P.C. Wen, P.F. Lu, X.Y. Shi, Y. Yao, H.D. Shi, H.Q. Liu, Y. Yu, Z.-S. Wu*

Advanced Energy Materials, 2021, 11, 2002930.

DOI: 10.1002/aenm.202002930 [PDF]

Solid-state sodium metal batteries (SMBs) are highly promising rechargeable batteries owing to the abundance and cost effectiveness of sodium resource. However, the low room-temperature ionic conductivity and narrow voltage window of solid-state electrolytes seriously inhibit the development of SMBs. Herein, a high room-temperature ionic conductive quasi-solid-state electrolyte (ETPTA-NaClO₄-QSSE) is developed by photopolymerization for high-energy-density solid-state SMBs. The ETPTA-NaClO₄-QSSE exhibits remarkable room-temperature ionic conductivity of 1.2 mS cm^-1, wide electrochemical window of > 4.7 Vvs.Na⁺/Na, and excellent flexibility. Owing to outstanding interfacial compatibility of this electrolyte with electrode, Na metal symmetrical batteries show ultralong cyclability with 1000 h at 0.1 mA cm^-2, and ultralow overpotential of 355 mV at 1 mA cm^-2, indicative of significant suppression of the dendrite growth of Na. Notably, Na₃V₂(PO₄)₃(NVP) full batteries (NVP||ETPTA-NaClO₄-QSSE||Na) display unprecedented rate capability, with a recorded capacity of 55 mAh g^-1at 15 C that has been not yet achieved so far in solid-state SMBs, and long-term cycling stability at 5 C, offering a capacity retention of 97% after 1000 cycles. Furthermore, NVP||ETPTA-NaClO₄-QSSE||Na pouch cells represent outstanding performance, excellent flexibility and exceptional safety, demonstrative of wide applicability. Therefore, this work will open new opportunities to develop room-temperature high-energy-density solid-state SMBs.