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