Engineering Functional Interface with Built‐in Catalytic and Self‐Oxidation Sites for Highly Stable Lithium–Sulfur Batteries

Lithium−sulfur (Li−S) batteries have attracted great attention due to their high theoretical energy density. The rapid redox conversion of lithium polysulfides (LiPS) is effective for solving the serious shuttle effect and improving the utilization of active materials. The functional design of the separator interface with fast charge transfer and active catalytic sites is desirable for accelerating the conversion of intermediates. Herein, a graphene‐wrapped MnCO3 nanowire (G@MC) was prepared and utilized to engineer the separator interface. G@MC with active Mn2+ sites can effectively anchor the LiPS by forming the Mn−S chemical bond according to our theoretical calculation results. In addition, the catalytic Mn2+ sites and conductive graphene layer of G@MC could accelerate the reversible conversion of LiPS via the spontaneous “self‐redox” reaction and the rapid electron transfer in electrochemical process. As a result, the G@MC‐based battery exhibits only 0.038 % capacity decay (per cycle) after 1000 cycles at 2.0 C. This work affords new insights for designing the integrated functional interface for stable Li−S batteries. More than a separator: An integrated functional interface on separator of lithium−sulfur battery is fabricated with graphene‐wrapped MnCO3 nanowires (G@MC). The G@MC possesses “built‐in” catalytic Mn2+ sites and good electronic conductivity, which endows the batteries with fast kinetic conversion of polysulfides and rapid electron transfer in electrochemical process. The reversible and strong chemical interaction between intermediates and G@MC is beneficial for achieving enhanced cycling stability and rate capability.