Core-shell Ni0.5TiOPO4/C composites as anode materials in Li ion batteries

Pristine Ni0.5TiOPO4 was prepared via a traditional solid-state reaction, and then Ni0.5TiOPO4/C composites with core-shell nanostructures were synthesized by hydrothermally treating Ni0.5TiOPO4 in glucose solution. X-ray diffraction patterns indicate that Ni0.5TiOPO4/C crystallizes in monoclinic P21/c space group. Scanning electron microscopy and transmission electron microscopy show that the small particles with different sizes are coated with uniform carbon film of ∼3 nm in thickness. Raman spectroscopy also confirms the presence of carbon in the composites. Ni0.5TiOPO4/C composites presented a capacity of 276 mAh g−1 after 30 cycles at the current density of 42.7 mA g−1, much higher than that of pristine Ni0.5TiOPO4 (155 mAh g−1). The improved electrochemical performances can be attributed to the existence of carbon shell.