One-Step Fabrication of Fe-Si-O/Carbon Nanotube Composite Anode Material with Excellent High-Rate Long-Term Cycling Stab
- PDF / 1,099,937 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 73 Downloads / 187 Views
One-Step Fabrication of Fe-Si-O/Carbon Nanotube Composite Anode Material with Excellent High-Rate Long-Term Cycling Stability Yun-Kai Sun†, Xue Bai, Tao Li, Gui-Xia Lu, Yong-Xin Qi, Ning Lun, Yun Tian*, Yu-Jun Bai* Key Laboratory for Liquid−Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, PR China * E-mail: [email protected] (Y.-J. Bai), [email protected] (Y. Tian) † Presenter E-mail: [email protected] (Y.-K. Sun) ABSTRACT: The composite Li-ion battery anode material of Fe2SiO4, Fe3O4, Fe3C (Fe-Si-O) and carbon nanotubes was prepared by a simple one-step reaction between ferrocene and tetraethyl orthosilicate. When cycled at 100 mA g-1, this material exhibited ever-increasing capacities and reached 588 mAh g-1 at the 280th cycle. At 500 mA g-1, a reversible capacity of 350 mAh g-1 was retained for 600 cycles. Compared with Fe3O4 materials, the Fe-Si-O/CNT exhibited superior long-term high-rate performance, which could mainly result from its enhanced stability and conductivities by introducing silicates and CNTs during the one-step synthesis.
1.
INTRODUCTION
As potential substitutes for graphite as Li-ion battery (LIB) anode material, transition metal oxide (TMO) anode materials possess priorities of high theoretical capacity, high energy density, low cost, eco-friendliness and natural abundance. However, their intrinsic problems of poor electrical and ionic conductivities, low Coulombic efficiency, large volume change and severe aggregation during cycling lead to poor high-rate cycling stability and fast capacity fading, which restrict their further applications in LIBs as anode materials [1]. To overcome these difficulties, varieties of modifications have been proposed, such as coating carbon on the surface, tailoring morphology and compositing with other materials [2-4]. Because of the beneficial carbon structure of CNTs, anode material of mechanically mixed commercial carbon nanotubes (CNTs) and Fe2O3 has been proposed recently [3]. However, some electrochemically beneficial compositions would be removed during the purification process of commercial CNTs fabricated by ferrocene catalyzed reactions [5, 6]. Recently, iron silicates have been reported by several groups as promising anode materials for LIBs due to their good structural stability, electrolyte penetration and Li-ion diffusion, which could benefit their cyclability and high-rate performance as anode materials for LIBs [7-10]. However, the investigations of silicate anode materials are still very limited up to now. In this work, we prepared a composite material with major components of Fe2SiO4, CNTs and Fe3O4 (Fe-Si-O/CNT) by one-step reaction of tetraethyl orthosilicate (TEOS) and ferrocene, which could uniformly disperse TMO particles and CNTs, produce structurally beneficial silicates and preserve the beneficial by-products in the one-step synthesis. The as-synthesized Fe-Si-O/CNT composite material demonstrated enhanced high-rate long-term performance.
Downloaded from https:/www.cambri
Data Loading...
