The fabrication of rechargeable lithium-ion batteries, whose components can be engineered into paint formulations and spray-painted directly on a variety of surfaces, is described in Scientific Reports this week. Energy-harvesting devices, such as solar cells, can then be integrated with these batteries to give any surface a stand-alone energy-capture and storage capability.

Lithium-ion (Li-ion) batteries power most of our portable electronics, due to their high energy and power density. Li-ion battery packs are compact but their ‘jellyroll’ design limits the batteries to rectangular or cylindrical shapes. Pulickel Ajayan and colleagues use a spray painting technique to fabricate batteries onto various surfaces, including diverse materials, such as glass, stainless steel and ceramic tiles, and diverse shapes, such as the curved surface of a ceramic mug. The substrate types were shown to have no effect on the performance of the batteries, suggesting that the technology could be integrated into a wide range of standard construction materials, and household objects.

One limitation of Li-ion batteries is the use of not-so-easy-to-handle liquid electrolytes and an oxygen- and moisture-free environment, which will bring limitations to the process in its current form. Further research using battery components that are less sensitive to moisture and oxygen could make the technique more efficient and commercially more viable.