Interfacial Self‐Reconstruction Engineering Enables Long‐Cyclability and Low‐Temperature Sodium Metal Batteries

ABSTRACT The implementation of sodium metal anodes (SMAs) is critically hindered by dendritic growth and interfacial instability, challenges that become particularly severe at low temperatures due to sluggish ion transport and increased interfacial resistance. To address this, a novel heterojunction artificial interphase comprising Na 3 Sb and Na 2 Te is constructed in situ on the sodium metal surface. This unique architecture exhibits a remarkable synergistic effect from the dual components. Specifically, the highly sodiophilic Na 3 Sb alloy phase offers superior mechanical properties and effective sodium anchoring sites, which adequately guide the uniform deposition of sodium, thereby enabling a highly stable and dendrite‐free sodium metal anode. Simultaneously, the Na 2 Te component, as an excellent electronic conductor, establishes an efficient electron transport network, drastically lowering the charge‐transfer resistance and accelerating interfacial reaction kinetics. Benefiting from this rational design, the symmetric cell achieves an extended cycling lifetime of 2100 h (0.5 mA cm −2 /1.0 mAh cm −2 ). More impressively, full cells paired with a Na 3 V 2 (PO 4 ) 3 cathode demonstrate exceptional cycling durability, retaining 4000 cycles at 5 C (25°C) and 1100 cycles at 4 C even under an ultra‐low temperature of −40°C. This work provides a strategic design of a multifunctional interphase for durable SMAs operable across a wide temperature range.