Shengkui Zhong

Synthesis and electrochemical properties of Ce-doped LiNi1/3Mn1/3Co1/3O2 cathode material for Li-ion batteries

Abstract The layered material of Ce-doped LiNi1/3Mn1/3Co1/3O2 with α-NaFeO2 was synthesized by a co-precipitation method. X-ray diffraction (XRD) showed that Ce-doped LiNi1/3Mn1/3Co1/3O2 had the same layered structure as the undoped LiNi1/3Mn1/3Co1/3O2. The scanning electron microscopy (SEM) images exhibited that the particle size of Ce-doped LiNi1/3Mn1/3Co1/3O2 was smaller than that of the undoped LiNi1/3Mn1/3Co1/3O2. The Ce-doped LiNi1/3Mn1/3Co1/3O2 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra (EIS). The optimal doping content of Ce was x=0.02 in the LiNi1/3–xMn1/3Co1/3CexO2 samples to achieve high discharge capacity and good cyclic stability. The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through Ce-doping. The improved electrochemical performances of the Ce-doped LiNi1/3Mn1/3Co1/3O2 cathode materials were attributed to the addition of Ce4+ ion by stabilizing the layer structure.

Synthesis of LiMnPO4/C composite material for lithium ion batteries by sol-gel method

Abstract The LiMnPO 4 /C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance tests were adopted to characterize the properties of LiMnPO 4 /C. The XRD studies show that the pure olivine phase LiMnPO 4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO 4 /C well. The LiMnPO 4 /C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA·h/g, retaining 112.4 mA·h/g over 30 cycles at 0.05 C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO 4 /C.

Synthesis and characterisation of high-performance 3Li4Ti5O12·NiO composite anode material for lithium-ion batteries

A 3Li4Ti5O12·NiO composite anode material was prepared by a spray-drying method. The physical and electrochemical properties of samples were characterised by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical test. X-ray diffraction results revealed that incorporation of NiO did not alter the structure of Li4Ti5O12. Scanning electron microscopy images of both Li4Ti5O12 and 3Li4Ti5O12·NiO exhibited spherical particles with the sizes of 0.5–3 μm. Electrochemical tests showed that the 3Li4Ti5O12·NiO composite material exhibited much better rate and cycling performances than those of Li4Ti5O12 per se. It delivered the specific capacities of 372.8, 252.6 and 204.8 mAh g− 1 at 0.1, 1 and 2°C rates, respectively. After 300 cycles, the discharge specific capacity remained as high as 202.1 mAh g− 1 at 2°C rate.