Lithium-ion Battery Of Studies On Novel Anode Materials NbO And SiC

Abstract:Cubic structure of a niobium oxide (NbO) and silicon carbide (SiC) materials because of their security, stability, environmental friendly, low prices and other advantages, are expected to become new type of lithium-ion battery anode materials. NbO material was prepared by the high temperature solid phase reduction method. SiC powder was direct purchased as raw material. XRD, SEM、laser particle size test、CV、EIS and galvanostic charge/discharge were used to studie physical properties and electrochemical properties of the material, and preliminarily explores the intercalated-li dynamics process of two kinds of materials. The main conclusions are as follows:(1) The NbO electrode materials were successfully synthesized by high temperature solid phase method using Nb powders and Nb2O5powders as raw materials. Through ball mill processing, NbO powder distribution more uniform and reduce the powder particle size, improving the electrochemical properties of materials. For the first discharge, a capacity of355mAh·g-1was obtained at a current of0.1C rate, and293mAh·g-1was maintained after50cycles. NbO material average Li storage voltage is nearly located at1.6V and the lithium intercalation into NbO remains a single phase process.(2) Using directly purchase the silicon carbide as raw materials. Through the ball milling, the initial discharge capacity of SiC electrode at0.02C is as high as468mAh·g-1, after50cycles, there are still335mAh·g-1of the reversible capacity, the irreversible capacity loss is28.4%. Under the condition of different ratios, the capacity of the SiC electrode retention rate is quite high. SiC material average Li storage voltage is nearly located at0.8V. The reaction mechanism of lithium with SiC was investigated by ex situ XRD studies. The results showed that the lithium intercalation into SiC remains a single phase process.(3) Three electrochemical analyses techniques, PITT, CV and EIS, have been employed to determine the chemical diffusion coefficient of Li ions in NbO and SiC electrode materials. The results show that the lithium diffusion coefficients calculated from the PITT measurement of NbO material is in the range of2.09℃10-10to5.33×10-11cm2·s-1. The CV measurement gives the lithium diffusion coefficients of NbO material in oxidation and reduction process are1.55×10-12and1.25×10-12cm2· s-1, respectively. Two methods of test results are similar, which means NbO electrode has good intercalation/deintercalation reversible ability. And the EIS measurement provides the lithium diffusion coefficients of SiC material is in the range of6.2×10-13to7.9×10-13cm2·s-1. The transfer resistance Rct had a minimum of265.4Ω in the0.8V, which indicates that the SiC electrode likely to occur interface charge transfer near by the potential platform.Research results show that both NbO and SiC materials could be used as novel anode materials for lithium ion batteries, and have certain prospect of industrialization.In this paper, there are39images,9tables and163references.