In order to improve the electrochemical performance of FePO 4, the method of Cr 3+ ion-doped FePO 4 was proposed in this paper. FePO 4 and doped Fe 1-x Cr x PO 4 (x = 0.02,0.04,0.06 and 0.08) were prepared by homogeneous co-precipitation followed by spray drying method, and then the samples were sintered at different temperatures (380°C, 460°C, 550°C and 650°C). Physical-chemical properties were characterized by using thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscope (SEM); electrochemical behavior of the samples were analyzed using charge–discharge test, electrochemical impedance spectroscopy (EIS). The results indicated that the Cr 3+ doping can effectively improve the electrochemical performance of FePO 4. Fe 0.96 Cr 0.04 PO 4 sintered at 460°C showed the highest specific capacity of 109.7 mAh/g for the 1st cycle at 0.05 C. In addition, the doping mechanism for FePO 4 was discussed in this paper.

Copper (Cu) nanofilms have been prepared on a molybdenum (Mo) substrate by the electrodeposition method from the electrolyte solutions of copper sulfate (CuSO4) and trisodium citrate (C6H5Na3O7) added by surfactant PEG-6000. The growth kinetics and microstructures of films were investigated by cyclic voltammetry (CV), chronoamperometry (CA), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Cyclic voltammetry and chronoamperometry clearly show that the electrodeposition is controlled by the diffusion process of copper ions. By means of Scharifker-Hills model, the Cu nucleation mechanism in 0.1mol/l CuSO4 and 0.2 mol/l C6H5Na3O7 solution is revealed to be an instantaneous nucleation. Potential, solution concentration and organic additive have an influence on the microstructure of copper film. SEM and AFM results show a uniform copper layer with 7.7 nm roughness can be fabricated when deposition charge quantity is 0.7 C/cm2 at −0.7 V vs SCE.

Tin (Sn) films have been prepared on a molybdenum substrate covered with copper (Mo/Cu) by the electrodeposition method from the electrolyte solutions of tin sulfate (SnSO 4 ) and trisodium citrate (C 6 H 5 Na 3 O 7 ). The formation mechanism and microstructures of the films were investigated by cyclic voltammetry (CV), chronoamperometry (CA), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The CV and CA measurements show the electrodeposition is controlled by the diffusion process of tin ions. By means of Scharifker-Hills model and microstructural analysis, the Sn nucleation mechanism is clarified to be an instantaneous nucleation mechanism. The influence of deposition time, solution concentration and the potential on microstructures of Sn films has been systematically investigated and the optimal growth parameters for preparing dense Sn films are obtained.In recent years, Cu 2 ZnSnS 4 (CZTS), as the most promising photovoltaic absorbing material for solar cells, has been intensively investigated due to the adaptable bandgap and large optical absorption coefficient. 1-3 Generally, the preparation of CZTS films involves two steps: synthesis of precursors and heat-treatment of the prepared precursors in Se or S atmosphere. So far, the preparation methods of the precursors have been divided into two categories: vacuum and non-vacuum techniques. Vacuum-based fabrication techniques involve sputtering or evaporation of target sources on a substrate. 4-6 Non-vacuum-based processes can be done by electrochemical deposition, spin coating of precursor solution and spray pyrolysis. 7-10 Presently, the research works focus on the preparation of high quality films with large sizes and uniform composition in order to improve device performance. The electrodeposition method is advantageous for the preparation of metallic films, e.g., low cost, low operation temperature (room temperature), easy controllability and good compatibility with large-scale industrial production. 11 It is worthy to note that the metallic films on foreign substrates by the electrodeposition method have been widely used for magnetic recording devices and the interconnection for integrated circuits. [12][13][14][15] There are also many reports about the preparation of CZTS films by electrodeposition. For example, S. Ahmed et al. fabricated CZTS solar cells with the conversion efficiency of 7.3% by a layer-by-layer electrodeposition. 7 According to the stack sequence, these techniques include layer-bylayer electrodeposition or one step co-electrodeposition. Regardless of the technique, however, smooth surface, controllable element proportion and film thickness are required for the CZTS films used for solar cells which are dramatically affected by growth parameters such as deposition potential, solution concentrations, and the types of additives and substrates. Therefore, it is necessary to study the electrodeposition process to obtain the optimized experimental conditions.In the process of preparing CZTS precursors by electroch...

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Zinc (Zn) films have been prepared on a molybdenum (Mo) substrate by the electrodeposition method from the electrolyte solutions of zinc chloride (ZnCl 2 ) and potassium chloride (KCl) added by surfactant PEG-6000. The influence of growth conditions on growth kinetics, morphologies and phase constitution of the films were investigated by cyclic voltammetry (CV), chronoamperometry (CA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Based on Scharifker-Hills model and microstructural analysis, it is found that the electrodeposition process of Zn films is mainly controlled by the diffusion process of zinc complex ions, and both progressive and instantaneous nucleation mechanisms are revealed and it is dependent on growth conditions such as main salt ZnCl 2 concentration and organic additive.