Structure and Composition Regulation of rGO-Coated SiO ₂ /TiO ₂ @C Hollow Microspheres for High-Performance Lithium–Sulfur Batteries

A novel rGO-coated, TiO 2 -decorated yolk–shell-like SiO 2 @C microsphere (STC@rGO) is synthesized and serves as a separator modification layer. In this system, a dual-oxide system of SiO 2 and TiO 2 is synergistically integrated with a dual-carbon framework consisting of carbon microspheres and rGO. The STC@rGO-modified separator efficiently suppresses polysulfide shuttling and accelerates reaction kinetics through the synergistic effects of physical confinement, chemical adsorption, and catalytic conversion toward polysulfides. The cells employing this modified separator achieve a discharge capacity of 453.2 mAh g –1 at 10 C with a 90% high sulfur loading. After 600 cycles at 1 C, the discharge capacity is maintained at 445.7 mAh g –1, with a capacity decay rate of only 0.059% per cycle. Even at a high areal sulfur loading of 3.35 mg cm –2, the cell still exhibits stable cycling performance. This study confirms the effectiveness of dual oxides and the dual-carbon framework in enhancing rate and cycling performance, providing new insights for the development of high-performance separator materials for Li–S batteries.