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.