Steric Hindrance‐Induced Amorphous Lithium Sulfide Deposition Accelerates Sulfur Redox Kinetics in Lithium–Sulfur Batteries

Abstract

Abstract Lithium–sulfur (Li─S) batteries are promising candidates for next‐generation energy storage due to their ultrahigh theoretical energy density. However, their practical application is severely hindered by the sluggish conversion kinetics, particularly during the crystalline lithium sulfide (Li 2 S) formation stage. Herein, a steric hindrance‐mediated engineering strategy is proposed that induces an amorphous Li 2 S deposition process, effectively boosting the sulfur redox kinetics in Li─S batteries. By introducing benzo‐15‐crown‐5 (B15C5) as an electrolyte additive, a strong coordination between B15C5 and lithium ion (Li + ) is established, which creates spatial confinement around Li 2 S and disrupts the crystallinity of Li 2 S during its deposition. Synchrotron pair distribution function analysis combined with in situ X‐ray diffraction reveals that the deposited Li 2 S with B15C5 exhibits significant local disorder with irregular Li─S bond oscillations, confirming the generation of an amorphous phase. This strategy not only ensures a uniform Li 2 S layer at the cathode/electrolyte interface but also lowers the energy barrier of sulfur species at the molecular scale, enabling the Li─S batteries with excellent cycling stability and overall enhanced sulfur reaction kinetics. This work provides a novel pathway for overcoming the intrinsic limitations of sluggish cathode conversion kinetics of Li─S batteries, paving the way for their practical deployment in high‐performance energy storage applications.