Effects of Co^(2+)Doping on the Crystal Structure and Electrochemical Performance of LiFePO_4

Co2＋-doped LiFePO4/C composite material was prepared by solid-state synthesis method using Fe2O3,Li2CO3 and NH4H2PO4 as the starting materials.The structures and elec-trochemical performance of samples were studied by XRD,SEM and constant current charge-discharge method.The results showed that the Co2＋ doping did not change the crystal structure of LiFePO4.The unit cell volume changed with the increase of Co2＋,and reached the maximum at x = 0.04.The LiFe0.96Co0.04PO4/C sample proved the best electrochemical properties.Its initial discharge capacity was 138.5 mA·h /g at 1 C rate.After 30 cycles,the capacity remained 127.7 mA·h /g,and the capacity retention rate was 92.2%.

Effect of tin addition on microstructure and electrochemical properties of rolled AZ61-Sn magnesium anodic materials

Microstructure characterization, corrosion behavior, and electrochemical properties of magnesium anode materials containing 1-3 wt.% Sn in AZ61 alloy were studied by optical microscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy-dispersive spec- troscopy （EDS）, constant current method, potential polarization, and drainage. The results showed that amount of Mg2Sn phase increased, and recrystallization ratio of Sn-contained Mg alloys during rolling process was improved with increasing of Sn content. This resulted in uniform and refined gains. The results also demonstrated that discharge potential was improved and hydrogen release rate was reduced with the addition of Sn. As the current density increased, the release hydrogen rate was rising, owing to negative variance effect of magnesium alloys. The current efficiency gets to 87% at 20 mA/cm2. The main components of the corrosion products are easy-to-peel-off MgO and Al2O3 that can lead to more negative and stable work potential and accelerate battery reaction continuously.

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of a New Dinuclear Copper Complex [C_2H_6ON]_2[Cu_2Cl_2(μ-CH_3COO)_4]

The hydrothermal reaction of copper chloride dihydrate and 5,5-dimethyl-imidazolidine,-2,4-dione with a mole ratio of 1：1 in acetonitrile resulted in the formation of a new acetate-bridged dinuclear copper complex, [C2H6ON]2[Cu2Cl2（μ-CH3COO）4]. Protonated acetamide in eaolie form and acetic acid were yielded by the hydrolysis of acetonitrile under hydrothennal condition. The rifle complex （C12H24Cl2Cu2N2O10） was characterized by X-ray single-crystal diffraction, IR spectrum, elemental and electrochemical analysis. It crystallizes in the monoclinic system, space group P21/c with a = 8.298004）, b = 14.358（2）, c = 12.0010（2） A^°, β= 130.620（3）°, V = 1085.3（2） A^°^3, Dc = 1.696 g/cm^3, 34, = 554.31, Z = 2, F（000） = 564 and μ = 2.254 mm^-1. The crystal structure consists of a tetraacetate-bridging dinulcear copper complex anion [Cu2Cl2（μ-CH3COO）4]^2-, with the chlorine anions in the axial positions, and two protonated acetamide cations [C2H6ON]^＋, which were connected through hydrogen bonds to form a three-dimensional infinite network.

Novel Semi-IPN Gel Electrolyte for Polymer Lithium-ion Battery

A new type of semi-IPN gel electrolyte was prepared by thermal polymerization in this article.The cross-linked PEG200 (MXPEG) was prepared by condensation reaction in the presence of methacryloxypropyltrimethoxysilane (MAPTMS),the condensation product was then blent with PMMA and polymerized to form polymer blends with semi-IPN fabric.Differential scanning calorimetry and X-ray diffraction spectroscopy were used to investigate the thermal transition behavior of the polymer blends prepared.Ion-conducting behaviors and the electrochemical stability window for semi-IPN gel electrolyte were investigated by means ofimpedance spectroscopy and linear sweep voltammetry.The Arrhenius-type relationship was observed in the temperature dependence ofionic conductivity.All the properties shows that the prepared semi-IPN gel electrolyte possesses certain levels of electrolye salt and plasticizer were expected to have applications of gel polymer electrolyte for lithium polymer secondary batteries.

