Synthesis, Characterization and Performance of Cu2SnSe3 for Solar Cell Application

Cu2SnSe3 (CTSe) powders were prepared by solvothermal (SR) and solid state reactions (SSR) using low cost starting materials. The crystal structure, morphology, UV-Vis absorbance, electrochemical and solar energy properties were investigated using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Electrochemical Impedance Spectroscopy (EIS) and solar energy applications using I-V characteristics measurements. A single cubic Cu2SnSe3 was obtained for the two methods of preparations. The calculated crystallite size (L) values for CTSe prepared by SR and SSR are 24.1 and 30.3 nm, respectively. UV-Vis. spectra for SR and SSR preparations showed maximum absorbencies at 240 nm with band gap (Eg) values of 0.9 and 1.4 eV, respectively. The charge transfer resistances (Rct) were equal to 3.5 and 24 for photoelectrochemical cells (PEC) and the calculated conductivities were equal to 3x10-2 and 2x10-2 S.cm for samples that prepared by SR and SSR methods, respectively. A good photoelectrochemical cell (PCE) has accomplished power conversion efficiency per unit area of about 0.84 and 0.64 % for cells prepared by SR and SSR, respectively

Synthesis and electrochemical studies on Li2CuSnO4 and Li2CuSnSiO6 as negative electrode in lithium batteries

Li2CuSnO4 and Li2CuSnSiO6 were prepared from their precursors compounds using Brij surfactant and a hydrothermal autoclave method. X-ray diffraction characterization revealed that the crystal structures of these compounds were tetragonal. Scanning electron microscope investigation showed the particle size morphology of Li2CuSnSiO6 is larger than that of Li2CuSnO4. Electrochemical impedance spectroscopy (EIS) explained that Li2CuSnO4 cell had higher charge transfer resistance (Rct = 2936Ω) than that of Li2CuSnSiO6 (38Ω). Furthermore, the reversible specific discharge capacity of the Li2CuSnSiO6 cell was 870 mAh/g in comparison with 780 mAh/g for the Li2CuSnO4 cell after 100 cycles

Preparation, characterization, and electrochemical performance of Li2CuSnO4 and Li2CuSnSiO6 electrodes for lithium batteries

Lithium copper tin silicon oxide was prepared from their precursor compounds using Brij surfactant and different sources of Si such as SiO2, SiC, and Si3N4. A hydrothermal autoclave method was used in the first stage of the preparation. X-ray diffraction characterization revealed that the crystal structures of these compounds were tetragonal. Scanning electron microscope investigation showed that the particle size morphology of Li2CuSnSiO6 is larger than that of Li2CuSnO4. Electrochemical impedance spectroscopy explained that the cell prepared from the Li2CuSnSiO6 electrode using Si3N4precursor had a lower charge-transfer resistance (38 Ω) than that of Li2CuSnO4 (Rct = 2936 Ω). Furthermore, the reversible specific discharge capacity of the Li2CuSnSiO6 cell was 870 mAh/g in comparison with 780 mAh/g for the Li2CuSnO4 cell after 100 cycles

Synthesis and electrochemical performance of Li2VxMn1-xO3 positive electrode for lithium batteries

Lithium excess manganese oxide, namely, Li2MnO3 is under investigations to improve its electrochemical performance as the next generation high capacity electrode material. Partial substitution of Mn by another metal is one of the ways to influence the properties of Li2MnO3. In the present study, vanadium is used to partially substitute Mn in various ratios. Li2VxMn1-xO3 (x = 0.1, 0.2, 0.3 and 0.4) samples are prepared by sol-gel method using stoichiometric ratios weights of Mn(CH3COO)(2)center dot 4H(2)O, Li2CO3 and NH4VO3. The crystalline phases are identified by X-ray diffraction. The particles morphology is studied with a scanning electron microscope. Furthermore, impedance measurements (EIS) are applied using frequency range between 10(6) and 10(-2) Hz. The optimum EIS is obtained with for the Li2V0.3Mn0.7O3 cell. Cyclic voltammetric measurements are carried out for the lithium manganate materials between 0.01 and 4.5 V versus Li+ with scan rate 0.1 mV s(-1). Also, galvanostatic charging and discharging cycling of the cells are achieved with the same potentials windows using charging and discharging current intensity of 10 mA g(-1) between 1.5 and 4.5 V versus Li+. It is observed that Li/Li2V0.3Mn0.7O3 cell has higher specific discharge capacity, 227 mAh g(-1) rather than the other cells

