Unveiling the Nanoarchitectonics of Interfacial Electronic Coupling in Atomically Thin 2D WO₃/WSe₂ Heterostructure for Sodium‐Ion Storage in Aqueous System

Abstract Aqueous sodium (Na⁺) ion storage systems face challenges due to sluggish adsorption and diffusion of Na⁺ ions with larger size, hindering their potential for stationary applications. This issue is addressed by evolving the interfacial electronic coupling in atomically thin 2D WO₃/WSe₂ heterostructure for efficient Na⁺ ion storage. Density functional theory (DFT) analysis elucidates the superior charge storage capability for the WO₃/WSe₂ heterostructure facilitated by the charge transfer from the WO₃ – WSe₂ (002). The charge transfer from the W‐5d and O‐2p orbitals of WO₃ to the valence W‐5d and Se‐4p orbitals of the WSe₂ (002) surface boosts the electronic conductivity. As a result, the WO₃/WSe₂ electrode demonstrates exceptional Na⁺ ion storage, with a specific capacitance of 378.1 F g⁻¹ at 1 A g⁻¹, excellent rate capability, and long‐lasting cycling durability. The full cell comprising WO₃/WSe₂ as the negative and MnSe/MnSe₂ as the positive electrode achieved a peak energy density of 82.1 Wh kg⁻¹ at a power density of 1873.5 W kg⁻¹, along with high rate capability and long‐cycle durability. Insights gained from this study pave the technique for the rational design and optimization of the interfacial electronic features in 2D heterostructures for next‐generation energy storage devices with enhanced performance and stability.