Direct Synthesis of cubic shaped Ag2S on Ni mesh as Binder-free Electrodes for Energy Storage Applications.

A facile approach of chemical bath deposition was proposed to fabricate direct synthesis of silver sulphide (Ag2S) on nickel (Ni) mesh without involvement for binders for supercapacitor electrodes. The phase purity, structure, composition, morphology, microstructure of the as-fabricated Ag2S electrode was validated from its corresponding comprehensive characterization tools. The electrochemical characteristics of the Ag2S electrodes were evaluated by recording the electrochemical measurements such as cyclic voltammetry and charge/discharge profile in a three electrode configuration system. Ag2S employed as working electrode demonstrates notable faradaic behaviour including high reversible specific capacitance value of 179 C/g at a constant charge/discharge current density of 1 A/g with high cyclic stability which is relatively good as compared with other sulphide based materials. The experimental results ensure fabricated binder-free Ag2S electrodes exhibits better electrochemical performance and suitable for potential electrodes in electrochemical energy storage applications.

Aloe vera Derived Activated High-Surface-Area Carbon for Flexible and High-Energy Supercapacitors.

Materials which possess high specific capacitance in device configuration with low cost are essential for viable application in supercapacitors. Herein, a flexible high-energy supercapacitor device was fabricated using porous activated high-surface-area carbon derived from aloe leaf (Aloe vera) as a precursor. The A. vera derived activated carbon showed mesoporous nature with high specific surface area of ∼1890 m2/g. A high specific capacitance of 410 and 306 F/g was achieved in three-electrode and symmetric two-electrode system configurations in aqueous electrolyte, respectively. The fabricated all-solid-state device showed a high specific capacitance of 244 F/g with an energy density of 8.6 Wh/kg. In an ionic liquid electrolyte, the fabricated device showed a high specific capacitance of 126 F/g and a wide potential window up to 3 V, which results in a high energy density of 40 Wh/kg. Furthermore, it was observed that the activation temperature has significant role in the electrochemical performance, as the activated sample at 700 °C showed best activity than the samples activated at 600 and 800 °C. The electron microscopic images (FE-SEM and HR-TEM) confirmed the formation of pores by the chemical activation. A fabricated supercapacitor device in ionic liquid with 3 V could power up a red LED for 30 min upon charging for 20s. Also, it is shown that the operation voltage and capacitance of flexible all-solid-state symmetric supercapacitors fabricated using aloe-derived activated carbon could be easily tuned by series and parallel combinations. The performance of fabricated supercapacitor devices using A. vera derived activated carbon in all-solid-state and ionic liquid indicates their viable applications in flexible devices and energy storage.