Vertically Aligned Binder-Free TiO2 Nanotube Arrays Doped with Fe, S and Fe-S for Li-ion Batteries.

Suriyakumar Dasarathan,Jun-Woo Park,Mukarram Ali,Tai-Jong Jung,Doohun Kim,Yoon-Cheol Ha,Junghwan Sung

doi:10.3390/nano11112924

Abstract

Vertically aligned Fe, S, and Fe-S doped anatase TiO2 nanotube arrays are prepared by an electrochemical anodization process using an organic electrolyte in which lactic acid is added as an additive. In the electrolyte, highly ordered TiO2 nanotube layers with greater thickness of 12 μm, inner diameter of approx. 90 nm and outer diameter of approx. 170 nm are successfully obtained. Doping of Fe, S, and Fe-S via simple wet impregnation method substituted Ti and O sites with Fe and S, which leads to enhance the rate performance at high discharge C-rates. Discharge capacities of TiO2 tubes increased from 0.13 mAh cm−2(bare) to 0.28 mAh cm−2 for Fe-S doped TiO2 at 0.5 C after 100 cycles with exceptional capacity retention of 85 % after 100 cycles. Owing to the enhancement of thermodynamic and kinetic properties by doping of Fe-S, Li-diffusion increased resulting in remarkable discharge capacities of 0.27 mAh cm−2 and 0.16 mAh cm−2 at 10 C, and 30 C, respectively.

Highlights

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Titanium based oxides have drawn great attention in the lithium ion battery (LIB). World because of their superior thermal stability compared with the conventional graphite anode
The electrochemical performance and the reversible capacity of titanium-based oxides mainly depend on their microscopic structure, morphology, and particle size [2]

Summary

Introduction

Titanium based oxides have drawn great attention in the lithium ion battery (LIB). World because of their superior thermal stability compared with the conventional graphite anode. This class of active material shows other interesting features such as low cost, non-toxicity, and small volume change process (2–3%) during the lithium insertion and extraction, along with an excellent cycling life [1]. The electrochemical performance and the reversible capacity of titanium-based oxides mainly depend on their microscopic structure, morphology, and particle size [2]. The nanostructured titanium oxide leads to a superior capacity, longer cycling life, and higher rate capacity than bulk TiO2 [2,3]

Methods

Results

Conclusion