Hydrothermal Synthesis Of Lithium Ion Battery Electrode Materials And Performance Analysis

Liquid lithium-ion batterys (LIBs) have been widely used in various electronic devices since its successful development in 1990, because they have the merits of high voltage, large energy density, large application temperature range, low self-discharge rate, long-life performance, free from contamination and no memory effect. In this dissertation, three lithium-ion battery electrode materials are synthesized through a hydrothermal process. These materials are characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scan electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adso rption/desorption analysis; still these electrodes are investigated by constant current charge-discharge test at room temperature, AC impedance, cycle voltammagram (CV), and other electrochemical test methods, thus we observe the impact on the performance of these electrode materials synthesized through different hydrothermal preparation process. The research mainly includes the following parts:1. Preparation and electrochemical properties of tetroxide iron/carbon nanocomposites. Tetroxide iron/carbon nanocomposites, particles average-20nm in diameter, are synthesized by a hydrothermal treatment under alkaline conditions. The paper discusses the effect of formaldehyde and mercaptophenol raw material proportion, pH value of the solution, sintering atmosphere, sintering time and the presence of mercaptophenol on the morphology and electrochemical properties of tetroxide iron/carbon electrode materials.2. Preparation and electrochemical properties of lithium titanate (Li4Ti5O12) and composite materials. Lithium titanate, lithium titanate/graphene and lithium titanate/iron (?) nanocomposites are synthesized by hydrothermal reaction and subsequent heat treatment. The amount of graphene in lithium titanate/graphene nanocomposites is 10mg, and this electrode shows the high first discharge capacity of 160.9mAh/g at IOC. After 100 cycles, there are still 120mAh/g specific capacity; Charge and discharge lithium titanate/iron (?) electrode also shows the high specific capacity at IOC. There are still 150mAh/g after 50 cycles. These composite electrodes of lithium titanate show a higher magnification of the rapid charge-discharge characteristics and good electrochemical cycling performance.3. Preparation and electrochemical properties of V2O5-SnO2/CNTs nanocomposites. We proposed a hydrothermal reaction synthesis of porous V2O5-SnO2/CNTs nanocomposite electrode. The electrode combines nano-architecture with carbon nanotube conductive network architecture design, shows good electrochemical cycling performance. The rate performance and cycling performance of the V2O5-SnO2/CNTs nanocomposites electrode is much better than that of commercial V2O5 electrode. The electrode shows the first discharge capacity of up to 250mAh/g at the current density of 100mA/g.