An armor-like artificial solid electrolyte interphase layer for high performance lithium-sulfur batteries

Abstract

As one of the most promising next generation energy storage systems, lithium sulfur (Li-S) batteries with high specific energy density have received extensive attention due to the advantages of resource abundance, low toxicity and super high specific energy density (>2500 Wh kg−1). However, the unfavorable shuttle effect caused by dissolved polysulfides during charging/discharging processes results in low Coulombic efficiency (CE), poor interfacial stability, uncontrolled lithium dendrite growth and rapid capacity degradation, hindering the practical application of Li-S batteries. Herein, a highly stable armor-like artificial solid electrolyte interphase (SEI) layer for Li metal anode was formed based on the spontaneous interaction between Li metal and 4-chlorophenylboronic acid (CPB). First, this artificial SEI layer can avoid the direct contact between Li anode and electrolyte, therefore eliminating the corrosion reaction between Li metal anode and polysulfides in electrolyte. Second, the artificial SEI layer with high durability can effectively suppress lithium dendrite growth and stabilize Li anode/electrolyte interface. As consequence, the Li/Li symmetric cells show the lengthened cycling life over 500 h with steady and low polarization voltage under the condition of 1.0 mA cm−2 for 1.0 mAh cm−2. Furthermore, the Li-S cells with modified Li metal anode deliver superior cycling performance and higher CE at various sulfur loadings and rate conditions than those of the cells with pristine Li. This work highlights the key role of artificial SEI layer on stabilizing the Li anode, providing a new pathway for Li metal protection in Li-S batteries development.