In-situ grown sweet alyssum flowers-like CoMoO4 for high performance hybrid supercapacitors

Effective optimization of the structure and morphology of the electrode materials of supercapacitors is thought to be a viable option for increasing their energy storage capacity. In this stydy, using a simple hydrothermal/solvothermal method, we synthesized nanostructured CoMoO4 (CMO) with a variety of morphologies, including sweet alyssum flowers, hydrangea flowers and rose petals that were grown directly on the surface of Ni foam. Water and mixed solvents of water plus ethanol, water plus ethylene glycol in 1:1 ratio were used in the CoMoO4 synthesis, and referred to as CMO-W, CMO-W:ET, and CMO-W:EG, respectively. Glucose played a vital role in regulating the morphology in different solvent media. CMO-W alyssum flowers benefit from the synergistic effect of high void space and hierarchical structure, which promotes the adequate exposure of numerous active sites, improves structural stability, and improves the energy storage performance. In view of electrochemical performance, the CMO-W electrode outperformed the other two electrodes, with a superior specific capacity of 1060 C g−1 at 0.5 A g−1 and impressive cycle stability at 5 A g−1, with a retention of 79.5 % after 4000 cycles. A hybrid supercapacitor device was built with CMO-W and activated carbon (AC) as the positive and negative electrodes respectively. This device had a notable long-term stability, with a retention of 80.6 % after 4000 cycles and also shown 68.7 Wh kg−1 of energy density at 824 W kg−1 of power density. Furthermore, two devices connected serially illuminated a red light-emitting diode (LED) for up to 6 min.