Improved cycle stability and high security of Li-B alloy anode for lithium–sulfur battery

Abstract

Lithium–sulfur (Li–S) batteries suffer from low capacity retention rate and high security risks, in large part because of the use of metallic lithium as anode. Here, by employing a Li-B alloy anode, we were able to enhance cycle performance and security of Li–S batteries. Li-B alloy has a unique structure with abundant free Li embedded in stable Li₇B₆ loofah sponge-like framework. The Li₇B₆ constituent functions in the following three aspects: (1) eliminates orientational crystallization of free lithium; (2) reduces effective current density and promotes the formation of SEI layers; and (3) protects alloy bulk materials from deformation, volume expansion or collapse when cycling.