Development of a novel SBA-15 templated mesoporous reduced graphitic oxide composite for high performance supercapacitors and fabrication of its device by an electrospinning technique†
A novel synthetic route is formulated for the development of mesoporous reduced graphitic oxide (RGO)–silica composites by wrapping SBA-15 between the graphene oxide (GO) layers followed by a chemical reduction process. To prepare the Santa Barbara Amorphous (SBA-15) grafted graphene oxide, amino groups are grafted onto SBA-15, fabricated through a sol–gel technique using Pluronic P-123 as a template, tetraethyl orthosilicate as a silica source and pre-prepared graphene oxide as an additive. The formation of a mesoporous channel with an average pore diameter of 3.14 nm and a high specific surface area of ∼10.58 m2 g−1 was confirmed by N2 adsorption–desorption. Raman spectroscopy data displayed an increase in the ID/IG ratio of GO upon reduction indicating the creation of structural defects. Further, scanning electron microscopic analysis revealed the formation of a regular and ordered rod-like structure and transmission electron microscopic analysis confirmed the wrapping of the SBA-15 channel between GO layers. The conductance of the composites is measured by the four probe method. The three-electrode cell in an aqueous electrolyte shows a high specific capacitance of 533.3 F g−1 with a high capacitance retention of 91% even after 2500 cycles. The composite delivers an energy and power density of 74.06 W h kg−1 and 8.33 kW kg−1, respectively, and these properties are much superior to those of graphene based supercapacitors reported in the literature. The fabricated supercapacitor device using the fibres developed by an electrospinning technique showed a high specific capacitance of 165.2 F g−1, with a high energy density of 22.94 W h kg−1. These electrochemical performances clearly indicate that mesoporous reduced graphene oxide could be used as a promising electrode material in supercapacitors for electrochemical energy storage.