Filter paper derived three-dimensional mesoporous carbon with Co3O4 loaded on surface: An excellent binder-free air-cathode for rechargeable Zinc-air battery

Abstract

As promising energy storage equipment, Zn-air battery exhibits the advantage of high energy density, lightweight and compact structure over other rechargeable batteries, which is an ideal choice for electric vehicles. For Zn-air battery, the activity of air cathode plays an important role in its performance. Here, we report the fabrication of Co3O4 based bulky electrode with three-dimensional mesoporous carbon as matrix, which originates from cheap filter paper precursor. This electrode exhibits excellent activity and durability in oxygen reduction (ORR) and oxygen evolution reaction (OER) process, which possesses small half-wave potential (ORR1/2 = 0.811 V) and low overpotential (OER10 = 1.518 V) for ORR and OER, respectively. With this electrode as air cathode directly, a rechargeable Zn-air battery is assembled successfully. During discharge process, the maximum power density of this Zn-air battery achieves 71 mW cm−2. Furthermore, it also exhibits high specific capacity (828 mAh g−1 at 20 mA cm−2, 544 mAh g−1 at 50 mA cm−2) and small voltage gap (0.91 V at 10 mA cm−2) in charge and discharge process. As a rechargeable battery, it also shows promising stability after long time charge-discharge experiments. Thus, we find out a simple and convenient method to fabricate cheap and effective bi-functional air cathode for rechargeable Zn-air battery.