MoO2–graphene nanocomposite as an electrocatalyst for high-performance vanadium redox flow battery

Recent Advances for Electrode Modifications in Flow Batteries: Properties, Mechanisms, and Outlooks

“…The same research group used the hydrothermal method and heat treatment to prepare MoO 2 -rGO modified GF electrodes as positive and negative electrodes of VFB. [88] MoO 2 contained abundant oxygen vacancies and rGO had high electrical conductivity and a large number of OCFs. The synergistic effect of MoO 2 nanoparticles and rGO could improve the wettability of MoO 2 -rGO, increase the effective surface area, improve the mass transport at the electrode interface, and avoid the restacking of rGO sheets and the aggregation of nanoparticles, increasing the effective surface area and active sites for vanadium ion redox reactions.…”

BiVO4-Decorated Graphite Felt as Highly Efficient Negative Electrode for All-Vanadium Redox Flow Batteries

“…Among various energy storage devices, the vanadium redox flow battery (VRFB), first invented by Skylla-Kazacos and co-workers in the 1980s, is one of the most promising large-scale energy storage devices owing to its design flexibility, extended cycle life, and safe operation. − Furthermore, the VRFB avoids the risk of cross-contamination issues due to the employment of the same electroactive element (vanadium) for both half-cells . The VRFB comprises three essential components: membrane, electrolyte, and electrode. − To store energy, it uses the redox couples of the electrolyte, V 3+ /V 2+ and VO 2+ /VO 2 + , on the negative and positive sides, respectively. , The membrane behaves as a separator for the two half-cells and maintains electroneutrality by passing hydrogen ions through it . The electrode does not participate in the redox reaction but provides a reaction site for active species .…”

Nitrogen-Doped Tungsten Carbide-Modified Graphite Felt as a Bifunctional Electrocatalyst for an All-Vanadium Redox Flow Battery

“…3 The VRFB is predominantly made of electrodes, an ion exchange membrane, and electrolyte. 6,7 Electrodes, as a core part, can directly affect the final cost as well as the effectiveness of the battery. 4 Various carbon materials (graphite felt, carbon cloth, carbon paper, and carbon felt) are extensively employed as electrodes for VRFBs thanks to their favorable characteristics, such as low cost, chemical stability, broad operational potential range, three-dimensional structure, and high electronic conductivity.…”

“…Owing to several desirable characteristics such as low maintenance cost, independent tunable capacity and power, and environmental friendliness, the vanadium redox flow battery (VRFB) has drawn wide attention in energy storage and conversion. − Furthermore, due to utilizing the same element, vanadium, in both half cells, VRFBs are free of crossover contaminations through the membrane and consequently prolong the batteries’ lifetime. , Despite several advantages, their relatively low energy efficiency and fabrication cost limit their commercial viability . The VRFB is predominantly made of electrodes, an ion exchange membrane, and electrolyte. , Electrodes, as a core part, can directly affect the final cost as well as the effectiveness of the battery …”

“…Different research findings have suggested that the performance of VRFBs can be improved by depositing noble metals including Bi, Pd, Au, Ru, and Pt; nevertheless, this approach is impractical due to susceptibility to the H 2 evolution process and high cost. − Hence, efforts to develop innovative electrodes having stability in acidic conditions and reasonable cost are required . Recently, the use of inexpensive metal oxides, for instance, PbO 2 , WO 3 , Mn 3 O 4 , Ta 2 O 5 , MnO 2 , TiO 2 , Nb 2 O 5 , CeZrO 2 , and LaBO 3 (B = V, Cr, Mn) perovskites, have been suggested. ,,,− However, the mentioned approach did not demonstrate a significant improvement in VRFB performance due to the low surface area, low conductivity, non-uniform distribution of the nanoparticles, and weak interaction with the carbon material. ,, The use of nitrogen-doped GF has been reported by He et al . Accordingly, N-doped GF shows an improvement in electrochemical performance toward the VO 2+ /VO 2 + and V 3+ /V 2+ redox reaction.…”