The Electrochemical Properties of Li2NixMn1-xSiO4 Cathode Material for Lithium Batteries

Li2NixMn1-xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) samples were prepared by solid state process. The structure of prepared samples of Li2NixMn1-xSiO4 is characterized by XRD. The crystal structure of the samples is orthorhombic having space group Pmn2(1). SEM investigations are carried out explaining the morphology of powders of these samples. Furthermore, electrochemical impedance spectra measurements are applied. The highest conductivity is achieved with the cell prepared from Li2Ni0.2Mn0.8SiO4 compound. Cyclic voltammetric measurements are carried out for Li2NixMn1-xSiO4 material between 0.1 and 4.5 V vs. Li+ with scan rate 0.1 mVs(-1). It is observed that Li/Li2Ni0.2Mn0.8SiO4 cell has initial capacity of 160 mAhg(-1). The cycle life performance is carried out for Li2NixMn1-xSiO4 cells. The prepared cells gave average capacities between 100 and 150 mAhg(-1)

Studies on elechtrochemical behaviour of zinc-doped LiFePO4 for lithium battery positive electrode

The effects of zinc oxide doping on LiFePO4 have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic measurements. The XRD patterns demonstrate that the samples have the phase of LiFePO4 with an ordered olivine structure indexed to the orthorhombic Pmna space group. Also, XRD patterns show with the presence of LiZnPO4 phase for zinc oxide doped samples. The EIS results showed that the conductivity is enhanced by zinc oxide doping. The 2.5% ZnO-doped LiFePO4 demonstrated higher conductivity than the 1.5% ZnO and 5% ZnO-doped LiFePO4 or the un-doped sample. The CV curves show that 2.5% ZnO-doped LiFePO4 has higher electrochemical reactivity for lithium insertion and extraction than the un-doped material. The mean redox potential is E1/2 = 3.45 V vs. Li+/Li. The first discharge curve of the 2.5% ZnO-doped LiFePO4 shows a mainly flat voltage plateau over the 3.45–3.5 V range, indicating the lithium extraction and insertion reactions between LiFePO4 and FePO4. A specific discharge capacity of about 177 mAh g−1 was achieved, with little decrease during cycling

Electrochemical behaviour of tin borophosphate negative electrodes for energy storage systems

Tin borophosphate compounds doped with antimony, Sn2BP1−xSbxO6 (x = 0–0.3), have been prepared and studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transmission infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) and galvanostatic measurements. XRD patterns of all the samples were indexed to the tetragonal system. The EIS showed that the conductivities are enhanced by antimony doping. It was observed that the Warburg impedance coefficient (σw) was 1163.265 Ω cm2 s−0.5 for the Sn2BP0.9Sb0.1O6 (x = 0.1) sample, and this was the lowest value compared to those of the other samples. Sn2BP0.9Sb0.1O6 (x = 0.1) showed the highest specific discharge capacity of 1050 mAh g−1 among all the samples and a reversible capacity of 540 mAh g−1 at the 150th cycle

Electrodeposition, characterization and photo electrochemical properties of CdSe and CdTe

CdSe and CdTe are electrodeposited using 0.1 M Cd2+ and different ion concentrations of Se and Te. The effect of the temperature on the electrodeposition process is also studied. The crystal structure of the deposited CdSe and CdTe is investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) of samples deposited at optimized parameters reveals that CdSe has spongy spherical grains while CdTe has coralloid morphology. Optical absorption shows the presence of direct transition with band gap energy 1.96 and 1.51 eV for CdSe and CdTe, respectively. The highest photo-conversion efficiencies of electrodeposited CdSe and CdTe films per unit area are 6% and 9.6%, respectively that achieved under simple laboratory conditions