Preparation Of Silicon-based Nanostructured Arrays For Lithium-ion Battery Anode Materials Through Voltage-control Technique And Their Electrochemical Performance

The development and application of new clean energy with high energy densities become one of the hotspot in the field of new energy resource because of the increasingly serious energy crisis and the growing demand for energy devices.Among them,lithium-ion batteries show a wide range of applications in a variety of electronic equipment,electric vehicles and many other fields due to its advantages of high energy density,high working voltage etc...Silicon-based anode material for lithium-ion batteries has high theoretical specific capacity(4200 mAh g-1)and low lithium de-lithiation potential(<0.5 V),which makes it one of the most promising anode materials for high-quality lithium-ion batteries.However,the volume expansion of silicon material in the process of lithium ion insertion and extraction and the low conductivity greatly limit the wide application of silicon-based anode material for lithium-ion batteries.The main purpose of this work is to reduce the volumetric effect of silicon material during the charge/discharge process,and improve the electrical conductivity of the electrodes material,thus can enhance the electrochemical performance of the silicon-based anode material for lithium-ion batteries.Concrete content is as follows:(1)The three-dimensional TiO2 nanorod array was prepared by spin-coating and hydrothermal methods.Amorphous silicon films were sputtered onto TiO2 nanorod arrays through Rf-sputtering method.The Ti-Li2O@Si core-shell nanorod arrays were prepared by voltage-controlled technique,preventing the Li+extraction during the charge process.Compared to the planar Ta@Si electrodes,the Ti-Li2O@Si core-shell nanorod array electrodes have greatly improved its electrochemical properties,such as cycle performance and rate performance.Its discharge capacity remains 1164 mAh g-1 after 150 cycles.(2)NiO nanowall arrays were grown in-situ on Ni foam substrate through hydrothermal and high-temperature solid state reaction methods.The preparation of the Ni-Li2O@Si core-shell nanowall arrays was performed in the way similar to Ti-Li2O@Si.The electrochemical performance of the Ni-Li2O@Si core-shell nanowall arrays electrodes,such as cycle performance and rate performance,was improved compared to the planar Ni@Si electrodes.Even compared to the Ti-Li2O@Si core-shell nanorod arrays electrodes,the electrochemical performance of Ni-Li2O@Si ishow the discharge capacity of 1690 mAh g-1 after 500 cycles.