Boosting reaction kinetics and improving long cycle life in lamellar VS2/MoS2 heterojunctions for superior sodium storage performance

The development of high-performance rechargeable batteries highly depends on the rational structure/phase design of advanced electrode materials. A unique 2D lamellar stacked nanosheet VS2/MoS2 heterostructure is synthesized using a simple hydrothermal treatment in this study. As demonstrated by both experimental characterizations and density functional theory (DFT) calculations, the designed VS2/MoS2 heterogeneous composite has multiple structural/compositional advantages as sodium-ion battery anodes, including improved Na+ reaction kinetics, increased Na+ storage capacity, reduced sodiation stress, and a stable solid-electrolyte interface. Consequently, the VS2/MoS2 heterostructure anode demonstrates excellent comprehensive electrochemical performances, e.g., better initial coulombic efficiency (80.6% at 0.5 A g(-1)), excellent rate capability (644.0 mA h g(-1) at an ultrahigh rate of 10 A g(-1)), and long cycle life performance (454.5 mA h g(-1) at 2 A g(-1) after 1000 cycles), thus providing more opportunities to realize the high storage capacity and long cycle life of sodium-ion batteries in future.