High Areal Capacity, Long Cycle Life Li–Air Batteries Enabled by Nano/Micro Hierarchical Porous Cathode

Abstract

AbstractThe limited cycle life of Li–air batteries (LABs) with high areal capacity remains the chief challenge that hinders their practical applications. Here, the study proposes a hierarchical porous electrode (HPE) design strategy, in which porous MnO nanoflowers are built into mesopore/macropore electrodes through a combination of chemical dealloying and physical de‐templating procedures. The MnO nanoflowers with 10–30 nm pore provides active sites to catalyze the O2 reduction and decomposition of discharged products. The 5–10 µm macroscopic pores in the cathode serve as channels of O2 transportation and facilitate the electrolyte permeation. The proposed HPE exhibits a full discharge capacity of 17.49 mAh cm−2 and stable cycle life >2000 h with a limited capacity of 6 mAh cm−2. These results suggest that the HPE design strategy for LABs can simultaneously provide large capacity and robust cycle life, which is promising for advanced metal–air batteries.