All-vanadium Redox Flow Battery Research Articles

The effect of Zn2+ on the positive electrolyte for all-vanadium redox flow battery

In this work, the effects of Zn2+ on the electrochemical activity of positive electrolyte were researched by cyclic voltammetry(CV), AC impedance. The results of CV showed that the positive electrolyte containing 2 wt% Zn2+ as additive had the best electrochemical activity. Compared with the electrolyte without any additive, the electrolyte with 2 wt% Zn2+ obviously enhanced electrochemical activity and reversibility of Farady reaction. In addition, the kinetic study of the mass transfer process indicated that the diffusion coefficient obviously increased. Besides, the results of electrochemical impedance spectroscopy implied that the internal charge transfer resistance of the electrolyte electrochemical system containing Zn2+ as an additive was significantly reduced. This indicated that the charge transfer was significantly accelerated, which was beneficial to the improvement of the electrochemical activity. Moreover, the study of the electrolyte stability showed that the electrolyte containing Zn2+ had superior stability yet after 30 cycles’ scanning.

Redox flow battery:Flow field design based on bionic mechanism with different obstructions

All-vanadium redox flow batteries (VRFBs) are pivotal for achieving large-scale, long-term energy storage. A critical factor in the overall performance of VRFBs is the design of the flow field. Drawing inspiration from biomimetic leaf veins, this study proposes three flow fields incorporating differently shaped obstacles in the main flow channel. These designs aim to enhance the electrolyte diversion into branches, achieving a more uniform electrolyte distribution. Among these, the structure featuring circular obstacles demonstrated superior performance, exhibiting the lowest charging voltage and the highest discharging voltage. It also achieved the highest concentration uniformity of the active species (0.903). In comparison, at the flow rate of 3ml/s and the current density of 40mA cm−2, the efficiency based on pump power saw a maximum increase of 1.7 % and the efficiency based on output power experienced a maximum improvement of 2.5 %. This work offers a new direction in studying biomimetic flow field design and holds considerable potential for practical engineering applications.

Self-Standing Covalent Organic Polymer Membrane with High Stability and Enhanced Ion-Sieving Effect for Flow Battery.

Fabrication of ion-conducting membranes with continuous sub-nanometer channels holds fundamental importance for flow batteries in achieving safe integration of renewable energy into grids. Self-standing covalent organic polymer (COP) membranes provide feasibility due to their rapid and selective ion transport. However, the development of a scale-up possible, mechanically robust and chemically stable membranes remains a significant challenge. Herein, using irreversible strong secondary amine linkage, we propose a self-standing COP membrane with sub-nanometer pores ranging from 4.5 to 6.4 Å, by a simple and efficient in-situ polymerization approach. This membrane exhibits enhanced selectivity for proton and vanadium ions, especially excellent electrochemical stability, delivering an energy efficiency of over 80% at the current density of 200 mA cm-2 over 1000 cycles for an all-vanadium redox flow battery (VFB). This study provides novel insights for COP-based ion-sieving membranes in sustainable energy fields.

Microfluidic Synthesis of Multifunctional Micro-/Nanomaterials from Process Intensification: Structural Engineering to High Electrochemical Energy Storage.

Multifunctional micro-/nanomaterials featuring functional superiority and high value-added physicochemical nature have received immense attention in electrochemical energy storage. Microfluidic synthesis has become an emergent technology for massively producing multifunctional micro-/nanomaterials with tunable microstructure and morphology due to its rapid mass/heat transfer and precise fluid controllability. In this review, the latest progresses and achievements in microfluidic-synthesized multifunctional micro-/nanomaterials are summarized via reaction process intensification, multifunctional micro-/nanostructural engineering and electrochemical energy storage applications. The reaction process intensification mechanisms of various micro-/nanomaterials, including quantum dots (QDs), metal materials, conducting polymers, metallic oxides, polyanionic compounds, metal-organic frameworks (MOFs) and two-dimensional (2D) materials, are discussed. Especially, the multifunctional structural engineering principles of as-fabricated micro-/nanomaterials, such as vertically aligned structure, heterostructure, core-shell structure, and tunable microsphere, are introduced. Subsequently, the electrochemical energy storage application of as-prepared multifunctional micro-/nanomaterials is clarified in supercapacitors, lithium-ion batteries, sodium-ion batteries, all-vanadium redox flow batteries, and dielectric capacitors. Finally, the current problems and future forecasts are illustrated.

