High-density Na-doped LiFePO4 synthesised by co-precipitation for lithium ion battery

Abstract

To improve the density and electrochemical performance of LiFePO4, Na-doping modified Li0·95Na0·05FePO4 cathode material was synthesised through co-precipitation method, using a spherical sample prepared by microwave heating as precursor. The morphology, structure, electrochemical performance and the tap density of the materials were characterised by scanning electron microscope, x-ray diffraction, cyclic voltammetry, constant current charge–discharge experiment and the tap density measurement. The results indicated that the samples have rules spherical or similar spherical morphology and simple pure olive-type phase. The Na-doped Li0·95Na0·05FePO4 material showed excellent performance with a tap density of 1·63 g cm−3. At room temperature, its initial discharge capacities reached 164·2, 151·5 and 130·5 mAh g−1 at 0·2, 1 and 2 C current rates, respectively.