Novel zinc anodes are synthesized via electroplating with organic additives in the plating solution. The selected organic additives are cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), polyethylene-glycol (PEG-8000), and thiourea (TU). The synthesized zinc anode materials, namely, Zn-CTAB, Zn-SDS, Zn-PEG, and Zn-TU, are characterized by powder X-ray diffraction and scanning electron microscopy. The results show that each additive produces distinctively different crystallographic orientation and surface texture. The surface electrochemical activity is characterized by linear polarization when the zinc is in contact with the battery's electrolyte. Tafel fitting on the linear polarization data reveals that the synthetic zinc materials using organic additives all exhibit 6-30 times lower corrosion currents. When using Zn-SDS as the anode in the rechargeable hybrid aqueous battery, the float current decreases as much as 2.5 times. The batteries with Zn-SDS, Zn-PEG, and Zn-TU anodes display the capacity retention of 79%, 76%, and 80% after 1000 cycles of charge-discharge at 4C rate, whereas only 67% obtained from the batteries using the anode prepared from commercial zinc foil. Among these electroplated anodes, Zn-SDS is the most suitable for aqueous batteries thanks to its low corrosion rate, low dendrite formation, low float current, and high capacity retention after 1000 cycles.

The organoarsenical p-arsanilic acid (p-AsA) is used in the U.S. poultry industry as a feed additive and its structure resembles one of the stable biodegradation products of Roxarsone (ROX) in anaerobic environments. With the implementation of recent EPA MCL of total arsenic in drinking water (10 ppb), thereareconcernsaboutthefate of organoarsenicals introduced to the environment through the application of arsenic-contaminated manure. We report herein, for the first time, the thermodynamics of p-AsA binding to Fe-(oxyhydr)oxides using ATR-FTIR. ATR-FTIR spectra were used to quantify surface coverage of p-AsA, p-AsA(ads), by analyzing the broadband assigned to v(As-O) at 837 cm(-1). Adsorption isotherms were measured in situ at 298 K and pH 7 in the concentration range 1 microM to 40 mM. Values of Keq were obtained from Langmuir model fits and they range from 1411 to 3228 M(-1). We also determined the maximum adsorption capacities of Fe-(oxyhydr)oxides to p-AsA, and they range from 1.9 x 10(13) to 2.6 x 10(13) molecules/cm2. Our results suggest that p-AsA is more mobile than methylated and inorganic forms of arsenic and that the transport of nanoparticles with p-AsA(ads) might play a role in its mobility in geochemical environments.

Rechargeable aqueous Zn-MnO 2 batteries are a promising candidate for large-scale energy storage systems due to their outstanding advantages, such as high energy density, high safety, low cost, and environmental friendliness. Considering the controversies surrounding the mechanism of this battery containing a mildly acidic electrolyte, the electrochemical behavior of this type of battery using β-MnO 2 as the cathode is systematically investigated. The results indicate that the reversible intercalation of Zn 2+ ions into MnO 2 is not likely to take place in the aqueous system. We conclude that it is the existence of the water molecule and its participation in the electrochemical reactions, for instance, the reversible insertion of proton into MnO 2 and the electrolysis of water, that makes the mechanism of aqueous Zn-MnO 2 batteries complicated. Besides, the capacity fading of this mildly acidic Zn-MnO 2 battery is assigned to the generation of the inert layer of Zn 4 SO 4 (OH) 6 •nH 2 O and the ZnMn 2 O 4 on the cathode via electrochemical conversion reactions, the dissolution of the active material during discharging, and the release of gases. When Mn 2+ ions are available in the electrolyte, they will be electrodeposited on the cathode during charging, and the kinetics of the electrochemical reactions of the electrode is improved, leading to the higher electrochemical performance of the battery.

Hydrogen adsorption and storage using solid‐state materials is an area of much current research interest, and one of the major stumbling blocks in realizing the hydrogen economy. However, no material yet researched comes close to reaching the DOE 2015 targets of 9 wt% and 80 kg m−3 at this time. To increase the physisorption capacities of these materials, the heats of adsorption must be increased to ∼20 kJ mol−1. This can be accomplished by optimizing the material structure, creating more active species on the surface, or improving the interaction of the surface with hydrogen. The main focus of this progress report are recent advances in physisorption materials exhibiting higher heats of adsorption and better hydrogen adsorption at room temperature based on exploiting the Kubas model for hydrogen binding: (η2‐H2)–metal interaction. Both computational approaches and synthetic achievements will be discussed. Materials exploiting the Kubas interaction represent a median on the continuum between metal hydrides and physisorption materials, and are becoming increasingly important as researchers learn more about their applications to hydrogen storage problems.

