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.

Automated summary

This study demonstrates a new strategy to enhance the electrochemical activity of transition metal dichalcogenides (TMDs) through interface design and atomic engineering. The use of MoSSe nanosheets vertically anchored on graphene as cathode for aqueous zinc-ion batteries (AZIBs) improves the conductivity and intercalation/deintercalation process, resulting in high-rate capability and long cycling life. The research also shows the potential application of this strategy in other TMDs for multivalent batteries.