This Paper-Thin, Biodegradable Battery Could Be the Future of Wearables

Researchers at Singapore’s Nanyang Technological University have developed a paper-thin biodegradable zinc battery and successfully demonstrated its ability to power a small electric fan for up to 45 minutes. The battery is comprised of electrodes screen-printed on both sides of a piece of cellulose paper, which has been reinforced with hydrogel. The team believes these batteries could be the future of wearables and other flexible electronics like foldable smartphones, especially as in tests bending the battery did not interrupt the power supply.

Paper electronics offer an environmentally sustainable option for wearable systems and, with currently available printing technologies, are easily manufactured. The hydrogel-reinforced cellulose paper (HCP), which can sustain a higher strain than pristine papers and biodegrades in a natural environment within four weeks, serves as both separator and solid electrolyte. Zinc batteries printed on HCP provide a high volumetric energy density, and you can cut and bend the printed circuit — perfect for flexible and eco-friendly environments.

Since it is non-toxic and requires no aluminum or plastic casings to encapsulate the battery components, not only is it eco-friendly but avoiding the packaging layers means higher capacity and, therefore more power within a smaller system. In fact, the battery is roughly 0.4mm thick or about the thickness of two strands of hair. Once the battery has been expended, it can be buried in soil, where it will break down in a matter of weeks.

In a paper published in Advanced Science, the researchers describe fabrication and performance, demonstrating a volumetric capacity and energy density that outperforms other currently available paper-based or thin-film energy storage units. Combine this with ease of synthesis and environmental sustainability, and this development spells a promising future for applications in printed electronics and integrated paper circuits.