Enhanced electrochemical performance of nano LiMnPO4 with multifunctional surface co-coating of Li2TiO3 and carbon

• Li2TiO3 and carbon co-coated LiMnPO4 with mixed conductive network is prepared.
• Co-coated LiMnPO4 has better rate and cycle performance than the pristine one.
• The capacity of 3 wt.% Li2TiO3-coated LiMnPO4 is 117.7 mAh g− 1 at 2 C between 2.5 and 4.5 V.

The nano LiMnPO4 composites with surface co-coating of Li2TiO3 and carbon have been successfully synthesized via quasi gel–sol method followed by thermal treatment. The samples have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive spectrometer (EDS), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The effect of surface coating with different amount of Li2TiO3 on the structure and electrochemical performance of LiMnPO4 is investigated. At a mass ratio of Li2TiO3/LiMnPO4 of 3%, the as-prepared products are composed of primary nanoparticles (30–50 nm), and Li2TiO3 by in-situ growing cross-links with the carbon to form the double coating on the surface of LiMnPO4. The co-coating layer of Li2TiO3/C distributes uniformly in the thickness of about 2.2 nm and 1.2 nm, respectively. Compared with the LiMnPO4/C sample, the Li2TiO3-coated LiMnPO4/C composite displays larger lithium ionic diffusion coefficient and higher cycle stability. Within, the 3 wt.% Li2TiO3-coated LiMnPO4 sample shows the best electrochemical performance, delivering the reversible capacity of 131.9, 125.8, 117.7 mAh g− 1 at 0.5, 1.0, 2.0 C, respectively, with a capacity retention of 92.9% after 240th at 2.0 C.