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

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.