Department Of Physics
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Item Enhanced Curie temperature and superior temperature stability by site selected doping in BCZT based lead-free ceramics(Elsevier Ltd, 2022-01-31T00:00:00) Kumari, Sapna; Kumar, Amit; Kumar, Aman; Kumar, V.; Thakur, Vikas N.; Kumar, Ashok; Goyal, P.K.; Gaur, Anurag; Arya, Anil; Sharma, A.L.In this work, Bi3+ doped Ba0.98-3x/2BixCa0.02Zr0.02Ti0.976Cu0.008O3 [0 ? x ? 0.03] lead free ceramics, to be employed for structural, dielectric and ferroelectric studies, have been synthesized via conventional solid state reaction method. Rietveld refinement of the X-ray diffraction (XRD) data evidences the existence of a pure perovskite phase with tetragonal symmetry for all ceramics. The Scanning Electron Microscopy (SEM) reveals that the grain size, which is 16.14 ?m for x = 0 reduced to 2.11 ?m for x = 0.03. Dielectric studies demonstrate excellent dielectric behavior with high Curie temperature (TC ?159 �C), high dielectric constant (?r ?834, ?max ? 3146), and a low dielectric loss (tan? ? 0.019), for an optimum value of x = 0.02. The analysis of temperature coefficient of the dielectric permittivity indicates the applicability of these materials in multilayer ceramic capacitors. Impedance studies, conducted to understand the underlying physical mechanisms, are found to be in good agreement with the results of structural and dielectric studies. Furthermore, the ferroelectric measurement confirms the ferroelectric nature for all samples with an energy storage efficiency (?) of ?42% for x = 0.02 composition. � 2022 Elsevier Ltd and Techna Group S.r.l.Item Fundamentals of Batteries and Supercapacitors: An Overview(CRC Press, 2021-09-06T00:00:00) Arya, Anil; Gaur, Anurag; Sharma, A.L.; Kumar, VijayEnergy plays an important role in daily human life and is the basic need in the present scenario. Nowadays, the development of energy sources is linked with the development of human civilization. The high energy density and high power density energy devices are on the radar of the research community. Batteries and supercapacitors (SCs) are two potential energy storage devices dominating the energy sector all over the world. This chapter starts with a focus on energy technologies and storage needs. Then, fundamentals of electrochemistry have been discussed followed by the working principle of battery and SC, and how energy is stored. Different types of batteries and SCs are discussed with their charge storage mechanisms. At last, important performance parameter and their influence on the overall device and its performance is presented. � 2022 Taylor & Francis Group, LLC.Item Role of energy loss-range profile of heavy ions in tailoring the optical properties of polycarbonate(Elsevier B.V., 2021-09-27T00:00:00) Chhokkar, Preeti; Kumar, V.; Goyal, Parveen K.; Kumar, Shyam; Tomar, A.K.; Gaur, Anurag; Arya, AnilPolycarbonate (PC) samples have been implanted with 115 keV N+, Ar+ and Kr+ at fluences ranging from 5x1014 to 1x1016 ions/cm2 to be employed for optical studies. A Decrease in optical energy gap, enhancement in reflectivity and reduction in transmittance, particularly in UV-region, is observed for all implanted samples. The change in optical properties of PC, first, by keeping energy deposited/cm2 constant (i.e. keeping energy*fluence constant) and then by keeping same depth of penetration for different ions have been analysed in detail. The changes are found to be more prominent for N+ compared to Ar+ and Kr+ when the fluence/energy deposited/cm2 by the ions is same. Further, the energy for N+ is reduced to 46 keV, while for Kr+ it is increased to 200 keV to ensure the same penetration depth for N+, Ar+ and Kr+ in PC. Finally, the results are explained on the basis of energy loss-range profiles of these ions in polycarbonate and through Raman spectroscopy. This study convincingly demonstrates that not only the types of ion species, their energies and fluences, but the total energy deposited by ions and their depth of penetration also plays an important role in tailoring the optical properties of polymeric materials. � 2021 Elsevier B.V.Item Energy Storage and Conversion Devices: Supercapacitors, Batteries, and Hydroelectric Cells(CRC Press, 2021-09-06T00:00:00) Gaur, Anurag; Sharma, A.L.; Arya, AnilThis book presents a state-of-the-art overview of the research and