Fabrication and characterization of a nanoporous NiO film with high specific energy and power via an electrochemical dealloying approach

A three-dimensional (3D) nanoporous NiO film was fabricated via a two-step process using an electrochemical route. This process included electrodeposition of the Ni/Zn alloy film and electrochemical dealloying using a direct-current power source. The scanning electron microscopy images suggest that the film has an irregular 3D interconnected nanosheet structure with open channels. The adsorption–desorption isotherms indicate that the as-prepared NiO film had a high specific surface area of 198 m g−1 and a narrow pore size distribution, with two peaks at 2.7 and 5.1 nm. The specific capacitance of the sample reached 1670 F g−1 at a discharge current density of 1 A g−1. In addition, the as-prepared nanoporous film exhibited high performance during a long-term cycling test. The maximum values for the specific energy and specific power at the 1.1 V potential window were 170 and 27.5 kW kg−1, respectively.