Scientists have made a battery that can be directly charged in sunlight without needing an external solar panel. Clever design of the battery electrodes facilitates photo-rechargeable zinc-ion batteries that could find applications as cheap devices for off-grid solar farms.

Solar energy is often stored in rechargeable batteries for later use. Currently, this process requires separate solar cells to harvest the energy, and batteries to store it. Now, a team led by Michael De Volder from the University of Cambridge in the UK has engineered a battery cathode that can take the place of the solar cell and recharge the battery without requring an external energy harvester.