A room temperature solid-state rechargeable sodium ion cell based on a ceramic Na-β″-Al2O3 electrolyte and NaTi2(PO4)3 cathode

• A Na-β”-Al2O3 ceramic thin film was fabricated through an environmentally-friendly tape casting method.
• For the first time, a solid-state cell based on the Na-β”-Al2O3 ceramic was characterized at room temperature.
• The solid-state sodium ion cell showed an extremely stable and flat discharge voltage plateau at approximately 2.1V.

In this work, a room temperature solid-state rechargeable sodium ion cell, consisting of a ceramic Na-β″-Al2O3 thin film as the electrolyte, a NaTi2(PO4)3 gel composite as the cathode and sodium metal as the anode, was developed for the first time. A dense Na-β″-Al2O3 thin film with a thickness of approximately 100 μm was obtained by non-toxic and hazard-free ceramic fabrication processes, including tape-casting and subsequent sintering. The solid-state sodium ion cell had a working window of 1.5–2.5 V upon charge-discharge processes and exhibited an extremely stable voltage plateau of approximately 2.1 V. A reversible capacity, based on the NaTi2(PO4)3 cathode, of 133 mAh g− 1 was observed during the first cycle, which remained approximately 100 mAh g− 1 after 50 cycles.