Mitigation of Negative-Electrode Degradation in Vanadium Redox Flow Batteries

Electrode overpotentials are among the major factors that impact the performance of redox flow batteries (RFBs). However, even though the all-vanadium redox flow battery (VRFB) is the most mature flow-battery chemistry, a recent review article has pointed out that “there is poor agreement between the reported values of kinetic parameters” [1]. Major contributors to this disagreement are the wide variety of carbon materials that are used as electrodes and because the kinetics of both the V(II)/V(III) and V(IV)/V(V) reactions on carbon depend on the electrode pretreatments. The role of surface functional groups and the mechanisms of electron transfer for these reactions is not well understood [1]. There is general agreement that the V(IV)/V(V) kinetics are more facile than the V(II)/V(III) kinetics [2, 3]. Multiple researcher groups have reported electrode overpotential increases with time, and “there is evidence that it occurs mainly on the negative electrode” [1]. Additionally, “reversing the polarity of the VRFB has been suggested as one strategy to recover lost performance but not all investigators have found this strategy effective” [1]. Exposing the V(II)/V(III) electrode to V(IV)/V(V) electrolyte may increase the roughness and oxidize the electrode, which can both improve the activity. It has also been suggested that reversing the polarity may remove impurities, such as copper metal from the negative electrode [4]. More recently, it has been proposed that surface activity may be improved by oxidizing adsorbed V(II) [5]. We hypothesize that V(II)/V(III) electrode degradation on graphitic carbon-fiber electrodes is primarily due to the adsorption of a contaminate that is oxidized when exposed to V(IV)/V(V) electrolyte. We will describe what we suspect is the relevant contaminate species, and we will show the stability of the V(II)/V(III) electrode can be substantially improved by simply removing certain electrolyte-wetted components from the VRFB test apparatus. References A. Bourke, D. N. Buckley, et.al., “JES, 170 (2020). 10.1149/1945-7111/acbc99 D. Aaron, T. A. Zawodzinski, et. al., ECS Electrochem. Letters, 2 (2013) 10.1149/2.001303eel N. Pour, Y. Shao-Horn, et.al., J. of Physical Chemistry C, 119 (2015).10.1021/jp5116806 D. Reynard, H. Girault, et.al., ChemSusChem, 12 (2019). 10.1002/cssc201802895T. Greese and G. Reichennauer, J. Power Sources, 500 (2021). 10.1016/j/jpowsour.2021.229958

Superior Activity of Carbon Felt Coated with PEDOT and Titanium Oxide Double Layers Towards V(II)/(VIII) Reaction in Redox Flow Batteries