development in designing electrode and electrolyte materials for Li-ion batteries and supercapacitors. Further, green energy production via the water splitting approach by the hydroelectric cell is also explored. Features include: � Provides details on the latest trends in design and optimization of electrode and electrolyte materials with key focus on enhancement of energy storage and conversion device performance � Focuses on existing nanostructured electrodes and polymer electrolytes for device fabrication, as well as new promising research routes toward the development of new materials for improving device performance � Features a dedicated chapter that explores electricity generation by dissociating water through hydroelectric cells, which are a nontoxic and green source of energy production � Describes challenges and offers a vision for next-generation devices This book is beneficial for advanced students and professionals working in energy storage across the disciplines of physics, materials science, chemistry, and chemical engineering. It is also a valuable reference for manufacturers of electrode/electrolyte materials for energy storage devices and hydroelectric cells. � 2022 Taylor & Francis Group, LLC.Item Challenges and Perspectives of Li-Ion Batteries, Supercapacitors, and Hydroelectric Cells(CRC Press, 2021-09-06T00:00:00) Arya, Anil; Gaur, Anurag; Sharma, A.L.This chapter provides an overview of challenges faced by different devices and their remedies. Supercapacitors are energy storage devices and have gained the attention of the scientific community due to their high power density, long cycle life, and a broad range of applications. The existing carbon/metal oxide-based electrode symmetric cell has a lower energy density. Energy density is an important parameter that needs to be improved with the existing high power density. The only feasible strategy is the development of hybrid architecture. The cell performance is strongly influenced by the contact between different components of the cell. The contact between the current collector as well as the active material needs to be improved for minimizing the interfacial resistance and for improving the charge transferability of the electrode material. The energy production through hydroelectric cells, based on metal oxides and their composites, by the splitting of water has turned out to be a feasible alternative to other green energy sources. � 2022 Taylor & Francis Group, LLC.Item Nanostructured Metal Oxides for Hybrid Supercapacitors(CRC Press, 2021-09-02T00:00:00) Arya, Anil; Gaur, Anurag; Kumar, Vijay; Tanwar, Shweta; Sharma, A.L.The present chapter highlights the fundamentals of supercapacitors (SCs), their classification with the main emphasis on the fabrication of hybrid SC using nanostructured transition metal oxide (TMO) based electrodes. The TMO based electrodes have grabbed the attention of researchers to point out a significant role in the enhancement of the SC device performance such as fast charging-discharging, energy density, power density, and cyclic stability. The tuning of valence charge and dominance of pseudocapacitive behavior is the key to achieve the superior performance of supercapacitors. In this article, we have focused on the hybrid approach to configuring the SC device and obtained enhanced electrochemical performance as compared to symmetric/non-hybrid supercapacitor. Consequently, this chapter provides insights about hybrid supercapacitors along with strategies to enhance cell performance. Furthermore, a glimpse of different TM based electrode material for the Hybrid SC device is also reported. � 2022 Taylor & Francis Group, LLC.Item Electrolytes for Li-Ion Batteries and Supercapacitors(CRC Press, 2021-09-06T00:00:00) Arya, Anil; Pandey, Lokesh; Gaur, Anurag; Kumar, Vijay; Sharma, A.L.This chapter is dedicated to the electrolyte that is a crucial component of any device. Electrolyte plays a dual role in the device, acts as a carpet for electrolyte ions, and also separates the electrodes to avoid short-circuiting or explosion. Initially, the characteristics parameter and selection criteria for the electrolyte will be discussed. Then, the organic electrolytes have been discussed followed by a focus on emerging novel gel/solid polymer electrolytes for application in battery and supercapacitor. The performance of the battery and