Preparation Of Titanium Oxide And TB5 Oxide Nanotube Arrays And Study On The Performance Of Lithium Batteries

As the fossil fuel energy consumed year by year, lithium-ion battery, one of the renewable resource systems is increasingly being attracted by the global attention. At present, the focus of the research on the lithium-ion battery is concentrated on improving the electrode material properties, and the nano-materials with excellent performance are considered to be the breakthrough point to overcome these difficult problems. Titanium dioxide, due to its high theoretical capacity, structural stability during charge and discharge process and the advantages of abundant in nature, has become the material which can replace the traditional graphite anode electrode in lithium-ion battery. However, due to the intrinsic characteristics of titanium dioxide itself, its discharge capacity can only deliver half of the theoretical capacity, which severely restricted its practical application.Electrochemical anodic oxidation process is a method which is simple and convenient operation to prepare the one-dimensional nano-materials. It widely used in the preparation of titanium dioxide nanotube arrays. The preparation of well-aligned even-spread one dimensional nanotube arrays has big potential advantages in the application in the lithium battery industry. In this experiment, pure titanium is used as anode, using electrochemical anodic oxidation to prepare titanium dioxide nanotube arrays. Anatase and rutile mixed phases are obtained by heat treatment process. The mixed phases material are used to assembly the lithium-ion battery. The charge discharge test shows that, the mixed phases material delivers230mAh/g and210mAh/g capacities at0.1C (1C=335mA/g), which is higher than the pure anatase of185mAh/g and173mAh/g. The mixed phases electrode materials maintain180mAh/g of the specific capacity after100cycles performance. It remains its80%initial specific capacity after being shocked by rate performance and returned to its initial current density. Cyclic voltammetry test of the mixed phases shows that the electrode has two lithium transports kinetic, and electrochemical impedance spectrum test shows that the resistance of the mixed phases is bigger than the pure anatase. These electrochemical results indicate that, the anatase and rutile mixed phase structure has a better electrochemical performance in terms of the three aspects:1) the nature of the nanometer rutile titanium dioxide itself,2) the lithium ions transfer promoted by crystal defect effect during charge discharge process and the electron transfer resisted by the enlarged grain boundary.This paper also studied a kind of Ti alloy material:TB5(Ti-15V-3Al-3Sn-3Cr) The morphology of the alloy after anodic oxidation process depicts an uneven micro-structure, and the surface layer consists of not only titanium dioxide but also other oxides.XPS analysis test showed that the elements vanadium and tin in the alloy are oxidized with titanium together in the anodic process and form into V2O5and SnO2. The cyclic voltammetry tests of the anodic alloy material as the electrode show that there is more than one lithium transport kinetic mechanism in the electrode surface. The charge and discharge performance of the anodic alloy material delivers5.5μAh/cm2of the specific capacity at5μA/cm2current density. EIS test shows that the anodic alloy material is ten times of that of anodic pure titanium, In addition, V2O5and SnO2coexisted in the whole electrode made the charge/discharge capacity unstable. The anodic alloy material performed more like a positive electrode after100cycles. Although the anodic alloy material has better lithium transport kinetics, the elements combination and large of the resistance make it difficult to be used as an ideal lithium battery electrode materials. Even so, the use of titanium alloy as the raw material is still a very promising way for the preparation of more superior performance electrode materials.