Energy consumption has become a great problem in the last few decades due to the dramatic increment in population and solo dependence on fossil fuels to fulfill energy requirements. The intense consumption of these limited non-renewable resources had harmful effects on humanity, making the adoption of renewable energy resources compulsory. High-efficiency storage systems are necessary for the integration of renewable energy sources into the electrical grid and for the provision of that energy when needed. For this application, all-vanadium redox flow batteries (VRFBs) hold great promise because of their high energy storage capacity, extended operational life, and long-life reusable solutions1. The enhancement of RFBs should be taken from many perspectives such as the enhancement of electrodes, membranes, or even the design of the cell. Enhancing the electrode performance is one of the important challenges that attracted the attention of researchers, with a variety of electrode modifications that have been studied such as using carbon, metals, and metal oxide materials2,3. Over a large number of metal oxides, TiO2 possesses interesting catalytic properties as it has been used in sensors, Li-ion batteries, and electrocatalysis, in addition to its ability to suppress the hydrogen evolution reaction (HER) which was a stumbling block for the negative side of VRFBs4.The goals of this work are to suppress the parasitic reaction of hydrogen evolution and improve the kinetics of the VRFBs' negative half-cell reaction (V(II)/V(III)). To achieve this goal, coating carbon felt (CF) with poly(3,4-ethylenedioxythiophene) (PEDOT) and Titanium Oxide double layers was proposed. The underlayer of PEDOT is expected to enhance the TiOx conductivity, and hence its electrocatalytic activity, but without enhancing the parasitic HER5. The PEDOT layer was formed using chronopotentiometric electropolymerization method, followed by the deposition of a TiOx layer using a solvothermal method. To understand the effect of the PEDOT and TiOx layers on the final electrode activity towards V(II)/V(III) redox reaction, several electrodes (CF\\PEDOT, CF\\G-PEDOT, CF\\TiOx CF\\PEDOT\\TiOx, and CF\\G-PEDOT\\TiOx) were fabricated. The physical and chemical properties of the synthesized electrodes were characterized using XRD, FESEM, EDX, UV-vis DRS, Raman spectroscopy, FTIR, contact angle measurements, and XPS. The performance of the fabricated electrodes towards V(II)/V(III) redox reaction was evaluated in 3-electrode and 2-electrode setups, using cyclic voltammetry, electrochemical impedance spectroscopy, and charging/discharging methods. The addition of an underlayer of PEDOT is found to generally enhance the TiO2 activity as a negative electrode in VRFB. References R. K. Sankaralingam, S. Seshadri, J. Sunarso, A. I. Bhatt, and A. Kapoor, J. Energy Storage, 41, 102857 (2021).Z. Huang, A. Mu, L. Wu, and H. Wang, J. Energy Storage, 45, 103526 (2022).Y. Lv et al., J. Mater. Sci. Technol., 75, 96–109 (2021).J. Vázquez-Galván et al., ChemSusChem, 10, 2089–2098 (2017).M. Heydari Gharahcheshmeh et al., Adv. Mater. Interfaces, 7, 2000855 (2020).

Operando Visualization of Redox Flow Batteries Using Fluorescence Spectroscopy with Alizarin Red S Electrolyte

Redox flow batteries (RFBs) charge and discharge by transferring electrons between two pairs of redox species separated by a proton exchange membrane. Unlike traditional batteries that store energy in redox-active materials within an enclosed cell, RFBs store energy in liquid electrolytes housed in external reservoirs1. These electrolytes are pumped through the cell, enabling redox reactions on the surface of electrodes. The energy storage capacity of RFBs is determined by the concentration of the active species and the size of the reservoirs, making them a promising technology for large-scale energy storage applications2. While RFBs possess advantages such as long lifetime, flexible design for battery capacity and power, and rapid response, they suffer from drawbacks like low energy density, power density, and energy efficiency3. Efforts to address these issues have primarily focused on modifications to the electrode materials or the flow field4 , 5. However, evidence supporting performance enhancements often relies on global parameters such as energy efficiency, energy density, and voltage drop, lacking detailed mechanistic and microscopic studies. Real-time observation of the electrode-electrolyte interface during redox reactions and the transport of redox species in the flow field holds the potential to significantly contribute to understanding the electrode structure and mass transport phenomena in RFBs6. This understanding, in turn, facilitates prediction and purposeful enhancement of battery performance by developing desirable structures for both electrode and flow fields. Microscopy, particularly confocal microscopy, serves as a powerful tool for observing microscopic structures. Confocal microscopes yield sharper images with higher resolution than widefield microscopy, enabling rapid acquisition of high-resolution images.In this study, we employed a confocal laser scanning microscope for operando visualization of RFBs. We designed a transparent framework for the battery, allowing light to pass through, and covered its surface with a glass cover to visualize the porous carbon electrode. We selected a fluorescent redox-active species, Alizarin Red S to enable visualization using fluorescence spectroscopy. Leveraging its unique fluorescence properties, we established a correlation between fluorescence intensity and the state of charge. This innovative approach enables us to observe the distribution of electrolytes, the dynamics of redox reactions on the electrode surface (with fast speed of imaging ＜0.2s), the mass transfer behavior of the electrolyte on the electrode surface, and the uniformity of electrolyte flow in the flow field, including areas of stagnation or recirculation. Zhang, J. et al. An all-aqueous redox flow battery with unprecedented energy density. Energy Environ. Sci. 11, 2010–2015 (2018).Rubio-Garcia, J., Kucernak, A. & Charleson, A. Direct visualization of reactant transport in forced convection electrochemical cells and its application to redox flow batteries. Electrochem. commun. 93, 128–132 (2018).Tolmachev, Y. V. Flow Batteries From 1879 To 2022 And Beyond. Qeios 1–79 (2023).Wang, R. et al. Gradient-distributed NiCo2O4 nanorod electrode for redox flow batteries: Establishing the ordered reaction interface to meet the anisotropic mass transport. Appl. Catal. B Environ. 332, 122773 (2023).Kumar, S. & Jayanti, S. Effect of flow field on the performance of an all-vanadium redox flow battery. J. Power Sources 307, 782–787 (2016).Wong, A. A., Rubinstein, S. M. & Aziz, M. J. Direct visualization of electrochemical reactions and heterogeneous transport within porous electrodes in operando by fluorescence microscopy. Cell Reports Phys. Sci. 2, 100388 (2021).

