Abstract:
A new type of mesoporous silica (MS) with high surface area and large pore volume has been synthesised
by employing a rapid sol–gel based inverse micelle method and electrochemically active metal center,
manganese, has been incorporated into it. The MnO2 decorated silica composites are obtained through
the wet impregnation technique using KMnO4 followed by their reduction under neutral conditions. The
structure and surface area of the samples have been characterised by powder X-ray diffraction (XRD), BET
surface area and pore size analysis, transmission and scanning electron microscopy (TEM and FE-SEM),
FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). Electrochemical techniques, i.e. cyclic
voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy
(EIS), have been used to evaluate the electrochemical properties of the composites. The resultant compo site MS/MnO2-3 with a significantly high surface area (453 m2 g−1
) is found to exhibit a superior specific
capacitance of 1158.50 F g−1 at a scan rate of 5 mV s−1 which is very close to the theoretical value and
retains 87.8% of its capacitance up to 1000 cycles at 1 A g−1 current density. The outstanding electro chemical performance of the composite can be attributed to the high surface area and uniform pore size
distribution of the novel silica host which simultaneously increases the electrochemically active centres,
promotes electrolyte penetration and enhances electron transport. The simplicity of the synthesis process
developed here is interesting for wide-scale production of MnO2-based electro-active materials
