Preparation Of Titanium Dioxide Nanotubes Prepared By Plasma Infiltration Of C, N, Fe And Ni And Their Lithium Performance

Titanium dioxide is one of most investigated semiconductors because of its low cost, easy availability, environmental friendliness and extremely broad applications. Anatase TiO2, due to its unique crystal structure and more established synthetic conditions, has been widely studied in photocatalysis, bio-sensing, energy storage and conversion and so on. When used as anode materials for LIBs, anatase TiO2 has shown excellent electrochemical performances and improved safety. It has been demonstrated that Li+ can insert/extract from anatase TiO2 with volume variation less than 4%, which can favourable to achieving high-rate performance. More importantly, the charge/discharge voltage plateaus locate at around 1.7 V vs. Li+/Li, thereby circumventing the safety problem by avoiding the evolution of Li dendrites. However, the low electrical conductivity and Li+ diffusivity hinder its practical application as the anode materials for high-power LIBs. The present study are basically doped modified TiO2 nanotubes to improve its performance. In this paper, plasma surface alloying technology was adopted to doping metal element(Fe, Ni) and non-metallic (C, N) into TiO2 nanotubes. It’s electrochemical properties as an anode material for lithium-ion batteries (LIBs) were investigated by cyclic voltammetry, galvanostatic discharge/charge test and electrochemical impendence spectroscopy. SEM and XRD patterns show that through plasma nitriding and plasma carbon the TiO2 nanotube structure has not been destroyed, but there were no TiC or TiN phase appear. By the high resolution XPS spectra, found that C and N via Interstitial diffusion mechanism were diffusion into the TiO2 crystal lattice and replaced part of oxygen atom, forming a Ti-O-N and Ti-O-C structure. Plasma Surface nonmetallic (C, N) showed very good lithium electrochemical performance. The initial discharge capacity of plasma nitriding and carburizing TiO2 nanotubes increase from 173mAhg-1 to 240mAhg-1 and 120mAhg-1 to 150mAhg-1, respectively. The EIS show that the impedance were reduced from 17Ω to 9Ω and 180Ω to 80Ω. The metal elements (Fe, Ni) were doped into TiO2 nanotube by double glow plasma surface alloying technology. Based on the analysis of XRD and XPS spectra, Fe2O3 has a higher lithium capacity which was exist in the plasma iron TiO2 nanotube samples.But in the plasma nickel TiO2 nanotube sample there was only metal Ni without Ni oxides. The plasma nickel and iron TiO2 nanotube samples show poor performance of lithium electrochemical, not only the capacity dropped to 28 mAhg-1 and 50 mAhg-1, the impedance also increased to 400Ω.