Carbon nano-onions triggering the supercapacitive performance of PEDOT-wrapped MoO 3 microstructures in hybrid ultracapacitors

The application of conducting polymers has increased significantly in supercapacitors due to their conducting and pseudocapacitive charge storage properties. Transition metal oxides such as MoO 3 possess a high theoretical capacitance of 1256 F g - 1 but low electrical conductivity, limiting electrochemical performance. This work reports the synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT)-MoO 3 @carbon nanoonions (CNO) composite materials by hydrothermal method followed by an oxidative polymerization process. The galvanostatic chargedischarge study displays that pristine PEDOT achieves a capacitance of 117 F g -1 , whereas PEDOT-MoO 3 composite delivers 365 F g - 1 at 1 A g - 1 . Further addition of 0D carbon nano onions enhanced the capacitance to 428 F g - 1 . Inspired by such effective electrochemical performance, PEDOT-MoO 3 @CNO composites have been used as anode material in lead -based hybrid-ultracapacitors. The electrochemical studies illustrate that the hybrid system delivers a capacitance of 348 F g - 1 with 76 % retention capacitance at the end of 6000 cycles at a high applied current density of 5 A g - 1 . The thin layer of a highly porous PEDOT network with CNOs over MoO 3 improves the redox behavior of composite and effective H + ion intercalation. This work depicts the simple and scalable synthesis approach for the PEDOT-MoO 3 @CNO composite materials having enhanced electrochemical performance in hybrid supercapacitors.