Li−O 2 batteries are considered the ultimate energy storage technology for their potential to store large amounts of electrical energy in a cost-effective and simple platform. Large overpotentials for the formation and oxidation of Li 2 O 2 during discharging and charging have thus far confined this technology to a scientific curiosity. Herein, we consider the role of catalytic intervention in the reversibility of the cathode reactions and find that semiconducting metal−organic polymer nanosheets composed of cobalt-tetramino-benzoquinone (Co-TABQ) function as a bifunctional catalyst that facilitates the kinetics of the cathode reactions under visible light. Upon discharging, we report that O 2 is first adsorbed on the Co atoms of Co-TABQ and accepts electrons under illumination from the d z 2 and d xz orbitals of Co atoms in the π 2p * orbitals, which facilitates reduction to LiO 2 . The LiO 2 is further shown to undergo a second reduction to the discharge product of Li 2 O 2 . In the reverse charge, the holes generated in the d z 2 orbitals of Co are mobilized under the action of the applied voltage to enable the fast decomposition of Li 2 O 2 to O 2 and Li + . Under illumination, the Li−O 2 battery exhibits respective discharge and charge voltages of 3.12 and 3.32 V for a round-trip efficiency of 94.0%. Our findings imply that the orbital interaction of metal ions with ligands in Co-TABQ nanosheets dictates the light harvesting and oxygen electrocatalysis for the Li−O 2 battery.

A photo‐involved Li‐O2 battery with carbon nitride (C3N4) is presented as a bifunctional photocatalyst to accelerate both oxygen reduction and evolution reactions. With illumination in a discharge process, photoelectrons generated in the conduction band (CB) of C3N4 are donated to O2 for O2−, which undergoes a second electron reduction to O22− and gives the final product of Li2O2; in a reverse process, holes left behind in the valence band (VB) of C3N4 plus an applied lower voltage than the equilibrium drive the Li2O2 oxidation. The discharge voltage is significantly increased to 3.22 V, surpassing the thermodynamic limit of 2.96 V, and the charge voltage is reduced to 3.38 V. This leads to a record‐high round‐trip efficiency of 95.3 % and energy density increase of 23.0 % compared to that in the dark.

Mn-based oxides have attracted extensive attention as electrode materials. However, the irreversible phase transition and Mn 2+ dissolution result in their structure instability and performance decay. Here, we report dual interphase layers in situ formed on P2-K 0.67 MnO 2 (P2-KMO) in 6.0 M of potassium bis(fluorosulfonyl)amide in diglyme (KFSI/G2) during charging. It is composed of a solidelectrolyte interphase (SEI) and K-poor spinel interlayer on P2-KMO, which are derived from the simultaneous decomposition of 6.0 M KFSI/G2 and disproportionation of surface Mn 3+ . They cooperatively enable the reversible phase transition of P24P 00 2 in the bulk P2-KMO and mitigate Mn loss. This leads to a high capacity retention of 90.5% and a Coulombic efficiency of 100% after 300 cycles. The investigation highlights the significance of interphase chemistry of electrode materials for potassium-ion batteries and beyond.

The storage of solar energy in battery systems is pivotal for a sustainable society, which faces many challenges. Herein, a Zn–air battery is constructed with two cathodes of poly(1,4‐di(2‐thienyl))benzene (PDTB) and TiO2 grown on carbon papers to sandwich a Zn anode. The PDTB cathode is illuminated in a discharging process, in which photoelectrons are excited into the conduction band of PDTB to promote oxygen reduction reaction (ORR) and raise the output voltage. In a reverse process, holes in the valence band of the illuminated TiO2 cathode are driven for the oxygen evolution reaction (OER) by an applied voltage. A record‐high discharge voltage of 1.90 V and an unprecedented low charge voltage of 0.59 V are achieved in the photo‐involved Zn–air battery, regardless of the equilibrium voltage. This work offers an innovative pathway for photo‐energy utilization in rechargeable batteries.

This review summarizes the recent findings regarding photoinvolved oxygen cathodes, battery configurations, and the stability of Li–O2 batteries, and aims to provide a fundamental understanding of photoinvolved Li–O2 batteries.