Abstract
The regenerative hydrogen/vanadium fuel cell (RHVFC) is investigated with Freudenberg carbon paper electrodes (CPs). Along with thermal treatment, the Freudenberg CPs are also treated with reduced graphene oxide (rGO) using electrophoretic deposition at 300 V. The rGO modified CP results in 25% higher power density than its untreated counterpart under the same operating conditions. In comparison to the first preliminary study, the power density reported herein is more than four times higher. Additionally, the Freudenberg CPs modified with heat treatment followed by rGO deposition facing the membrane (rGOHTFM) provide the best electrolyte discharge utilization (UE) of 99%, followed by untreated (98%) and heat treated samples (97%) at 50 mA cm(-2). The rGOHTFM also record high charge and discharge energy efficiencies (eta(E)) of 93% at the same current density, which is slightly higher than untreated CPs (eta(E) = 91%). Cycling the system 10 times also results in higher eta(E) and UE for rGOHTFM CP (eta(E) = 92% and UE = 99% on average) in comparison to untreated electrodes (eta(E) = 86% and UE = 97% on average). In comparison the widely investigated SGL 10AA CP has lower efficiencies and utilization as expected (eta(E) = 74% and UE = 83% on average). (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.