Electrochemical performance of nano-LiFePO4 embedded ordered mesoporous nitrogenous carbon composite as cathode material for Li-ion battery applications

We report here the preparation and electrochemical characterization of nano-sized LiFePO4, starting from Fe(III) precursor, embedded in ordered mesoporous nitrogenous carbon (LFP/MNC-31). For comparison, LFP nanoparticles embedded in nitrogen-free ordered mesoporous carbon (LFP/CMK-3) was also prepared and studied. Both these composites were characterized using XRD, FT-Raman, TEM, SEM and nitrogen sorption studies prior to electrochemical testing. The ordered and mesoporous nature of the carbon in the composites was established by small-angle XRD and BET isotherms. Reitveld refined XRD data reveals single phase formation of LFP with good crystallinity. TEM studies show that the LFP nanoparticles are embedded in the mesopores of the carbon matrix. Electrochemical studies in half-cell mode (vs. Li+ /Li) reveal that the Li-ion diffusion coefficient values in the composites are remarkably higher (6-7 orders of magnitude) compared to pristine LFP. Furthermore, the LFP/MNC-31 composite shows relatively better electrochemical properties in terms of specific capacity, rate capability and cyclic stability vis-a-vis LFP/CMK-3 highlighting the importance of nitrogen doping in the carbon matrix in enhancing the electrochemical performance.