Intercalated hydrates stabilize bulky MoS2 anode for Lithium-Ion battery

Bulky molybdenum disulfide (MoS2) has rarely been considered as a promising anode for lithium-ion battery due to the high volume strain and structural collapse caused by conversion reaction. In this work, a bulky K(H2O)MoS2 is rationally designed by intercalating hydrated potassium into commercial 2H MoS2, which exhibits a high volumetric capacity of 1566.7 mAh cm−3 along with an extremely enhanced capacity retention from 16% to 102% after 400 cycles at 1 A/g. Moreover, the assembled LiCoO2//K(H2O)MoS2 full cell delivers an energy density of 223.2 Wh/kg and a capacity retention of 89.6% after 100 cycles at 0.5 A/g. Based on the results of in situ X-ray diffraction (XRD) and Raman spectrum, differential electrochemical mass spectrometry (DEMS), time-of-flight secondary mass spectrometry (TOF-SIMS), and theoretical calculations, the stable lithium storage of K(H2O)MoS2 benefits from the buffer interlayers composed of “confined Li-O species and S-H bonds”, which limit the complete conversion reaction and preserve the layered structure. The proposed strategy of introducing intercalated hydrates for improving the cycling stability of bulky MoS2 raises the prospect of practical applications in layered metal chalcogenides anodes.