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Although liquid mercury (Hg) has been known since antiquity, the formation of stable solid nano forms of Hg at room temperature has not been reported so far. Here, for the first time, we report a simple sonochemical route to obtain solid mercury nanoparticles, stabilized by reduced graphene oxide at ambient conditions. The as-formed solid Hg nanoparticles were found to exhibit remarkable rhombohedral morphology and crystallinity at room temperature. Extensive characterization using various physicochemical techniques revealed the unique properties of the solid nanoparticles of Hg compared to its bulk liquid metal phase. Furthermore, the solid nature of the Hg nanoparticles was studied electrochemically, revealing distinctive properties. We believe that solid Hg nanoparticles have the potential for important applications in the fields of electroanalytical chemistry and electrocatalysis., Formation of the stable solid mercury nanoparticles by acoustic cavitation and their electrochemical activity compared to its bulk liquid metal.

Wastewater reclamation is becoming a top global interest as population growth and rapid industrialization pose a major challenge that requires development of sustainable cost-effective technologies and strategies for wastewater treatment. Carbon nanomembranes (CNMs)-synthetic 2D carbon sheets-can be tailored chemically with specific surface functions and/or physically with nanopores of well-defined size as a strategy for multifunctional membrane design. Here, we explore a bifunctional design for combined secondary wastewater effluent treatment with dual action of membrane separation and advanced oxidation processes (AOP), exploiting dissolved oxygen. The bifunctional membrane consists of a CNM layer on top of a commercial ultrafiltration membrane (Microlon (TM)) and a spray-coated reduced graphene oxide (rGO) thin film as the bottom layer. The CNM/support/rGO membrane was characterized by helium ion and atomic force microscopy, FTIR, XPS with a four-point conductivity probe, cyclic voltammetry, galvanostatic measurements, and impedance spectroscopy. Combined treatment of water by nanofiltration and AOP was demonstrated, employing a unique three electrode-dead end filtration setup that enables concurrent application of potential and pressure on the integrated membrane. For the model organic compound methylene blue, oxidation (by the Fenton reaction) was evaluated using UV-vis (610 nm). The rejection rate and permeability provided by the CNM layer were evaluated by dissolving polyethylene glycol (400 and 1000 Da) in the feed solution and applying pressure up to 1.5 bar. This demonstration of combined membrane separation and AOP using an integrated membrane opens up a new strategy for wastewater treatment.

The use of sodium manganese oxide as an intercalation electrode for water treatment was recently explored, and referred to as a “desalination battery” and “hybrid capacitive deionization”. Here, we examine the feasibility of using such a desalination battery, comprising crystalline Na4Mn9O18 as the cathode and Ag/AgCl/Cl− electrode as the anode, to extract energy from low-grade waste heat sources. Sodium manganese oxide electrode's material was produced via a solid-state synthesis. Electrodes were produced by spray-coated onto graphite foils, and showed a temperature dependence of the electrode potential, namely, ∂ E / ∂ T , of −0.63 mV/K (whereas, the Ag/AgCl/Cl− mesh electrode showed much lower temperature dependence

Electrodeposited ZnO coatings suffer severe capacity fading when used as conversion anodes in sealed Li cells. Capacity fading is attributed to (i) the large charge transfer resistance, $$R_{\mathrm{ct}}$$ (300–700 $$\Omega $$ ) and (ii) the low $$\hbox {Li}^{+}$$ ion diffusion coefficient, $$D_{\mathrm{Li}}^{+}\ (10^{-15}$$ to $$10^{-13}\hbox { cm}^{2}\hbox { s}^{-1})$$ . The measured value of $$R_{\mathrm{ct}}$$ is nearly 10 times higher and $$D_{\mathrm{Li}}^{+}$$ 10–100 times lower than the corresponding values for $$\hbox {Cu}_{2}\hbox {O}$$ , which delivers a stable reversible capacity.

