Raviraja T. Patil’s research while affiliated with Shivaji University and other places

Interconnected nanoflakes of cobalt hydroxide Co(OH)2 were deposited potentiostatically on nickel mesh (NM) at various potentials (− 0.9 V, − 1.0 V, − 1.1 V) and various times (1 min, 2 min, 3 min, 4 min, and 5 min). The FE-SEM, XRD, FT-IR, and EDS etc. studied the morphological and structural properties. The electrochemical properties evaluated in 1 M KOH electrolyte using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The Co(OH)2 nanoflakes deposited on nickel mesh with − 1.0 V for 5 min. electrode exhibits a good specific capacitance of 1035 F g⁻¹, at a current density of 1 mA cm⁻² 1 M KOH electrolyte. In conclusion, the deposition potential and the deposition time affect the surface morphology and the electrochemical performance of the deposited Co(OH)2 electrode.

The redox additive in an aqueous gel electrolyte is reported as one of the efficient methods to improve the electrochemical supercapacitor performance. Here, we report the role of redox additive, potassium ferricyanide((K3[Fe(CN)6]), referred to as KFCN) for improving the electrochemical performance of binder-free, CuCo2O4 (CCO) nanowire arrays (NWs) based solid state symmetric supercapacitors (SSCs). The crystal structure and morphology of prepared CCO films are confirmed by X-ray diffraction (XRD) and field emission-transmission electron microscopy (FE-TEM). The elemental composition of CCO films is estimated as Cu0.5Co2.77O3.82 via energy-dispersive X-ray spectroscopy (EDS) analysis. Surprisingly, the areal capacitance (or energy density at 5 mAcm−2) is significantly improved from 0.58 F cm−2 (or 0.016 mWh cm−2) to 10.5 F cm−2 (or 0.296 mWh cm−2), respectively, after the addition of KFCN to aqueous KOH electrolyte, as compared to bare KOH. Furthermore, CCO exhibits decent cyclic stability with 90 % capacitance retention up to 5000 CV cycles at the scan rate of 100 mV s−1. Moreover, 2-terminal CCO NWs-based SSCs, employed with PVA-KOH-KFCN gel electrolyte, demonstrate a wider potential window of −0.9 to 0.9 V (1.8 V) with a 7-fold increase of energy density from 9.1 to 65 Wh kg−1, as compared with that of PVA-KOH gel electrolyte. As practical validation, the operation of Red-LED for 3 min is demonstrated with PVA-KOH-KFCN gel-based SSC, manifesting that adding redox substance in aqueous electrolytes is one of the promising strategies for portable and wearable energy storage systems

In this work, the 3D interconnected cobalt oxide nanoflakes (CON) were grown successfully on nickel foam (NF) at ambient conditions by the electrodeposition method, further followed by calcination. The deposition of Co3O4 was carried out for different deposition times of 10 min, 15 min, and 20 min and enumerated as CON-10, CON-15, and CON-20 respectively. The CON samples were characterized for their Physico-chemical studies by XRD, FT-IR, FE-SEM, and EDS. FE-SEM micrographs of CON nanostructures showed the uniform deposition of the 3D interconnected nanoflakes on NF. The sample CON-15 exhibited the highest specific capacitance (Cs) of 444 Fg⁻¹ also the specific energy (SE) of 26.07 Whkg⁻¹, specific power (SP) of 541.66 Wkg⁻¹, and efficiency (ɳ) of 77 % at 1 mAg⁻¹ with outstanding cycling stability of 86 % capacitance retention after 1000 cycles.