Preparation of Enhanced-Performance LiMn0.6Fe0.4PO4/C Cathode Material for Lithium-Ion Batteries by using a Divalent Transition-Metal Phosphate as an Intermediate

The olivine-structured LiMn0.6Fe0.4PO4/C composite is an alternative cathode material for lithium-ion batteries with excellent high-rate capability and cycle stability. A facile synthesis is achieved by applying a divalent transition metal phosphate as intermediate, spray drying, and annealing. A phosphate hydrate with a low degree of crystallinity is coprecipitated and characterized by XRD and SEM. SEM and TEM investigations show that the LiMn0.6Fe0.4PO4/C particles are porous microspheres with a diameter of 2-5 mu m, and that the primary nanoparticles are wrapped by a 4-6nm-thick carbon layer. Compared with LiFePO4/C and LiMnPO4/C, the LiMn0.6Fe0.4PO4/C microspheres exhibit higher energy density and enhanced discharge capacities of 156, 147, and 133mAhg(-1) at 0.1, 1 and 10C, respectively, as well as excellent cycle performance at high rates.