Electrospun Thin-Walled CuCo<sub>2</sub>O<sub>4</sub>@C Nanotubes as Bifunctional Oxygen Electrocatalysts for Rechargeable Zn-Air Batteries.

Wang, Xiaojun; Li, Yang; Jin, Ting; Meng, Jing; Jiao, Lifang; Zhu, Min; Chen, Jun · Nano Lett · 2017

basic_science · Level V

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Abstract

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 CuCo<sub>2</sub>O<sub>4</sub>@C with abundant nitrogen-doped nanotubes via coaxial electrospinning technique. Benefiting from high catalytic activity of ultrasmall CuCo<sub>2</sub>O<sub>4</sub> particles, double active specific surface area of mesoporous nanotubes, and strong coupling with N-doped carbon matrix, the obtained CuCo<sub>2</sub>O<sub>4</sub>@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<sup>-2</sup>) for oxygen evolution reaction (OER). Significantly, when used as cathode catalyst for Zn-air batteries, CuCo<sub>2</sub>O<sub>4</sub>@C also displays a low charge-discharge voltage gap (0.79 V at 10 mA cm<sup>-2</sup>) and a long cycling life (up to 160 cycles for 80 h). With desirable architecture and excellent electrocatalytic properties, the CuCo<sub>2</sub>O<sub>4</sub>@C is considered a promising electrocatalyst for Zn-air batteries.