Preparation of NiMoO4 porous nanosheets by freezing method as adhesive-free electrodes for high-performance flexible supercapacitors

This article successfully prepared porous NiMoO4 sheet-like structured nanomaterials deposited on carbon cloth using the freeze-drying method. The morphology and phase structure were characterized by SEM, TEM, and XRD, proving that the material is NiMoO4 porous nanosheets. The NiMoO4 porous nanosheets have a large specific surface area, which increases the reaction sites of the material, shortens the transmission distance of electrons and ions, accelerates the reaction rate, and thus improves the charge storage capacity. We conducted electrochemical performance tests on the material, and the test results showed that the specific capacity was 1683 F/g at a current density of 5 A/g. After 5000 cycles, the capacitance retention rate was 99.7%. We further assembled NiMoO4 porous nanosheets as positive electrodes and CNTs as negative electrodes to form solid-state asymmetric capacitor devices. At a current density of 15 A/g and a working window voltage of 1.6 V, the asymmetric device has an energy density of 70.8 Wh/Kg and a power density of 7000 W/Kg. After 10,000 cycles at a current density of 5 A/g, the device exhibits excellent cycling stability with a capacitance retention rate of 87.6%. This article provides a valuable reference for the development of electrode materials for capacitors.