supercapacitor is shown for different electrolytes. � 2022 Taylor & Francis Group, LLC.Item Fabrication of activated carbon electrodes derived from peanut shell for high-performance supercapacitors(Springer Science and Business Media Deutschland GmbH, 2021-07-06T00:00:00) Pandey, Lokesh; Sarkar, Subhajit; Arya, Anil; Sharma, A.L.; Panwar, Amrish; Kotnala, R.K.; Gaur, AnuragIn this work, the activated carbon (AC) is derived from the waste material of peanut shells. The obtained activated carbon has been synthesized using the chemical activation process via impregnation with NaOH at various proportions (1:2 and 1:3). The structural, morphological, and electrochemical properties of obtained AC are examined by X-ray diffraction (XRD), BET surface analysis, scanning electron microscopy (SEM), and electrochemical techniques. The resulting AC shows the enhancement in specific surface area (SSA) from 584 to 735 m2/g at 1:2 ratio and 826 m2/g at 1:3 ratio after the activation process. The electrodes are fabricated using derived activated carbon for electrochemical characterization. It has been observed through cyclic voltammetry and galvanostatic charge�discharge measurements that 1:3 NaOH-activated samples reveal the maximum value of specific capacitance (263 F/g at 10�mV/s and 290 F/gat 0.2A/g). The sample also conveys the pre-dominant ~ 98% of efficiency from 400 to 1000th cycle with fast and almost constant capacitance. The electrochemical impedance spectroscopy (EIS) result suggests the pure capacitive nature of the sample and indicates the dominating electric double-layer capacitive (EDLC) behavior. The obtained results demonstrate that the peanut shell�derived activated carbon is a potential candidate as an electrode material for supercapacitors. Graphical abstract: [Figure not available: see fulltext.] � 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Effect of oxygen vacancies, lattice distortions and secondary phase on the structural, optical, dielectric and ferroelectric properties in Cd-doped Bi2Ti2O7 nanoparticles(Elsevier Ltd, 2021-04-27T00:00:00) Anu; Yadav, Kamlesh; Gaur, Anurag; Haldar, Krishna Kanta(Bi1-xCdx)2Ti2O7 (x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10 and 0.12) nanoparticles are synthesised using the co-precipitation method. The prepared samples show pyrochlore phase formation except for x = 0.02 and 0.08, where Bi4Ti3O12 appears as a secondary phase. The crystallite size and unit cell volume decrease while the strain and dislocation density increase with an increase in Cd-doping. The vibrational bands corresponding to Cd?O and C[dbnd]O are red-shifted, while the H[sbnd]O[sbnd]H bending band is blue-shifted with increasing Cd-doping. The band gap energy for x = 0.00 is found to be 1.78 eV. It increases with an increase in �x� up to 0.06 and then decreases with a further increase in �x� except for x = 0.02 and x = 0.08. The impedance data show non-Debye type relaxation. The pyrochlore phase is found to be non-ferroelectric. However, the samples with x = 0.02 and x = 0.08 having the secondary phase (Bi4Ti3O12) are ferroelectric. � 2021 Elsevier LtdItem Transition metal dichalcogenide (TMDs) electrodes for supercapacitors: A comprehensive review(IOP Publishing Ltd, 2021-04-24T00:00:00) Tanwar, Shweta; Arya, Anil; Gaur, Anurag; Sharma, A.L.As globally, the main focus of the researchers is to develop novel electrode materials that exhibit high energy and power density for efficient performance energy storage devices. This review covers the up-to-date progress achieved in transition metal dichalcogenides (TMDs) (e.g. MoS2, WS2, MoSe2, and WSe2) as electrode material for supercapacitors (SCs). The TMDs have remarkable properties like large surface area, high electrical conductivity with variable oxidation states. These properties enable the TMDs as the most promising candidates to store electrical energy via hybrid charge storage mechanisms. Consequently, this review article provides a detailed study of TMDs structure, properties, and evolution. The characteristics technique and electrochemical performances of all the efficient TMDs are highlighted meticulously. In brief, the present review article shines a light on the structural and electrochemical properties of TMD electrodes. Furthermore, the latest fabricated TMDs based symmetric/asymmetric SCs have also been reported. � 2021 IOP Publishing Ltd.