Oleaster (Elaeagnus angustifolia L.) fruit peel as a novel natural separator in supercapacitors

Abstract

Electrode materials and separators are the most important components of supercapacitors. In this current study, activated carbons (ACs) were produced from the flesh fraction of the oleaster fruit by using KOH and ZnCl₂ as activation agents. The peel of the fruit was used for the first time as a novel natural separator in supercapacitors. In addition, the performance results were compared with those from a commercial separator. The specific capacitance values of the supercapacitors using commercial (CS), oleaster fruit peel (OS) and ultrasonicated oleaster fruit peel (UOS) as separators in the presence of the AC produced with ZnCl₂ were 40.97 F/g, 56.86 F/g and 61.19 F/g at 1 A/g current density, respectively. The specific capacitances were obtained from the CS and UOS cells as 82.77 F/g and 132.35 F/g at 1 A/g current density using AC produced with KOH. However, the equivalent series resistance (ESR) of the OS was higher than the CS. In the presence of the ACs produced with ZnCl₂ and KOH, the long-term performance of the cells using the OS was much better than the CS. The results obviously showed that the OS could be a good model for producing a new and efficient CS.