Recently, many development efforts towards energy storage materials by researchers have resulted in the design and fabrication of various electrode materials for efficient energy storage applications. Transition metal phosphates have attracted much interest among the reported materials due to their superior properties. Herein, we report urea-based nickel molybdenum phosphate nanopetals embedded microspheres (UNMP NPs@MSs) with a morphology closely resembling a marigold flower via an ion exchange synthesis technique. The addition of phosphorus leads to the procedural enhancement of transition metal oxides. Furthermore, this work also specifies the necessity of a suitable morphology to push the working material to its maximum limit. In a three-electrode configuration, the UNMP NPs@MSs-coated nickel foam (UNMP NPs@MSs/NF) electrode delivers an areal capacity value of 166.6 μAh cm−2, accompanied by a capacity retention of 99.5% after 50 000 cycles. Additionally, the hybrid supercapacitor (HSC) device is assembled with UNMP NPs@MSs/NF as a positive electrode and activated carbon as a negative electrode. The HSC device exhibits an areal capacitance value of 453.95 mF cm−2 with energy and power density values of 34.34 Wh kg−1 and 5106.38 W kg−1, respectively. Remarkably, the as-assembled HSC shows outstanding long-term cycling stability with 109% retention even after the completion of 100 000 cycles. Finally, the fabricated HSC device is employed to power electronic components to verify its real-time utilization and the results are reported.

The development of aqueous zinc-ion batteries (AZiBs) towards practical implementations is hampered by unsuitable host cathode materials. Herein, we reported a high-capacity, stable, and long-cycle-life (10 000 cycles) oxygenated copper vanadium selenide composite material (Cu0.59V2O5/Cu0.828V2O5@Cu1.8Se1/Cu3Se2, denoted as O–CuVSe) as a cathode for AZiBs. The newly constructed O–CuVSe composite cathode can be operated in the wide potential window of 0.4–2.0 V, exhibiting a high specific capacity of 154 mA h g−1 at 0.2 A g−1 over 100 cycles. Interestingly, the O–CuVSe composite cathode delivered excellent specific capacities of 117 and 101.4 mA h g−1 over 1000 cycles at 1 and 2 A g−1, respectively. Even at a high current density of 5 A g−1, the cathode delivered a high reversible capacity of 74.5 mA h g−1 over an ultra-long cycling life of 10 000 cycles with no obvious capacity fading. Apart from this, the cathode exhibited excellent rate capability at different current densities. The superior electrochemical properties originate from the synergistic effects between the oxygen vacancy engineering and interlayer doping of Cu ions to increase the structural stability during the cycling, enhancing the electron/ion transport kinetics. Moreover, the Zn2+ storage mechanism in the Zn/O–CuVSe aqueous rechargeable battery was explored. This study provides a new opportunity for the fabrication of different kinds of a new class of cathode materials for high-voltage and high-capacity AZiBs and other energy storage devices.