Preparation and electrochemical applications of spherical maltose-based templated carbon/MnOx composite materials

Abstract

The composite material of maltose-based templated carbon and manganese oxide was used to synthesise a novel electrode material for supercapacitors. The material was analysed by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermal gravity-differential thermal analysis, and X-ray photoelectron spectroscopy. Results demonstrate that the materials appear as spherical particles by assembling nano particles and that manganese oxide is composed of multiple valence forms. The influence of manganese content and calcination temperature on the electrochemical performance of the composite electrode was investigated. Results show that the electrode with a manganese content of 80wt.% has the best electrochemical properties; the specific capacitance reaches 492.4 F·g−1 at 5 mA·cm−2 in 2M KOH electrolyte and 347.4 F·g−1 when the current density is 15mA·cm−2. Moreover, the series resistance and the Faraday charge-transfer resistance of the composites are 0.78 and 0.03Ω, respectively. Cycle stability tests show that the specific capacitance retention rate is more than 70% after 1500 charge–discharge cycles. All of these findings suggest that the as-prepared composite is promising electrode material for electrochemical capacitors.