IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Ga-Doped LLZO Solid-State Electrolyte with Unique ``Plate-like'' Morphology Derived from Water Hyacinth (Eichhornia crassipes) Aquatic Weed: Waste to Wealth Conversion
No full textAn attempt has been made for the first time to convert waste biomass such as water hyacinth (WH) to a functional energy material in a cost-effective way. The present research describes a novel exo-templating methodology to develop engineered microstructure of Ga-doped Li7La3Zr2O12 (Li6.25La3Ga0.25Zr2O12, referred as WH-Ga-LLZO) solid-state electrolyte for its use in all solid-state lithium batteries (ASSLBs) by mimicking the intercellular structure of water hyacinth (Eichhornia crassipes), an invasive and noxious aquatic plant. The developed exo-templated methodology offers a low calcination temperature of 1000 degrees C in air where all the major peaks could be indexed as cubic garnet, as confirmed by XRD. The FESEM micrographs revealed a unique ``plate-like'' morphology that mimicked the intercellular structure of water hyacinth fiber. The bulk lithium-ion conductivity in the WH-Ga-LLZO electrolyte was found to be 3.94 x 10(-5) S/cm. Li/WH-Ga-LLZO/Li cells were galvanostatically cycled for a continuous 295 h with increasing step current densities from 28 mu A/cm(3) without a short circuit. The highest current density as measured for maximum polarization in a symmetric cell was found to be 452 mu A/cm(2). The WH exotemplated methodology was thus developed and optimized and can be extended for synthesizing any application-specific multifunctional materials
Piezoelectric Nanogenerators based on Lead Zirconate Titanate nanostructures: an insight into the effect of potential barrier and morphology on the output power generation
No full textThe high internal resistance of the perovskite materials used in Nanogenerators (NGs) lowers the power generation. It severely restricts their application for mechanical energy harvesting from the ambient source. In this work, we demonstrate a flexible Piezoelectric NG (PENG) with an improved device structure. Hydrothermally grown one-dimensional Lead Zirconate Titanate (Pb(ZrTi)O-3) of different morphologies are used as the generating material. The morphology of the PZT nanostructures, engineered from nanoparticles to needle-shaped nanowires to increase the surface to volume ratio, provides effective mechanical contact with the electrode. The reduction of the internal resistance of the PENG has been achieved by two ways: (i) fabrication of interdigitated electrodes (IDE) to increase the interfacial polarization and (ii) lowering of Schottky barrier height (SBH) at the junction of the PZT nanostructure and the metal electrode by varying the electrode materials of different work functions. We find that lowering of the SBH at the interface contributes to an increased piezo voltage generation. The flexible nano needles-based PENG can deliver output voltage 9.5 V and power density 615 mu W cm(-2) on application low mechanical pressure (similar to 1 kPa) by tapping motion. The internal resistance of the device is similar to 0.65 M omega. It can charge a 35 mu F super-capacitor up to 5 V within 20 s. This study provides a systematic pathway to solve the bottlenecks in the piezoelectric nanogenerators due to the high internal resistance
Elucidating the influence of structure and Ag+ -Na+ ion-exchange on crack-resistance and ionic conductivity of Na3Al1.8Si1.65 P-1.8 O-12 glass electrolyte
No full textGlasses are emerging as promising and efficient solid electrolytes for all-solid-state sodium-ion batteries. However, they still suffer from poor ionic conductivity and crack-resistance, which need to be improved for better battery performance, reliability, and service life. The current study shows a significant enhancement in crack resistance (from 11.3 N to 32.9 N) for Na3Al (1.8) Si-1.65 P1.8O12 glass (Ag-0 glass) upon Na+ -Ag+ ion-exchange (IE) due to compressive stresses generated in the glass surface while the ionic conductivity values (similar to 10(-5) S/cm at 473 K) were retained. In this study, magic angle spinning-nuclear magnetic resonance (MAS-NMR), molecular dynamics (MD) simulations, Vickers micro hardness, and impedance spectroscopic techniques were used to evaluate the intermediate-range structure, atomic structure, crack resistance and conductivity of the glass. MAS-NMR and MD simulations confirm the presence of Si-OAl-O-P groups in the glass, thus enabling formation of Na percolated channel regions. AC-conductivity analysis for Ag-0 and ion-exchanged Ag-0 glass suggests that the mobility of Na+ ion increases with increasing temperature. It is observed that the measured mean square displacement (root ) for sodium cations using AC-conductivity isotherms is nearly constant up to 448 K and then increases with increasing temperature up to 523 K. From the impedance spectra for ion-exchanged Ag-0 glass, it is identified that the increase in root and thereby, the mobility of sodium-ions for Ag-0 glass is due to the structural variations in the Ag-0 glass with increasing the temperature. Overall, the mechanisms presented in this article helps in formulating better glass based electrolyte materials for room temperature or high temperature sodium-ion batteries. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
