Gel polymer electrolytes (GPEs) were prepared by mixing hydroponics polymer gel (HPG) with 6 M
potassium hydroxide (KOH), and the control sample was produced by mixing HPG with distilled water
(H2O). The optimum absorbed volumes obtained for HPG + 6 M KOH and HPG + H2O were 40 and
10 ml, respectively. The swelling percentage for HPG + 6 M KOH was lower than that for
HPG + H2O. However, both samples reached maximum expansion within 60 min. The engineering
strain experienced by HPG + 6 M KOH was lower than that of HPG + H2O, whereas the compressive
stress–strain for HPG + 6 M KOH was higher than that for HPG + H2O. The maximum conductivity of
the gels was obtained at 40 ml of 6 M KOH. Subsequently, Zn–MnO2 alkaline batteries were
fabricated, which provided a discharge capacity ca. 148 mAh g
-1
and the maximum power density was
7.8 mW cm
-2
. Moreover, the double-layer capacitances before and after discharge were found to be
different.