Electrochemical performance of nickel/metal hydride batteries under unconventional conditions and degradation analysis

The charge discharge performance and cycle stability of D size Ni/MH batteries at -20 ℃, 25 ℃ and 55 ℃ were examined. The results show that the decline rate of Ni/MH battery discharge capacity at -20 ℃ and 55 ℃ are 12.1% and 13.6%,and the average discharge voltage decreases by a value of 0.13 V and 0.06 V respectively, cycling stability declines obviously at various temperatures. The capacity degradation of Ni/MH batteries under low temperature is reversible, belonging to transient degradation and that of high and normal temperatures are not reversible, belonging to permanent degradation. Electrochemical impedance spectroscopy, scanning electron microscope and energy dispersive X ray analyzer were introduced to study the main causes of cycling deterioration of Ni/MH batteries.

Degradation Behavior of Electrochemical Performance of Sealed-Type Nickel/Metal Hydride Batteries

The degradation mechanism of electrochemical performance of sealed type nickel/metal hydride batteries was investigated. The results indicate that the degradation behavior of Ni/MH battery is not only owing to the lack of electrolyte, but also the deterioration of the active materials on the positive and negative electrodes of Ni/MH batteries. Scanning electron micrographs (SEM), X ray diffraction (XRD) and laser granularity analyses are presented. The particle pulverization and oxidation during charge/discharge are identified as the main causes for deterioration of the negative and positive electrode in nickel/metal hydride batteries, as well as the cross section cracking of both anode and cathode.

Preparation and Photocatalytic Activity of Nanocrystalline GdFeO_3

With Gd2O3, Fe （NO3）3· 9H2O, and nitric acid （ 1： 1 volume fraction） as starting materials, nanocrystalline material of rare-earth composite oxide GdFeO3 with perovskite-type structure was synthesized by sol-gel method in the system of citric acid. Structural characteristics were characterized by XRD and TEM, which indicate that the sample is nanocrystallite with uniform grain size distribution and the average grain size is about 21 nm. Its crystal structure includes a certain amount of lattice distortion due to decrease of grain size and increase of surface area. Photocatalytic properties of this material were tested by decolorization of various water-soluble dyes. Effects of irradiation time and amount of GdFeO3 on photocatalytic activity were also investigated. The results show that nano-sized GdFeO3 exhibits high photocatalytic activity and that increase of irradiation time and the amount of GdFeO3 can improve its photocatalytic activity.

A Mild and Efficient Deprotection of Geminal Diacetates Catalyzed by FeCl3 ·6H2O in Ionic Liquid

The selective deprotection of geminal diacetates promoted by FeCl3·6H2O in the ionic liquid [bmim] [BF4] canbe efficiently achieved in good yields. The ionic liquid and the catalyst can be recycled easily and the process is car ried out under mild conditions.……

A novel synthesis of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction in ionic liquid

An efficient and novel procedure for the preparation of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or cyanoacetate in [bmim][BF4] is described in this paper. Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.

Effects of iron phthalocyanine on performance of MH/Ni battery

Oxygen evolution causes a high inner pressure during charge and overcharge for MH/Ni battery, and an inappropriate eliminating way of the oxygen in the battery results in accumulation of heat. This is the main obstacle to develop and apply high capability and high power battery. How to reduce the ratio of the chemical catalysis rate to the electric catalysis rate in MH/Ni battery is considered as an urgent question. Iron phthalocyanine(FePc) was chosen as an electrochemical catalyst. The batteries were prepared by adding iron phthalocyanine with different dosages. The inner pressure, the capacity attenuation, the discharge voltage and capacity at high current of these three batteries were compared. The battery with 1 mg FePc in the negative electrode exhibits a good performance.

Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.

Theoretical Investigation on the Charge Transport Properties of 2,5-Di(cyanovinyl)-thiophene/furan with the Kinetic Monte Carlo Method

Exploring, designing, and synthesizing novel organic field-effect transistor （OFET） materials have kept an important and hot issue in organic electronics. In the current work, the charge transport properties for 2,5-di（cyanovinyl）thiophene/furan crystal associating two pentafluorophenyl units linked via the azomethine bond, CTE and CFE have been theoretically investigated by means of density functional theory （DFT） calculations coupled with the incoherent charge-hopping mechanism and the kinetic Monte Carlo simulation. Results show that these two compounds possess remarkably low-lying HOMO （-7.0 eV） and LUMO （-4.0 eV） levels, as well as large electron affinities （〉 3.0 eV）, which indicate their high stability exposed to air as promising OFET materials. However, the ph value at room temperature （T = 300 K） is predicted to be 2.058x10^7 cm26Vl·s-1, and the is as low as 9.834^10-8 cm2-V-l.s-1 for CFT crystal. Meanwhile, these two values are 7.561 x 10-8 and 8.437 x 10-8 cm2.V-I.s-1 for the CFE crystal, respectively. Furthermore, the simulation of angle-dependent mobility in the a-b, a-c, and b-c crystal planes shows that the charge transport in CTE and CFE crystals is remarkably anisotropic, which maybe is helpful for the fabrication of high-performance OFET devices.

