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

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.