Na0.6[Li0.2Ni0.2Mn0.6]O2 is synthesized by a self-combustion reaction (SCR) and studied for the first time as a cathode material for Na-ion batteries. The Na0.6[Li0.2Ni0.2Mn0.6]O2 cathode presents remarkable high rate capability and prolonged stability under galvanostatic cycling. A detailed analysis of X-ray diffraction (XRD) patterns at various states of cycling reveals that the excellent structural stability is due to a primarily solid-solution sodiation/desodiation mechanism of the material during cycling. Moreover, a meaningful comparison with Na0.6MnO2 and Na0.6[Li0.2Mn0.8]O2 reveals that the Na0.6[Li0.2Ni0.2Mn0.6]O2 cathode achieves a very high working-average voltage that outperforms most of the lithium-doped manganese-oxide cathodes published to date. Fil: de la Llave, Ezequiel Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Bar-Ilan University; Israel Fil: Nayak, Prasant Kumar. Bar-Ilan University; Israel Fil: Levi, Elena. Bar-Ilan University; Israel Fil: Tirupathi Rao, Penki. Bar-Ilan University; Israel Fil: Bublil, Shaul. Bar-Ilan University; Israel Fil: Hartmann, Pascal. Basf; Alemania Fil: Chesneau, Frederick Francois. Basf; Alemania Fil: Greenstein, Miri. Bar-Ilan University; Israel Fil: Nazar, Linda F.. University of Waterloo; Canadá Fil: Aurbach, Doron. Bar-Ilan University; Israel

Porous flower-like alpha-Fe2O3 nanostructures have been synthesized by ethylene glycol mediated iron alkoxide as an intermediate and studied as an anode material of Li-ion battery. The iron alkoxide precursor is heated at different temperatures from 300 to 700 degrees C. The alpha-Fe2O3 samples possess porosity and high surface area. There is a decrease in pore volume as well as surface area by increasing the preparation temperature. The reversible cycling properties of the alpha-Fe2O3 nanostructures have been evaluated by cyclic voltammetry, galvanostatic charge discharge cycling, and galvanostatic intermittent titration measurements at ambient temperature. The initial discharge capacity values of 1063, 1168,1183, 1152 and 968 mAh g(-1) at a specific current of 50 mA g(-1) are obtained for the samples prepared at 300, 400, 500, 600 and 700 degrees C, respectively. The samples prepared at 500 and 600 degrees C exhibit good cycling performance with high rate capability. The high rate capacity is attributed to porous nature of the materials. As the iron oxides are inexpensive and environmental friendly, the alpha-Fe2O3 has potential application as anode material for rechargeable Li batteries. (C) 2015 Elsevier Ltd. All rights reserved.

In the present work, Li2-x MnO3-y (LMO) thin films have been deposited by radio frequency (RF) reactive magnetron sputtering using acid-treated Li2MnO3 powder target. Systematic investigations have been carried out to study the effect of RF power on the physicochemical properties of LMO thin films deposited on platinized silicon substrates. X-ray diffraction, electron microscopy, surface chemical analysis and electrochemical studies were carried out for the LMO films after post deposition annealing treatment at 500 A degrees C for 1 h in air ambience. Galvanostatic charge discharge studies carried out using the LMO thin film electrodes, delivered a highest discharge capacity of 139 mu Ah mu m(-1) cm(-2) in the potential window 2.0-3.5 V vs. Li/Li+ at 100 W RF power and lowest discharge capacity of 80 mu Ah mu m(-1) cm(-2) at 75 W RF power. Thereafter, the physicochemical properties of LMO films deposited using optimized RF power 100 W on stainless steel substrates has been studied in the thickness range of 70 to 300 nm as a case study. From the galvanostatic charge discharge experiments, a stable discharge capacity of 68 mu Ah mu m(-1) cm(-2) was achieved in the potential window 2.0-4.2 V vs. Li/Li+ tested up to 30 cycles. As the thickness increased, the specific discharge capacity started reducing with higher magnitude of capacity fading.

Carbonization of milk-free coconut kernel pulp is carried out at low temperatures. The carbon samples are activated using KOH, and electrical double-layer capacitor (EDLC) properties are studied. Among the several samples prepared, activated carbon prepared at 600 °C has a large surface area (1,200 m2 g−1). There is a decrease in surface area with increasing temperature of preparation. Cyclic voltammetry and galvanostatic charge–discharge studies suggest that activated carbons derived from coconut kernel pulp are appropriate materials for EDLC studies in acidic, alkaline, and non-aqueous electrolytes. Specific capacitance of 173 F g−1 is obtained in 1 M H2SO4 electrolyte for the activated carbon prepared at 600 °C. The supercapacitor properties of activated carbon sample prepared at 600 °C are superior to the samples prepared at higher temperatures.

