ZrO2 nanoparticle embedded carbon nanofibers by electrospinning technique as advanced negative electrode materials for vanadium redox flow battery

Abstract

ZrO2 nanoparticle decorated carbon nanofibers (ZrO2/CNF) were explored by electrospinning technique with ZrOCl2·8H2O and polyacrilonitrile (PAN) as precursors, and were considered as negative electrode for vanadium redox flow battery (VRFB). It is found that the ZrO2 nanoparticle uniformly embedded in the CNF not only increases the disorder of CNF, but also improves the catalytic activity of CNF, further resulting in good electrochemical activity. Specially, the sample with proper content of ZrO2 (CNFZrO2-18) shows superior electrochemical activity for the negative couple for VRFB. Furthermore, the charge-discharge tests verify that CNFZrO2-18 can enhance performance of cell. At 100 mA cm−2, the discharge capacity and energy efficiency of the cell with CNFZrO2-18 arrive at 91.5 mA h and 73.3%, 8.7% and 8.3% more than those of pristine cell, respectively. After charging and discharging for 50 cycles at 80 mA cm−2, the cell exhibits outstanding stability with initial discharge capacity retention of 95.0%. The high electrochemical performance of ZrO2/CNF mainly comes from the good electrocatalytic properties of ZrO2 and in situ decoration for CNF by electrospinning technique.