Recent publications on lead/acid batteries and related phenomena: 1993, No. 2, B19–B36

The aim of this abstracting service is to provide workers with a review of paper titles in the area of lead/acid batteries, and in particular to assist those workers who do not have ready access to citation facilities. The intention is to publish the compilation half-yearly and an author index for a given year will be provided when citations for that year are complete.The publications are grouped under broad titles and, where possible, are numbered in chronological sequences that will be continued in each succeeding issue. Due to the unavoidable delay between the appearance and the citation of papers, the two issues of each year will necessarily include items published both during that year and during the previous year.     

Li–B–O–N electrolytes for all-solid-state thin film batteries

We report for the first time new Li⁺ ion conducting thin film solid electrolytes based on Li–B–O–N system. Substitution of oxygen in xLi₂O–B₂O₃ (x = 1, 3, 5) by nitrogen was successfully achieved by reactive sputtering under nitrogen plasma. FTIR and XPS analyses indicated that N atom was incorporated in the Li–B–O matrix film, and an increase in the composition of Li₂O together with N-substitution caused the structural conversion from ring-type borate to open structured one, where more free space and ionic bonding characteristic are offered for higher mobility of Li⁺ ions. A high ionic conductivity of ca. 2.3 × 10⁻⁶ S cm⁻¹ at room temperature was obtained from the thin film electrolyte of Li_3.09BO_2.53N_0.52 glass that was prepared using 3Li₂O–B₂O₃ target. Electrochemical analyses suggest the high Li⁺ ion conductivity is induced by the reduced activation energy through the control of the composition and the structure.     

Multifunctional Co–B–O@CoxB catalysts for efficient hydrogen generation

The development of efficient and non-noble catalyst is of great significance to hydrogen generation techniques. Three surface-oxidized cobalt borides of Co–B–O@Co_xB (x = 0.5, 1 and 2) have been synthesized that can functionalize as active catalysts in both alkaline water electrolysis and the hydrolysis of sodium borohydride (NaBH₄) solution. It is discovered that oxidation layer and low boron content favor the oxygen evolution reaction (OER) activity of Co–B–O@Co_xB in alkaline water electrolysis. And surface-oxidized cobalt boride with low boron content is more active toward hydrolysis of NaBH₄ solution. An alkaline electrolyzer fabricated using the optimized electrodes of Co–B–O@CoB₂/Ni as cathode and Co–B–O@Co₂B/Ni as anode can deliver current density of 10 mA cm⁻² at 1.54 V for overall water splitting with satisfactory stability. Meanwhile, Co–B–O@Co₂B affords the highest hydrogen generation rate of 3.85 L min⁻¹ g⁻¹ for hydrolysis of NaBH₄ at 25 °C.     

New La–Fe–B ternary system hydrogen storage alloys

The new La₈Fe₂₈B₂₄-, La₁₅Fe₇₇B₈- and La₁₇Fe₇₆B₇-type alloys have multiphase structures including LaNi₅, La₃Ni₁₃B₂ and (Fe, Ni) phases. The amount of La₃Ni₁₃B₂ phase increased and that of (Fe, Ni) phase decreased with an increasing La/(Fe + B) atomic ratio. The measurement of P–C–I curves revealed that the maximum hydrogen capacity exceeded 1.12 wt% at 313 K in the pressure range of 10⁻³ MPa–2.0 MPa. The alloys exhibited good absorption/desorption kinetics at room temperature, and electrochemical experiments showed that all of the alloy electrodes exhibited good activation characteristics, high-rate dischargeability (HRD) and low-temperature (233 K) dischargeability (LTD).     

