By Hauwa Ali
Researchers at the Cellulose & Wood Materials Laboratory at the Swiss Federal Laboratories for Materials Science and Technology (Empa) have invented a new disposable battery made of paper, which is activated with a few drops of water.
This inventors published a paper in Scientific Reports recently, describing the new water-activated paper battery they developed out of environmentally friendly materials.
The battery was demonstrated by the researchers as biodegradable, made from sustainable materials, and cheap to put together.
“We present a printed paper battery developed to power single-use disposable electronics and to minimize their environmental impact,” write the researchers in their published paper.
“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.” They added.
The battery was also described to be made from sodium chloride salt-diffused paper, can measure as little as one square centimeter (0.15 square inches), and is based on printed inks: one ink contains graphite flakes and acts as the cathode (positive end), while another on the other side of the paper contains zinc powder and acts as the anode (negative end).
A third ink, composed of graphite flakes and carbon black, is printed on both sides, on top of the other two inks, connecting the positive and negative ends to two wires, attached at one end of the paper, dipped in wax.
All that’s needed to activate it is a small amount of water, as little as two drops which dissolves the salts within the paper, releasing charged ions that then activate the battery as they travel.
The circuit is closed by attaching the wires to the electrical device, meaning that electrons can be transferred from the negative to the positive ends.
With a stable voltage of 1.2 volts, the paper battery is close to the level of a standard AA alkaline battery at 1.5 volts.
The battery starts producing power around 20 seconds after water is added, according to the team.
“This demonstration shows that despite its limited power density when compared to standard technologies, our battery is still relevant for a wide range of low-power electronics and the Internet of Things ecosystem,” the researchers wrote.
Although the performance decreases over time as the paper dries out, it can be topped up to some extent with more water.
The invention is indeed a huge breakthrough asdiscarded electronics are piling up fast, and researchers areexploring creative ways to reduce the resulting trash, known as e-waste.
The wires, screens and batteries that make other devices—the plastic, metal and other materials that encase them—are filling up landfills with hazardous debris.
Other e-wasteold flip phones, air conditioners and radios and is more insidious ones such as electronic single-use medical diagnostic kits, environmental sensors and smart labels that contain disposable batteries and other equipments are dangerously impacting the environment and human lives negatively.
The newly invented water-activated disposable battery made of paper and other sustainable materials is indeed environmental friendly and a sustainable alternative to the more harmful batteries that are common in low-power devices.
The researchers say they want to improve the efficiency of the battery in the future, and get it working for longer.
“With a rising awareness of the e-waste problem and the emergence of single-use electronics for applications like pbenvironmental sensing and food monitoring, there is a growing need for low environmental impact batteries,” the researchers wrote.
“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.”They added.
