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

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.