TiO2@MnO2 Core-shell Nanofibers as Positive Electrodes for Asymmetric Supercapacitors

Abstract

Manganese dioxide coated titanium dioxide (MnO2-TiO2) nanofibers, prepared by electrospinning and post-hydrothermal process exhibited high electrochemical properties in aqueous Na2SO4 electrolyte. The thin MnO2 shell with average thickness of 10 nm contributed to the high electrochemical performance for charge storage by redox reaction and intercalation mechanisms, while the anatase phase TiO2 core provided an easy pathway for electronic transport with additional electrochemical stability over thousands of charge-discharge cycles. An asymmetric supercapacitor designed from the MnO2-TiO2 nanofibers and single walled carbon nanotubes showed high voltage window (2.2 V) with maximum gravimetric capacitance of 111.5 Fg-1.