All-solid-state Na+ ion supercapacitors using Na3Zr2Si2PO12-polymer hybrid films as electrolyte

We report all-solid-state Na+ ion electrical double layer capacitors (EDLCs) for the first time in this study. These are fabricated using a novel Na+ ion solid polymer electrolyte (SPE) and high surface area (877 m(2)-g(-1)) activated carbon electrodes. Using salt (NaI), polyethylene oxide (PEO) and nano particles of Na3Zr2Si2PO12 (NZSP), hybrid electrolyte films with compositions 10NaI-90[PEO(1-x)NZSP(x)], where 0 <= x <= 0.7 are synthesized by a novel milling assisted route. The freestanding flexible film for x = 0.7 exhibits a maximum ionic conductivity of -10-4 Omega(-1) cm(-1) at room temperature. The 2032 type EDLC with graphite current collector and polymer electrolyte film of composition x = 0.4 exhibits notably high value of specific capacitance (10(4) F.g(-1)), and specific energy (44 Wh-Kg(-1)) with a voltage stability window of similar to 2 volts. The NZSP content in the electrolyte influence the EDLC performance. The EDLCs with graphite sheet as current collector offer superior performance as compared to copper. Galvanostatic charge-discharge studies suggest stability of these supercapacitors at least upto similar to 400 cycles.

Automated summary

In this study, all-solid-state Na+ ion electrical double layer capacitors (EDLCs) were reported for the first time, utilizing a novel Na+ ion solid polymer electrolyte and high surface area activated carbon electrodes. By synthesizing hybrid electrolyte films, EDLCs with high ionic conductivity and superior performance were successfully achieved.