Compound Zn2Sn0.8Ti0.2O4 was synthesized by a hydrothermal method in which SnCl4-5H2O,TiCl4,ZnCl2 and N2H4-H2O were used as reactants.The composite Zn2Sn0.8Ti0.2O4/C was then prepared through a carbothermic reduction process using the as-prepared Zn2Sn0.8Ti0.2O4 and glucose as reactants.The structure,morphology and electrochemical properties of the as-prepared products were investigated by XRD,XPS,TEM and electrochemical measurements.In addition,electrochemical Li insertion/extraction in composite Zn2Sn0.8Ti0.2O4/C were examined by ex situ XRD and SEM.The first discharge capacity of Zn2SnO4 is about 1670.8 mA-h/g,with a capacity retain of 342.7 mA-h/g in the 40th cycle at a constant current density of 100 mA/g in the voltage range of 0.05-3.0 V.Comparing with the Zn2SnO4,some improved electrochemical properties are obtained for Zn2Sn0.8Ti0.2O4,Zn2SnO4/C and Zn2Sn0.8Ti0.2O4/C.The composite Zn2Sn0.8Ti0.2O4/C shows the best electrochemical properties,and its first discharge capacity is about 1530.0 mA-h/g,with a capacity retain of 479.1 mA-h/g the 100th cycle.
The initial nickel deposition for the direct electro le ss nickel plating on non-catalytically active magnesium alloy is critical.The s urface morphology and composition of the initial nickel plating coating are obta ined by means of the scanning electron microscopy (SEM) and the energy dispersiv e X-ray (EDS).In addition, the mass gain/loss in the initial nickel deposition process was measured by using the electro-balance.The results showed that the M gO coating was gradually corroded by the plating solution, at the same time, MgF 2 produced by F-,H+ and MgO was deposited on the substrate during the init ial electroless plating process.The nickel of the initial electroless plating wa s mostly growing on the boundary between the MgF 2 coating and the MgO coating of the activation substrate, and then came to two sides.After that, the Ni-P co ating growth rate to cover with the MgF 2 coating was prior to the MgO coating. The electroless plating was in company with the substrate corrosion,but the elec troless plating rate catalyzed by the exchanged nickel was more than the substra te corrosion rate.