Theoretical Prediction of the Photovoltaic Properties of BFBPD-PC61 BM System as a Promising Organic Solar Cell

In this work,the photovoltaic properties of BFBPD-PC61 BM system as a promising high-performance organic solar cell（OSC） were theoretically investigated by means of quantum chemistry and molecular dynamics calculations coupled with the incoherent charge-hopping model.Moreover,the hole carrier mobility of BFBPD thin-film was also estimated with the aid of an amorphous cell including 100 BFBPD molecules.Results revealed that the BFBPD-PC61 BM system possesses a middle-sized open-circuit voltage of 0.70 V,large short-circuit current density of 17.26 mA ·cm^-2,high fill factor of 0.846,and power conversion efficiency of 10%.With the Marcus model,in the BFBPD-PC61 BM interface,the exciton-dissociation rate,kdis,was predicted to be 2.684×10^13 s^-1,which is as 3-5 orders of magnitude large as the decay（radiative and non-radiative） one（10-8-10^10s^-1）,indicating a high exciton-dissociation efficiency of 100% in the BFBPD-PC61 BM interface.Furthermore,by the molecular dynamics simulation,the hole mobility of BFBPD thin-film was predicted to be as high as 1.265 × 10^-2 cm-2·V^-1·s^-1,which can be attributed to its dense packing in solid state.

Effect of Cobalt Phthalocyanine on Floating-Charge Performance of Nickel-Metal Hydride Battery

In Ni-MH battery, oxygen evolution causes a high inner pressure during charge and overdischarge, and an inappropriate eliminating way of the oxygen in the battery results in accumulation of heat. This is the main obstacle to develop and apply high capability and high power battery. In this paper, effect of cobalt phthalocyanine (CoPc) on the floating-charge performance of Ni-MH batteries are examined. Experimental results show that the battery with CoPc additive by appropriate adding way displayed a better capability of floating charge and discharge than the one without CoPc. The battery with CoPc added into electrolyte shows the best charging efficiency and cycleability and the slowest increasing speed of inner pressure after 2000th charge and discharge.

An unexpected reaction of cyanothioacetamide:Novel preparation of pyrazolo[3,4-b]-pyridine derivatives under MWI

An unexpected multi-component reaction of cyanothioacetarnide with aldehyde and aminopyrazole under MWI was reported. Through this reaction, a series of pyrazolo[3,4-b]-pyridine derivatives was prepared in high yields via simple operational procedure.

Recycling of waste residue in aluminum production process

The preparation of crystal form of Al（OH）3 from the deposited residues of anodizing lines in the process of producing aluminum was studied. Alkali is used to dissolve the residue, and then blow CO2 is bellowed in, finally a kind of useful crystal Al（OH）3 is accessed by hydrolysis. The yield of the crystal Al（OH）3 was affected by temperature, pH and flow rate of CO2. The experimental results showed that under constant stirring, the optimized conditions was to control the temperature of 75-85℃, pH 7.5-9.0, CO/flow rate 60-80 mL/min. Using this method, the purpose of recovering valuable resources of Al, cleaning up the environment, and recycling of the by-product of Na2CO3 was achieved. It was of good economic and social benefits.

A Novel Preparation of 2,4-Disubstituted Quinolines Catalyzed by FeCl3 ·6H2O in Ionic Liquids

Quinolines and their derivatives occur in numerous natural products. Many quinolines display interesting physi ological activities and have found attractive applications as pharmaceuticals and agrochemicals as well as being general synthetic building blocks. [1] Many synthetic methods have been developed for quinolines, [2] but due to their great importance, the development of novel synthetic methods remains an active research area. [3]……

A comparison of iron phthalocyanine and cobalt porphyrin on the electrochemical catalysis in Ni-MH battery

The effects of iron phthalocyanine (FePc) and cobalt porphyrin (CoPp) on inner pressure and cycle behavior of sealed Ni-MH batteries were investigated in this study. The morphology of battery elec- trode was observed by SEM. The electrochemical impedance spectroscopy of floating-charge/dis- charge battery was also measured. Experimental results show that the addition of FePc or CoPp to the alloy electrode is an effective approach to decrease the internal pressure of battery during the process of charge and overcharge. In contrast to CoPp, the battery with FePc exhibits a slower capacity decay and a smaller overpotential at the same charge-discharge rate. As an electrocatalyst, FePc may more effectively speed up the reduction of oxygen, and decrease its reduction potential. As a result, the charge process is accelerated, the gas evolution is reduced and the pulverization of electrode materials is slowed down.

