Insights on the Electrochemical Activity of Porous Carbonaceous Electrodes in Non-Aqueous Vanadium Redox Flow Batteries

Ibrahim Mustafa, Musbaudeen O. Bamgbopa, Eman Alraeesi, Yang Shao-Horn, Hong Sun, Saif Almheiri
2017 Journal of the Electrochemical Society  
Porous carbonaceous electrodes have the potential utility as electrodes for non-aqueous VRFBs due to being inexpensive, chemically stable, and electrochemically active. In this work, we provide insights on the electrochemical kinetics of [V(acac) 3 ] 0 /[V(acac) 3 ] + and [V(acac) 3 ] 0 /[V(acac) 3 ] − redox reactions at freestanding sheets of multiwalled carbon nanotubes (MWCNTs), or buckypapers (BPs), and graphitized carbon fiber-based nonwovens papers (CPs). The use of freestanding sheets
more » ... estanding sheets eliminates the need for a metal substrate; thus, the true electrochemical response at these electrodes is measured. Even though porous carbonaceous electrodes provide high surface area for the electrochemical reaction, their porous nature poses a fundamental challenge caused by thin-film-like diffusion process; leading to a marked ohmic resistance within the pores of the electrodes. Higher current densities are obtained with the BP electrode due to their larger surface area in comparison to the CP electrode; however, the BP electrode show less efficient kinetic facility for the investigated redox couples as evident by electrochemical impedance spectroscopy and polarization curves results. Charge-discharge cycling demonstrates that porous carbonaceous electrodes may require various treatments to modify the surface chemistries to obtain improved cycling efficiencies. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP A3674 Journal of The Electrochemical Society, 164 (14) A3673-A3683 (2017) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP A3676 Journal of The Electrochemical Society, 164 (14) A3673-A3683 (2017) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP A3680 Journal of The Electrochemical Society, 164 (14) A3673-A3683 (2017) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 80.82.77.83 Downloaded on 2017-12-02 to IP
doi:10.1149/2.0621714jes fatcat:mz3y7ndf7rfwfpt3ss6featvr4