Performance enhancement in vanadium redox flow battery using platinum-based electrocatalyst synthesized by polyol process

Advanced electrode enabled by lignin-derived carbon for high-performance vanadium redox flow battery

Vanadium redox flow batteries (VRFBs) are promising energy storage systems with the potential to bridge the gap between intermittent renewable electricity generation and continuous supply of reliable electricity. The electrodes found in VRFB cells affect their energy efficiency (EE) and power density. It is important to fabricate electrodes with intriguing properties to enable VRFBs to have high performance. Herein, the abundant and cost-effective lignin is employed as the precursor to produce amorphous carbon particles after undergoing thermal decomposition treatment. The carbon particles cover the surface of carbon felt (CF). The resulting CF modified by lignin-derived carbon particles (Lignin-CF) with increased active sites and improved hydrophilicity displays superior electrochemical activity towards the VO2+/VO2+ pair than both the pristine CF and the heated bare CF. Remarkably, the VRFB consisting of Lignin-CF which acts as the positive electrode shows high performance in terms of the average EE (83.3 %) and average voltage efficiency (VE) (85.0 %) over 1000 cycles (long cycling life) for more than 16 days at 100 mA cm-2, and high power density of 1053.2 mW cm-2. It is noted that the EE and VE are comparable to the highest reported value of CF modified by carbon-based materials, aside having evidently longer cycling life. This study provides a feasible strategy for fabricating an affordable electrode for high-performance VRFBs.

Evolution of Vanadium Redox Flow Battery in Electrode

The vanadium redox flow battery (VRFB) is a highly regarded technology for large-scale energy storage due to its outstanding features, such as scalability, efficiency, long lifespan, and site independence. This paper provides a comprehensive analysis of its performance in carbon-based electrodes, along with a comprehensive review of the system's principles and mechanisms. It discusses potential applications, recent industrial involvement, and economic factors associated with VRFB technology. The study also covers the latest advancements in VRFB electrodes, including electrode surface modification and electrocatalyst materials, and highlights their effects on the VRFB system's performance. Additionally, the potential of two-dimensional material MXene to enhance electrode performance is evaluated, and the author concludes that MXenes offer significant advantages for use in high-power VRFB at a low cost. Finally, the paper reviews the challenges and future development of VRFB technology.

Biomass-derived carbon materials for vanadium redox flow battery: From structure to property

Biomass-derived carbon (BDC) materials are suitable as electrode or catalyst materials for vanadium redox flow battery (VRFB), owing to the characteristics of vast material sources, environmental friendliness, and multifarious structures. A timely and comprehensive review of the structure and property significantly facilitates the development of BDC materials. Here, the paper starts with the preparation of biomass materials, including carbonization and activation. It is designed to summarize the lastest developments in BDC materials of VRFB in four different structural dimensions from zero dimension (0D) to three dimension (3D). Every dimension begins with meticulously selected examples to introduce the structural characteristics of materials and then illustrates the improved performance of the VRFB due to the structure. Simultaneously, challenges, solutions, and prospects are indicated for the further development of BDC materials. Overall, this review will help researchers select excellent strategies for the fabrication of BDC materials, thereby facilitating the use of BDC materials in VRFB design.

Review on the Applications of Biomass-Derived Carbon Materials in Vanadium Redox Flow Batteries

The development of vanadium redox flow batteries (VRFBs) requires the exploration of effective and affordable electrodes. In order to increase the electrochemical activity of these electrodes and decrease the polarizations, they are doped with an electrocatalyst. In this context, the use of biomass-derived materials as electrocatalysts in VRFBs has received much attention recently due to their widespread availability, renewable nature, low cost, and high energy efficiency. This paper aims to review the synthesis methods of biomass-derived carbon materials and their applications in VRFBs. In line with this aim, recent developments in carbon-based electrode modification methods and their electrochemical performance in VRFBs are summarized. The studies show that porous carbon electrocatalysts increase energy efficiency by reducing overpotentials and improving electrocatalytic activation. In addition, it is thought that biomass carbon doped electrocatalysts can improve the hydrophilicity of the electrodes, the transfer of vanadium ions, and the reaction kinetics. The highest charge voltage decrease rate of 8.61% was obtained in the Scaphium scaphigerum, whereas the highest discharge voltage increase rate of 14.29% was observed in the twin cocoon, as in all reviewed studies. Furthermore, the maximum energy efficiency (75%) was achieved in a VRFB equipped with an electrode doped with carbon derived from Scaphium scaphigerum and cuttlefish. It can be concluded from the reviewed studies that the electrochemical performances of electrodes doped with biomass-derived carbons in VRFBs are more effective than those of the bare electrodes.