Corrosion of novel Pb–Mg–Al–B nuclear shielding alloy in fluoride medium

Abstract

Five kinds of Pb–Mg–Al–B alloys with B atomic fraction of 0, 1·84, 3·62, 5·36 and 7·06% were prepared by induction melting. The corrosion behaviour of Pb–Mg–Al–B in 3·5 wt-%NaF solution was investigated by immersion tests, neutral salt spray and electrochemical measurements. The surface morphology and corrosion products of alloys were measured using scanning electron microscopy (SEM), X-ray diffraction and X-ray photoelectron spectroscopy. Results show that the Pb–Mg–Al–B alloy with 5·36%B shows the best corrosion resistance; the volume fraction and distribution of Mg₂Pb, Mg₁₇Al₁₂ and other phases affect the corrosion resistance significantly; the major corrosion products are Mg₁₇Al₁₂, Pb, PbO, Al₂O₃, etc., and Mg is apt to form a microgalvanic cell with Mg₂Pb (Mg₂Pb–Mg) in corrosive solution, and a bit of product of MgF₂ film has a role to protect alloys; and the different corrosion resistances are caused by the different microstructure of alloys with different B additions.     

Ni–Fe–B catalysts for NaBH4 hydrolysis

A series of Ni–Fe–B catalysts with different Fe/(Fe + Ni) molar ratios, used for the hydrolysis of NaBH₄, were prepared by chemical reduction of NiCl₂ and FeCl₃ mixed solution with NaBH₄. The measurements revealed that the catalysts with the molar ratio of Fe/(Fe + Ni) (30%) exhibited the highest catalytic activity, and the optimal reduction temperature is 348 K. In addition, the effects of the concentration of NaBH₄, NaOH and the hydrolytic temperature of NaBH₄ were discussed in detail. The results show that the reaction rate of hydrolysis first rises up and then goes down subsequently with the increase of NaBH₄ concentration, as well as the concentration of NaOH. The activation energy of the hydrolysis for Ni–Fe–B catalysts is fitted to 57 kJ/mol. The maximum value of hydrogen generation is 2910 ml/(min g) at 298 K.     

Partial phosphorization of porous Co–Ni–B for efficient hydrogen evolution electrocatalysis

Design of cost-effective and high-efficient electrocatalysts for hydrogen evolution reaction (HER) is of vital significance for the current renewable energy devices — fuel cells. Herein, we report a facile strategy to prepare partial phosphorization of Co–Ni–B material with porous structure via a water-bath boronizing and subsequent phosphorization process at moderate temperature. The optimal atomic proportion of Co to Ni is investigated via physical and electrochemical characterization. As a result, Co₉–Ni₁–B–P exhibits the best HER activity, which require an lower overpotential of ~192 mV to deliver a current density value of 10 mA cm⁻² and a smaller Tafel slope of 94 mV dec⁻¹ in alkaline media, relative to P-free Co–Ni–B catalysts, Co₉–Ni₁–B–P with other Co: Ni proportion and mono metallic borides The excellent electrocatalytic performance of Co₉–Ni₁–B–P is mainly ascribed to the three-dimensional (3D) porous structure and the coordinate functionalization between the borides and phosphides. This work provides a promising strategy for the exploration of quaternary composites as efficient and cost-effective electrocatalysts for HER.     

Chitosan-mediated Co–Ce–B nanoparticles for catalyzing the hydrolysis of sodium borohydride

Highly dispersed Co–Ce–B nanoparticles supported on chitosan-derived carbon (Co–Ce–B/Chi–C) were synthesized through chemical reduction and carbonization. The morphology and microstructure of the Co–Ce–B/Chi–C nanocomposite were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Brunauer–Emmett–Teller adsorption analysis. This nanocomposite had uniform morphology and large surface area, and it showed high catalytic activity for NaBH₄ hydrolysis and good cycle stability. Compared with unsupported Co–Ce–B particles, this nanocomposite showed greatly increased catalytic activity for NaBH₄ hydrolysis. A remarkably high hydrogen generation rate of 4760 mL^?1 min^?1 g^?1 at 30 °C was achieved with low activation energy of 33.1 kJ mol^?1. These results indicate that the Co–Ce–B/Chi–C nanocomposite is a promising catalyst for on-demand hydrogen generation via NaBH₄ hydrolysis.     

