Gelatin-assisted co-exfoliation of graphene nanoplatelets/MoS2 for high-performance supercapacitors

Abstract

Past decades have seen an enormous innovation with 2D layered materials especially related to their facile industrial-scale production and their applicability in the areas of clean energy and energy storage. Also, combining two different 2D layered materials offers exciting possibilities especially in attaining synergistic mechanical and electrical properties. The present study reports “one-step” liquid phase co-exfoliation of graphene (G) and MoS₂ together i.e., graphene nanoplatelets (GNP)/MoS₂ using high-temperature ultrasonication and gelatin. The co-exfoliated GNP/MoS₂ reveals the presence of both “GNP” and “MoS₂” nanosheets together as authenticated by Raman and UV-vis spectroscopy. Further, transmission electron microscope (TEM) images also confirmed that both GNP and MoS₂ were embedded together. As prepared GNP/MoS₂ was then explored for supercapacitor application. GNP/MoS₂ nanosheets showed a specific capacitance (C_s) value of 311.14 F g⁻¹ at 1 A g⁻¹ with excellent cycling stability (∼98.35% over 2000 cycles). Furthermore, an asymmetric supercapacitor device (ASC) was fabricated utilizing GNP/MoS₂ and carbon black (CB). The fabricated device can operate in a wide potential window (0–1.8 V) showing a specific capacitance value of 80 F g⁻¹ and was used for lighting a commercial LED of ∼1.8 V for up to 90 s. To the best of our knowledge, this is the first report on a new and facile synthesis pathway for producing high-quality co-exfoliated 2D nanosheets of MoS₂ and graphene (G) hybrid which demonstrate superior supercapacitor performance.