Effects of LiNO3 additive on the electrochemical properties of lithium-sulfur batteries

Abstract

Lithium-sulfur batteries are considered to very attractive candidates due to their high energy density of 2,600 Wh/kg [1-3]. Elemental sulfur has the highest theoretical capacity of cathode material for lithium secondary batteries compared to other materials. Although lithium-sulfur batteries have many advantages, the utilization of sulfur can be limited unless the electrolyte is suitable [4-6]. The sulfur forms various lithium polysulfides (Li2Sn) as a result of reduction during the discharge. Due to their high solubility in the organic electrolyte, polysulfide anions are easy to dissolve into the electrolyte and react with lithium anode. Therefore, the cycling efficiency and cycle life of lithium-sulfur batteries are rather poor. Among the components of lithium-sulfur batteries, electrolytes play an important role in improving not only the cycle efficiency but also the cycle stability. In this work, we examine an electrolyte system based on a binary mixture of tetra(ethylene glycol)dimethyl ether(TEGDME) and 1,3-dioxolane(DOL) with different volume ratios using various lithium salts. We also investigated the effects of LiNO3 additive on the electrochemical properties of lithium-sulfur batteries in binary electrolytes.