2D high-ordered nanoporous NiMoO4 for high-performance supercapacitors

Abstract 2D high-ordered nanocrystalline nanoporous NiMoO 4 has been synthesized by nanocasting from mesoporous silica SBA-15. The structure has been characterized by means of low and wide-angle powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), BET, and BJH techniques, confirming formation of 2D high-ordered nanoporous structure of NiMoO 4 with high specific surface area (174 m 2 g −1 ), nanocrystalline walls (7–8 nm) and uniform pore size distribution (5.4 nm). The electrochemical properties of the nanoporous NiMoO 4 have been evaluated as electrode material for supercapacitor in a three-electrode configuration in aqueous 3 M KOH solution. The material exhibits superior electrochemical performance including high specific capacitance of 2351 F g −1 at 2 A g −1 , excellent rate capability (1080 F g −1 at 80 A g −1 ), excellent cycling stability in 6000 continuous cycles at different current densities (only 9.3% loss after 3000 cycles at 5 A g −1 ), and high energy and power densities (117.5 W h kg −1 in 0.6 kW kg −1 , and 54 W h kg −1 in 24 kW kg −1 ). The superior electrochemical performance of the 2D nanoporous NiMoO 4 electrode has been attributed to its structural features, including 2D highly ordered nanoporous structure which facilitates mass transfer and electrolyte accessibility, high specific surface area which provides more active sites for the pseudocapacitive reactions, and nanosized walls which shorten diffusion paths. These results reveal that the nanoporous NiMoO 4 is a promising candidate for high-performance supercapacitor electrode materials.