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

Titanium and nitrogen codoped LiFePO4 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 LiFePO4. 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, LiFe0.94Ti0.04PO4-σN0.04 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.