Recent Advances of Functional Electrolyte Additives for Lithium-Sulfur Batteries

Xiuqing Zhang, College of Chemistry, Zhengzhou University, Zhengzhou, PR China
Shuai Tang, College of Chemistry, Zhengzhou University, Zhengzhou, PR China
Yongzhu Fu, College of Chemistry, Zhengzhou University, Zhengzhou, PR China

Abstract

Lithium-sulfur (Li-S) batteries have become one of the most promising next-generation battery systems due to the high energy density and low cost. However, the application of Li-S batteries still faces critical challenges, such as the low conductivity of S and Li2S, shuttle effect of polysulfides and dendrite growth of Li etc. The optimization of the electrolyte can ameliorate the electrolyte|electrode interphase, conveniently regulating the parasitic reaction and improving the performance of the resultant batteries. The functional additives in electrolytes provide chances to tune the interphase and even the redox mechanism to improve the performance of the batteries. In this review, we systematically summarize the latest progresses of additives for Li-S batteries and the additives are classified according to the category that the effects of the additives lie on the protection of Li metal anode or the stabilization of the S cathode. The functions of additives on the S cathode such as the inhibition of the dissolution and shuttle of the polysulfides, the redox mediators, the activation and of Li2S deposits are discussed in details. Finally, the prospects of additives for Li-S batteries are supplied in brief. We hope the review can supply a guidance for the design of electrolyte for high-performance Li-S batteries.