Electrochemical Titanium Diboride TiB2 Synthesis from Fluoride Melts

进行燃料电池催化剂研究的仪器配置方案，荷兰IVIUM双恒电位仪Vertex.C.EIS和旋转还盘电极装置IVI.RRDE

研究领域：锂离子电池电极材料 交流阻抗频率范围：500kHz - 0.01Hz Nanoparticle–nanorod core–shell LiNi0.5Mn1.5O4 spinel cathodes for Li-ion batteries were prepared using a hollow MnO2 precursor. The core and shell parts consisted of nanoparticle
100 nm and nanorod assemblies, respectively. The core–shell cathode exhibited greatly improved discharge capacities compared to nanoparticles prepared by a sol–gel method. The core–shell spinel exhibited discharge capacities of 121 and 100 mAh/g at 0.1C and 7C rates, respectively, whereas a spinel cathode prepared by a sol–gel method exhibited 99 and 80 mAh/g at those respective rates. In addition, the core–shell spinels demonstrated an energy density value that was enhanced by 52% to 1.6 Wh/cm3 compared to an analogous sample prepared by a sol–gel method, which showed a value of 0.9 Wh/cm3.

研究领域：锂离子电池电极材料 交流阻抗频率范围：5000Hz - 0.1Hz The cycling performance of a LiNi0.8Co0.15Al0.05O2 cathode at 60°C was substantially improved by direct SiO2 dry coating. The SiO2-coated cathode was obtained from firing of the mixture consisting of SiO2 nanoparticles and the cathode powders with a weight ratio of 99:1 at 700°C for 5 h. The first discharge capacity of the coated cathode was 172 mAh/g, whereas the uncoated one showed 182 mAh/g at 60°C. However, the coulombic efficiency of the coated sample was 95%, which was 2% higher than that of the uncoated sample. Moreover, the discharge capacities of the coated cathode at 60°C was about 2.5 times larger than those of the uncoated sample at rates of 0.5 and 1C, showing 146 and 109 mA/g, respectively. This capacity improvement at 60°C is related to the fact that the highly distributed Si element near the surface, as a type of solid solution with LiNi0.8Co0.15Al0.05O2, diminishes the side reactions of the cathode and electrolyte at 60°C.

研究领域：锂离子电池固体电解质 交流阻抗频率范围：200kHz - 10mHz The impact of ambient air exposure on LiFePO4/C nanocomposites has been investigated. A pristine sample was prepared without any exposure to ambient air through the whole process of synthesis and characterization and compared to the exposed samples. A small amount of lithium deintercalates from the olivine structure during exposure, a majority of which can be electrochemically reintercalated. This phenomenon changes the initial surface and bulk properties and should be taken into account when diminishing the particle size of LiFePO4. Keeping nanocomposites away from oxidative moisture atmosphere could be a solution to minimize these side reactions.