Research on micro-structure and catalysis properties of nanosized Ce_(1–x)(Fe_(0.5)Eu_(0.5))_xO_(2–δ) solid solutions

Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diffraction technique, and the spectrum features were identified by UV-Vis and Raman spectroscopy, respectively. It was observed that the cell parameters were first increased then decreased by increasing the doped ions content. The phase separation was detected when the dopant concentration reached to x=0.30. UV-Vis spectrum showed that the width of the band gap gradually reduced by increasing the doped content, and the solid solubility was determined to be x=0.20. The Raman technique displayed that the peak position of F2g mode gradually shifted to lower frequencies from 465 cm^–1 for x=0.00 to 440 cm^–1 for x=0.20. The catalytic effects of Ce1-x（Fe0.5Eu0.5）xO2-δsolid solutions on the electrochemistry properties of Mg2Ni/Ni were measured by mixing them together via ball milling technique. The electrochemical properties of the Mg_2Ni/Ni-Ce1-x（Fe0.5Eu0.5）xO2-δcomposites showed that the maximum discharge capability Cmax and the cycle stability were improved obviously. Meanwhile, the EIS characteristic also indicated that the doped solid solutions could enhance the rate of charge transfer on the surface of alloy. The catalytic effect of the solid solutions was speculated to rely on both the concentration of oxygen vacancies and the cell volumes of the solid solutions.

A study on hydrogen storage and electrochemical properties of La_(0.55)Pr_(0.05)Nd_(0.15)Mg_(0.25)Ni_(3.5) (Co_(0.5)Al_(0.5))_x (x=0.0, 0.1, 0.3, 0.5) alloys

The La0.55Pr0.05Nd0.15Mg0.25Ni3.5（Co0.5Al0.5）x（x=0.0, 0.1, 0.3, 0.5） alloys were prepared by magnetic levitation melting under an Ar atmosphere, and the effects of Co and Al on the hydrogen storage and electrochemical properties were systematically investigated by pressure composition isotherms, cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy testing. The results showed that the alloy phases were mainly consisted of （La,Pr）（Ni,Co）5, LaMg2Ni9, （La,Nd）2Ni7 and LaNi3 phases, and the cell volumes of （La,Pr）（Ni,Co）5, LaMg2Ni9, （La,Nd）2Ni7 and LaNi3 phases expanded with Co and Al element added. The hydrogen storage capacity initially increased from 1.36 （x=0） to 1.47 wt.% （x=0.3） and then decreased to 1.22 wt.% （x=0.5）. The discharge capacity retention and cycle stability of the alloy electrodes were improved with the increase of Co and Al contents. The La0.55Pr0.05Nd0.15Mg0.25Ni3.5（Co0.5Al0.5）0.3 alloy electrode possessed better electrochemical kinetic characteristic.

Bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) Complexes Containing 2-Arylimidazo-phenanthroline: Syntheses, Characterization and Third-order Nonlinear Optical Properties

Four novel mononuclear ruthenium(II) complexes [Ru-(dmb) 2L] 2+ [dmb=4,4′-dimethyl-2,2′-bipyridine, L=imid-azo-[4,5-f]phenanthroline (IP), 2-phenylimidazo-phenanthroline (PIP), 2-(4′-hydroxyphenyl)imidazo-phenanthroline (HOP), 2-(4′-dimethylami- nophenyl)imidazo-phenanthroline (DMNP)] were synthesized and characterized by ES-MS, 1H NMR, UV-vis and electrochemistry. The nonlinear optical properties of the ruthenium(II) complexes were investigated by Z-scan techniques with 12 ns laser pulse at 540 nm, and all of them exhibit both nonlinear optical (NLO) absorption and self-defocusing effect. The corresponding effective NLO susceptibility |χ 3| of the complexes is in the range of 2.68×10 -12-4.57×10 -12 esu.