Preparation of manganese dioxide/multiwalled carbon nanotubes hybrid hollow microspheres via layer-by-layer assembly for supercapacitor

Abstract

Manganese dioxide/multiwalled carbon nanotubes hybrid hollow microspheres were prepared via layer-by-layer assembly technique by alternately adsorbing aminated manganese dioxide (AMnO₂) and carboxylated multiwalled carbon nanotubes (CMWCNTs) using polystyrene sulfonate microspheres as sacrificial templates. The structures and morphologies of the hybrid hollow microspheres were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and field emission scanning electron microscope. Capacitive properties of the prepared hybrid hollow microspheres were investigated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in a three-electrode experimental setup using 1.0 mol L⁻¹ Na₂SO₄ solution as electrolyte. The result showed that the specific capacitance increased with the increase in the content of AMnO₂ and CMWCNTs, which reached 169 F g⁻¹ at a current density of 0.5 A g⁻¹ when AMnO₂ and CMWCNTs alternately adsorbed for ten times. And the capacitance retention was about 82 % after 800 times of cyclic voltammetry tests at a scan rate of 80 mV s⁻¹.