Abstract:
　　A facile approach to densely packed freestanding hybrid films for supercapacitor electrodes is developed by self-assembling graphene nanosheets with Ni(OH)2 nanoplates intercalated. In the obtained graphene@Ni(OH)2 hybrid films, the Ni(OH)2 nanoplates act as not only effective space inhibitors to prevent graphene restacking but also pseudocapacitors to improve the overall supercapacitance, while the highly conductive graphene nanosheets serve as expressways for efficient electronic transportation. The as-prepared graphene@Ni(OH)2 film electrodes exhibit superior supercapacitor performance including high gravimetric capacitance (~ 605 F/g), high volumetric capacitance (~677 F/cm3), excellent rate capability (only 27.7% capacitance loss of its initial value with a current density increased from 0.2 to 50 A/g) and superior cycling stability (167% capacitance increase of its initial capacitance after 5000 cycles). Moreover, such densely packed freestanding hybrid film electrodes are highly bendable, which have promising applications in flexible energy storage devices. The fabrication process of the graphene@Ni(OH)2 films developed in this work is universe, which is applicable to many other composites with the combinations among 0-D, 1-D and 2-D materials.