Ultralong lifespan solid-state sodium battery with a supersodiophilic and fast ionic conductive composite sodium anode

Solid-state sodium batteries (SSNBs) are considered as a promising alternative to organic liquid-based batteries due to their excellent safety, high energy density and cost-effectiveness. However, SSNBs suffer from undesirable interfacial contact between Na and solid-state electrolytes such as NASICON-type Na3Zr2Si2PO12 (NZSP), dendritic growth and dramatic volume changes during cycling, which hinder their development towards actual applications. Herein, dendrite-free composite-type Na/NZSP module with ultrafast built-in ionic conductive framework is designed to promote the Na diffusion kinetics, partially restrict the volume effect, and simultaneously improve the wettability towards NZSP. Thanks to the unique module with supersodiophilic property, the thus-made all-solid-state Na-symmetric cells offer a reduced area specific resistance by more than two orders of magnitudes (from 1774.0 S2 cm(2) for the pristine Na/NZSP to 14.1 S2 cm(2) for the composite-type Na/NZSP module) and endow an ultralong lifespan of 7800 h at room temperature. Moreover, a full SSNB coupling with the Na/NZSP module and Na3V2(PO4)(3) cathode achieves extremely long and stable cycling of more than 5760 cycles at 1.0 C with 87.9 % of capacity retention and high-rate capability at 3.0 C, being among the best achievements reported so far. The findings open a new window of composite-type Na/NZSP module design for high-performance SSNBs.