Facile Synthesis of Poly(3,4-ethylene dioxythiophene) Intercalated Potassium Vanadate Nanofiber and Their Application in Cathode Active Materials of Zinc-ion Batteries
2022 Fall meeting & Academic Presentation of the Korean Electrochemical Society, BEXCO BUSAN, Korea (2022)
Yong Yeol Park, Se Hun Lee, Ok Sung Jeon, Young Pyo Jeon, Dongpyo Hong, Seoyoung Kang, Sang Yoon Park, Yuanzhe Piao
Abstract
Since lithium-ion batteries (LIBs) have problems such as, high prices (lithium, 70.66 $ kg-1) by lack of raw material reserves (lithium, 13 million tons), and intrinsic safety issues by flammability/toxicity.
Therefore, research on aqueous zinc ion batteries (AZIBs) with characteristics such as abundant reserves (Zinc, 280 million tons), eco-friendliness, and high stability is in the spotlight. The vanadate, one of the representative cathode materials of AZIBs, can indicate high capacity in a multivalent state, have abundant reserves, and have a layered structure, which facilitates intercalation/de-intercalation of zinc ions into the lattice of vanadate. Recently, many studies have been reported on vanadate having the structure of MxV6O16 * nH2O containing cationic metal ions & water molecules that can provide a pillar & lubricant effect. However, these vanadates still have some challenges to overcome. First, most of the methods for synthesizing vanadates with the structure of MxV6O16 * nH2O use the hydrothermal method, which is difficult to scale-up and requires a long reaction time. Second, it is necessary to solve the problem of low conductivity, which is an inherent problem of vanadium-based compounds. In this study, we synthesized one-dimensional (ID) structured potassium vanadete nanofibers (PVNF) in a relativey short reaction time compared to hydrothernal methods using the sonochemical method. In addition, to further improve electrical cinductivity, a composite (E-PVNF) in which a PEDOT is inseted between PVNF layers was designed. The synthesized PVNF and E-PVNF have a 1D morphology, so the rate capability can be improved by short ion pathways and large active areas in the device. In particular, the E-PVNF was avle to further widen the distance between the PVNF layers from 0.81 nm to 0.94 nm by intercalating a PEDOT. Such a wide interlayer distance of E-PVNF enables a faster ion diffusion and shows excellent rate capability.