Electronic-Structure Engineering Coordinates Na Nucleation Thermodynamics and Deposition Kinetics for Stable Sodium Metal Batteries.

Abstract

Sodium metal batteries are limited by uncontrolled Na nucleation and nonuniform deposition, which originate from insufficient interfacial sodiophilicity and heterogeneous ion/electric-field transport. Herein, we design a flexible lotus-root-like hierarchical porous carbon nanofiber framework embedded with ultrafine vanadium nitride (VN) nanoparticles (VN@HPCNF) is developed to synchronously coordinate these two processes through synergistic electronic-structure and structural engineering. Density functional theory calculations reveal that the electronic structure of VN creates intrinsically sodiophilic sites, where electron-rich N atoms initiate Na adsorption and V centers stabilize Na through Na-3s/V-3d orbital hybridization, thereby lowering the nucleation barrier. Meanwhile, COMSOL simulations reveal that the interconnected porous architecture simultaneously homogenizes the electric-field distribution and Na+ flux, alleviates localized current-density accumulation, and guides confined and homogeneous Na deposition. The synergistic regulation of atomic-scale electronic interactions and structural-scale ion/electric-field transport enables dendrite-free Na growth. Consequently, VN@HPCNF exhibits stable cycling over 1000 h at 2 mA cm-2, a low plating/stripping overpotential of ≈16 mV, and a high Coulombic efficiency (CE) of 99.86% at 4 mA cm-2. This work identifies electronic-structure-induced sodiophilicity as a decisive descriptor for regulating Na deposition, providing a mechanistic design principle for stable alkali-metal anodes.