High performance all-solid-state sodium batteries actualized by polyethylene oxide/Na2Zn2TeO6 composite solid electrolytes

To address sluggish kinetics of ions in all-solid-state sodium batteries, composite solid electrolytes (CSEs), i.e. polyethylene oxide (PEO) with dispersed Ga doped-Na2Zn2TeO6 (NZTO) particles, and a nanostructured Na2V3(PO4)3 cathode are applied to assemble batteries. The conductivity of the PEO/NZTO CSE is increased by a factor of ~40 from 1 × 10−6 S cm−1 to 4 × 10−5 S cm−1 at 30 °C and 1 × 10−3 S cm−1 at 80 °C, due to the high conductivity of doped-NZTO and the suppressed crystallization of PEO. In addition, CSEs own excellent thermal and electrochemical stabilities, and are more resistant to the penetration of sodium dendrites. The CSE allying with nanostructured Na2V3(PO4)3 confers upon the all-solid-state sodium battery an initial discharge capacity of ~106 mA h g−1 (99 mA h g−1 after 100 cycles) at 0.2C and 80 °C, remarkably better than those of the batteries using the PEO:NaTFSI electrolyte.