P‐Block Compounds Incorporated into SEI Enable Ultra‐Stable Cell Cycling in Low‐Temperature Sodium‐Metal Batteries

Abstract

Abstract Sodium metal anodes (SMAs) are pivotal for high‐energy‐density batteries but suffer from uncontrolled dendrite growth and interfacial instability caused by infinite volume expansion and a fragile solid electrolyte interphase (SEI). Herein, an innovative strategy is proposed, in which a p‐block matrix is in‐situ formed from NiTe 2 nanocrystals onto N‐doped carbon hollow microspheres (NiTe 2 @NC) during electrochemical activation to overcome these challenges. The p‐block matrix with sodiophilic Na 2 Te and conductive metallic nickel effectively reduces the nucleation barrier and establishes bi‐continuous ion/electron conduction networks, guiding uniform Na plating. Critically, Na 2 Te dominates the formation of a gradient inorganic‐rich SEI with high Young's modulus and low Na⁺ diffusion barrier, significantly enhancing mechanical resilience and ion transport kinetics. Consequently, the NiTe 2 @NC electrode achieves exceptional cyclability (1,000 cycles at 1.0 mA cm − 2 /1.0 mAh cm − 2 with an average Coulombic efficiency of 99.79%). When configured in full‐cells with a Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 cathode, it maintains the capacity retention of over 96.1% (103.9 mAh g − 1 ) after 1,200 cycles at 10.0 C. Critically, the full‐cell maintains superior electrochemical resilience with high discharge‐capacity and >90% retention at low‐temperatures (−20 and −40 °C), demonstrating exceptional practicality for sodium metal batteries. This work establishes a new paradigm for stabilizing reactive metal anodes via in‐situ‐constructed multifunctional interfaces.