Regulated interface conduction in halide solid electrolyte for all-solid-state sodium batteries

All-solid-state sodium-ion batteries (ASSSIBs) that applied inorganic solid electrolytes offer enhanced safety and stand out as promising contenders for the next-generation energy storage systems. Herein, an oxygen-incorporated Na 2 ZrCl 6 (NZC) composite electrolyte with high ionic conductivity (1.52 × 10 ‒4  S·cm ‒1 ) at an ambient temperature was reported. The composite electrolyte, which was prepared through a mechanochemical reaction and formed a highly ionic conductive interface, consists of oxide between ZrO 2 and NZC. A series of characterization confirmed that oxygen interacted with sodium ions, resulting in enhanced Na + diffusivity at the interface. The ASSSIBs, which comprise a NaNi 1/3 Fe 1/3 Mn 1/3 O 2 cathode, a Na 15 Sn 4 anode, and a Na 3 PS 4 anodic interlayer with ZrO 2 -NZC electrolyte, demonstrate a high discharged capacity of 104.9 mAh·g ‒1 , and significantly outstrip the baseline NZC electrolyte. This work offers an idea of methods for improving ion migration in halide solid electrolytes for practical feasibility in all-solid-state batteries. Graphical abstract