Dual-Regulation of Na Deposition Kinetics via Sodiophilic ZnO/Carbon Cloth Host and Magnetohydrodynamic Convection...

The practical development of sodium metal anodes is severely impeded by uncontrollable dendrite growth and infinite volume change. While three-dimensional (3D) sodiophilic scaffolds can mitigate these issues to some extent, the sluggish Na⁺ transport kinetics often leads to concentration polarization and localized dendrite resurgence. Herein, we propose a dual-regulation strategy that synergistically couples a 3D sodiophilic host with an external magnetic field intervention to fundamentally homogenize Na deposition kinetics. A ZnO-nanorod-decorated carbon cloth (ZnO/CC) framework is fabricated to provide abundant nucleation sites and buffer volume expansion. Concurrently, an applied static magnetic field (200 mT) induces magnetohydrodynamic (MHD) convection, which effectively stirs the electrolyte, enhances Na⁺ mass transfer, and eliminates local ion depletion. This synergistic "site-regulation and field-regulation" mechanism results in remarkably low Na nucleation overpotential (8 mV) and significantly enhanced ion diffusion coefficient. Consequently, the ZnO/CC@Na symmetric cell performs for 1100 h at 1 mA cm^-2/1 mAh cm^-2 and ZnO/CC@Na||Na₃V₂(PO₄)₃ full cells maintain good cycle stability with a capacity retention of 96% at 1 C over 200 cycles. This work introduces a physical-electrochemical synergistic regulation paradigm, which could open a facile and effective avenue toward safe and durable metal batteries.