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.