Figure 5. Cyclability of capacitor with SAPO-PTFE composite electrolyte, 105% H₃PO₄ electrode ionomer, and HNO₃-activated carbon.

a) Galvanostatic charge-discharge curve measured with a current density of 6 A g⁻¹ at 200°C. b) Energy density as a function of cycle number measured at various temperatures with the current density set in the range of 4.5–6 A g⁻¹. c) EIS spectra for the capacitor before and after 1000 cycles at 200°C.