Seeking advanced energy conversion devices, which are sustainable as well as environment friendly, is extremely challenging in our modern society. [3,4] In this regard, the metal-air battery is among the alternative costeffective battery technologies with high energy density, environmentally friendly, and which is composed of an air electrode and a metal electrode, generating electricity through the redox reaction. [5] Among the various metal-air batteries, Li-air and Zn-air batteries have received the most extensive attention. [6] Although Li-air battery exhibits extremely high theoretical energy density (3500 Wh kg −1 ), Li is so reactive that the Li-air battery inevitably faces security risks. [7,8] Iron (Fe) is the fourth most abundant element in the world. In addition, Fe is also a cheap, safe, and environmentally friendly anode material for metal-air batteries. [9] Therefore, compared with the Zn anode, Fe as the anode can reduce battery cost for its abundant reserves. [10] The Fe-air battery has been considered as a low-cost, environmentally benign electrochemical energy-storage system. [11][12][13] Fe-air battery can sustain more charge-discharge cycles than Zn-air battery due to its lower susceptibility to dendrite formation. [8] Intrinsically, the Fe-air battery can store/ release energy repeatedly as needed via oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) but this process is always plagued by slow kinetics of OER/ORR. [14] Therefore, the study on improving reaction kinetics or lowering overpotential of OER/ORR has garnered considerable research interest in recent years. [5,15] Yu et al. used IrO 2 /Ti as the electrode of Fe-air battery to reduce the overpotential of OER and it can achieve a charge voltage of 1.65 V at 1 mA cm −2 . [12] To further reduce the OER/ORR overpotential of metal-air battery, the combination of solar energy and battery is a new research field with fascinating prospects. [16] Solar energy has been utilized in various electrochemical devices for improved reaction kinetics and lowered overpotential, such as hydrogen evolution reaction, water spilling, and pollutant degradation. [17][18][19][20][21] For the aqueous metal-air battery, it usually involves a semiconductor that, upon illumination, could generate Effective utilization of solar energy in battery systems is a promising solution to achieve sustainable and green development. In this work, a photoassisted Fe-air battery (PFAB) with two photoelectrodes of ZnO-TiO 2 heterostructure and polyterthiophene (pTTh)-coated CuO (pTTh-CuO) grown on fluorinedoped tin oxide (FTO) is proposed. The band structure of semiconductors and the charge-transfer mechanism of heterostructure are studied. The electrochemical results show that the photogenerated electrons and holes play key roles in reducing the oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) overpotential in the discharging and charging processes, respectively. The short-circuit current density, the open-circuit voltage, and the maximum power outpu...