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Fundamental insights into the reaction kinetics of organic–inorganic lead halide perovskite nanocrystals (LHP NCs) are still limited due to their ultrafast formation rate. Herein, we develop a water–oil interfacial synthesis of MAPbBr3 NCs (MA=CH3NH3+), which prolongs the reaction time to tens of minutes. This method makes it possible to monitor in situ the formation process of MAPbBr3 NCs and observe successive spectral evolutions from 438 to 534 nm in a single reaction by extending reaction time. The implementation of this method depends on reducing the formation rate of PbBr64− octahedra and the diffusion rate of MA. The formation of PbBr64− is a rate‐determining step, and the biphasic system offers a favorable reaction condition to control the mass transfer of MA. The effects of temperature and concentration of precursor and ligand are investigated in detail. [ABSTRACT FROM AUTHOR]

Abstract: Free‐standing macroporous air electrodes with enhanced interfacial contact, rapid mass transport, and tailored deposition space for large amounts of Li2O2 are essential for improving the rate performance of Li‐O2 batteries. An ordered mesoporous carbon membrane with continuous macroporous channels was prepared by inversely topological transformation from ZnO nanorod array. Utilized as a free‐standing air cathode for Li‐O2 battery, the hierarchically porous carbon membrane shows superior rate performance. However, the increased cross‐sectional area of the continuous macropores on the cathode surface leads to a kinetic overpotential with large voltage hysteresis and linear voltage variation against Butler–Volmer behavior. The kinetics were investigated based on the rate‐determining step of second electron transfer accompanied by migration of Li+ in solid or quasi‐solid intermediates. These discoveries shed light on the design of the air cathode for Li‐O2 batteries with high‐rate performance. [ABSTRACT FROM AUTHOR]