Self‐healable Mn‐doped PVA‐borax hydrogel electrodes for supercapacitor applications

Abstract This study aims to investigate the effect of Mn doping on the performance of polyvinyl alcohol/borax‐structured (PMB) supercapacitor electrodes for high‐capacity, flexible, and self‐healing supercapacitor electrodes. The PMB electrodes were characterized by x‐ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Electrochemical characterization was conducted using cyclic voltammetry (CV), which revealed that redox reactions, which are evident at low scan rates, enhance capacitive performance. However, high scan rates introduce limitations owing to the increased vibrations of the PVA chains and incomplete electrolyte polarization. The PMB electrodes exhibited remarkable electrochemical properties and capacitive performances, which were significantly affected by the MnO₂ structure. The electrodes exhibited self‐healing properties and demonstrated flexibility to stretch by up to 40%. In addition, the results indicate that the electrode capacity of the PVA/borax system increased by 2.03 times after 1000 cycles with manganese doping. The solid electrolyte interface (SEI) layer formed on the electrode surface plays a critical role in stabilizing the capacity loss during prolonged charge–discharge cycles. The study concluded that PMB supercapacitors offer higher capacitance in 0‐2 V applications compared to other PVA/borax combination hydrogels. Moreover, the incorporation of metal‐based additives, particularly manganese, enhanced the capacitive performance, and operating voltage levels.