Carbon Fiber‐Supported Co‐based MOF Derivatives as Cathode Catalysts for Zinc‐Air Batteries

Abstract

AbstractThe overuse of fossil fuels has led to energy shortage and environmental pollution. Therefore, new ways of energy storage and conversion are constantly sought. Zinc‐air batteries (ZABs) are considered to be one of the most potential renewable clean energy sources, because of their high energy density, cost‐effective and environmentally friendly advantages. However, due to the lack of stable and efficient oxygen electrocatalysts, it is difficult for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) to fully realize the effective conversion of chemistry and electric energy, which seriously affects the performance of zinc‐air batteries. Herein, Cobalt‐based composite catalyst CoP/CNF was prepared by electrospinning technology and applied to zinc‐air batteries. High power density and long‐term cycling stability of Zn‐air batteries are achieved due to the synergistic effect of transition metal phosphides and MOF‐derived M−N−C. The OER overpotential at 10 mA cm−2 of CoP/CNF is 330 mV and the ORR half‐wave potential of CoP/CNF is 0.78 V under alkaline conditions. In addition, the ZABs assembled with CoP/CNF as the catalyst has a peak power density of 164 mW cm−2 and an ultra‐long cycle stability of 1200 h at a current density of 5 mA cm−2. Even at 10 mA cm−2, the ZAB (CoP/CNF) can maintain stable cycle up to 420 h. More impressive, two ZABs (CoP/CNF) connected in series can charge the small bulb and LED screen.