One pot preparation of CoMoO4 nanowires covered by CoMoO4 nanosheets for application in asymmetric supercapacitors

In this work, we report for the first time to prepare the CoMoO4 materials by a one-step simple water bath heating process. The morphology of the materials changes greatly when the temperature changes at a certain stage. The experimental results indicate the CoMoO4 is nanowire structure at 90 °C. When the temperature is 150 °C, the morphology of CoMoO4 is nanosheet structure. What is interesting in the experiment is that when we continuously adjust the temperature from 90 to 150 °C, we found that the CoMoO4 nanowires were covered by CoMoO4 nanosheets. The electrochemical performances of CoMoO4 nanowires, CoMoO4 nanosheets, and CoMoO4 nanowires covered by CoMoO4 nanosheets were researched. The electrochemical test results show that the CoMoO4 nanowires covered by CoMoO4 nanosheets demonstrate high specific capacitance 1960 F/g at a current density of 1 A/g, rate property 64.29%, and cycle performance with 98.79% capacitance retention after 10000 cycles. Furthermore, the CoMoO4 nanowires covered by CoMoO4 nanosheets were used as the positive material and active carbon as the negative material were assembled into the asymmetric supercapacitor device. This asymmetric supercapacitor device shows high energy density 55.47 Wh/kg and power density 12000 Wh/kg, and cycle performance with the capacitance retention 92.86% after 10000 cycles. These excellent results indicate the CoMoO4 nanowires covered by CoMoO4 nanosheets have potential competition in energy storage.