Investigation of Sulfide-based Solid Electrolytes for Sodium All-Solid-State Rechargeable Batteries

摘要

All-solid-state sodium-ion batteries are promising candidates for large-scale energy storage applications. The key enabler for an all-solid-state architecture is a sodium solid electrolyte that exhibits high Na+ conductivity at ambient temperatures, as well as excellent phase and electrochemical stability. In this work, we present the synthesis of a novel Cl-doped tetragonal Na 3PS4 (t-Na3-xPS4-xCl x) solid electrolyte with a room-temperature Na+ conductivity exceeding 1 mS cm-1. We demonstrate that an all-solid-state TiS2/ t-Na3-xPS4-xClx/Na cell utilizing this solid electrolyte can be cycled at room-temperature at a rate of C/10 with a capacity of over 100 mAh g-1 over 10 cycles. Finally, we provide experimental evidence that this excellent electrochemical performance is not only due to the high Na+ conductivity of the solid electrolyte, but also due to the effect that "salting" Na3PS4 has on the formation of an electronically insulating, ionically conducting solid electrolyte interphase.