An all-solid state NASICON sodium battery operating at 200 °C

An all-solid state symmetric monolithic sodium ion battery operating at 200 °C is described, using NASICON-type electrodes and electrolyte. Na3V2(PO4)3 is used at both electrodes as the active material while Na3Zr2Si2PO12 stands the role of the Na+ solid electrolyte. Both compositions present order-disorder phase transitions and present decent ionic conductivity properties, 1.5 × 10−3 S cm−1 and 1.9 × 10−4 S cm−1 at 200 °C for Na3Zr2Si2PO12 and Na3V2(PO4)3, respectively. The full battery (560 μm in thickness) was assembled in a 10′ single step by spark plasma sintering at 900 °C. The electrochemical characteristics at high temperature (200 °C) were evaluated thanks to a new experimental set-up. The battery operates at 1.8 V with 85% of the theoretical capacity attained at C/10 with satisfactory capacity retention, for an overall energy density of 1.87 × 10−3 W h cm−2 and a capacity of 1.04 mA h cm−2.