Electrospinning Derived Hierarchically Porous Hollow CuCo₂O₄ Nanotubes as an Effectively Bifunctional Catalyst for Reversible Li-O₂ Batteries

The structural engineering and design of effectively bifunctional cathode catalysts perform a vital role in enhancing the oxygen-electrode kinetics for achieving highly reversible Li-O₂ batteries. Herein, one-dimensional CuCo₂O₄ nanotubes are fabricated by a cost-efficient electrospinning technique as a bifunctional cathodic catalyst for a lithium-oxygen battery for the first time. The as-fabricated CuCo₂O₄ nanotubes with hollow and hierarchically mesoporous/macroporous architecture accelerate the mass (O₂ and Li⁺) transport and alleviate the clog of insoluble discharge products. Along with their highly intrinsic activity toward oxygen reduction and evolution reactions, the CuCo₂O₄ nanotubes-based lithium-oxygen battery demonstrates remarkably improved electrochemical performance, such as low overpotential, high discharge capacities (8778 mAh g^-1 at 100 mA g^-1), superb rate capability, and superior reversibility up to 128 cycles under a controlled capacity of 1000 mAh g^-1 at 200 mA g^-1. The further ex-situ SEM and XRD analyses reveal that the disk-like toroidal-shaped Li₂O₂ product can be efficiently decomposed during the recharging process, confirming the good reversibility of CuCo₂O₄ nanotubes-based cathode. These outcomes demonstrate the good prospect of CuCo₂O₄ nanotubes as an effectively non-noble metal catalyst in the reversible Li-O₂ battery.