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

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.