Integration of Ionomer-based Separator in High-performance Quasi-Solid-State Zinc Ion Hybrid Photo-supercapacitors

Renewable energy generation and storage on a single, compact device is a promising approach to addressing current energy problems. In this regard, recent advancements in zinc-ion hybrid photo-supercapacitors (Zn-HPSCs) have been noteworthy. However, their lower energy density compared to rechargeable batteries remains a major bottleneck that limits their widespread applications. We developed a quasi-solid-state Zn-HPSCs device using manganese-doped zinc oxide(Mn:ZnO) nanoparticles as the photoactive material and Zn+2-treated NafionTM115(N115) ionomer as the separator, achieving a performance that is 3.9 times higher than that of a device made with filter paper (FP) under UV illumination. Moreover, both devices having FP and N115 separators showed a significant increase in specific capacitance (Cp) with UV illumination. More specifically, the Cp of the device was calculated from cyclic voltammetry at 1 mVs-1 scan rate, having the FP separator increase 212% compared to the dark condition and reach 1786 Fg-1. On the other hand, the increase in the Cp of the N115 device (6952 Fg-1) under the same conditions was 1014%. It is believed that this high-performance, compact device will pave the way for next-generation energy storage devices, which can both absorb and store solar energy.