Nitrogen-Doped Carbon Coated Lithium Titanate (LTO) By Simple Reflux Method for High Power Energy Storage Devices

Wednesday, 27 May 2015
Salon C (Hilton Chicago)
D. H. Long (Korea University of Science and Technology, Korea Institute of Science and Technology), M. K. Jeong (Korea Institute of Science and Technology), I. H. Oh (Korea Institute of Science and Technology, , Korea University of Science and Technology), and H. G. Jung (Korea University of Science and Technology, Korea Institute of Science and Technology)
Nitrogen doped carbon which is homogeneous coated on lithium titanate (Li4Ti5O12, LTO) is prepared via a facile chemical refluxing process with use of ethylenediamine (EDA) solution as the carbon and nitrogen source. The process incorporates a carbon coating layer doped with a relatively high nitrogen content which formed a conducting network in LTO matrix. Moreover, the introduction of N-dopant in the carbon layer leads to buckling up on the surface with a certain higher variation for the carbon atoms against the carbon layer itself, thereby relates to the lattice mismatch of two materials which are absorbed carbon layer and LTO. It is a process of the production of more C-vacancies, and correspondingly this resulted to the improvement of the lithium diffusion. Furthermore, the increasing of electrical conductivity is also caused by the reduction of Ti4+ to more conducive phase, Ti3+ which is ascribed to the presence of Ti-N phase. The nitrogen doped carbon coated LTO (LTO-NC) anode exhibits significantly improved rate capability and cycling performance compared with the pristine LTO in a half cell of Lithium-Ion battery. The specific capacity of LTO-NC at charge/discharge rate of 20C is 127.31 mA h g-1. Additionally, LTO-NC anode achieved high capacity retentions of 97% and 86.94% at 1C and 10C rates after 100 cycles, respectively.