Highly Active Electrospinning Electrode Based on MOF for High-Performance Vanadium Flow Batteries

Abstract

Electrospinning technology has demonstrated excellent prospects in the preparation of structurally controllable functional carbon nanofibers for vanadium redox flow batteries. However, traditional electrospinning carbon nanofibers used for vanadium flow batteries still suffer from defects in electrochemical activity. Herein, a highly active carbon nanofiber electrode based on metal-organic framework materials has been prepared. The introduction and carbonization of the metal-organic framework UiO-66 in the fibers increase the mesoporous structure of the electrode surface. Additionally, the carbonized UiO-66 forms catalytic ZrO2, which enhances the catalytic activity of the carbon nanofibers. Compared to traditional electrospinning carbon nanofibers, the carbon nanofiber electrode based on metal-organic framework exhibits significantly improved wettability and electrochemical properties, which enhance the mass transfer performance and electrochemical activity. The vanadium flow battery adopting active carbon nanofibers achieves an energy efficiency of 83.33% at 200 mA cm-2, and possesses excellent durability performance with unobvious decay after 1000 charge-discharge cycles at 200 mA cm-2. This study provides guidance for further synthesis of high-performance electrodes for vanadium redox flow batteries.

Bimetallic metal–organic framework: an efficient electrocatalyst for bromine-based flow batteries

“…It is observed that the I D / I G ratio is much higher for the NiCo-MOF@GF (1.7) than for the bare electrode (1.1), which suggests that the graphitic domain is rich in defects including functionalization, vacancies, and defective edge sites. 53 The higher defective formation in the NiCo-MOF@GF electrode is attributed to the breakdown of graphitized carbon during thermal treatment leading to disordered graphitic domains. Further, some of the ligands in the NiCo-MOF@GF get partially degraded during thermal treatment to form unsaturated metal coordination sites, which would be highly beneficial for electrocatalytic activity.…”