The synthesis of novel zinc electrodes has been successfully implemented by using the electroplating method with the aid of inorganic additives in the electroplating solution. The selected inorganic additives are indium sulfate, tin oxide, and boric acid. From X-ray diffraction results, these synthesized zinc electrodes prefer (002) and/or (103) crystallographic orientations, representing basal morphology and high resistance to dendrite growth. The corrosion rates of these electroplated zinc samples decrease as much as 11 times smaller than the corrosion rate on zinc foil when the zinc materials are in contact with the aqueous electrolyte of a rechargeable hybrid aqueous battery (ReHAB). The ReHABs employing these anodes exhibit up to a threefold decrease in float charge current density after a seven-day constant-voltage charging at 2.1 V versus Zn /Zn. Furthermore, the capacity retention is up to 15 % higher than the performance of battery containing commercial Zn after 1000 cycles of charge-discharge. The significant advancements are attributed to the careful preparation of the anode, which contains appropriate crystallographic orientation and morphology.

In this paper we demonstrate that the Kubas interaction, a nondissociative form of weak hydrogen chemisorption with binding enthalpies in the ideal 20-30 kJ/mol range for room-temperature hydrogen storage, can be exploited in the design of a new class of hydrogen storage materials which avoid the shortcomings of hydrides and physisorpion materials. This was accomplished through the synthesis of novel vanadium hydrazide gels that use low-coordinate V centers as the principal Kubas H(2) binding sites with only a negligible contribution from physisorption. Materials were synthesized at vanadium-to-hydrazine ratios of 4:3, 1:1, 1:1.5, and 1:2 and characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption, elemental analysis, infrared spectroscopy, and electron paramagnetic resonance spectroscopy. The material with the highest capacity possesses an excess reversible storage of 4.04 wt % at 77 K and 85 bar, corresponding to a true volumetric adsorption of 80 kg H(2)/m(3) and an excess volumetric adsorption of 60.01 kg/m(3). These values are in the range of the ultimate U.S. Department of Energy goal for volumetric density (70 kg/m(3)) as well as the best physisorption material studied to date (49 kg H(2)/m(3) for MOF-177). This material also displays a surprisingly high volumetric density of 23.2 kg H(2)/m(3) at room temperature and 85 bar--roughly 3 times higher than that of compressed gas and approaching the DOE 2010 goal of 28 kg H(2)/m(3). These materials possess linear isotherms and enthalpies that rise on coverage and have little or no kinetic barrier to adsorption or desorption. In a practical system these materials would use pressure instead of temperature as a toggle and can thus be used in compressed gas tanks, currently employed in many hydrogen test vehicles, to dramatically increase the amount of hydrogen stored and therefore the range of any vehicle.

The all-vanadium redox flow battery (VRFB) is one of the most promising energy storage systems to be associated with the grid. The system has been developed for almost 30 years. A key component for VRFBs is the membrane separator, which separates the positive and negative half-cells and prevents the cross-mixing of vanadium ions, while providing required ionic conductivity. In general, research is to solve a multi-variable problem which requires optimization in both physical characteristics and electrochemical performance of the 10 membrane. Nafion and its derivatives are still important materials thanks to their high chemical stability and ionic conductivity. However, weaknesses of these materials, such as high vanadium ion crossover and high cost, stimulate new approaches in materials design for VRFBs. New achievements in material sciences and polymer chemistry allow further development of other types of polymeric materials and composites as separators in VRFBs. This includes new cation exchange membranes, anion exchange membranes, amphoteric 15 ion-exchange membranes, and non-ionic porous materials. Each type of material exhibits its advantages, accompanying with its weaknesses. Recent articles in polymer-containing membranes for use as separators in VRFBs are reviewed.Journal Name, [year], [vol], 00-00 | 5 vanadium crossover in s-Radel in comparison with that in Nafion.

Hydrogen is the ideal fuel because it contains the most energy per gram of any chemical substance and forms water as the only byproduct of consumption. However, storage still remains a formidable challenge because of the thermodynamic and kinetic issues encountered when binding hydrogen to a carrier. In this study, we demonstrate how the principal binding sites in a new class of hydrogen storage materials based on the Kubas interaction can be tuned by variation of the coordination sphere about the metal to dramatically increase the binding enthalpies and performance, while also avoiding the shortcomings of hydrides and physisorpion materials, which have dominated most research to date. This was accomplished through hydrogenation of chromium alkyl hydrazide gels, synthesized from bis(trimethylsilylmethyl) chromium and hydrazine, to form materials with low-coordinate Cr hydride centers as the principal H(2) binding sites, thus exploiting the fact that metal hydrides form stronger Kubas interactions than the corresponding metal alkyls. This led to up to a 6-fold increase in storage capacity at room temperature. The material with the highest capacity has an excess reversible storage of 3.23 wt % at 298 K and 170 bar without saturation, corresponding to 40.8 kg H(2)/m(3), comparable to the 2015 DOE system goal for volumetric density (40 kg/m(3)) at a safe operating pressure. These materials possess linear isotherms and enthalpies that rise on coverage, retain up to 100% of their adsorption capacities on warming from 77 to 298 K, and have no kinetic barrier to adsorption or desorption. In a practical system, these materials would use pressure instead of temperature as a toggle and can thus be used in compressed gas tanks, currently employed in the majority of hydrogen test vehicles, to dramatically increase the amount of hydrogen stored, and therefore range of any vehicle.