Interlayer Engineering of VS 2 Nanosheets via In Situ Aniline Intercalative Polymerization toward Long-Cycling Magnesium-Ion Batteries.

Rechargeable magnesium batteries (RMBs) show great potential in large-scale energy storage systems, due to Mg ²⁺ with high polarity leading to strong interactions within the cathode lattice, and the limited discovery of functional cathode materials with rapid kinetics of Mg ²⁺ diffusion and desirable cyclability retards their development. Herein, we innovatively report the confined synthesis of VS ₂ /polyaniline (VS ₂ /PANI) hybrid nanosheets. The VS ₂ /PANI hybrids with expanded interlayer spacing are successfully prepared through the exfoliation of VS ₂ and in situ polymerization between VS ₂ nanosheets and aniline. The intercalated PANI increases the interlayer spacing of VS ₂ from 0.57 to 0.95 nm and improves its electronic conductivity, leading to rapid Mg-ion diffusivity of 10 ^-10 -10 ^-12 cm ² s ^-1 . Besides, the PANI sandwiched between layers of VS ₂ is conducive to maintaining the structural integrity of electrode materials. Benefiting from the above advantages, the VS ₂ /PANI-1 hybrids present remarkable performance for Mg ²⁺ storage, showing high reversible discharge capacity (245 mA h g ^-1 at 100 mA g ^-1 ) and impressive long lifespan (91 mA h g ^-1 after 2000 cycles at 500 mA g ^-1 ). This work provides new perspectives for designing high-performance cathode materials based on layered materials for RMBs.