Synthesis and hydrogen storage characteristics of Mg–B–H compounds by a gas–solid reaction

Magnesium borohydride [Mg(BH₄)₂] is an attractive complex hydride for hydrogen storage. In this study, attempts to synthesize Mg(BH₄)₂ were carried out by a solid–gas reaction through MgH₂ and B₂H₆ in the absence of a liquid medium. The source of B₂H₆ was obtained by heating a mixture of NaBH₄ and ZnCl₂. The profile of pressure versus temperature indicated that the absorption kinetics of B₂H₆ by MgH₂ were slow. Structural analysis confirmed the formation of Mg–B–H compounds. The reaction products presented two-step hydrogen release during heating. A small amount of hydrogen could be released from the as-synthesized Mg–B–H compounds at a low temperature of 215 °C. The slow reaction kinetics were significantly affected by the surface conditions of the MgH₂ powders.     

Electrochemical behavior of Mg–Li,Mg–Li–Al and Mg–Li–Al–Ce in sodium chloride solution

Mg–Li, Mg–Li–Al and Mg–Li–Al–Ce alloys were prepared and their electrochemical behavior in 0.7 M NaCl solutions was investigated by means of potentiodynamic polarization, potentiostatic current–time and electrochemical impedance spectroscopy measurements as well as by scanning electron microscopy examination. The effect of gallium oxide as an electrolyte additive on the potentiostatic discharge performance of these magnesium alloys was studied. The discharge activities and utilization efficiencies of these alloys increase in the order: Mg–Li < Mg–Li–Al < Mg–Li–Al–Ce, both in the absence and presence of Ga₂O₃. These alloys are more active than commercial magnesium alloy AZ31. The addition of Ga₂O₃ into NaCl electrolyte solution improved the discharging currents of the alloys by more than 4%, and enhanced the utilization efficiencies of the alloys by more than 6%. It also shortened the transition time for the discharge current to reach to a steady value. Electrochemical impedance spectroscopy measurements showed that the polarization resistance of the alloys decreases in the following order: Mg–Li > Mg–Li–Al > Mg–Li–Al–Ce. Mg–Li–Al–Ce exhibited the best performance in term of activity, utilization efficiency and activation time.     

Remarkable decrease in dehydrogenation temperature of Li–B–N–H hydrogen storage system with CoO additive

Cobalt monoxide (CoO) was introduced into the Li–B–N–H system as a catalyst precursor, and the hydrogen desorption behavior of the LiBH₄–2LiNH₂–xCoO (x = 0–0.20) composites was investigated. It was observed that the majority of hydrogen desorption from the CoO-added sample occurred simultaneously with the melting of α-Li₄BN₃H₁₀. Moreover, the 0.05CoO-added sample exhibited optimized dehydrogenation properties, desorbing 9.9 wt% hydrogen completely with an onset temperature of 100 °C and exhibiting a decrease of more than 120 °C in the onset dehydrogenation temperature with respect to that of the additive-free sample. The activation energy of hydrogen desorption for the 0.05CoO-added sample was reduced by 30%. XAFS measurements showed that the CoO additive was first reduced chemically to metallic Co during the initial stage of thermal dehydrogenation, and the newly produced metallic Co acted as the catalytic active species in favor of the creation of B–N bonding. More importantly, approximately 1.1 wt% of hydrogen could be recharged into the fully dehydrogenated 0.05CoO-added sample at 350 °C and a hydrogen pressure of 110 atm, which represents much better performance than that exhibited by the pristine sample.     

Hydrogen generation from catalytic hydrolysis of sodium borohydride solution using Cobalt–Copper–Boride (Co–Cu–B) catalysts

Co–Cu–B, as a catalyst toward hydrolysis of sodium borohydride solution, has been prepared through chemical reduction of metal salts, CoCl₂·6H₂O and CuCl₂, by an alkaline solution composed of 7.5wt% NaBH₄ and 7.5wt% NaOH. The effects of Co/Cu molar ratio, calcination temperature, NaOH and NaBH₄ concentration and reaction temperature on catalytic activity of Co–Cu–B for hydrogen generation from alkaline NaBH₄ solution have been studied. X-ray diffraction (XRD), scanning electron microscope (SEM) and Nitrogen adsorption–desorption isotherm have been employed to understand the results. The Co–Cu–B catalyst with a Co/Cu molar ratio of 3:1 and calcinated at 400 °C showed the best catalytic activity at ambient temperature. The activation energy of this catalytic reaction is calculated to be 49.6 kJ mol⁻¹.     