Room-temperature surface multiferroicity in Y2NiMnO6 nanorods
No full textWe report observation of surface-defect-induced room-temperature multiferroicity-surface ferromagnetism (M-S at 50 kOe approximate to 0.005 emu/g), ferroelectricity (P-R approximate to 2nC/cm(2)), and significantly large magnetoelectric coupling (decrease in P-R by approximate to 80% under approximate to 15 kOe field)-in nanorods (diameter approximate to 100 nm) of double perovskite Y2NiMnO6 compound. In bulk form, this system exhibits multiferroicity only below its magnetic transition temperature T-N approximate to 70 K. On the other hand, the oxygen vacancies, formed at the surface region (thickness approximate to 10 nm) of the nanorods, yield long-range magnetic order as well as ferroelectricity via Dzyloshinskii-Moriya exchange coupling interactions with strong Rashba spin-orbit coupling. Sharp drop in P-R under magnetic field indicates strong cross coupling between magnetism and ferroelectricity as well. Observation of room-temperature magnetoelectric coupling in nanoscale for a compound which, in bulk form, exhibits multiferroicity only below 70 K underscores an alternative pathway for inducing magnetoelectric multiferroicity via surface defects and, thus, in line with magnetoelectric property observed, for example, in domain walls or boundaries or interfaces of heteroepitaxially grown thin films which do not exhibit such features in their bulk
Electric-field-driven resistive transition in multiferroic SrCo2Fe16O27/Sr3Co2Fe24O41 composite
No full textWe report on the observation of electric-field-driven resistive transition abrupt rise in resistivity (p)] at a characteristic threshold field E-th(T) in an off-stoichiometric composite of W-and Z-type hexaferrite (-80%)SrCo2Fe16O27/(similar to 20%)Sr3Co2Fe24O41. The dielectric constant epsilon and the relaxation time constants tau also exhibit anomalous jump at E-th(T). The E-th(T), the extent of jump in resistivity (triangle rho), and the hysteresis associated with the jump |triangle E-th(T)| are found to decrease systematically with the increase in temperature (T) across a range of 10-200 K. They also depend on the extent of nonstoichiometry. In addition, several temperature-driven phase transitions have been noticed both in the low and high resistive states. The entire set of observations has been discussed within the framework of structural evolution of the point defect (cation vacancies or oxygen excess) network and its influence on electronic conduction. The magnetocapacitive effect, measured under similar to 20 kOe field, turns out to be substantial (similar to 4%-12%) and exhibits clear anomaly at E-th. This comprehensive map of esoteric rho -E -T and epsilon -E -T patterns provides insights on defect-driven effects in a multiferroic composite. These effects could be useful for tuning both the resistive transition and the multiferroicity. Published under an exclusive license by AIP Publishing
Arthrospira sp. mediated bioremediation of gray water in ceramic membrane based photobioreactor: process optimization by response surface methodology
No full textNovelty statement The study elucidated the application of indigenously designed and devised ceramic membranes in an algal photobioreactor for viable production of Arthrospira sp. employing gray water, aided by photosynthetic CO2 sequestration and microalgal biorefinery. A highly encouraging result was achieved in the microalgal process under optimized culture conditions with >95% removal of organics. It may be stressed here that the process ran effectively without any elaborate arrangement of external aeration, thereby reducing the investment and operating costs to the minimum. Direct discharge of raw domestic sewage enriched with nitrogenous and phosphorous compounds into the water bodies causes eutrophication and other environmental hazards with detrimental impacts on public and ecosystem health. The present study focuses on phycoremediation of gray water with Arthrospira sp. using an innovative hydrophobic ceramic membrane-based photobioreactor system integrated with CO2 biofixation and biodiesel production, aiming for green technology development. Surfactant and oil-rich gray water collected from the domestic kitchen was used wherein, chloride, sulfate, and surfactant concentrations were statistically optimized using response surface methodology (RSM), considering maximum microalgal growth rate as a response for the design. Ideal concentrations (mg/L) of working parameters were found to be 7.91 (sulfate), 880.49 (chloride), and 144.02 (surfactant), respectively to achieve optimum growth rate of 0.43 g(dwt)/L/day. Enhancement of growth rate of targeted microalgae by 150% with suitable CO2 (19.5%) supply and illumination in the photobioreactor affirms its efficient operation. Additionally, harvested microalgal biomass obtained from the process showed a biodiesel content of around 5.33% (dry weight). The microalgal treatment enabled about 96.82, 87.5, and 99.8% reductions in BOD, COD, and TOC, respectively, indicating the potential of the process in pollutant assimilation and recycling of such wastewater along with value-added product generation
Solution-processed light-induced multilevel non-volatile wearable memory device based on CsPb2Br5 perovskite
