Paramecium‐Like Iron Oxide Nanotubes as a Cost‐Efficient Catalyst for Nonaqueous Lithium‐Oxygen Batteries

Fe 2 O 3 ‐based catalysts have been developed to achieve a low overpotential and a long cycle life for nonaqueous Li–O 2 batteries. However, previous studies focus mainly on nanoparticles or nanoflakes, which have shown limited improvements for battery performance. Here, paramecium‐like Fe 2 O 3 nanotubes (FNTs) are synthesized by a hard‐template method and applied as the catalyst in a nonaqueous Li–O 2 battery. The large specific surface area and unique tubular structure of the FNTs allow the nonaqueous Li–O 2 battery to deliver a high capacity of 6000 mAh g −1 at a discharge current density of 500 mA g −1 with a low discharge and charge overpotential of approximately 0.19 and 0.85 V, respectively. Moreover, the battery can be operated at a discharge current density as high as 1000 mA g −1 with a capacity of 3940 mAh g −1 and demonstrates an excellent rate capability. The prepared catalyst enables the battery to maintain the discharge capacity and Coulombic efficiency without any degradation for 150 cycles at 500 mA g −1 with a fixed capacity of 500 mAh g −1 , which is 110 more cycles than the battery without the catalyst.