| Lithium-ion batteries are widely used in portable electronic devices and electric vehicles, because of high energy storage density, high voltage, little self-discharge, large specific capacity, long cycle life, no memory effect, pollution-free to environment, and so on. The electricity storage ability of Li-ion rechargeable batteries critically depends on the selection of electrode material, in particularly the anode material. In present commercial lithium-ion batteries, various carbon materials, such as graphite, coke, are widely used as an anode material. However, as the voltage of lithium intercalation into carbon materials closes to lithium metal, some Li-ions may deposit on the surface of the anode leading to lithium dendrite and hence safety concerns. On the other hand, SEI (Solid Electrolyte Interface) Film is essential to form for carbon electrode on the first charge cycle, which leads to a large irreversible capacity loss.And also, the SEI film formation may increase the impedance of electrode/electrolyte interface, and don't facilitate the reversible insertion and extraction of Li-ions. The anode materials of present have reached their ultimate properties, what's more, these disadvantages of carbon materials improve the development of a new material technology becomes an urgent task for the lithium ion batteries. So looking for new type anode materials with better safety performance, higher specific capacity and longer cycle life, becomes hotspot in the research for lithium ion batteries. As a kind of tin-zinc composite oxide, for example, Zn2SnO4,ZnSnO3,CaSnO3,Ca2SnO4 and Mg2SnO4. Relatively cheap and do not pollute the environment, based on morphology and crystal structure with different binary and ternary iron oxides, for example, Fe2O3,Fe3O4,FePO4,ZnFe2O4 and CoFe2O4. Among these materials, Zn2SnO4 and ZnFe2O4 are paid more attention because of their advantages such as high theoretical specific capacity, low cost, no toxicity.During the past few years, Zn2SnO4 and ZnFe2O4 have been successfully synthesized by various methods, such as thermal evaporation, sol-gel route, high-temperature calcinations, hydrothermal method, etc. Nevertheless, the electrochemical features of Zn2SnO4 prepared by a solid state reaction at 800oC and ZnFe2O4 prepared by hydrothermal method have rarely been reported. In this paper, Zn2SnO4 and ZnFe2O4 with good electrochemical properties were synthesized by a solid state reaction and hydrothermal method, which are convenient, low-cost and easily adapt to mass production.In recent years, Zn2SnO4 and ZnFe2O4 have attracted widespread attention, because the large specific surface area can buffer the process of charging and discharging volume changes, reduce the distance over which Li+ must diffuse in the material, facilitate the reversible insertion and extraction of Li-ions, better to release the strain during lithium insertion and extraction, prolong the cycle life, and the larger electrode/electrolyte contact area increases the charge/discharge rate. Comparatively, Zn2SnO4 and ZnFe2O4 electrode materials have more excellent electrochemical properties than traditional anode electrode material. They are very promising anode material for lithium-ion batteries, because their preparation methods are simple, and they have a higher surface area and can provide more lithium intercalation location.The inverse spinel structure Zn2SnO4, with good electrochemical properties and simple preparation method which is convenient, low-cost and easily adapt to mass production, might be promising for high energy density LIBs. In this thesis, on basis of the preparation of Zn2SnO4 as well as the condition of our lab, we synthesized Zn2SnO4 and ZnFe2O4 by solid state reaction and hydrothermal, the study have been done about the electrochemical properties of lithium insertion as follows:1. Zn2SnO4 and ZnFe2O4 were synthesized by solid state recation. The charge capacities of the product at different treating temperature were studied. The result showed that, the appropriate solid-phase reaction time was 3 hours and 6 hours, the Zn2SnO4 formed at 800oC and 900 oC in air, still have good thermal stability, to maintain its shape unchanged. And the charge capacity of the obtained material in 800 oC is higher than its capacity at 900 oC. Simultaneously, the charge and discharge performance of the ZnFe2O4 formed at 800 oC is the best.2. The electrochemical performance of Zn2SnO4 prepared by hydrothermal treatment was studied. The experimental results showed that, the Zn2SnO4 exhibited excellent in capacity and rate capability in comparison to others. But there are still large irreversible capacities in the first cycle.3 By comparison of the electrochemical properties of ZnFe2O4 prepared by hydrothermal synthesize and solid state reaction, the result showed that, the electrochemical properties and capacity retention obtained by hydrothermal synthesize is better than that of solid state reaction.
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