Carbon has been prepared by pyrolysis of grated, milk-extracted coconut kernel at 600 o C under nitrogen atmosphere. The disordered carbon has sheet like morphology. The carbon exhibits a high reversible Li + intercalation capacity in a non-aqueous electrolyte. The initial charge and discharge capacities are 990 and 400 mAh g -1 , thus resulting in an irreversible capacity loss of 590 mAh g -1 . Nevertheless, subsequent discharge capacity is stable over a large number of charge-discharge cycles. The electrodes withstand charge-discharge currents as high as 1257 mA g -1 and they deliver discharge capacity of 80 mAh g -1 . Diffusion coefficient of Li + obtained from galvanostatic intermittent titration is 6.7 x 10 -12 cm 2 s -1 . Thus the coconut kernel derived carbon is a suitable anode material for Li-ion batteries. Copyright © 2014 VBRI press.

LiCoO2 thin films used as cathode layers in thin-film solid-state batteries have been deposited from LiCoO2 powder target using radio frequency (rf) magnetron sputtering in a cost effective approach in terms of material consumption and processing time. Xray diffraction (XRD) studies of the films after post deposition annealing treatment revealed (104) orientation, which is the characteristic of rf sputtered LiCoO2 films. Raman spectroscopy was used to identify the different modes of vibration of atoms in the film. The surface morphology and cross-section of the samples were characterized using field emission scanning electron microscopy (SEM). The chemical analysis of LiCoO2 thin films was examined by X-ray photoelectron spectroscopy (XPS) showed atomic ratio of Li/Co as 0.9 which is close to the ideal value 1. Electrochemical characterization such as charge – discharge and cyclic voltammetry were conducted for LiCoO2 films deposited on platinized silicon substrates in the potential range 3.0 to 4.2 V vs Li/Li + . The maximum discharge capacity of 64 µAh.µm -1 . cm -2 and 52 µAh. µm -1 .cm -2 were achieved when discharged at a current of 5 µA and 50 µA for the first discharge cycle respectively. Moreover the electrochemical investigations of LiCoO2 thin films on flexible copper substrates also investigated and achieved an initial discharge capacity of 83 mAh/g. The possible reasons for degradation in the electrochemical properties have been discussed. The present work indicates suitability of sputtering from powder targets for thin film battery fabrication. Copyright © 2013 VBRI press.

Amongst a number of different cathode materials, the layered nickel-rich LiNiyCoxMn1−y−xO2 and the integrated lithium-rich xLi2MnO3·(1 − x)Li[NiaCobMnc]O2 (a + b + c = 1) have received considerable attention over the last decade due to their high capacities of ~195 and ~250 mAh·g−1, respectively. Both materials are believed to play a vital role in the development of future electric vehicles, which makes them highly attractive for researchers from academia and industry alike. The review at hand deals with both cathode materials and highlights recent achievements to enhance capacity stability, voltage stability, and rate capability, etc. The focus of this paper is on novel strategies and established methods such as coatings and dopings.

Lithium manganese oxide (Li2-xMnO3-y) thin films have been deposited from activated Li2MnO3 powder by radio frequency magnetron sputtering for the first time in the literature and subjected to electrochemical characterization. Physicochemical characterization by X-ray diffraction has revealed the formation of the thin films with crystallographic phase identical to that of the powder target made of Li2-xMnO3-y. The Li:Mn atomic ratio for the powder and film are calculated by X-ray photoelectron spectroscopy and it is found to be 1.6:1.0. From galvanostatic charge discharge studies, a specific discharge capacity of 139 mu Ah mu m(-1) cm(-2) was obtained when cycled between 2.00 and 3.50 V vs Li/Li+. Additionally the rate capability of the thin film electrodes was studied by subjecting the cells to charge-discharge cycling at different current densities in the range from 10 mu A cm(-2) to 100 mu A cm(-2). (C) 2013 The Electrochemical Society. All rights reserved.

