Ultrastable All-Solid-State Sodium Rechargeable Batteries

The insufficient ionic conductivity of oxide-based solid electrolytes and the large interfacial resistance between the cathode material and the solid electrolyte severely limit the performance of room-temperature all-solid-state sodium rechargeable batteries. A NASICON solid electrolyte Na3.4Zr1.9Zn0.1Si2.2P0.8O12, with superior room-temperature conductivity of 5.27 × 10–3 S cm–1, is achieved by simultaneous substitution of Zr4+ by aliovalent Zn2+ and P5+ by Si4+ in Na3Zr2Si2PO12. The bulk conductivity and grain boundary conductivity of Na3.4Zr1.9Zn0.1Si2.2P0.8O12 are nearly 20 times and almost 50 times greater than those of pristine Na3Zr2Si2PO12, respectively. The FeS2||polydopamine-Na3.4Zr1.9Zn0.1Si2.2P0.8O12||Na all-solid-state sodium batteries, with a polydopamine modification thin layer between the solid electrolyte and the cathode, maintain a high reversible capacity of 236.5 mAh g–1 at a 0.1 C rate for 100 cycles and a capacity of 133.1 mAh g–1 at 0.5 C for 300 cycles, demonstrating high performance for all-solid-state sodium batteries.