TixOy loaded carbon felt as high performance negative for vanadium redox flow battery

To improve the power density and energy density of vanadium flow batteries (VFBs), a novel Ti x O y -loaded carbon felt (Ti x O y -CF) electrode is designed, fabricated, and applied. Ti x O y (consisted of TiO 2 and Ti 4 O 7 ) has the advantages of easy preparation, high electrical conductivity , good stability, etc. It is evenly distributed on carbon felt and shows high catalytic efficiency on V 2+ /V 3+ redox couple to facilitate the electrochemical kinetics of the vanadium redox reactions . As a result, the VFB assembled with Ti x O y -CF achieves a high energy efficiency of 82.0% at a current density of 200 mA cm −2 , and maintains 77.9% energy efficiency at 260 mA cm −2 . In addition, the VFB with Ti x O y -CF exhibits good stability and high capacity retention within 400 cycles at 100 mA cm −2 . This work provides a new perspective for the development of highly active electrodes for VFBs.