Insights into Interlayer Dislocation Augmented Zinc-Ion Storage Kinetics in MoS 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 (MoS), 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 MoS, resulting in increased interlayer spacing (0.8 nm) and rich interlayer dislocations. MoS@N-CQDs attain a high specific capacity (258 mAh g at 0.1 A g), good cycle life (94.5% after 2000 cycles), and an ultrahigh diffusion coefficient (10 to 10 cm s), much better than pristine MoS. 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 MoS layers. Atomistic insight into the interlayer dislocation-induced Zn-ion storage of MoS is unveiled by molecular dynamic simulations. Finally, rocking-chair ZIB with MoS@N-CQDs anode and a ZnMnO cathode is realized, which achieved a maximum energy density of 120.3 Wh kg and excellent cyclic stability with 97% retention after 15 000 cycles.