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 serve to power temporary devices used in medical and industrial areas, where e-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 to remedy the environmental impact generated by single-use electronics. These batteries would be fundamental for the medical and industrial area that generate large volumes of daily waste.
Other advantages of this ecological battery are that it is very cheap to manufacture and its shape and size can be adapted to every need.
As an 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 doesn’t have enough power, for example, to charge a laptop. These batteries are ideal for low power sensors and trackers.
“Featuring a printed paper battery designed to power single-use disposable electronics while minimizing their environmental impact“, write the researchers in the article published in Scientific Reports. “The battery is based on a metal-to-air electrochemical cell that uses zinc as the biodegradable metal at the anode, graphite at the cathode, paper as a separator between the electrodes, and a water-based electrolyte.“.
How is paper battery made?
The battery, made of paper greased with sodium chloride salt, can measure just one square centimeter and is based on printed inks: one ink contains graphite flakes and acts as a cathode (positive end), while another, on the other side of the paper. , contains zinc dust and acts as an anode (negative end). A third ink, composed of carbon black and graphite flakes, is printed on both sides, on top of the other two inks, connecting the positive and negative ends to two wires. These are fixed to one end of the paper, dipped in wax.
How does this new stack work?
A very small amount of water is needed to activate the mechanism, two drops are enough. The water will dissolve the salts inside the paper, releasing charged ions that will activate the battery in its path. The circuit is closed by connecting the wires to the electrical device, which means that electrons can be transferred from negative to positive.
The paper battery starts producing power only about 20 seconds after adding water, according to the team’s experiments.
“This demo shows that despite its limited power density compared to standard technologies, our battery is still relevant to a wide range of low-power electronics and the Internet of Things ecosystem.“, write the researchers.
Stack performance degrades over time as the paper dries. However, it can be filled to a certain extent with more water and it will still work. In this way, the battery can still produce 0.5 volts two hours after being activated for the first time.
first tests
For now, this is just a test and the scientists want to improve the battery’s efficiency for the future, so it will work longer. The battery, yes, is not difficult to produce.
“With the growing awareness of the problem of e-waste and the advent 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-oriented figures of merit creates new opportunities for unconventional materials and designs that can provide a balance between performance and environmental impact.“.
Reference: Poulin, A., Aeby, X. & Nyström, G. 2022. Water activated disposable paper battery. Scientific Reports. DOI: https://doi.org/10.1038/s41598-022-15900-5
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