Hydrangea-like MoS2/carbon dots anode for high-performance sodium storage

Owing to their quantum size, edge effects, and abundant surface functional groups, carbon dots (CDs) have attracted significant attention. In this study, chitin-derived carbon dots (CT-CDs) were prepared and used to synthesize MoS 2 /CT-CDs. The abundant functional groups on the surface of the CT-CDs facilitated the orderly arrangement of MoS 2 nanosheets , resulting in a hydrangea-like structure. When employed as the anode in a sodium-ion battery, MoS 2 /CT-CDs exhibited an excellent initial charging capacity of 492.6 mAh·g −1 at 0.1 A·g −1 with an initial Coulomb efficiency of 74.4%. Even after 100 cycles, the reversible capacity remained at 338.9 mAh·g −1 . Furthermore, the reversible capacity of MoS 2 /CT-CDs remained at 219.9 mAh·g −1 after 260 cycles when subjected to 1 A·g −1 . The hydrangea-like structure of MoS 2 /CT-CDs, with expanded layer spacing, enhances ion/electron transport while providing additional active sites for sodium-ion storage, resulting in exceptional cycling and rate performances.