Insights into Interlayer Dislocation Augmented Zinc-Ion Storage Kinetics in MoS2 Nanosheets for Rocking-Chair Zinc-Ion Batteries with Ultralong Cycle-Life

Increasing attention to sustainability and cost-effectiveness in energy storage sector has catalyzed the rise of rechargeable Zinc-ion batteries (ZIBs). However, finding replacement for limited cycle-life Zn-anode is a major challenge. Molybdenum disulfide (MoS2), an insertion-type 2D layered material, has shown promising characteristics as a ZIB anode. Nevertheless, its high Zn-ion diffusion barrier because of limited interlayer spacing substantiates the need for interlayer modifications. Here, N-doped carbon quantum dots (N-CQDs) are used to modify the interlayers of MoS2, resulting in increased interlayer spacing (0.8 nm) and rich interlayer dislocations. MoS2@N-CQDs attain a high specific capacity (258 mAh g(-1) at 0.1 A g(-1)), good cycle life (94.5% after 2000 cycles), and an ultrahigh diffusion coefficient (10(-6) to 10(-8) cm(2) s(-1)), much better than pristine MoS2. Ex situ Raman studies at charge/discharge states reveal that the N-CQDs-induced interlayer expansion and dislocations can reversibly accommodate the volume strain created by Zn-ion diffusion within MoS2 layers. Atomistic insight into the interlayer dislocation-induced Zn-ion storage of MoS2 is unveiled by molecular dynamic simulations. Finally, rocking-chair ZIB with MoS2@N-CQDs anode and a ZnxMnO2 cathode is realized, which achieved a maximum energy density of 120.3 Wh kg(-1) and excellent cyclic stability with 97% retention after 15 000 cycles.