Sandip K. Patil

Bio: Sandip K. Patil is an academic researcher from Shivaji University. The author has contributed to research in topics: Ionic liquid & Electrolyte. The author has an hindex of 11, co-authored 19 publications receiving 296 citations.

Mechanochemical growth of a porous ZnFe2O4 nano-flake thin film as an electrode for supercapacitor application

Abstract: Herein, we are reporting a simple, economic, easy to handle, scalable and reproducible mechanochemical i.e. rotational chemical bath deposition (R-CBD) approach for the synthesis of well adhered nano-flake ZnFe2O4 thin films (NFs-ZnFe2O4) with uniform morphology on a stainless steel (SS) substrate, in comparison with nano-grain ZnFe2O4 thin films (NGs-ZnFe2O4) prepared using a conventional CBD approach. The influence of rotation on the evolution of the nano-flake morphology in NFs-ZnFe2O4 is also investigated. The porous NFs-ZnFe2O4 thin films demonstrated excellent pseudocapacitor properties with higher specific capacitance of 768 F g−1 at high current density of 5 mA cm−2, stability upto 5000 cycles (88% retention), higher energy density (106 W h kg−1) and power density (18 kW kg−1) compared to NGs-ZnFe2O4. The results were also found to be higher than those reported earlier for MFe2O4 based systems.

Comparative Study of Individual and Mixed Aqueous Electrolytes with ZnFe2O4 Nano–flakes Thin Film as an Electrode for Supercapacitor Application

Abstract: In the present work, ZnFe2O4 nano-flakes thin films are grown on stainless steel substrate using mechanochemical approach. The prepared thin films are characterized and used as working electrodes for supercapacitor application. Investigation for an ideal electrolyte is systematically carried out by comparing three aqueous electrolytes such as LiOH, NaOH, KOH (1 M) and their binary mixtures (1:1 v/v of 1 M each electrolyte) on the basis of their supercapacitive performances. Among the electrolytes, 1 M KOH is found to be an ideal electrolyte, which demonstrates higher specific capacitance (433 F g−1), cycle stability (91 % retention up to 4000 cycles), energy density (86 Wh kg−1), respectively. The binary mixtures of LiOH-NaOH, NaOH-KOH and LiOH-KOH electrolytes show relatively less specific capacitance of 106, 146 and 180 F g−1, respectively. The use of mixed electrolytes and underlying factors affecting the performance are investigated in detail for the first time. The physical parameters such as conductivity, density, viscosity, contact angle and hydrated ionic radius of aqueous electrolytes influencing the specific capacitance of the ZnFe2O4 nano-flakes based electrode is studied.

Facile synthesis of CuO nanosheets as electrode for supercapacitor with long cyclic stability in novel methyl imidazole-based ionic liquid electrolyte

Abstract: Hierarchical CuO nanosheets were synthesized through a facile, eco-friendly reflux deposition approach for supercapacitor electrode material for energy storage. The resultant CuO nanosheets were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption isotherm techniques. The supercapacitor behavior of CuO nanosheets was investigated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy in novel 0.1 M aqueous 1-(1′-methyl-2′-oxo-propyl)-3-dimethylimidazolium chloride [MOPMIM][Cl] ionic liquid as an electrolyte. The result demonstrate that CuO nanosheets exhibit specific capacitance of 180 F g−1 at 10 mV s−1 scan rate which is the highest value in ionic liquid electrolyte and 87% specific capacitance retention after 5000th cycle. The electrochemical performance proves CuO nanosheets as electrode with ionic liquid electrolyte for developing green chemistry approach in supercapacitor.

Principles Of Fluorescence Spectroscopy

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Towards establishing standard performance metrics for batteries, supercapacitors and beyond.

