Tailored Porous ZnCo₂O₄ Nanofibrous Electrocatalysts for Lithium–Oxygen Batteries

Abstract

Abstract Lithium‐oxygen batteries are considered a next‐generation technology owing to their extremely high theoretical energy density despite many challenges such as low round‐trip efficiency and poor cyclability. The air‐cathode structure and pore properties play a key role in solving these problems. In this study, we fabricate ZnCo 2 O 4 nanofibers and design a porous nanostructure using a facile electrospinning process and selective etching of ZnO as the cathode material in lithium‐oxygen batteries. First, non‐porous ZnCo 2 O 4 nanofiber electrodes accomplish high catalytic activity and good cycling stability during 116 cycles with a limited capacity of 1000 mA h g −1 at a current density of 500 mA g −1 . For enhanced catalytic activity and cyclability, ZnO included ZnCo 2 O 4 nanofibers are prepared using a Zn‐excess electrospun solution and porous ZnCo 2 O 4 nanofibers are fabricated via selective etching of ZnO. Porous ZnCo 2 O 4 nanofiber electrodes exhibit excellent electrocatalytic activity and cyclability for 226 cycles with a limited capacity of 1000 mA h g −1 at a current density of 500 mA g −1 . The exceptional catalytic properties explain the synergistic effect of the one‐dimensional nanostructure and porous structure with an appropriate pore diameter, providing a large active site and an efficient electron pathway during the Li 2 O 2 formation/decomposition process.