2D/3D heterostructure of h-BN/reduced graphite oxide as a remarkable electrode Material for supercapacitor

We employed a facile approach to synthesize a ‘two dimensional/three dimensional (2D/3D)’ heterostructure of hexagonal boron nitride and reduced graphite oxide (h-BN/rGO). Interestingly, 2 wt% h-BN loaded heterostructure (i.e. BN/rGO-2) exhibits a superior capacitive performance, including specific capacitance (C_sp) of 304 and 226 F g⁻¹ at 1 A g⁻¹ in alkaline and acidic conditions respectively with an excellent rate capability (~98% retention @10k cycles). Importantly, the electrochemical analysis confirms the accumulation of charge solely on the surface/near-surface reactions (capacitive contribution) and not due to the diffusion-limited processes. The solid-state symmetric supercapacitor cell exhibits specific energy of 1.25 Wh kg⁻¹ corresponding to the high power density of 1800 W kg⁻¹. The enhancement in the C_sp is mainly attributed to the non-hierarchical assembly of a 2D/3D heterostructure, which provides a special interface to the electroactive species. Furthermore, the mechanically activated GO (A-GO) plays a crucial role by enhancing the specific surface area and mesoporosity, thus establishing a positive synergistic effect on capacitive properties, upon composite formation with h-BN. Our theoretical assessment shows that the surface functionalities of GO, as well as h-BN, help to enhance the quantum capacitance of graphene-related materials.