Integrating molybdenum sulfide selenide-based cathode with C-O-Mo heterointerface design and atomic engineering for superior aqueous Zn-ion batteries

Transition metal dichalcogenides(TMDs)have been regarded as promising cathodes for aqueous zinc-ion batteries(AZIBs)but suffer from sluggish reaction kinetics due to their poor conductivity and the strong electrostatic interaction between Zn-ion and cathode materials.Herein,a well-defined structure with MoSSe nanosheets vertically anchored on graphene is used as the cathode for AZIBs.The dissolution of Se into MoS2 lattice together with heterointerface design via developing C-O-Mo bonds improves the inherent conductivity,enlarges interlayer spacing,and generates abundant anionic vacancies.As a result,the Zn2+intercalation/deintercalation process is greatly improved,which is confirmed by theoretical modeling and ex-situ experimental results.Remarkably,the assembled AZIBs exhibit high-rate capability(124.2 mAh·g^(−1)at 5 A·g^(−1))and long cycling life(83%capacity retention after 1,200 cycles at 2 A·g^(−1)).Moreover,the assembled quasi-solid-state Zn-ion batteries demonstrate a stable cycling performance over 100 cycles and high capacity retention over 94%after 2,500 bending cycles.This study provides a new strategy to unlock the electrochemical activity of TMDs via interface design and atomic engineering,which can also be applied to other TMDs for multivalent batteries.