A simple method for the preparation of a nickel selenide and cobalt selenide mixed catalyst to enhance bifunctional oxygen activity for Zn–air batteries. Issue 32 (28th May 2021) - Peng, Li-Juan
Abstract : The mixture Ni0.85 Se/Co0.85 Se-NHCS-2 displayed superior electrocatalytic performance to that of Ni0.85 Se-NHCS or Co0.85 Se-NHCS alone. This provided a simple approach to develop ORR/OER bifunctional electrocatalysts for zinc–air batteries. Abstract : Developing a low-cost, simple, and efficient method to prepare excellent bifunctional electrocatalysts toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical in rechargeable zinc–air batteries. Non-stoichiometric M0.85 Se (M = Ni or Co) nanoparticles are synthesized and modified on nitrogen-doped hollow carbon sphere (NHCS). The NHCS loaded Ni0.85 Se (Ni0.85 Se-NHCS) with rich Ni 3+ presents higher OER activity, whereas the NHCS-loaded Co0.85 Se (Co0.85 Se-NHCS) with abundant Co 2+ displays better ORR activity, respectively. When Co0.85 Se-NHCS is mixed with Ni0.85 Se-NHCS in a mass ratio of 1 : 1, the resulting mixture (Ni0.85 Se/Co0.85 Se-NHCS-2) shows better ORR and OER dual catalytic functions than a single selenide. Moreover, zinc–air batteries equipped with Ni0.85 Se/Co0.85 Se-NHCS-2 as the oxygen electrode catalyst exhibit excellent charge and discharge performance as well as improved stability over precious metals. This work has developed a simple and effective method to prepare excellent bifunctional electrocatalysts for ORR and OER, which is beneficial for the practical large-scale application of zinc–air batteries.