Abstract
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 Li(2)S/Li(2)S(2). Here, we demonstrate the intrinsic autocatalytic activity of the Li(2)S (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 Li(2)S(2) and short-chain LiPS on the Li(2)S (100) plane. Subsequently, Li(2)S(2) undergoes further lithiation to Li(2)S on the Li(2)S (100) surface, generating a new Li(2)S (100) layer, thus enabling the autocatalytic formation of a new Li(2)S (100) surface. Benefiting from the autocatalytic growth of Li(2)S, 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.