Addressing electrode passivation in lithium–sulfur batteries by site‐selective morphology‐controlled Li2S formation

Abstract The sulfur utilization efficiency of lithium–sulfur batteries is often limited by the uncontrolled electrodeposition of the insulating Li 2 S and the resulting electrode passivation. Herein, purposeful electrode and electrolyte design is used to realize site‐selective three‐dimensional (3D) Li 2 S electrodeposition and thus mitigate the above problem. Site‐selective Li 2 S nucleation is induced at the tips of CoP nanoneedles grown on a carbon cloth electrode, and the 3D growth of Li 2 S at these tips without the passivation of the inner part is achieved using a LiBr‐containing high‐donor‐number electrolyte. The controlled Li 2 S morphology is rationalized by considering the tip effect, the energy of Li 2 S binding on the electrode surface, and the solubility of Li 2 S in the electrolyte. Owing to the suppressed electrode passivation, CoP nanoneedle–decorated carbon cloth electrode and LiBr‐containing electrolyte deliver a capacity of >1400 mAh g s −1 at a current density of 0.33 A g s −1 . Thus, this work paves the way for the active control of Li 2 S morphology for high‐performance lithium–sulfur batteries. image