매우 신축성이 우수한 아연-공기 배터리를 위한 다(多)기능성 에어로겔

Abstract

Multi-functional Electrocatalysts for Highly Compressible Zinc-Air Batteries Park, Seung Hee Advisor : Prof. Ahn, Sung Hoon, Ph.D. Department of Chemical Engineering Graduate School of Chosun University According to the increasing demand of wearable storage devices, Zinc-Air Batteries (ZABs) that can be controlled into various shapes are promising candidates for next generation energy storage devices. Customizable electrodes provide many advantages, including application to wearable devices and new form factors. However, existing electrodes are brittle to be applied to new types of energy storage devices and suffer from insufficient mechanical strength. In this study, para-aramid fibers were converted into nano-scale fibers, and then self-assembled to make aramid nanofiber (ANF) aerogel (AG). By controlling the concentration of the ANF hydrogel solution, customizable electrodes support with various thicknesses, porosity, flexibility, and compressibility could be fabricated. As a result, the mechanical properties of these electrodes not only design various customizable electrodes, but also satisfy battery performance. ANF hydrogels with aligned ANFs were prepared in layered ranging from TFs of milli-meters to AGs of centi-meters introducing directional freezing method. By having a layered structure with aligned pores, the manufactured AGs showed superelasticity that could be variously twisted or bent in shape and compressed. Carbon Nano Tubes (CNTs) and trace amounts of Ru and Mn were coated on the surface of the AGs and TFs to impart electro-conductivity and electro-chemical activity to the aramid-based AGs and TFs as insulator. The well-coated AGs and TFs demonstrate good tri-functional activity of superior HER activities (e.g. η10 = 10 mV in 1M KOH) than Pt/C (e.g. η10 = 43 mV in 1M KOH), OER activities (e.g. η10 = 220 in 1M KOH) than Ir/C (e.g. η10 = 294 mV in 1M KOH), and ORR activities (e.g. E1/2 = 0.81 V in 0.1M KOH). Each reaction showed a very stable voltage for more than 50 h and had good durability. The AG and TF electrodes with these performances could be applied to solid-state ZABs with a very low voltage gap of 0.18 V and stable performance for mote than 200 h. These customizable electrode design promise for developing versatile, high performance and wearable energy storage devices.