High-performance rechargeable metal-air batteries enabled by efficient charge transport in multielement random alloy electrocatalyst

Abstract

The integration of bifunctionally active sites of multielement random alloy catalysts with other metal oxide electrocatalysts is a promising strategy for efficient electrochemical reactions. In this study, a novel combination of virtual crystal approximation and hydrothermal synthesis was used to investigate the composition-dependent structure and electrical property in a Ag1-xNix catalyst. The combination showed that a hexagonal closed-packed structure of Ag1-xNix with a compositional ratio of 6:4 (Ag:Ni) had electrical conductivity of similar to 2 x 10(7) S center dot cm(- 1) and an ionization potential of - 5.4 eV. Furthermore, the bifunctional oxygen electrocatalytic efficiencies of Ag0.6Ni0.4 were improved by forming a heterointerface with the CoNb2O6 electrocatalyst, resulting in a discharge-charge voltage gap of 0.81 V over 587 h, peak power density of 178.9 mW center dot cm(-2), and specific capacity of 806.8 mA center dot h center dot g(-1) in a zinc-air battery. This approach was applied to pouch-type zinc-air batteries, resulting in long-term stability of over 158.6 h at 10 mA center dot cm(- 2).