Atmospheric Pressure Tornado Plasma Jet of Polydopamine Coating on Graphite Felt for Improving Electrochemical Performance in Vanadium Redox Flow Batteries

The intrinsic hydrophobicity of graphite felt (GF) is typically altered for the purpose of the surface wettability and providing active sites for the enhancement of electrochemical performance. In this work, commercial GF is used as the electrodes. The GF electrode with a coated-polydopamine catalyst is achieved to enhance the electrocatalytic activity of GF for the redox reaction of vanadium ions in vanadium redox flow battery (VRFB). Materials characteristics proved that a facile coating via atmospheric pressure plasma jet (APPJ) to alter the surface superhydrophilicity and to deposit polydopamine on GF for providing the more active sites is feasibly achieved. Due to the synergistic effects of the presence of more active sites on the superhydrophilic surface of modified electrodes, the electrochemical performance toward VO2+/VO2+ reaction was evidently improved. We believed that using the APPJ technique as a coating method for electrocatalyst preparation offers the oxygen-containing functional groups on the substrate surface on giving a hydrogen bonding with the grafted functional polymeric materials.

Inexpensive, Three-Dimensional, Open-Cell, Fluid-Permeable, Noble-Metal Electrodes for Electroanalysis and Electrocatalysis

This study describes the fabrication of three-dimensional, open-cell, noble-metal (Au, Ag, and Pt) electrodes that have a complex geometry, i.e., wire mesh, metallic foam, "origami" wire mesh, and helix wire mesh. The electrodes were fabricated using an ultrasonication-assisted electroplating method that deposits a thin, continuous, and defect-free layer of noble metal (i.e., Au, Ag, or Pt) on an inexpensive copper substrate that has the desired geometry. The method is inexpensive, easy to use, and capable of fabricating noble-metal electrodes of complex geometries that cannot be fabricated using established techniques like screen printing or physical vapor deposition. By minimizing the amount of the pure noble metal in the electrodes, their cost drops significantly and could become low enough even for single-use applications; for example, the cost of metal in a Au wire-mesh electrode is $0.007/cm² of exposed area that is about 400 times lower than that of a wire-mesh electrode composed entirely of Au. The electrodes exhibit an almost identical electrochemical performance to noble-metal electrodes of similar shape composed of bulk noble metal; therefore, these electrodes could replace two-dimensional noble-metal electrodes (e.g., rods, disks, foils) in numerous electroanalytical and electrocatalytical systems or even allow the use of noble-metal electrodes in new applications such as flow-based electrochemical systems. In this study, wire-mesh and metallic foam noble-metal electrodes have been successfully used as working electrodes for the electrocatalytical oxidation of methanol and for the electrochemical detection of redox mediators, lead ions, and nitrobenzene using various electroanalytical techniques.

Antimony-doped tin oxide as an efficient electrocatalyst toward the VO2+/VO2+ redox couple of the vanadium redox flow battery

Enhanced electrocatalytic activity of ATO toward the VO²⁺/VO²⁺ redox reaction by adjusting electronic conductivity.

Vanadium Redox Flow Batteries Using meta-Polybenzimidazole-Based Membranes of Different Thicknesses

15, 25, and 35 μm thick meta-polybenzimidazole (PBI) membranes are doped with H₂SO₄ and tested in a vanadium redox flow battery (VRFB). Their performances are compared with those of Nafion membranes. Immersed in 2 M H₂SO₄, PBI absorbs about 2 mol of H₂SO₄ per mole of repeat unit. This results in low conductivity and low voltage efficiency (VE). In ex-situ tests, meta-PBI shows a negligible crossover of V³⁺ and V⁴⁺ ions, much lower than that of Nafion. This is due to electrostatic repulsive forces between vanadium cations and positively charged protonated PBI backbones, and the molecular sieving effect of PBI's nanosized pores. It turns out that charge efficiency (CE) of VRFBs using meta-PBI-based membranes is unaffected by or slightly increases with decreasing membrane thickness. Thick meta-PBI membranes require about 100 mV larger potentials to achieve the same charging current as thin meta-PBI membranes. This additional potential may increase side reactions or enable more vanadium ions to overcome the electrostatic energy barrier and to enter the membrane. On this basis, H₂SO₄-doped meta-PBI membranes should be thin to achieve high VE and CE. The energy efficiency of 15 μm thick PBI reaches 92%, exceeding that of Nafion 212 and 117 (N212 and N117) at 40 mA cm^-2.

Synergistic catalytic effects of oxygen and nitrogen functional groups on active carbon electrodes for all-vanadium redox flow batteries

Thin pyroprotein coating layers containing numerous oxygen and nitrogen heteroatoms were introduced on the surface of CFs (P-CFs), and their catalytic effects on the redox reaction of V²⁺/V³⁺ couples for VRFBs were investigated.

MoO2 nanocrystals interconnected on mesocellular carbon foam as a powerful catalyst for vanadium redox flow battery

MoO₂ nanocrystals on mesocellular carbon foam are used for a high performance vanadium redox flow battery. This improves the slow reaction of the VO²⁺/VO²⁺ redox couple, inducing high efficiencies with high specific capacity.

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

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).