Hierarchical carbon nanofiber-based hybrid film on lightweight magnesium foil for ultrahigh energy density supercapacitors

A novel hierarchical CNFs/Ni 3 P-Ni hybrid film has been successfully deposited on magnesium. Taking advantage of its super lightweight current collector and combinatorial battery-like/capacitor energy storage mechanisms, the constructed symmetric SC delivers a superior energy density (52.1 W h kg −1 ) with exceptional cycling stability (remaining 94% after 10 000 cycles). Combinatorial battery-like/capacitor energy storage mechanisms as well as an ultralight current collector have been combined to achieve high performance supercapacitors with superior energy density and cyclic life span.