A new thin-film flexible battery has been developed by researchers at Uppsala University in Sweden, consisting of two common, non-toxic materials: salt and paper. This discovery could be the cheap, easily manufactured, and green solution for portable rechargeable power.

“We introduce a novel nanostructured high-surface area electrode material for energy storage applications composed of cellulose fibers of algal origin individually coated with a 50 nm thin layer of polypyrrole. Our results show the hitherto highest reported charge capacities and charging rates for an all polymer paper-based battery.”

The salt solution acts as the electrolyte, and the polymer coated paper (pressed cellulose fibers) becomes the electrodes. Suggestions for real-world applications are medical diagnostics devices or sensors on packaging materials or embedded into fabric.

According to the researchers, “You don’t need advanced equipment to make the batteries, so they could be made on site in developing countries.”

“The aqueous-based batteries, which are entirely based on cellulose and polypyrrole and exhibit charge capacities between 25 and 33 mAh g−1 or 38−50 mAh g−1 per weight of the active material, open up new possibilities for the production of environmentally friendly, cost efficient, up-scalable and lightweight energy storage systems.”

The research paper, Ultrafast All-Polymer Paper-Based Batteries, is published at NANO Letters.