Nano/micro-hierarchical-structured LiMn0.85Fe0.15PO4 cathode material for advanced lithium ion battery.

Nano/micro-hierarchical-structured LiMn0.85Fe0.15PO4/C cathode materials were prepared by solvothermal synthesis combined with spray pyrolysis. XRD patterns and HRTEM images indicate that the LiMn0.85Fe0.15PO4/C are well crystallized and no impurity is observed. The as-prepared LiMn0.85Fe0.15PO4/C porous spherical (0.5-11 m) are accumulated by primary nanoparticles (~50 nm in width, 50-250 m in length). Adopting the sucrose as a carbon source, the cathode delivers a reversible discharge capacity of 171.2 mAh g-1 at 0.1C, almost exactly its theoretical capacity (~170 mAh g-1). Moreover, the composite exhibits high cycle stability without apparent capacity fading after 100 cycles at rates of 0.1C and 1C. The outstanding electrochemical performances are partially due to Fe2+ substituting and carbon coating which improve the electrical conductivity, and importantly due to its nano/micro-hierarchical structure, where primary nanoparticles exhibit high electrochemical activity, abundant mesopores benefit electrolyte penetration and hierarchical structure ensure the cycling stability.