Li+/Mg2+ co-intercalation SnS2-SPAN cathode for super-stable magnesium-based batteries

• SnS 2 -SPAN hybrid cathode with strong C-Sn bond and rich defects is ingeniously constructed to realize Mg 2+ /Li + co-intercalation. • The physical and chemical double-confinement synergistic engineering of sulfurized polyacrylonitrile (SPAN) can suppress the agglomeration of SnS 2 nanoparticles and the volume expansion, simultaneously promote charge transfer and enhance structural stability. • The introduced abundant sulfur vacancies provide more active sites for Mg 2+ /Li + co-intercalation by the SnS 2 -SPAN cathode and exhibits high specific capacity and ultra-long cycling life in MLHBs. Magnesium-lithium hybrid batteries (MLHBs) have gained increasing attention due to their combined advantages of rapid ion insertion/extraction cathode and magnesium metal anode. Herein, SnS 2 -SPAN hybrid cathode with strong C-Sn bond and rich defects is ingeniously constructed to realize Mg 2+ /Li + co-intercalation. The physical and chemical double-confinement synergistic engineering of sulfurized polyacrylonitrile can suppress the agglomeration of SnS 2 nanoparticles and the volume expansion, simultaneously promote charge transfer and enhance structural stability. The introduced abundant sulfur vacancies provide more active sites for Mg 2+ /Li + co-intercalation. Meanwhile, the beneficial effects of rich sulfur defects and C-Sn bond on enhanced electrochemical properties are further evidenced by density-functional theory (DFT) calculations. Therefore, compared with pristine SnS 2 , SnS 2 -SPAN cathode displays high specific capacity (218 mAh g −1 at 0.5 A g −1 over 700 cycles) and ultra-long cycling life (101 mAh g −1 at 5 A g −1 up to 28,000 cycles). And a high energy density of 307 Wh kg −1 can be realized by the SnS 2 -SPAN//Mg pouch cell. Such elaborate and simple design supplies a reference for the exploitation of advanced cathode materials with excellent electrochemical properties for MLHBs.