Enhanced Electrochemical Performance of LiFePO4 as Cathode for Lithium Ion Battery by Codoping with Titanium and Nitrogen

Titanium and nitrogen codoped LiFePO 4 was synthesized via a simple solid state reaction using TiN as the dopant source. The morphology, structure, valence state and electrochemical performance of all the samples were investigated and compared with the undoped LiFePO 4 . The results showed that the codoped samples maintained an olivine structure with modified lattice parameters and exhibited a prominent improved electrochemical performance. Among all the codoped samples, LiFe 0.94 Ti 0.04 PO 4-σ N 0.04 showed the best rate capability of 108.1 mAh g -1 even at a high rate of 5 C and exhibited a capacity retention of about 94% after 100 cycles at 1 C.