Kinetics of the hydrogen-induced diffusive phase transformation in Nd–Fe–B industrial alloy

The kinetics of the hydrogen-induced diffusive phase transformation in industrial alloy Nd–Fe–B has been investigated. The isothermal kinetic curves were received for temperatures from 750 to 620°C at the hydrogen pressure 0.1 MPa. An isothermal kinetics diagram was obtained. This diagram is similar to the ones of the transformations in steels during heating. It is shown that the investigated phase transformation is a diffusion-controlled one with the mechanism of nucleation and growth.     

Investigation of the thermodynamic and kinetic properties of La–Fe–B system hydrogen-storage alloys

La–Fe–B hydrogen-storage alloys were prepared using a vacuum induction-quenching furnace with a rotating copper wheel. The thermodynamic and kinetic properties of the La–Fe–B hydrogen-storage alloys were investigated in this work. The P–C–I curves of the La–Fe–B alloys were measured over a H₂ pressure range of 10⁻³ MPa to 2.0 MPa at temperatures of 313, 328, 343 and 353 K. The P–C–I curves revealed that the maximum hydrogen-storage capacity of the alloys exceeded 1.23 wt% at a pressure of approximately 1.0 MPa and temperature of 313 K. The standard enthalpy of formation ΔH and standard entropy of formation ΔS for the alloys' hydrides, obtained according to the van't Hoff equation, were consistent with their application as anode materials in alkaline media. The alloys also exhibited good absorption/desorption kinetics at room temperature.     

China's oil use, 1990–2008

Over the past two decades, China's oil demand has risen steeply. In 1990, it was only about 25% higher than that of 1978, the year economic reform was introduced. By 2008, it had reached 396.0 million tons, roughly four times the 1978 level, making China the second largest oil user worldwide. The country became a net oil importer in 1993, and between 1993 and 2008, its net import dependency—a yardstick for energy security—soared from 7.5% to 50.0%. China's increased demand for oil has made the country a global energy player of critical importance. Although the literature on the global implications of China's oil use has proliferated, relatively few studies have attempted to examine “how China uses oil.” Hence, this study covers every oil-consuming facility and sector in China, exploring the patterns of, and factors involved in, oil demand by power plants, oil refineries, heat plants and, gas-works, and industrial, transport, agricultural, household and commercial sectors. It concludes that in virtually all sectors in China, oil demand will grow, with transport and industry leading the way.     

Hydrogen generation from hydrolysis of sodium borohydride by cubic Co–La–Zr–B nano particles as novel catalyst

Cubic Co–La–Zr–B nano particles were prepared in situ for the first time from the reduction of Co(II), La(III) and Zr(IV) chloride by sodium borohydride in methanol under reflux condition. Poly N-vinyl-2-pyrrolidone (PVP) as stabilizing agent was used for preparation of Co–La–Zr–B nano particles. Obtained powders were characterized by XRD, BET, ICP, SEM, TEM and UV–vis techniques. XRD patterns declare that under argon atmosphere only metalboride phase has been crystallized and it was not seen any oxide phase of metals. TEM image depicts that PVP stabilized nano particles are square shaped particles that containing many nanoclusters. Cubic Co–La–Zr–B nano particles were also confirmed by SEM image. Co–La–Zr–B is highly active catalysts for hydrogen generation from the hydrolysis of sodium borohydride. The reported work also includes the full experimental details for the collection of a wealth of kinetic data to determine the activation energy (E_a = 53 kJ mol⁻¹) and effects of the catalyst dosage, amount of NaBH₄, and temperature on the rate of the catalytic hydrolysis of sodium borohydride. Catalytic hydrolysis of NaBH₄ is first order with respect to the catalyst concentration and also first order to the NaBH₄ concentration in the case of cubic Co–La–Zr–B nano particles.     

