Enhanced ionic conductivity of an F--assisted Na3Zr2Si2PO12solid electrolyte for solid-state sodium batteries

Na3Zr2Si2PO12(NZSP) is considered to be one of the most promising solid electrolytes for solid-state sodium batteries. However, the low ionic conductivity of NZSP is one of the main challenges for its practical application. Herein, an F(-)assisting strategy to improve the ionic conductivity of NZSP is proposed. The F(-)assisting in NZSP electrolyte promotes the formation of a microstructure with large grains, low grain boundary concentration and high relative density, which is favorable to obtain high ionic conductivity. Consequently, the F--assisted NZSP solid electrolyte exhibits a high ionic conductivity of 1.41 x 10(-3)S cm(-1)at 27 degrees C, which is about six times that of the un-assisted NZSP electrolyte (2.32 x 10(-4)S cm(-1)). Moreover, the Na/Na3V2(PO4)(3)solid-state sodium battery with the F--assisted NZSP electrolyte exhibits an excellent cyclability with 97.8% capacity retention (85.9 mA h g(-1)) after 100 cycles at 0.5C at 40 degrees C. This F(-)assisting strategy provides a new way for the development of other classes of ceramic solid electrolytes for solid-state batteries.