Highly Sodiophilic Heterostructures Toward Dendrite-Free Sodium Metal Batteries

The utilization of Al current collector for the sodium deposition is considered ideal for achieving a low-cost, high-energy-density sodium metal battery. However, the poor affinity between sodium and Al leads to uneven sodium plating/stripping, which poses a significant challenge in the pursuit of a stable sodium metal anode. Herein, a heterostructure (V/VOx)-modified Al current collector is proposed, which effectively enables a highly reversible Na plating/stripping process, and inhibits Na dendrites growth. Experimental results and theoretical calculations demonstrate that the V/VOx@Al not only exhibits strong sodiophilicity, but also ensures a uniform current density distribution. Thanks to these merits, the assembled cells demonstrate excellent performances with low nucleation overpotential (11 mV at 1 mA cm-2), and long cycle life (2750 h) with minimal voltage polarization (13 mV at 1 mA cm-2). More impressively, the assembled full cell displays remarkable stability, sustaining 1400 cycles at 10 C. This work provides valuable insights for the development of more stable sodium metal batteries. A heterostructure (V/VOx)-modified Al current collector is developed, which not only has strong sodiophilic properties, but also can uniformly distribute the current density, thereby realizing uniform Na deposition. As a result, the assembled full cell can stably operate over 1400 cycles at 10 C, and maintain 97% capacity retention. image