Enhanced capacitive desalination of MnO2 by forming composite with multi-walled carbon nanotubes

Abstract

The morphology and structure of the prepared MnO₂/MWCNTs (multi-walled carbon nanotubes) composite are characterized by XRD, SEM, TEM, and N₂ sorption analysis. The electrochemical performance of the composite is studied by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge evaluation. The composite has a specific capacitance of 144 F g⁻¹ at the current density of 1 A g⁻¹. It has higher conductivity which is affirmed by electrochemical impedance spectroscopy (EIS). The capacitive deionization (CDI) test was conducted in a bath mode apparatus by assembling a capacitor. The capacitor made from MnO₂/MWCNTs composite shows a higher desalination capacity of (6.65 mg g⁻¹) in NaCl aqueous solution, higher than that made from the virginal MnO₂ (1.60 mg g⁻¹) and those of the formerly reported. Furthermore, the MnO₂/MWCNTs composite electrode shows excellent recyclability with an efficient and rapid regeneration process.