SnF₂‐Induced Highly Current‐Tolerant Solid Electrolytes for Solid‐State Sodium Batteries

Solid-state sodium batteries have garnered considerable interest. However, their electrochemical performance is hampered by severe interfacial resistance between metal and inorganic solid electrolytes, as well Na dendrite growth within the electrolytes. To address these issues, a uniform compact SnF2 film first introduced onto surface of electrolyte Na3.2Zr1.9Ca0.1Si2PO12 (NCZSP) to improve contact through an effective straightforward process. Through experiments computations, in situ conversion reaction molten adequately confirmed, resulting composite conductive layer containing NaxSn alloys NaF at interface. As result, Na/NCZSP significantly decreased from 813 5 Ω cm2, critical current density dramatically increased 1.8 mA cm−2, opposed 0.2 cm−2 with bare NCZSP. The symmetric cell able cycle stably for 1300 h 30 °C exhibits excellent tolerance 0.3 0.5 cm−2. Moreover, Na3V2(PO4)3/SnF2-NCZSP/Na full displays rate cycling stability. SnF2-induced interlayer proves significant improving restraining propagation, thus promoting development solid-state batteries.