Controlled synthesis of hierarchical NiO nanosheet hollow spheres with enhanced supercapacitive performance

In this work, we report a facile strategy for the controlled synthesis of nickel oxide (NiO) hollow spheres (HSs) assembled from nanosheets (NSs). The Ni2CO3(OH)(2) NSs are first grown on sulfonated polystyrene (sPS) hollow spheres by a low-temperature solution route. NiO HSs with well preserved morphology are then obtained by calcining the as-prepared sPS@ Ni2CO3(OH)(2) NSs composite HSs. Because of the hollow interior and hierarchical structure, these NiO nanosheet hollow spheres have a relatively high specific surface area of 62 m(2) g(-1). When evaluated for supercapacitive performance, these hierarchical NiO HSs demonstrate improved electrochemical properties with a high capacitance of 415 F g(-1) even at a high charge-discharge current rate of 3 A g(-1) and 91% of which can be retained after 1000 charge-discharge cycles.