A Collaboratively Polar Conductive Interface for Accelerating Polysulfide Redox Conversion

In order to alleviate the inferior cycle stability of the sulfur cathode, a self-assembled SnO₂-doped manganese silicate nanobubble (SMN) is designed as a sulfur/polysulfide host to immobilize the intermediate Li₂S _x, and nitrogen-doped carbon (N-C) is coated on SMN (SMN@C). The exquisite N-C conductive network not only provides sufficient free space for the volume expansion during the phase transition of solid sulfur into lithium sulfide but also reduces R_ct of SMN. During cycling, the soluble polysulfide could be fastened by the silicate with an oxygen-rich functional group and heteronitrogen atoms through chemical bonding, enabling a confined shuttle effect. The synergistic effect between N-C and SMN could also effectively facilitate the interconversion between lithium polysulfides and Li₂S, reducing the potential barrier and accelerating the redox kinetics. With an areal sulfur loading of 2 mg/cm², the S-SMN@C cathodes demonstrate a high initial capacity of 1204 mA·h/g at 0.1 C, and an outstanding cycle stability with a capacity fading rate of 0.0277%, ranging from the 2nd cycle to the 1000th cycle at 2 C.