Solar Rechargeable Batteries Based on Lead–Organohalide Electrolyte

A dye‐sensitized solar cell (DSC) with in situ energy storage capacity is demonstrated using a lead–organohalide electrolyte CH3NH3I·PbCl2 (LOC) to replace the conventional I−/I3− electrolyte. The coupling of lead and iodine in one electrolyte creates a dual‐function rechargeable solar battery that combines the working processes of photoelectrochemical cells with electrochemical batteries. Optimization of the H+ concentration in the electrolyte leads to increased photocharging efficiency and storage. The power conversion efficiency of the LOC–DSC is 8.6% under one sun illumination (AM 1.5, 100 mW cm−2) as a DSC. When operating as a battery, Faraday efficiency can be achieved as high as 81.5% using a bromide‐based CH3NH3Br·PbBr2 (LOB) electrolyte in a DSC configuration. This new cell design suggests a means of combining photovoltaic energy conversion and electrical energy storage.