Li fast ion conductive La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C microspheres with enhanced high-rate performance as cathode materials

Highlights: • Various content of La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C are firstly prepared by an ammonia assisted hydrothermal route. • The inlaid La_0.56Li_0.33TiO₃ can enhance the transfer kinetics of both Li⁺ and electrons. • Among all of samples, 2 wt.% La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C shows the best rate capability and cycling stability. • La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C is an effective way to improve the performance of LiFePO₄ power battery. - Abstract: Monodisperse spherical La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C composites with various La_0.56Li_0.33TiO₃ content (from 0 wt.% to 3 wt.%) are firstly prepared by an ammonia assisted hydrothermal route. The compositions, morphology and structure of samples are characterized by means of inductively coupled plasma (ICP), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), respectively. The results reveal that nano La_0.56Li_0.33TiO₃ particles inlay on the surface of spherical LiFePO₄, which is coated by a continuous and uniform carbon layer with the thickness of 1∼2 nm. The charge/discharge tests and electrochemical impedance spectroscopy (EIS) measurements indicate that the kinetics of La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C is better than that of LiFePO₄/C. With the change of La_0.56Li_0.33TiO₃ content, 2 wt.% La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C composites reveal a excellent high-rate capability and cycling stability. The initial discharge capacity of the sample is 126.3 and 108.9 mAh/g, and the capacity retention achieves as high as 98.3% and 88.8% till 100 cycles at 5 C and 200 cycles at 10 C, respectively. Furthermore, it still exhibits a high discharge capacity of 62.3 mAh/g even at high rate of 30 C. The improved electrochemical performance of La_0.56Li_0.33TiO₃ inlaid LiFePO₄/C composites can be attributed to reduce the charge transfer resistance and enhance the transfer kinetics of both the lithium ions and electrons