Vertically Oriented MoS₂ with Spatially Controlled Geometry on Nitrogenous Graphene Sheets for High-Performance Sodium-Ion Batteries

Inspired by the great success of graphite in lithium-ion batteries, anode materials that undergo an intercalation mechanism are considered to provide stable and reversible electrochemical sodium-ion storage for sodium-ion battery (SIB) applications. Though MoS₂ is a promising 2D material for SIBs, it suffers from deformation of its layered structure during repeated intercalation of Na⁺, resulting in undesirable electrochemical behaviors. In this study, vertically oriented MoS₂ on nitrogenous reduced graphene oxide sheets (VO-MoS₂/N-RGO) is presented with designed spatial geometries, including sheet density and height, which can deliver a remarkably high reversible capacity of 255 mA h g⁻¹ at a current density of 0.2 A g⁻¹ and 245 mA h g⁻¹ at a current density of 1 A g⁻¹, with a total fluctuation of 5.35% over 1300 cycles. These results are superior to those obtained with well-developed hard carbon structures. Furthermore, a SIB full cell composed of the optimized VO-MoS₂/N-RGO anode and a Na₂V₃(PO₄)₃ cathode reaches a specific capacity of 262 mA h g⁻¹ (based on the anode mass) during 50 cycles, with an operated voltage range of 2.4 V, demonstrating the potentially rewarding SIB performance, which is useful for further battery development.