Ultrasound-assisted facile one-pot synthesis of ternary MWCNT/MnO/rGO nanocomposite for high performance supercapacitors with commercial-level mass loadings.

Commercial application of supercapacitors (SCs) requires high mass loading electrodes simultaneously with high energy density and long cycle life. Herein, we have reported a ternary multi-walled carbon nanotube (MWCNT)/MnO/reduced graphene oxide (rGO) nanocomposite for SCs with commercial-level mass loadings. The ternary nanocomposite was synthesized using a facile ultrasound-assisted one-pot method. The symmetric SC fabricated with ternary MWCNT/MnO/rGO nanocomposite demonstrated marked enhancement in capacitive performance as compared to those with binary nanocomposites (MnO/rGO and MnO/MWCNT). The synergistic effect from simultaneous growth of MnO on the graphene and MWCNTs under ultrasonic irradiation resulted in the formation of a porous ternary structure with efficient ion diffusion channels and high electrochemically active surface area. The symmetric SC with commercial-level mass loading electrodes (∼12 mg cm) offered a high specific capacitance (314.6 F g) and energy density (21.1 W h kg at 150 W kg) at a wide operating voltage of 1.5 V. Moreover, the SC exhibits no loss of capacitance after 5000 charge-discharge cycles showcasing excellent cycle life.