Highly efficient bifunctional layered triple Co, Fe, Ru hydroxides and oxides composite electrocatalysts for Zinc-Air batteries

The preparation of bifunctional catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is of great practical significance for the development of zinc-air batteries (ZAB). Layered double hydroxides (LDH) have been widely used in OER due to their low cost and adjustable structure. However, the poor ORR performance of LDH has hindered the development and application of zinc-air battery. In this work, CoFeRu-LDH was synthesized by hydrothermal method and then it was partially oxidized to obtain the oxides/LDH. As a bifunctional catalyst, RuO2, Fe2O3 and LDH have a high activity towards OER, while Co3O4 shows high reactivity towards ORR. Therefore, the catalyst oxides/LDH shows an excellent bifunctional activity with the voltage difference (Delta E) between E10 and E1/2 of 0.734 V. The assembled ZAB with the catalyst as the air electrode has a power density of 163 mW cm-2, a discharge specific capacity of 730 mAh g-1 and cycle stability of up to 210 h, proving its potential practical application in ZABs.