Enhancing Dendrite Suppression Capability of Na3sbs4 Solid Electrolyte Via Electrostatic Shielding by Licl Doping

Abstract

Na3SbS4 solid-state electrolytes (SSEs) have emerged as promising candidates for all-solid-state sodium batteries (ASSSBs) owing to their exceptional room-temperature ionic conductivity and broad electrochemical stability window. Nevertheless, their practical implementation remains constrained by inadequate critical current density (CCD), which cannot prevent metallic sodium penetration through electrolyte matrices. To address this fundamental limitation, an electrostatic shielding strategy is proposed to shield the initial growth tips from subsequent dendrite propagation via LiCl doping. In detail, a series of Na3SbS4-xLiCl (x = 0.5, 1, 1.5, 2), Na3SbS4-Li2S and Na3SbS4 SSEs were synthesized via melt-quenching. Systematic investigation reveals that the Li+/Cl− co-doping could establish a localized electric field at interface between Na anode and Na3SbS4 SSEs, which could regulate uniform Na+ flux distribution through space-charge-mediated ion redistribution, effectively suppressing uneven current that leads to dendrite growth. The Na3SbS4-0.5LiCl solid state electrolyte retain its crystal phase after doping while its CCD was enhanced to 1.89 mA cm-2. The Na-Na symmetric battery based on this SSEs demonstrates an excellent cycling life of 300 hours. This composite design strategy establishes fundamental material criteria for mitigating dendrite propagation in chalcogenide SSEs through interfacial charge redistribution and ion transport kinetics optimization, thereby advancing the engineering roadmap for high-energy-density ASSSBs.

Keywords: chalcogenide solid state electrolyte, Na3SbS4, critical current density, electrostatic shielding, doping modification