(684f) The Effect of Solid-Electrolyte Interphase on Lithium/Sulfur Liquid Battery Performance

Negar Mosavati, Steven O. Salleyand K. Y. Simon Ng

Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202

Lithium-Sulfur batteries (Li-S) are one of the most attractive power sources and promising candidates to replace the conventional state-of-the-art lithium ion batteries. Sulfur as a cathode active material is a by-product of petroleum and has the advantages of high natural abundance and low cost. Although a Li-S battery can deliver almost 5 fold higher theoretical capacity than lithium ion batteries (1675 mAh/g sulfur) with a theoretical specific energy (~2600 Wh/kg), it suffers from several drawbacks. The major barrier is the redox shuttle reactions in which lithium polysulfides are reduced by the Li anode and fail to reoxidize back completely to elemental sulfur at the cathode side upon charging. This leads to low active material utilization, poor capacity retention, high self-discharge and a short cycle life.

In current research, we have introduced a dense ionic conductive passivation solid electrolyte interface (SEI) layer on the Li anode, which effectively prevents soluble polysulfide penetration into the Li bulk and subsequent parasitic reactions. As a result, the redox shuttle reaction and the sulfur active material loss on the Li anode surface decreases. Consequently, the overall Li-S battery electrochemical performance and capacity retention improved substantially. In order to accomplish a profound understanding of the chemical and electrochemical aspects that influence SEI layer formation and overall Li-S battery performance, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and charge-discharge measurements have been conducted under controlled conditions.