate the mechanism, a very small amount of water is needed, two drops are enough. The water will dissolve the salts in the paper, releasing charged ions which will then activate the battery on its way. The circuit is closed by attaching the wires to the electrical device, which means electrons can be transferred from the negative ends to the positive ends.
The paper battery starts producing power just about 20 seconds after the water is added, according to the team’s experiments.
“This demo shows that despite its limited power density compared to standard technologies, our battery remains relevant for a wide range of low-power electronics and the Internet of Things ecosystem.write the researchers.
Battery performance declines over time as the paper dries. However, it can be filled up to a certain point with more water and it will still work. In this way, the battery can still produce 0.5 volts two hours after its first activation.
For now, this is just a test and the scientists want to improve the battery efficiency for the future, so that it works longer. The battery, yes, is not difficult to produce.
“With the growing awareness of the problem of electronic waste and the emergence of single-use electronics for applications such as environmental sensing and food monitoring, there is a growing need for batteries with low environmental impact.write the researchers in the study.
“This shift from traditional performance-driven merit values creates new opportunities for unconventional materials and designs that can provide a balance of performance and environmental impact.“.
Reference: Poulin, A., Aeby, X. & Nyström, G. 2022. Water-activated disposable paper cell. Scientific reports. DOI: https://doi.org/10.1038/s41598-022-15900-5