Multiscale Structural Engineering of Ni‐Doped CoO Nanosheets for Zinc–Air Batteries with High Power Density

Abstract

Zinc–air batteries offer a possible solution for large‐scale energy storage due to their superhigh theoretical energy density, reliable safety, low cost, and long durability. However, their widespread application is hindered by low power density. Herein, a multiscale structural engineering of Ni‐doped CoO nanosheets (NSs) for zinc–air batteries with superior high power density/energy density and durability is reported for the first time. In micro‐ and nanoscale, robust 2D architecture together with numerous nanopores inside the nanosheets provides an advantageous micro/nanostructured surface for O 2 diffusion and a high electrocatalytic active surface area. In atomic scale, Ni doping significantly enhances the intrinsic oxygen reduction reaction activity per active site. As a result of controlled multiscale structure, the primary zinc–air battery with engineered Ni‐doped CoO NSs electrode shows excellent performance with a record‐high discharge peak power density of 377 mW cm−2, and works stable for >400 h at 5 mA cm−2. Rechargeable zinc–air battery based on Ni‐doped CoO NSs affords an unprecedented small charge–discharge voltage of 0.63 V, outperforming state‐of‐the‐art Pt/C catalyst‐based device. Moreover, it is shown that Ni‐doped CoO NSs assembled into all‐solid‐state coin cells can power 17 light‐emitting diodes and charge an iPhone 7 mobile phone.