MoS2 with high 1T phase content enables fast reversible zinc-ion storage via pseudocapacitance

Zinc-ion batteries (ZIBs) have garnered considerable interest due to their inherent high safety, low cost, and environmental friendliness. However, the reaction mechanism of cathode material in ZIBs is not entirely clear. Herein, Mixed-phase MoS2 with a high proportion (66%) of 1T phase and 2H phase (TH-MoS2), synthesized by the hydrothermal method, is reported as the cathode material for ZIBs. Material characterizations show that TH-MoS2 have obvious two phase MoS2 with different crystal structures causes sulfur vacancies, increases interlayer spacing and intercalation water. TH-MoS2 cathode delivers excellent electrochemical performance, a satisfactory capacity of 156 mAh g−1, and an excellent cycling performance with 97.3% capacity retention after 500 cycles at 1 A g−1. The ex-situ characterizations elucidate that TH-MoS2 achieves highly reversible Zn2+ storage with negligible phase transition, volume change, and lattice distortion upon cycle. Based on kinetic analysis and first-principles calculations results, Zn2+ and H+ can be stored in TH-MoS2 and the energy storage mechanism of TH-MoS2 electrode is dominated by pseudocapacitance. Understanding the MoS2 reaction mechanism will facilitate comprehension of cathode materials for ZIBs.