Bo Jin

Electrochemical properties of lithium–sulfur batteries

Abstract Lithium–sulfur cells are fabricated in a dry room, and comprise a positive (cathode) active material of sulfur, a negative (anode) active material of lithium metal, and an electrolyte of 1xa0M LiCF 3 SO 3 dissolved in tetraglyme (TG)/1,3-dioxolane (DIOX). For types of electrolyte with different contents of TG and DIOX are prepared. The electrochemical properties of the batteries are analyzed by scanning electron microscopy, cyclic voltammetry, ac impedance experiments, and charge–discharge tests. The conductivity of the four different electrolytes are investigated. The conductivity of an electrolyte of 1xa0M LiCF 3 SO 3 dissolved in TG/DIOX (50:50, vol.) is greater than that of the other three types of electrolyte with different volume ratios (70:30, 30:70) and a single solvent (TG). A cell with 1xa0M LiCF 3 SO 3 dissolved in TG/DIOX (50:50, vol.) gives the best reversibility and cycle performance.

Structural and Electrochemical Characterization of LiFePO 4 Synthesized by Hydrothermal Method

Phospho-olivine cathode materials were prepared by hydrothermal reaction. Carbon black was added to enhance the electrical conductivity of . The structural and morphological performance of and -C powders were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). /Li and -C/Li cells were characterized electrochemically by cyclic voltammogram (CV), charge/discharge experiments and ac impedance spectroscopy. The results showed that the discharge capacity of /Li cell was 147 mAh/g at the first cycle and 118 mAh/g after 30 cycles, respectively. The discharge capacity of -C/Li cell with 5 wt% carbon black was the largest among -C/Li cells, 133 mAh/g at the first cycle and 128 mAh/g after 30 cycles, respectively. It was demonstrated that cycling performance of -C/Li cell with 5 wt% carbon black was better than that of /Li cell.

A Novel Sulphur Cathode Materials for Rechargeable Lithium Batteries

Lithium-sulphur batteries were fabricated in a dry room, and their electrochemical properties were analyzed by scanning electron microscopy (SEM), cyclic voltammetry (CV), and charge-discharge tests. SEM results showed that sulphur and nanocarbon powders were mixed homogeneously, and sulphur powders were enwrapped by a large amount of carbon powders. The charge-discharge test results demonstrated that the lithium-sulphur battery displayed excellent reversibility and cycling performance, which supplied a discharge capacity of at the first cycle and after 71 cycles at room temperature, respectively.