Grooved Cathode Enabled High Areal Capacity Lithium–Air Batteries

The competitive transportation of O2, ions, and electrons in the thick cathode of Li-air batteries (LABs) limits their access to catalyst active sites, making it challenging to achieve a high areal capacity and thus practical applications. Herein, we present the design of a heterostructure catalyst, Fe3O4@MnO2, and by modulating the porous fabrication process, the tortuosities of the electrodes have been precisely tuned to 5.05, 2.58, and 1.31. The optimized cathode features vertically aligned channels with low tortuosity (1.31) and a multiporous structure, synergistically enabling rapid O2/Li+ transport along the depth direction while accommodating discharge products. Consequently, the LABs deliver a record areal capacity of 23.01 mAh cm-2 in ambient air and sustain 1600 h of cycling at 6 mAh cm-2. This work pioneers grooved a cathode design for practical ambient-air LABs, bridging structural engineering with performance breakthroughs.