Insights into interlayer dislocation augmented Zinc‐ion storage kinetics in MoS2 nanosheets for rocking‐chair Zinc‐ion batteries with ultralong cycle‐life

AbstractIncreasing 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 cm2 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.