Carbon coated nano-sized LiMn0.8Fe0.2PO4 porous microsphere cathode material for Li-ion batteries

Carbon coated nano-sized LiMn0.8Fe0.2PO4 (LMFP) microspheres are synthesized by a modified spray drying process. This material shows a microsphere of 10–20 μm in diameter and with a primary particle of 100 nm and a carbon-coated layer (5 nm) on the particle. The material exhibits a very good rate capability and superior cycling stability as a cathode material for LIBs. This cathode material delivers a discharge of 140 mA h g−1 at 0.2C and 110 mA h g−1 at 10 C rate in the voltage range of 2.7–4.3 V. It keeps a capacity retention of 90.2% after 200 cycles at 0.2 C at 25 °C and 95.0% after 100 cycles at 1 C rate at 55 °C. Differential scanning calorimetry (DSC) experiment confirms that the thermodynamics stability of the blended electrode of LMFP and LiNi0.6Mn0.2Co0.2O2 (NMC) is improved compared with the pure NMC. Also, the LMFP/NMC composite material can achieve a suitable capacity and good cycling stability.