Synthesis of graphene nanoplatelets/polythiophene as a high performance supercapacitor electrode material

Abstract

The preparation of a stable, efficient, inexpensive and high capacitance electrode material for supercapacitors is posing great challenges for researchers. In this report, we demonstrate the synthesis of a stable, conductive and highly active graphene nanoplatelet (GNPL) enriched polythiophene via in situ chemical polymerization for supercapacitor applications. The characteristic X-ray diffraction patterns proved the formation of the as-prepared nanomaterials. The morphological studies revealed that PTh NPs are successfully anchored onto the surface of the GNPLs during polymerization. The elemental mapping revealed the presence of carbon, oxygen, and sulfur in the GNPLs/PTh. The cyclic voltammetry (CV) measurements showed that the 50% GNPLs/PTh electrode exhibited a maximum specific capacitance of 960.71 F g⁻¹ at a scan rate of 10 mv s⁻¹. The gravimetric capacitance of the designed electrodes reached 673 F g⁻¹ at a current density of 0.25 A g⁻¹, corresponding to an energy density of 2.25 W h kg⁻¹ and a power density of 23.55 W kg⁻¹. The EIS results of the 50% GNPLs/PTh showed a minimum resistance of charge transfer (R_ct) and equivalent series resistance, signifying the superior charge propagation behavior at the interfacial region. The cycling stability investigation highlighted that the 50% GNPLs/PTh based supercapacitor can retain 84.9% of the initial capacitance after 1500 successive CV cycles, suggesting excellent cycling stability of the material. These findings conclude the high potential of the newly synthesized GNPLs/PTh as an electrode material for charge storage devices.