synthesis of core-shell nanostructures for high-performance supercapacitor

Abstract: recently, owing to increasing concern about the depletion of fossil fuels and environmental pollution, there is an urgent need for clean, efficient, and sustainable energy resources to maintain a sustained, healthy and rapid economic development. among the promising electrical energy storage devices, lithium-ion batteries (libs) and supercapacitors (scs) have attracted worldwide attentions. owing to their fast recharge ability, high power performance, long cycle life, and low maintenance cost, supercapacitors have gained enormous interests swiftly [1]. recently, nanocomposite materials have drawn considerable attention because they can provide better characteristics than the single materials [2]. core–shell nanoparticles (csns) are a class of nanostructured materials recently have received increased attention because of their exciting properties and broad range of applications in catalysis, biology, materials chemistry and sensors. it is possible to fabricate a range of core–shell nanoparticles with tailorable properties that can play important roles in various catalytic processes and offer sustainable solutions to current energy problems. traditionally, composite nanomaterials constructed with cores and shells, both at nanoscale, are broadly defined as csns (core–shell nanoparticles) [3].in the present work, the core-shell of zno@znco2o4 were directly grown on nickel foam substrate through a facile hydrothermal method. these nanomaterials were analyzed using x-ray diffraction spectroscopy (xrd), scanning electron and transmission electron microscopies (sem and tem). also, zno@znco2o4 electrode was investigated using cyclic voltammetry (cv), galvanostatic charge–discharge (gcd) and electrochemical impedance spectroscopy (eis) to check the supercapacitive behavior. the zno@znco2o4/nf exhibited a high specific capacitance of 1655.76 f g-1 at 1.25 a g-1 in 2 m koh solution. our findings confirm that zno@znco2o4/nf electrode can be considered as an outstanding candidate for high performance energy storage devices.