A Pyrolysis‐Free Method Toward Large‐Scale Synthesis of Ultra‐Highly Efficient Bifunctional Oxygen Electrocatalyst for Zinc‐Air Flow Batteries
Xueli Li, Di Liu, Qingbin Liu, Zhonghua Xiang
Abstract
Abstract The transition‐metal nitrogen‐carbon (M‐N‐C) catalysts, as one of the optimal bifunctional oxygen catalysts, are vital for cathodic oxygen electrode of Zn‐based air flow batteries (ZAFBs). However, chemical complexity of M‐N‐C catalysts prepared via the traditional pyrolytic process increases the difficulties of precise control toward configuration and repeatability, especially in large‐scale synthesis. Herein, a bifunctional oxygen catalyst via a pyrolysis‐free approach based on closed π‐conjugated covalent organic polymers (COPs, microwave synthesis) is developed, which inherits the advantage of the well‐defined configuration in an atomic manner. Profited from distinct catalytic centers and strong electronic coupling at the interface between COP and layered double hydroxides, the as‐synthesized catalyst not only more easily permits large quantity production (>1 kg per batch), but also maintains an ultrahigh bifunctional activity and a long cycle stability even after scale synthesis (Δ E [ E j 10 – E 1/2 ] = 591 mV; energy efficiency drops by only 2.02% after 1200 cycles), which overwhelmingly exceeds the benchmark Pt/C+IrO 2 and the state‐of‐the‐art pyrolytic bifunctional M‐N‐C oxygen catalysts.