No full textDespite the recent advancements in memory devices, the quest for building materials with low power consumption is still on, with the ultimate focus on the durability of the system and reliability and reproducibility of its performance. Halide perovskites (HPs), which have several intriguing photoelectrical traits, have recently been utilized for memory applications; one of the highlights of these materials is the ionic-motion-based fast switching in their crystal structure. In this work, a CsPb2Br5 film is applied as a switching layer to implement memory devices with a flexible Al/CsPb2Br5/ITO-PET structure. The device exhibits a pronounced bipolar resistive switching (RS) characteristic at low operating voltage. The as-fabricated flexible device presented RS features with no initial forming process, concentrated distributions of high and low resistance states (HRS and LRS), uniform switching, endurance over 100 cycles, and a long retention time of 10(3) s with a high on/off ratio of around 10(2). Multilevel data-storage capability was also observed via subtle control of the compliance current (CC). Considering the current demand for smart, wearable, and flexible electronic gadgets, the current-voltage (I-V) characteristics of the as-fabricated all-inorganic halide-perovskite-based memory device were further explored under different bending conditions to determine its electrical reliability and mechanical stability. This flexible device exhibited no discernible difference in device performance under flat or bent conditions, and the performance remained nearly the same even after 500 bending cycles. In addition to control of the RS effect of the device using an electrical field, the performance of the device under light was also explored. Blue light modulates the resistive states by regulating the condition of photo-generated electron-hole pairs, and the SET and RESET voltages are changed from 2.34 to 2.14 V and from -2.04 to -1.90 V, respectively. The observed RS behavior is explained on the basis of the creation and partial annihilation of conductive multifilaments, which is dominated by the migration of bromine ions and their associated vacancies in the HP layer. We believe that this work will offer a new context to understand the intrinsic characteristics of HPs for RS applications at low voltage and validate their potential in the design of next-generation stable and nonvolatile memory devices for future flexible electronic systems
Laser-based directed energy deposition (DED-LB) of advanced materials
No full textDirected energy deposition (DED) has matured into an essential additive manufacturing (AM) branch. DED has been broadly implemented in the design and fabrication of novel materials. These include metals, ceramics, and composites. Successful DED operation requires a good understanding of many critical phenomena, including laser-material interactions, fundamentals of casting and solidification of alloys, welding metallurgy and joining interfaces, along with microstructure-mechanical properties relations. Also critical are powder flowability, heat transfer, and various machine-related parameters. Several review articles have been published in recent years on metal AM via powder bed fusion (PBF) and DED, focusing on either a specific material system, mapping the recent technologies for AM, or issues related to the deposition process or material properties. Yet, no recent review is dedicated to a comprehensive presentation of material systems, design, fabrication, challenges, and the relationship between microstructures and mechanical properties of various DED'ed material families. Since the DED-based approach is becoming popular to manufacture bimetallic and multi-material structures, repair high-value structures, and alloy design, this comprehensive review focuses on materials design via DED, including a survey of a variety of monolithic and multi-material compositions. Finally, the critical challenges and oppor-tunities in this area are highlighted
Improved photoluminescence and spectroscopic features of Sm3+-doped alkali borate glasses by embedding silver nanoparticles
No full textInfluence of Ag nanoparticles (NPs) on the improvement in photoluminescence and spectroscopic features of Sm3+-doped alkali borate glass synthesized by the melt quenching process was systematically studied and analyzed. The increasing particle size of Ag NPs with the increase of AgCl concentration (0.1 - 0.5 mol%) causes the surface plasmon resonance peak to shift to a higher wavelength (red-shift) side. Electron microscopic investigation confirmed the presence of silver NPs in the SmLAB-1 glass sample with a median size of 4.57 nm. A significant enhancement in emission was noticed for 0.1 mol% AgCl concentration. Such improved emission was attributed to the enhanced local electric field by metallic NPs in the vicinity of Sm3+ ions and efficient energy transfer between Sm3+ ions and silver NPs. The Judd-Ofelt parameter, Omega(2) decreased as the concentration of Ag NPs increases, indicating increased symmetry and ionicity between the trivalent samarium ions and their ligands. These prepared glass compositions could have applications in solid-state devices such as LEDs and display applications