Pre-Intercalation of TMA Cations in MoS 2 Interlayers for Fast and Stable Zinc Ion Storage.

Applications of aqueous zinc ion batteries (ZIBs) for grid-scale energy storage are hindered by the lacking of stable cathodes with large capacity and fast redox kinetics. Herein, the intercalation of tetramethylammonium (TMA + ) cations is reported into MoS 2 interlayers to expand its spacing from 0.63 to 1.06 nm. The pre-intercalation of TMA + induces phase transition of MoS 2 from 2H to 1T phase, contributing to an enhanced conductivity and better wettability. Besides, The calculation from density functional theory indicates that those TMA + can effectively shield the interactions between Zn 2+ and MoS 2 layers. Consequently, two orders magnitude high Zn 2+ ions diffusion coefficient and 11 times enhancement in specific capacity (212.4 vs 18.9 mAh g ‒1 at 0.1 A g ‒1 ) are achieved. The electrochemical investigations reveal both Zn 2+ and H + can be reversibly co-inserted into the MoS 2 -TMA electrode. Moreover, the steady habitat of TMA + between MoS 2 interlayers affords the MoS 2 -TMA with remarkable cycling stability (90.1% capacity retention after 2000 cycles at 5.0 A g ‒1 ). These performances are superior to most of the recent zinc ion batteries assembled with MoS 2 or VS 2 -based cathodes. This work offers a new avenue to tuning the structure of MoS 2 for aqueous ZIBs.