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

Recently, discovering high-performance electrocatalytic materials for vanadium redox flow batteries (VRFB) has been one of the most crucial tasks. This paper successfully fabricates low-cost plate-like bismuth vanadate (BiVO4) material through a simple one-step hydrothermal route, employed as an electrocatalyst to adorn the graphite felt (GF) for use as the negative electrode in VRFB. The experimental results show that BiVO4-3h exhibits the optimal electrocatalytic activity and reversibility for the vanadium redox couples among all samples. The energy efficiency of the VRFB cell assembled with BiVO4-decorated GF as the negative electrode is found to be 75.42% at 100 mA cm−2, which is about 10.24% more efficient than that of the cell assembled with heat-treated graphite felt (HT-GF) electrode. The possible reasons for the activity enhancement can be ascribed to the existence of oxygen vacancies in the BiVO4 lattice structure and the relatively high surface area of BiVO4, which provide more active sites for facilitating the vanadium redox reactions. Furthermore, the BiVO4-GF electrode obstructs the competitive irreversible hydrogen evolution reaction on the negative side of the cell, and it also has better wettability. Impressively, BiVO4-GF as the negative electrode shows good stability over 100 cycles.

Evaluation of the effect of hydrogen evolution reaction on the performance of all-vanadium redox flow batteries

The exceptional advantages of vanadium redox flow batteries (VRFBs) have garnered significant attention, establishing them as the preferred choice for large-scale and long-term energy storage solutions. However, side reactions such as hydrogen evolution reaction (HER) lead to suboptimal performance of VRFB parameters, resulting in an overall decrease in VRFB performance. Therefore, it is imperative to investigate the mechanism by which HER affects VRFB performance and identify effective methods to mitigate its impact. In light of this, critical parameters such as charge-discharge curve, internal resistance, pressure-drop, pump power consumption, efficiency, and capacity retention rate are selected to evaluate the impact of HER on VRFB performance. Experimental results demonstrate that HER causes an increases in voltage during charging and a decrease during discharging stages leading to voltage loss; additionally, bubble generation significantly increases pressure drop and pump power consumption; furthermore, blockage of flow channels and electrodes due to bubbles leads to an increase in ohmic resistance. Finally, HER has a substantial impact on efficiency and capacity with an average energy efficiency of 2.92 %. After 60 cycles, the capacity retention rate decreased by nearly 7.69 %.

Bioinspired flow Fields: A numerical investigation into Nature-Mimicking designs for boosting vanadium redox flow batteries

Efficient flow field structures are crucial for improving the performance of all-vanadium redox flow batteries (VRFBs). Considering the large pressure drop and pump losses in traditional serpentine flow fields (SFF), this paper proposes a novel biomimetic flow field structure (BFF) for VRFB. A three-dimensional multiphysics model comparing SFF and BFF designs for VRFB is developed, the assessment was further enhanced by considering the impact of electrolyte flow rates on multiple performance indicators. The results show that BFF’s unique design substantially reduces pressure drop, especially at higher flow rates. For both SFF and BFF designs, at a low flow rate of 60 ml/min, the SFF has a slightly higher pump-based voltage efficiency, but as the flow rate increases to 120 ml/min and 180 ml/min, the BFF outperforms the SFF, demonstrating advantages of 2.057 % and 6.888 %, respectively. This comprehensive VRFB modeling analysis provides valuable insights into optimizing future flow battery designs.

