Urea-assisted synthesis of CoMoO4–NiMoO4 microspheres for the electrochemical energy storage

A series of CoMoO4–NiMoO4 materials have been successfully synthesized via a urea-assisted hydrothermal method. During the process of this strategy, the composition of the materials can be easily controlled by adding different mole ratios of Co to Ni, while the morphology of the Co–Ni molybdate remains unchanged. Owing to their unique architecture and the synergetic effect of CoMoO4 and NiMoO4, the resulting CoMoO4–NiMoO4 microspheres show the enhanced energy storage performance of 587 C g−1 at 5 mA cm−2. The hybrid supercapacitor device based on this molybdate further demonstrated the favorable properties with the maximal capacitance of 80 F g−1 and the energy density of 28.4 Wh kg−1 at the power density of 222 Wh kg−1. Electrochemical results obtained from the two types of electrode systems reveal that this bimetallic Co–Ni molybdate can be used in the practical areas of energy storage.