A paper battery, which is activated with water. It is not a joke but one new discovery carried out in the Laboratory for Cellulose and Wood Materials, in Dübendorf, Switzerland. The researchers used a special disposable paper with conductive capabilities, which can be activated via water. It is an invention that promises, in the case of application success, to have a great impact on disposable electronics, that is, that universe of temporary gadgets, sensors and low-power trackers used in the medical and industrial fields. The advantage, in addition to the low costs, would be that of not using polluting material, in a sector where electronic waste accumulates rapidly.
The biodegradable battery of paper and water
The Swiss study demonstrates how this battery can work while being biodegradable, made with sustainable materials and inexpensive to assemble. In laboratory tests, a two-cell battery made with this technology was able to power an LCD alarm clock.
The scientists explain that “The battery is based on a metal-air electrochemical cell that 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”.
That is, it is about blown paper with sodium chloride saltabout the size of a square centimeter, equipped with printed ink circuits in which there are flakes of graphite on one side (positive end) and zinc dust on the other (negative end).
A third ink, consisting of graphite flakes and carbon black, is printed on both sides, on top of the other two inks, to connect the positive and negative ends to two wires. The latter are attached to one end of the paper, dipped in a wax paste.
How the paper battery works
A small amount of water is enough to make this small object work like a battery, even if only two drops are desired. The water dissolves the salts inside the paper, releasing ions that activate the battery within 20 seconds. The circuit is closed by connecting the wires to an electrical device: electrons can then be transferred from the negative to the positive ends.
What is the power of the ‘natural’ microbattery? The paper explains that with a stable voltage of 1.2 volts, the paper battery approaches the level of a standard 1.5 volt AA alkaline battery.
It can also be molded at will in the formdepending on industrial needs.
A defect? Performance decreases over time as the paper dries, but just adding more to extend the life: “This demonstration shows that despite the limited power density compared to standard technologies, our battery is still relevant to a wide range of low-power electronic devices and the Internet of Things ecosystem, “write the researchers. Which now continue the work for improve battery efficiency.