SiO2–CaO–B2O3–Al2O3 ceramic glaze as sealant for planar ITSOFC

A series of ceramic glazes based on the SiO₂–CaO–B₂O₃–Al₂O₃ system as sealant for intermediate temperature solid oxide fuel cell (ITSOFC) were investigated. Different ratios of B₂O₃/SiO₂ and Al₂O₃/CaO were investigated to control softening process, phase separation, and crystallization. When B₂O₃/SiO₂ ratio was in the range of 0.14–0.27, the glazes showed good wetting and bonding behavior with both 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte and stainless steel interconnect which could satisfy the sealing demand at 850 °C. And the dimension stability can be kept for over 100 h by introducing ceramic felt and controlling the glazes viscosity in the range of 10⁴ to 10⁶ Pa s. By means of controlling Al₂O₃/CaO ratio in the range of 0.4–0.68, phase separation and crystallization were restrained effectively. After holding at 850 °C for 100 h, non-crystalline network in the glazes could be found, and a suitable viscous flow could well relax thermal stress. The sealing was effective even after 10 thermal cycles. Element analysis showed a good chemical stability at the ceramic glazes/stainless steel interconnect and ceramic glazes/8YSZ electrolyte interfaces.     

Tunable microstructure,de-/hydrogenation kinetics and thermodynamics performance of Mg–Ni–La–Ti–H systems

In the light of positive effects of rare earth and transition metals on the hydrogen absorption/desorption properties of magnesium, the Mg20La–5TiH₂, Mg20Ni–5TiH₂ and Mg10Ni10La–5TiH₂ composites have been prepared in this work to ameliorate the de-/hydrogenation kinetics and thermodynamic performance. The results indicate that the as-prepared composites are mainly composed of Mg, Mg₂Ni/LaH₃ and TiH₂ phases after activation, and LaH₃ and TiH₂ are stable during de-/hydrogenation cycles. The morphology observations give evidences that LaH₃ with size about ~20 nm and Mg₂Ni with size about ~1 μm are uniformly distributed in the composites. It is noted that the de-/hydriding kinetics of the as-prepared composites are significantly improved after internal and surface modification, of which the Mg10Ni10La–5TiH₂ composite can desorb as high as 5.66 wt% hydrogen within 3 min at 623 K. Moreover, the thermodynamic properties of the experimental composites have also been investigated and discussed according to the pressure-composition isothermal curves and corresponding calculation by Van't Hoff equation. The improved hydrogen storage properties of the as-prepared composites are mainly attributed to the uniformly distributed LaH₃, Mg₂Ni and TiH₂ phases, which provide a large amount of phase boundaries, diffusion paths and nucleation sites for de-/hydrogenation reactions.     

Novel Ni–Co–B hollow nanospheres promote hydrogen generation from the hydrolysis of sodium borohydride

Ni–Co–B hollow nanospheres were synthesized by the galvanic replacement reaction using a Co–B amorphous alloy and a NiCl₂ solution as the template and additional reagent, respectively. The Ni–Co–B hollow nanospheres that were synthesized in 60 min (Ni–Co–B-60) showed the best catalytic activity at 303 K, with a hydrogen production rate of 6400 mL_hydrogenmin^?1g_catalyst^?1 and activation energy of 33.1 kJ/mol for the NaBH₄ hydrolysis reaction. The high catalytic activity was attributed to the high surface area of the hollow structure and the electronic effect. The transfer of an electron from B to Co resulted in higher electron density at Co sites. It was also found that Ni was dispersed on the Co–B alloy surface as result of the galvanic replacement reaction. This, in turn, facilitated an efficient hydrolysis reaction to enhance the hydrogen production rate. The parameters that influenced the hydrolysis of NaBH₄ over Ni–Co–B hollow nanospheres (e.g., NaOH concentration, reaction temperature, and catalyst loading) were investigated. The reusability test results show that the catalyst is active, even after the fifth run. Thus, the Ni–Co–B hollow nanospheres are a practical material for the generation of hydrogen from chemical hydrides.