Numerical simulation of all-vanadium redox flow battery performance optimization based on flow channel cross-sectional shape design

This paper numerically investigates optimizing trapezoidal flow channel cross-sectional shapes to improve all‑vanadium redox flow battery performance. A 3D steady-state multiphysics model coupling fluid dynamics, mass transfer, and electrochemistry was developed in COMSOL. Eight trapezoidal and one rectangular cross-section serpentine flow fields were simulated at varied flow rates. Results showed the TCS-T06 design reduced pressure drop by 12 % and pump power by 12 % versus the RCS. The concentration distribution of VO2+ was also improved, enhancing mass transfer. At 60 mA/cm2, TCS-T06 achieved 0.9 % higher pump power-based voltage efficiency. The optimized trapezoidal cross-section was proven to minimize losses, improve electrolyte distribution, and enhance VRFB performance. This work provides guidance for optimizing trapezoidal flow channel cross-sections to improve VRFB performance via enhanced mass transfer and reduced pressure drop.

Numerical Analysis and Research on Mass Transfer Performance of Vanadium Redox Flow Battery Based on Novel Spiral Flow Field

The high safety factor of all-vanadium redox flow batteries (VRFBs) has positioned them as a leading choice for large-scale stationary energy storage. However, their further development is limited by their low energy density and high cost. Flow field performance emerges as a critical factor significantly influencing battery performance. In this paper, we propose a novel spiral flow field (NSFF), which deviates from the commonly serpentine and parallel flow fields. Our research findings demonstrate that, at a flow rate of 180 ml min−1 and a current density of 90 mA cm−2, the NSFF achieves, respectively, 3.65% and 9.8% higher energy efficiency compared to the serpentine and parallel flow fields. Moreover, the state of health of the NSFF after multiple cycles reaches an impressive level of 72.18%, surpassing that of the serpentine and parallel flow fields by 9.97% and 32.12%, respectively.

Study of 10 kW Vanadium Flow Battery Discharge Characteristics at Different Load Powers

Vanadium redox flow batteries are promising energy storage devices and are already ahead of lead–acid batteries in terms of installed capacity in energy systems due to their long service life and possibility of recycling. One of the crucial tasks today is the development of models for assessing battery performance and its residual resource based on the battery’s present state. A promising method for estimating battery capacity is based on analyzing present voltage and current values under various load conditions. This paper analyzes the discharge characteristics of a 10 kW all-vanadium redox flow battery at fixed load powers from 6 to 12 kW. A linear dependence of operating voltage and initial discharge voltage on load power is established. It is also determined that the slope of the discharge curve linear section does not increase linearly in absolute value, and the Box–Lucas model can be used to describe it. Models for predicting current VRFB capacity based on different curve fitting functions are proposed. These models can be used to roughly estimate battery capacity at different load powers.

In situ growth of covalent organic framework on graphene oxide nanosheet enable proton-selective transport in flow battery membrane

Perfluorosulfonic acid (PFSA) is the most widely used membrane material for all-vanadium redox flow batteries (VRFB). However, severe vanadium ion permeation of PFSA membranes remains to be solved. In this work, a series of PFSA-based composite membranes are prepared by introducing two-dimensional continuous covalent organic framework (COF) to achieve enhanced performance. Two dimensional continuous Schiff base network-type COFs (GO/SNW) are synthesized by using the two-dimensional multi-functionalized surface of graphene oxide (GO) as a reaction site. Compared to the original form of agglomerated particles, two-dimensional continuous structure obtained a larger vanadium resistance area. Comparing to conventional PFSA membranes, the special pores of COF have a size sieving mechanism for selectively proton transfer, leading to simultaneously enhancement of proton conductivity and vanadium barrier property. VRFB assembled with PFSA-GO/SNW-7 showed high Coulombic efficiency (CE: 97.47%–98.18 % VS PFSA: 80.73%–91.92 %) and energy efficiency (EE: 93.04%–85.71 % VS PFSA: 77.53%–81.78 %) at 40–120 mA cm−2. In addition, there is no significant decrease in the efficiency of battery assembled with PFSA-GO/SNW-7 after 800 cycle (than 650 h) tests. This work provides a new direction in the design of fillers for mixed matrix membranes.

