Electrochemical properties of lithium–sulfur batteries

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 1 M LiCF3SO3 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 1 M LiCF3SO3 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 1 M LiCF3SO3 dissolved in TG/DIOX (50:50, vol.) gives the best reversibility and cycle performance.