Ionic Liquid‐Intercalated Metallic MoS2 as a Superior Electrode for Energy Storage Applications

Abstract The development of MoS 2 in the metallic phase (1T‐MoS 2 ) is of paramount interest as it exhibits superior electrochemical activities compared to its semiconducting polymorph (2H‐MoS 2 ). In this work, an ionic liquid (IL)‐assisted solvothermal method was employed to produce the thermodynamically metastable 1T‐MoS 2 . Structural characterization of the material suggests the intercalation of the IL into MoS 2 . De‐intercalation of ILs from 1T‐MoS 2 leads to the formation of 2H‐MoS 2 . Carbon cloth‐supported 1T‐MoS 2 (1T‐MoS 2 @CC) shows higher electrocatalytic activity towards acidic hydrogen evolution reaction (HER) by delivering a current density of 50 mA/cm 2 at an overpotential of 210 mV whereas 2H‐MoS 2 @CC requires an overpotential of 260 mV to reach the same current density. In addition, the 1T‐MoS 2 @CC electrode delivers a high electrochemical double‐layer storage ability compared to 2H‐MoS 2 @CC in 1 M Na 2 SO 4 . The enhanced electrochemical activity of 1T‐MoS 2 over 2H‐MoS 2 may be due to the existence of conducting basal planes and the high interlayer spacing (about 1 nm) caused by the intercalation of ILs into the MoS 2 layers.