Synthesis, fabrication and characterization of 2-naphthyloxy group-substituted bis(2-pyridylimino)isoindoline and its derivatives as a positive electrode for vanadium redox flow battery applications

Selin Gümrükçü,  Mukaddes Özçeşmeci,  Nilüfer Koçyiğit, Kerem Kaya, Ahmet Gül,  Yücel Şahin* and İbrahim Özçeşmeci *

In this research has been examined by Associate Professor Dr. İbrahim Özçeşmeci’s laboratory group. The present work has been supported scholarship via the Technological Research Council of Türkiye (TUBITAK; 2211C) and published in the RSC Dalton Transactions. 1,3-bis(2-pyridylimino)isoindole (BPIs) compounds are good candidates for a wide range of feasible applications owing to their ease in synthesis, simple to modify structure, and high stability. In this research study, a 1,3-bis(2-pyridylimino) isoindoline derivative bearing a naphthoxy unit and its palladium complex (PdBPI) were synthesized and detailed structural characterizations of the synthesized substances were performed. For the first time, an innovative electrode design for the VRB systems was developed utilizing a single-step electrodeposition approach on the PGE surface, including metal-free (BPI) and palladium(II) (PdBPI) complexes. Innovative electrode materials were characterized using advanced spectroscopic methods. The catalytic effect of the BPI and PdBPI-modified PGEs on the V(4)/V(5) reaction was approximately 5 and 7 times higher than the pristine PGE, respectively. The behaviors of the BPI modified carbon felt electrode (BPI-CF) and PdBPI-modified carbon felt electrode (PdBPI-CF) were investigated in the redox flow battery (RFB) applications. For the first time in the literature, the performance of these chemical compounds in a vanadium redox flow battery (VRB) system has been investigated.  Since these electrode materials have been utilized successfully for the VRB system,  this work can be a pioneer work for future studies.