Researchers create a paper-based battery that is water-activated

For more than two thousand years, paper has served as a cornerstone of human progress. Nowadays, however, its utility extends beyond mere writing. It is at the forefront of ushering in a more sustainable future.

Devices made from paper, being both lightweight and thin, lessen reliance on metals or plastics while offering an eco-friendlier disposal method. Scientists are leveraging paper's versatility for numerous purposes: from paper-based diagnostic tools providing quick, affordable infectious disease detection to paper-based batteries and energy devices presenting greener power generation alternatives.

A research team from Tohoku University has introduced a noteworthy innovation in this area: a high-performance magnesium-air (Mg-air) battery crafted from paper and activated with water.

"We drew inspiration for this device from the respiration mechanism of plants," shared Hiroshi Yabu, one of the study's lead authors. "Photosynthesis is analogous to the charge and discharge process in batteries. Just as plants harness solar energy to synthesise sugar from water in the ground and carbon dioxide from the air, our battery utilises magnesium as a substrate to generate power from oxygen and water."

The creation of the battery involved adhering magnesium foil to paper, with the cathode catalyst and gas diffusion layer added to the paper's opposite side. The paper battery demonstrated significant performance: an open circuit voltage of 1.8 volts, a current density of 100 mA/cm² at 1.0 volt, and a peak output of 103 milliwatts/cm².

"Not only did the battery demonstrate impressive performance results, it operates without using toxic materials - instead using carbon cathodes and a pigment electrocatalyst that have passed stringent assessments," adds Yabu.

To showcase the battery's practical applications, the researchers employed it in both a pulse oximeter sensor and a GPS sensor, demonstrating its potential in wearable technology.

This innovation was detailed in an article published in the journal 'RSC Applied Interfaces' on 18th March 2024, highlighting the battery's adaptability for various wearable devices. Such applications underscore the battery's role in advancing eco-friendly and efficient power sources, further broadening the scope of paper-based technology in the realm of sustainable development.