Titania and nitrogen-doped carbon co-modification: Their synergic effects on the electrochemical performance of LiFePO4

Abstract

TiO2 and N-doped carbon co-modified LiFePO4 composites (LFP-TiO2-C-N) have been successfully synthesized by using tetrabutyl titanate (TBOT) and dopamine (DPA) as titanium and N-doped carbon sources, respectively. The LiFePO4 modification is performed by dopamine polymerization in the alkaline environment supplied by the TBOT hydrolyzation process. The resulting LFP-TiO2-C-N materials are characterized by EDS, XPS, TG, ICP and HRTEM to confirm the close adhesion of TiO2 nanoparticles and N-doped carbon layers on the LiFePO4 surfaces. The charge–discharge tests demonstrate that the LFP-TiO2-C-N composites deliver a superior initial capacity of 165.3 mAh·g−1 at 0.1 C and high rate performance with discharge capacities of 145 mAh·g−1 at 1 C and 124 mAh·g−1 at 2 C. The LFP-TiO2-C-N composites can retain 99.4% of the initial capacity after 50 cycles at 1 C, revealing a stable cycling stability. Therefore, the synergistic growth of TiO2 and N-doped carbon on the LFP surface could result in the synergic improvement in the electrochemical performance of cathode.