RuO₂/MWCNT/ stainless steel mesh as a novel positive electrode in vanadium redox flow batteries

Abstract

The present work describes the preparation and electrochemical characterization of RuO2/MWCNT/Stainless Steel Mesh (SSM) electrode as compared with a MWCNT/SSM electrode in the positive half-cell of a Vanadium Redox Flow Battery (VRFB). The electrochemical characterization of prepared electrode was carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge procedures. The electrochemical activity of MWCNT/SSM modified with RuO2 as positive electrode in a VRFB was notably improved. The RuO2-included electrodes demonstrated high peak current ratio, small peak potential difference and high electron transfer rate constant, confirming excellent electro-catalytic activity and reversibility. These good electrochemical results, together with the long term stability of the prepared electrode, represent a significant step forward in the development of highly effective positive electrode materials for VRFBs. IntroductionAmong a wide range of energy storage technologies, redox flow batteries (RFB) offer several unique advantages, including the system scalability, long cycle life, and high energy efficiency [1]. RFBs are electrochemical energy storage devices where the energy is stored and converted through chemical changes of species dissolved in a working fluid. Among various kinds of RFB, vanadium RFB (VRFB) consisting of [VO] 2+ /[VO 2 ] + redox couples in the positive electrode and [V] 3+ /[V] +2

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

“…RuO 2 deposited electrochemically on MWCNT attached with a binder (PVC) to a stainless steel mesh has been proposed as a positive electrode in a VRFB [431]. Corrosion rate of the steel was considered to be acceptable.…”

Metal and Metal Oxide Electrocatalysts for Redox Flow Batteries

“…RuO 2 and other tetravalent ruthenium oxides are reported to be suitable materials for electrode components in many electrochemical systems. [ 126 ] Thus, Gobal et al [ 126 ] suggested the use of RuO 2 to enhance the V(IV)/V(V) reaction and fabricated a catalyst by incorporating the oxide into MWCNTs supported by a stainless steel mesh (SSM) substrate. The RuO 2 ‐MWCNT completely covered the surface of the SSM substrate to prevent its corrosion by the electrolyte.…”

“…Half‐cell galvanostatic charge/discharge of V(IV)/V(V) redox reaction on RuO 2 ‐MWCNT‐SSM electrode for the first and 10 th days. Extracted with permission from [ 126 ] .…”

Unveiling the Role of Heteroatom Gradient-Distributed Carbon Fibers for Vanadium Redox Flow Batteries with Long Service Life

“…For example, the deposited noble metal (Pt , and Ir) catalysts exhibit high activity for positive or negative redox reactions, but these metals are expensive and prone to gas evolution. Inexpensive metal (Bi) or metal oxides (Nb 2 O 5 , Mn 3 O 4 , , TiO 2 , RuO 2 , and WO 3 ) have been used as substitutes for noble metal catalysts to enhance the activity of vanadium ion reaction. However, the electrocatalytic activity of the abovementioned electrodes is inhibited by the nonhomogeneous distribution and low activity caused by the large size, and their preparation processes are tedious and intricate.…”