Enhanced rate and specific capacity in nanorod-like core-shell crystalline NiMoO4@amorphous cobalt boride materials enabled by Mott-Schottky heterostructure as positive electrode for hybrid supercapacitors

Abstract

The supercapacitor electrode materials suffer from structure pulverization and sluggish electrode kinetics under high current rates. Herein, a unique NiMoO4@Co-B heterostructure composed of highly conductive Co-B nanoflakes and a semiconductive NiMoO4 nanorod is designed as an electrode material to exert the energy storage effect on supercapacitors. The formed Mott-Schottky heterostructure is helpful to overcome the ion diffusion barrier and charge transfer resistance during charging and discharging. Moreover, this crystalline-amorphous heterogeneous phase could provide additional ion storage sites and better strain adaptability. Remarkably, the optimized NiMoO4@Co-B hierarchical nanorods (the mass ratio of NiMoO4/Co-B is 3:1) present greatly enhanced electrochemical characteristics compared with other components, and show superior specific capacity of 236.2 mA h g−1 at the current density of 0.5 A g−1, as well as remarked rate capability. The present work broadens the horizons of advanced electrode design with distinct heterogeneous interface in other energy storage and conversion field.