Electrospun Thin-Walled CuCo₂O₄@C Nanotubes as Bifunctional Oxygen Electrocatalysts for Rechargeable Zn-Air Batteries

Rational design of optimal bifunctional oxygen electrocatalyst with low cost and high activity is greatly desired for realization of rechargeable Zn-air batteries. Herein, we fabricate mesoporous thin-walled CuCo₂O₄@C with abundant nitrogen-doped nanotubes via coaxial electrospinning technique. Benefiting from high catalytic activity of ultrasmall CuCo₂O₄ particles, double active specific surface area of mesoporous nanotubes, and strong coupling with N-doped carbon matrix, the obtained CuCo₂O₄@C exhibits outstanding oxygen electrocatalytic activity and stability, in terms of a positive onset potential (0.951 V) for oxygen reduction reaction (ORR) and a low overpotential (327 mV at 10 mA cm^-2) for oxygen evolution reaction (OER). Significantly, when used as cathode catalyst for Zn-air batteries, CuCo₂O₄@C also displays a low charge-discharge voltage gap (0.79 V at 10 mA cm^-2) and a long cycling life (up to 160 cycles for 80 h). With desirable architecture and excellent electrocatalytic properties, the CuCo₂O₄@C is considered a promising electrocatalyst for Zn-air batteries.