Interface Engineering with ZrS₂: Achieving 10000-Cycle Lifespan in High-Rate Sodium Metal Batteries

Abstract

Sodium metal batteries (SMBs) have emerged as promising alternatives to lithium-ion batteries for low-cost, high-energy-density energy storage. However, their practical application is hindered by uncontrolled dendrite growth and unstable interfacial reactions. In this study, a ZrS₂-based interlayer is introduced to enable dendrite-free, high-capacity SMBs with exceptional long-term stability. The 2D ZrS₂ sheets form a tightly bonded interface with the Na metal, effectively suppressing parasitic reactions at the electrolyte|Na interface. Additionally, ZrS₂ offers strong Na⁺ adsorption and features confined 2D ion transport channels, which facilitate uniform, planar Na deposition decoupled from the desolvation process. Importantly, the ZrS₂ interlayer demonstrates high Na⁺ diffusivity and accommodates Na⁺ via a reversible intercalation mechanism, thereby maintaining structural integrity under high current densities and prolonged cycling. As a result, the ZrS₂-modified Na anode achieves a remarkable cycle life of 4800 h at 2 mA cm⁻² with an areal capacity of 10 mAh cm⁻² in symmetric cells. In full-cell configurations, it delivers outstanding cycling stability over 10000 cycles at an ultrahigh rate of 50 C. This work provides a new design paradigm for interfacial engineering in SMBs and demonstrates a practical route toward safe, high-performance SMBs with enhanced durability.