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

Abstract

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.