Graphene quantum dot effect on biomaterial (Peltophorum pterocarpum) electrolyte incorporated with NH₄NO₃ for electrochemical devices

At this present study, the biomaterial Peltophorum pterocarpum (PP) flowerlets have been prepared as bio-membrane electrolyte by using simple solution casting technique. The objective is to develop a highest proton-conducting bio-membranes using Peltophorum pterocarpum (PP) incorporated with ammonium nitrate (NH₄NO₃). Addition of 0.5 ml GQD with the highest ion-conducting membrane resulted with better ionic conductivity values. All prepared bio-membranes with ammonium nitrate have been characterised by various characterisation techniques XRD, DSC, AC impedance, LSV, and transference number measurement. The amorphous/crystalline nature of prepared bio-membranes has been analysed by using XRD. The glass transition (T_g) temperature of the bio-membranes has been obtained by using DSC analysis. By using AC impedance analysis, the highest proton-conductivity of 6.91 × 10⁻⁴ has been obtained for the composition of 1 g PP with 0.7 NH₄NO₃. The improved ionic conductivity value of 3.83 × 10⁻³ has been obtained due to the addition of 0.5 ml GQD with 1 g PP with 0.7 NH₄NO₃. The electrochemical stability window of 3.1 V for (1 g PP with 0.7 NH₄NO₃) and 3.5 V for (1 g PP with 0.7 NH₄NO₃ + 0.5 ml GQD) have been found using linear sweep voltammetry. Transference number measurement has been done by using Wagner’s polarisation. The highest proton-conducting bio-membrane and highest conducting membrane with 0.5 ml GQD has been utilised to fabricate the primary proton battery and proton exchange membrane fuel cell (PEMFC). The observed open-circuit voltage for primary proton battery is 1.60 V (without GQD) and 1.62 V (with GQD). Proton exchange membrane fuel cell (PEMFC) has been constructed and it shows a voltage of 625 mV and its performance has been studied.