Efficient supercapattery behavior of mesoporous hydrous and anhydrous cobalt molybdate nanostructures

Abstract

Hydrous forms of cobalt molybdate binary metal oxide nanoaggregates were synthesized via a simple chemical co-precipitation technique. The subsequent heat treatment at 400 °C converted the sample into anhydrous cobalt molybdate (CoMoO4) with mesoporous nanostructure. The anhydrous cobalt molybdate possess surface area and pore volume of 63.92 m2g-1 and 0.1802 cm3g-1 which is much higher than the hydrous cobalt molybdate (1.215 m2g-1 and 0.0072 cm3 g−1). The electrodes designed using these materials exhibited a battery-like behavior with maximum specific capacity of 97 Cg-1 and 177 Cg-1 for hydrous and anhydrous cobalt molybdate samples respectively. In addition, a supercapattery was fabricated utilizing anhydrous cobalt molybdate//activated carbon electrodes, which showed maximum specific capacity value of 64 Cg-1 at 1 Ag-1 discharge specific current and showed better specific energy ∼18.89 Whkg−1 for a specific power of 1.06 kWkg−1. Moreover, the supercapattery exhibited good capacity retention ∼93% after 5000 charge/discharge cycles.