Department Of Physics
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Item Structural, electrical properties and dielectric relaxations in Na+-ion-conducting solid polymer electrolyte(Institute of Physics Publishing, 2018) Arya, A.; Sharma, A.L.In this paper, we have studied the structural, microstructural, electrical, dielectric properties and ion dynamics of a sodium-ion-conducting solid polymer electrolyte film comprising PEO8-NaPF6+ x wt. % succinonitrile. The structural and surface morphology properties have been investigated, respectively using x-ray diffraction and field emission scanning electron microscopy. The complex formation was examined using Fourier transform infrared spectroscopy, and the fraction of free anions/ion pairs obtained via deconvolution. The complex dielectric permittivity and loss tangent has been analyzed across the whole frequency window, and enables us to estimate the DC conductivity, dielectric strength, double layer capacitance and relaxation time. The presence of relaxing dipoles was determined by the addition of succinonitrile (wt./wt.) and the peak shift towards high frequency indicates the decrease of relaxation time. Further, relations among various relaxation times () have been elucidated. The complex conductivity has been examined across the whole frequency window; it obeys the Universal Power Law, and displays strong dependency on succinonitrile content. The sigma representation () was introduced in order to explore the ion dynamics by highlighting the dispersion region in the Cole-Cole plot () in the lower frequency window; increase in the semicircle radius indicates a decrease of relaxation time. This observation is accompanied by enhancement in ionic conductivity and faster ion transport. A convincing, logical scheme to justify the experimental data has been proposed. ? 2018 IOP Publishing Ltd.Item Insights into the use of polyethylene oxide in energy storage/conversion devices: A critical review(Institute of Physics Publishing, 2017) Arya, A.; Sharma, A.L.In this review, the latest updates in poly (ethylene oxide) based electrolytes are summarized. The ultimate goal of researchers globally is towards the development of free-standing solid polymeric separators for energy storage devices. This single free-standing solid polymeric separator may replace the liquid and separator (organic/inorganic) used in existing efficient/smart energy technology. As an example, polyethylene oxide (PEO) consists of an electron donor-rich group which provides coordinating sites to the cation for migration. Owing to this exclusive structure, PEO exhibits some remarkable properties, such as a low glass transition temperature, excellent flexibility, and the ability to make complexation with various metal salts which are unattainable by another polymer host. Hence, the PEO is an emerging candidate that has been most examined or is currently under consideration for application in energy storage devices. This review article first provides a detailed study of the PEO properties, characteristics of the constituents of the polymer electrolyte, and suitable approaches for the modification of polymer electrolytes. Then, the synthesization and characterizations techniques are outlined. The structures, characteristics, and performance during charge-discharge of four types of electrolyte/separators (liquid, plasticized, and dispersed and intercalated electrolyte) are highlighted. The suitable ion transport mechanism proposed by researchers in different renowned groups have been discussed for the better understanding of the ion dynamics in such systems. ? 2017 IOP Publishing Ltd.Item Polymer electrolytes for lithium ion batteries: a critical study(Institute for Ionics, 2017) Arya, A.; Sharma, A. L.Polymer electrolytes (PEs) are an essential component being used in most energy storage/conversion devices. The present review article on a brief history, advantage, and their brief application of polymer electrolyte systems. It consists of a glimpse on liquid, gel, and solid polymer electrolyte and a contrast comparison concerning benefits/disadvantages among the three. The article started with a brief introduction of polymer electrolytes followed by their varieties and extreme uses. The role of host polymer matrix by taking numerous examples of polymer electrolyte published by the different renowned group of the concerned field has been explored. The criteria for selection of appropriate host polymer, salt, inorganic filler/clay, and aprotic solvents to be used in polymer electrolyte have been discussed in detail. The mostly used polymer, salt, solvents, and inorganic filler/clay list has been prepared in order to keep the data bank at one place for new researchers. This article comprises different methodologies for the preparation of polymer electrolyte films. The different self-proposed mechanisms (like VTF, WLF, free volume theory, dispersed/intercalated mechanisms, etc.) have been discussed in order to explain the lithium ion conduction in polymer electrolyte systems. A numerous characterization techniques and their resulting analysis have been summarized from the different published reports at one place for better awareness of the scientific community/reader of the area. ? 2017, Springer-Verlag Berlin Heidelberg.