FeF3-coated LiNi0.8Co0.15Al0.05O2 cathode materials with improved electrochemical properties

The surface of a LiNi0.8Co0.15Al0.05O2 cathode material is coated by a 10-20 nm thick FeF3layer using a solventing-out crystallization process. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results demonstrate that the morphology and structure of LiNi0.8Co0.15Al0.05O2 are not affected by FeF3 layer. Electrochemical properties of bare and FeF3-coated LiNi0.8Co0.15Al0.05O2 are investigated at room and high temperatures. Compared with bare LiNi0.8Co0.15Al0.05O2, FeF3-coated LiNi0.8Co0.15Al0.05O2 shows higher discharge capacity and capacity retention at different rates at 25 °C, in addition to better cycle performance at 55 °C. Furthermore, differential scanning calorimetry (DSC) analysis shows that the existence of FeF3coating helps to enhance the thermal stability of LiNi0.8Co0.15Al0.05O2.