All-solid-state electric double layer supercapacitors using Li1.3Al0.3Ti1.7(PO4)3 reinforced solid polymer electrolyte

In this work, we report the fabrication and characterization of all-solid-state supercapacitors based on a conductive filler dispersed solid polymer electrolyte. Fast ionic Li1.3Al0.3Ti1.7(PO4)3 (LATP) reinforced PEO-PEG-LITFSI composite solid polymer electrolyte (CSPE) membranes are prepared by milling assisted route. The electric double-layer capacitor (EDLC) cells, using a hot-roll lamination technique, are fabricated using a CSPE membrane as electrolyte and activated charcoal (surface area ∼ 817m2g−1) on graphite sheet as electrode. The EDLCs display appreciable areal capacitance of ∼ 12 Fcm−2 and ∼40 Fcm−2 at 40 °C and 80 °C, respectively at ∼0.65 mAcm2 and 2 V. These solid-state EDLCs at 40 °C exhibit stability up to ∼16,000 cycles. Further, the electrode-electrolyte (solid-solid) interface remains quite stable after the charge-discharge cycling. The electrical conductivity of the CSPE membranes correlates well with the EDLC performance. The LATP content in the CSPE membranes play important role in enhancing the capacitance. The present investigation suggests that CSPE membranes with conductivity between ∼10−4–10−5 Scm−1 are useful for low-power EDLC applications. The EDLCs cells with LATP dispersed CSPE exhibit better stability during thermal cycling between 40 °C-80 °C.