Boosting zinc-ion intercalation in hydrated MoS2 nanosheets toward substantially improved performance

Abstract

Rechargeable aqueous zinc-ion batteries hold great prospects in grid-level energy storage due to their virtues of good safety, low cost and eco-friendliness. However, the sluggish intercalation kinetics of divalent Zn2+ makes the exploration of a suitable Zn2+-host cathode being a formidable challenge. In this work, we unveil the crucial role of crystal water on boosting the Zn2+ intercalation kinetics of layered MoS2 host. The crystal water molecules could function as structural pillars to enlarge the interlayer distance of MoS2 and improve the surface hydrophilicity. Notably, a substantially-enhanced Zn2+ intercalation kinetics is realized by accelerating the charge-transfer transportation and Zn2+ diffusivity. Consequently, the hydrated MoS2 nanosheets enable efficacious Zn2+ insertion/extraction to achieve a high specific capacity of 182 mAh g−1 at 0.1 A g−1 and superior rate/cycling performance. The present study will enlighten the water implantation strategy to engineering hydrated cathode materials toward high-performance aqueous batteries.