Unveiling the autocatalytic growth of LiS crystals at the solid-liquid interface in lithium-sulfur batteries.

Electrocatalysts are extensively employed to suppress the shuttling effect in lithium-sulfur (Li-S) batteries. However, it remains challenging to probe the sulfur redox reactions and mechanism at the electrocatalyst/LiPS interface after the active sites are covered by the solid discharge products LiS/LiS. Here, we demonstrate the intrinsic autocatalytic activity of the LiS (100) plane towards lithium polysulfides on single-atom nickel (SANi) electrocatalysts. Guided by theoretical models and experimental data, it is concluded that LiPS dissociates into LiS and short-chain LiPS on the LiS (100) plane. Subsequently, LiS undergoes further lithiation to LiS on the LiS (100) surface, generating a new LiS (100) layer, thus enabling the autocatalytic formation of a new LiS (100) surface. Benefiting from the autocatalytic growth of LiS, the concentration of LiPS in the electrolyte remains at a lower level, enabling Li-S batteries under high loading and low electrolyte conditions to exhibit superior electrochemical performance.