Phthalocyanine Based Metal–Organic Framework Ultrathin Nanosheet for Efficient Photocathode toward Light‐Assisted Li–CO2 Battery

Abstract

AbstractLight‐assisted Li–CO2 battery, emerging as a powerful battery‐technology to utilize light‐energy, has attracted much attention yet it is still limited by the lack of efficient photocathode catalysts toward simultaneously promoted CO2 activation/evolution processes. Here, a kind of phthalocyanine‐based metal–organic framework nanosheet (CoPc–Mn–O) is prepared and applied as efficient photocathode catalyst in light‐assisted Li–CO2 battery. Thus‐produced CoPc–Mn–O shows nanosheet‐morphology (≈1 nm), dual active metal‐sites (i.e., Co–N4 and Mn–O4), high conductivity, and photosensitivity. The resulting battery delivers a high round‐trip efficiency of 98.5% with an ultralow voltage hysteresis of 0.05 V and superior cycling‐stability (81.3%) for 60 h at 0.02 mA cm−2, which is represented to be one of the best photo‐cathodes to date. Density functional theory calculations and characterizations prove that the presence of photosensitive CoPc–Mn–O with dual active metal‐sites endows an activation energy (3.2 eV) for CO2 activation under light condition and simultaneously promote the CO2 evolution to enhance the battery efficiency.