TIN thin films with (200) fibre texture are deposited on Cu substrate at room temperature using reactive magnetron sputtering. They exhibit a discharge capacity of 172 mu Ah cm(-2) mu m(-1) (300 mAh g(-1)) in a non-aqueous electrolyte containing a Li salt. There is a graded decrease in discharge capacity when cycled between 0.01 and 3.0 V. Electron microscopy investigations indicate significant changes in surface morphology of the cycled TiN electrodes in comparison with the as deposited TiN films. From XPS depth profile analysis, it is inferred that Li intercalated TIN films consist of lithium compounds, hydroxyl groups, titanium sub oxides and TiN. Lithium diffusivity and reactivity decrease with increase in depth and the major reaction with lithium takes place at film surface and grain boundaries. (C) 2014 Elsevier Ltd. All rights reserved.

Since commercializing of the first lithium-ion battery by Sony Corporation in 1991, graphitic carbons have been used as anode materials. Graphitic carbons owe to their favorable characteristics such as eco-friendly, stability upon cycling, low operating potential versus Li/Li+, etc. however, carbon materials also poses several challenges that include limited specific capacity (~ 372 mAh g-1), formation of a solid-electrolyte interphase (SEI), lithium plating or formation of a surface film at high current rates, etc. To overcome these difficulties, research has been focused on transition metal oxides as alternate anode materials. Various metal oxides (to mention a few Co3O4, MnO2, Fe3O4 and Fe2O3) have been reported to undergo conversion reactions while exhibiting lower voltages with high reversible capacities than the traditional graphitic carbon counterparts. This has motivated many researchers to study the conversion reaction of oxide materials.1 Among the transition metal oxides studied, hematite α-Fe2O3 has been intensively studied due to its low cost, excellent stability, environmental friendly properties and also providing high theoretical capacity 1007 mAh g-1 based on 6 Li+per formula unit. One of the challenging issues in conversion reaction of a bulk electrode material is to maintain structural integrity during electrochemical cycling with associated issues such as volume changes, pulverization, etc., which affect the performance.2Congruently, through nanostructured materials such as nanoparticles, nanocubes, nanorods, nanotubes and nanoflowers, we may facilitate an increase in the electrochemical performance due to short diffusion length for Li-ion and electronic transport. Among these, porous materials have been studied widely because of the easy percolation of electrolyte into core of particles which result in high rate capability. Porous materials can also sustain mechanical stress generated by volume expansion/contraction during the electrochemical cycling. In the present work, we report synthesis of iron alkoxide precursors using 4.4 mmol FeCl3.6H20, 90 mmol urea and 124 mmol tetra butyl ammonium bromide are added to 180 ml of ethylene glycol in 250 ml round bottomed flask, stirred for 10 min to get homogeneous solution and refluxed at 195 oC for 30 min. The obtained green precipitate of iron alkoxide is washed with ethanol and dried at 60 oC for 12 h. The resultant dried powder is calcined at a range of temperatures from 300 to 500 oC for 3 h in air.3 A porous flower-like nanostructured α-Fe2O3 is obtained by subsequent calcination of iron alkoxide precursor. The phase purity and morphology of the final product (α-Fe2O3) are studied by XRD, SEM and TEM analysis. The microscopic images show (Fig. 1) a flower-like morphology. The BET surface area and its pore size of the α-Fe2O3 are measured and they are 64 m2 g-1 and 6 nm, respectively. The α-Fe2O3 powder is subjected to galvanostatic charge/discharge experiments between 0.01 and 3.0 V versus Li/Li+. The charge-discharge profile is shown in Fig. 2. The discharge capacities obtained for 1st, 10th and 20th cycle are of 1058, 1044 and 917 mAh g-1 respectively for the sample prepared at 300 oC. These values are greater than the values reported so far on α-Fe2O3. Porous nature of α-Fe2O3 prepared in the present study is responsible for high discharge capacity and also high rate capability. Results of these studies including both physical and electrochemical investigations will be presented. Acknowledgements: SS and TRP acknowledge University Grants Commission (UGC), Government of India for Dr. D. S. Kothari fellowship and Senior Research Fellowship, respectively. References: 1. M. V. Reddy et al, Adv. Funct. Mater., 2007 17,2792. 2. P. G. Bruce et al, Angew. Chem. Int. Ed., 2008, 47, 2930. 3. S. Shivakumara et al, Electrochem. Lett., 2013, 2, A60.