Efficient photo-rechargeable aqueous zinc-ion batteries using lead-free perovskite photocathodes

Abstract

Photo-rechargeable zinc-ion batteries represent a promising advancement in energy storage devices, possibly offering a sustainable and efficient solution for future renewable energy storage. By integrating a photovoltaic device with zinc-ion chemistry in a single unit, these systems offer a dual mechanism for energy harvesting and storage. In the present study, the use of a Ag incorporated caesium bismuth iodide perovskite photocathode is explored for both photo-assisted and photo-only chargeable aqueous zinc-ion batteries. The cell exhibits an enhancement in the specific capacity from 250 mAh g⁻¹ to 321 mAh g⁻¹ under 1 sun illumination at a current rate of 500 mA g⁻¹ in the photo-assisted charging mode. In addition, it has been demonstrated that the photo-generated charges in the perovskite electrode exhibit the capability to directly charge the battery without the need for an external bias. A photoconversion efficiency of 2.1% has been achieved in the photo-only charging mode under 1 sun illumination. The proposed photocathode based on a perovskite is considered an emerging candidate for photo-rechargeable batteries due to its superior performance and intrinsic safety.