Abstract: Over the past decade, electrochemical energy storage (EES) devices have greatly improved, as a wide variety of advanced electrode active materials and new device architectures have been developed. These new materials and devices should be evaluated against clear and rigorous metrics, primarily based on the evidence of real performances. A series of criteria are commonly used to characterize and report performance of EES systems in the literature. However, as advanced EES systems are becoming more and more sophisticated, the methodologies to reliably evaluate the performance of the electrode active materials and EES devices need to be refined to realize the true promise as well as the limitations of these fast-moving technologies, and target areas for further development. In the absence of a commonly accepted core group of metrics, inconsistencies may arise between the values attributed to the materials or devices and their real performances. Herein, we provide an overview of the energy storage devices from conventional capacitors to supercapacitors to hybrid systems and ultimately to batteries. The metrics for evaluation of energy storage systems are described, although the focus is kept on capacitive and hybrid energy storage systems. In addition, we discuss the challenges that still need to be addressed for establishing more sophisticated criteria for evaluating EES systems. We hope this effort will foster ongoing dialog and promote greater understanding of these metrics to develop an international protocol for accurate assessment of EES systems.

Metallic Layered Polyester Fabric Enabled Nickel Selenide Nanostructures as Highly Conductive and Binderless Electrode with Superior Energy Storage Performance

Abstract: Highly flexible and conductive fabric (CF)-supported cauliflower-like nickel selenide nanostructures (Ni3Se2 NSs) are facilely synthesized by a single-step chronoamperometry voltage-assisted electrochemical deposition (ECD) method and used as a positive electrode in supercapacitors (SCs) The CF substrate composed of multi-layered metallic films on the surface of polyester fibers enables to provide high electrical conductivity as a working electrode in ECD process Owing to good electrical conductivity, high porosity and intertwined fibrous framework of CF, cauliflower-like Ni3Se2 NSs are densely integrated onto the entire surface of CF (Ni3Se2 NSs@CF) substrate with reliable adhesion by applying a chronoamperometry voltage of −10 V for 240 s The electrochemical performance of the synthesized cauliflower-like Ni3Se2 NSs@CF electrode exhibits a maximum specific capacity (CSC) of 1196 mA h g−1 at a discharge current density of 2 A g−1 in aqueous 1 m KOH electrolyte solution Remarkably, the specific capacity of the same electrode is greatly enhanced by introducing a small quantity of redox-additive electrolyte into the aqueous KOH solution, indicating the CSC≈25182 mA h g−1 at 2 A g−1 with good capacity retention Furthermore, the assembled textile-based asymmetric SCs achieve remarkable electrochemical performance such as higher energy and power densities, which are able to light up different colored light-emitting diodes

Advanced materials and technologies for supercapacitors used in energy conversion and storage: a review

Abstract: Supercapacitors are increasingly used for energy conversion and storage systems in sustainable nanotechnologies. Graphite is a conventional electrode utilized in Li-ion-based batteries, yet its specific capacitance of 372 mA h g−1 is not adequate for supercapacitor applications. Interest in supercapacitors is due to their high-energy capacity, storage for a shorter period and longer lifetime. This review compares the following materials used to fabricate supercapacitors: spinel ferrites, e.g., MFe2O4, MMoO4 and MCo2O4 where M denotes a transition metal ion; perovskite oxides; transition metals sulfides; carbon materials; and conducting polymers. The application window of perovskite can be controlled by cations in sublattice sites. Cations increase the specific capacitance because cations possess large orbital valence electrons which grow the oxygen vacancies. Electrodes made of transition metal sulfides, e.g., ZnCo2S4, display a high specific capacitance of 1269 F g−1, which is four times higher than those of transition metals oxides, e.g., Zn–Co ferrite, of 296 F g−1. This is explained by the low charge-transfer resistance and the high ion diffusion rate of transition metals sulfides. Composites made of magnetic oxides or transition metal sulfides with conducting polymers or carbon materials have the highest capacitance activity and cyclic stability. This is attributed to oxygen and sulfur active sites which foster electrolyte penetration during cycling, and, in turn, create new active sites.