Preparation and Electrochemical properties of Pt-Ru/Mn3O4/C Bifunctional Catalysts for Lithium-air Secondary Battery

초록

Rechargeable lithium-air battery has been attractive as future energy storage device because of its higher energy density than lithium-ion battery. However, in practice, there are many fundamental challenges to solve for commercialization of Lithium-air battery, including poor cyclability, low capacity and high charge overpotential. Among them, the development of bifunctional catalyst with advanced activity and stability is especially important. [1, 2]. Various catalysts have been investigated, such as transition metal oxides, precious and non-precious metal based materials. Most of all, Pt and Ru have been reported as promising catalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In addition, manganese oxide has attracted much attention as electrochemical catalyst due to its low cost and abundance. In this work, Pt-Ru/Mn3O4/C composite was synthesized by both precipitation and impregnation method. Then, their catalytic properties as air electrode of lithium-air battery were evaluated. X-ray diffraction (XRD) analysis was used to investigate the crystallinity of the synthesized catalysts. The morphologies of catalysts were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The charge-discharge behaviors were examined in O2 atmosphere for evaluation of performance of synthesized catalysts. In summary, Pt-Ru/Mn3O4/C composite catalyst showed improved catalytic performance, reducing overpotentials for both charging and discharging and improving cyclic properties.