R.N. Bulakhe

Electrochemical performance of a portable asymmetric supercapacitor device based on cinnamon-like La2Te3 prepared by a chemical synthesis route

A cinnamon-like La2Te3 nanostructure has been prepared by a simple chemical bath deposition (CBD) route. Field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy techniques have been used to characterize the morphological and structural properties of the La2Te3 thin films. The prepared La2Te3 thin film electrodes are applied in a supercapacitor, in which they exhibited a high specific capacitance value of 469 F g−1 at a scan rate of 2 mV s−1 with an excellent cycling performance up to 1000 cycles. Even at a specific power of 2.5 kW kg−1, the La2Te3 electrode possessed a specific energy of ∼126 Wh kg−1. At a relatively high discharge current density of 4 mA cm−2, the specific capacitance was still maintained at 220 F g−1. Furthermore, portable La2Te3 asymmetric supercapacitor devices have been fabricated using an aqueous 1 M KOH electrolyte with good specific energy and specific power. Such an impressive portable asymmetric supercapacitor is a promising candidate for applications in high-performance energy storage systems.

Supercapacitive performance of hydrous ruthenium oxide (RuO2·nH2O) thin films synthesized by chemical route at low temperature

In the present investigation, we report the synthesis of ruthenium oxide (RuO2 · nH2O) thin films by simple chemical bath deposition (CBD) method at low temperature on the stainless steel substrate. The prepared thin films are characterized for their structural and morphological properties by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). The structural study revealed that the ruthenium oxide thin films are amorphous. Scanning electron microscopy study shows compact morphology with small overgrown particles on the surface of the substrate. FT–IR study confirms the formation of RuO2 · nH2O material. The supercapacitor behaviour of RuO2 · nH2O thin film was studied using cyclic voltammetry (CV) technique in 0 · 5 M H2SO4electrolyte. RuO2 · nH2O film showed maximum specific capacitance of 192 F · g− 1at a scan rate of 20 mV · s− 1. The charge–discharge studies of RuO2 · nH2O carried out at 300 μA · cm− 2current density revealed the specific power of 1 · 5 kW.kg− 1and specific energy of 41 · 6 Wh.kg− 1with 95% coulombic efficiency.

Polyaniline–RuO2 composite for high performance supercapacitors: chemical synthesis and properties

Composite thin films of polyaniline–ruthenium oxide (PANI–RuO2) are prepared by a chemical bath deposition (CBD) method. The prepared thin films are characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and FT-Raman spectroscopy. XRD patterns reveal the amorphous nature of the composite thin films. FT-IR and FT-Raman spectroscopy confirm PANI–RuO2 composite formation. Cyclic voltammetry, galvanostatic charge–discharge and impedance analysis are carried out in order to investigate the applicability of the composite electrode as a supercapacitor. The PANI–RuO2 composite electrode demonstrate the maximum specific capacitance of 830 F g−1. The specific energy and specific power of the PANI–RuO2 composite electrode are 216 W h kg−1 and 4.16 kW kg−1, respectively. The observed specific capacitance is the best yet reported for a PANI–RuO2 composite supercapacitor in H2SO4 electrolyte. Moreover, the composite electrode shows enhanced cycling stability. These results demonstrate the potential of developing the PANI–RuO2 composite electrode material for high-performance supercapacitors.