High-performance vanadium redox flow batteries employing IrOx/ TiO2 NTs/Ti substrate as a thin bipolar plate

초록

Thin DSA as bipolar plates designed to replace a glassy carbon plate was used for the first time to enhance improved dimensions and electrochemical catalytic properties in all-vanadium redox flow batteries (VRFBs). In this study, we found that a 0.127 mm-thick DSA consisting of TiO2 nanotube arrays on Ti metal substrate coated with IrOx layer worked extremely well as the bipolar plate for enhancing performance of VRFBs. Using this material, overpotential and charge transfer resistance for charging and discharging were reduced due to the catalytic properties and conductivity of IrOx, which improved the transfer of electrons or the electrical current. Furthermore, the stability of the IrOx layer on the TiO2 nanotube arrays grown from the Ti metal substrate was confirmed after 100 cycles. The energy efficiency of the VRFBs based on the improved bipolar plate increased up to 4 % compared to that of the glassy carbon plate, suggesting that this thin bipolar plate offers not only dimensional advantages, but also electrochemical advantages for VRFBs.