Preparation,characterization of Y^(3+)-doped TiO_2 nanoparticles and their photocatalytic activities for methyl orange degradation

A series of pure and Y3＋-doped TiO2 nanoparticles with high photocatalytic activities were prepared by a sol-gel method using tetra-n-butyl titanate as precursor.The as-prepared catalysts were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and diffuse reflectance spectroscopy（DRS）.The results indicated that yttrium doping could effectively reduce the crystalline size,inhibit the anatase-to-rutile phase transformation and surppress the recombination of the photogenerated electron-hole pairs.The DRS results showed that the optical absorption edge shifted to red direction owing to yttrium ion doping.The photocatalytic activities of samples were evaluated by the photodegradation of methyl orange（MO） aqueous solution under 300 W high pressure mercury lamp irradiation.Photodegradation results revealed that Y3＋ doping could greatly improve the photocatalytic activity of TiO2.In this experiment,the optimal dosage was 1.5 mol.% when samples were calcined at 773 K for 2 h,which caused a MO photodegradation rate of 99.8% under UV irradiation for 70 min.

Chemical Constituents in Essential Oils from Elsholtzia ciliata and Their Antimicrobial Activities

Objective To compare the chemical constituents in the essential oils from the leaves, flowers, and seeds of Elsholtzia ciliata and their antimicrobial activities. Methods The chemical constituents in essential oils were extracted by the hydro-distillation method and analyzed by GC-MS. The chemical constituents in essential oils were identified on the basis of comparison on their retention indices and MS spectrum with published data. Moreover, the antimicrobial activities of the chemical constituents in the oils against the growth of six bacteria strains and one pathogenic yeast strain were evaluated by using minimum inhibitory concentration and minimum bactericidal concentration methods. Results A total of 58 compounds were identified, while compounds 31, 35, and 36 were identified in the essential oils from the leaves, flowers, and seeds, respectively. Fifteen compounds were identified as shared constituents in the leaves, flowers, and seeds. The chemical constituents in the essential oils showed the inhibitory activities against the six bacteria strains and the yeast strain. Conclusion The major constituents are different in the essential oils of the leaves, flowers, and seeds. The major chemical constituents in the essential oils are monoterpenoids and sesquiterpenoids. And the chemical constituents in the essential oils obtained from the leaves show higher inhibitory activities especially against Bacillus subtillis CMCC63501 and Escherichia coli ATCC25922.

Ionic Liquid [bmim][BF_4] as a Green Medium for Passerini Reaction

The Passerini three-component reaction of carboxylic acid, aromatic aldehyde and isocyanide was carried out smoothly and efficiently in ionic liquid [bmim]BF4. Through this reaction, a series of α-acyloxycarboxamides were obtained in high yields. Advantages of this proccedure include a green nature, high efficiency and operational simplicity

Significant Enhancement in Photovoltaic Performances for C217-based Dye Sensitizers via Introducing Electron-withdrawing Substituents: a Theoretical Study

Dye-sensitized solar cells(DSSCs) are one of the most promising photovoltaic technologies, and the development of efficient dye sensitizers, especially inexpensive metal-free organic dyes, is always crucial for fabricating new DSSC devices. In this paper, a series of novel metal-free dyes with the D-A-π-A structure were designed by introducing electron-withdrawing substituents into the C217 molecular skeleton, and then their photovoltaic parameters were predicted by means of density functional theory(DFT) and time-dependent DFT(TD-DFT) calculations in combination with the Marcus charge transfer model. Our results showed that compared with C217, the introduction of trifluoromethyl(-CF3), cyano(-CN), and nitryl(-NO2) can efficiently narrow the HOMO-LUMO gap, and remarkably enhance the dye’s sunlight harvesting. With the(TiO2)38 cluster model, the photoelectric conversion efficiency(PCE) for the C217 dye was predicted to be up to 9.82%, which is in good agreement with the measured value(9.6%~9.8%), suggesting that our scheme used in this paper is reliable. Based on the same method, the PCE of most designed dyes was estimated to exceed over 10%, denoting that the molecular design strategy recommended by us in this work is reasonable. Especially, the PCE values of the dye 1, 4, and 6 were found to be as high as 14.75%, 16.02% and 15.75% respectively, suggesting that these three dyes are potential candidates as efficient sensitizers, and are worth further experimental study.