Binder-Free CNT-Modified Excellent Electrodes for All-Vanadium Redox Flow Batteries.

Electrodes are one of the key components that influence the performance of all-vanadium redox flow batteries (VRFBs). A porous graphite felt with modified fiber surfaces that can provide a high specific activation surface is preferred as the electrode of a VRFB. In this study, a simple binder-free approach is developed for preparing stable carbon nanotube modified graphite felt electrodes (CNT-GFs). Heat-treated graphite felt electrodes (H-GFs) are dip-coated using CNT homogeneous solution. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results conclude that CNT-GFs have less resistance, better reaction currents, and reversibility as compared to H-GF. Cell performances showed that CNT-GFs significantly improve the performance of a VRFB, especially for the CNT-GF served in the positive side of the VRFB. CNT presence increases the electrochemical properties of the graphite electrode; as a result, reaction kinetics for both VO2+/VO2+ and V3+/V2+ are improved. Positive CNT-GF (P-CNT-GF) configured VRFB exhibits voltage efficiency, coulombic efficiency, and energy efficiency of 85%, 97%, and 82%, respectively, at the operating current density of 100 mA cm-2. At high current density of 200 mA cm-2, the VRFB with P-CNT-GF shows 73%, 98%, and 72% of the voltage, coulombic, and energy efficiencies, respectively. The energy efficiency of the CNT-GF is 6% higher when compared with that of B-H-GF. The VRFB with CNT-GF can provide stable performance for 300 cycles at 200 mA cm-2.

A Review of Capacity Decay Studies of All-vanadium Redox Flow Batteries: Mechanism and State Estimation.

As a promising large-scale energy storage technology, all-vanadium redox flow battery has garnered considerable attention. However, the issue of capacity decay significantly hinders its further development, and thus the problem remains to be systematically sorted out and further explored. This review provides comprehensive insights into the multiple factors contributing to capacity decay, encompassing vanadium cross-over, self-discharge reactions, water molecules migration, gas evolution reactions, and vanadium precipitation. Subsequently, it analyzes the impact of various battery parameters on capacity. Based on this foundation, the article expounds upon the significance of battery internal state estimation technology. Additionally, the review also summarizes domestic and international mathematical models utilized for simulating capacity decay, serving as a valuable reference for future research endeavors. Finally, through the comparison of traditional experimental methods and mathematical modeling methods, this article offers effective guidance for the future development direction of battery state monitoring. This review generally overview the problems related to the capacity attenuation of all-vanadium flow batteries, which is of great significance for understanding the mechanism behind capacity decay and state monitoring technology of all-vanadium redox flow battery.

Highly ion-selective sulfonated poly (4,4′-diphenylether-5,5′-bibenzimidazole) membranes for vanadium redox flow battery

Renewable energy requires long-duration energy storage technologies, of which vanadium flow battery is regarded as the ­most suitable candidate for safe and long-duration energy storage ­applications. However, vanadium flow batteries still suffer from capacity decay and low power density, which arise from membrane degradation and high resistance. Herein, a sulfonated poly (4,4′-diphenylether-5,5′-bibenzimidazole) (SOPBI) membrane is reported for use in vanadium redox flow batteries. The prepared SOPBI membranes show an area resistance of 0.63 Ω cm2 at room temperature after doped with 3 M H2SO4. Moreover, membranes with 3 M H2SO4 doping exhibit tensile stress at break of 15.1 MPa. Benefiting from the SOPBI membrane, the all-vanadium redox flow battery delivers a superior energy efficiency of 77.7% at 140 mA cm−2 while operating stably at a current density of 120 mA cm−2 for 200 cycles.

Revealing the Effects of Impurities among Phosphoric Acid Electrolytes for the Stability of All-Vanadium Redox Flow Batteries

Revealing the Effects of Impurities among Phosphoric Acid Electrolytes for the Stability of All-Vanadium Redox Flow Batteries

Robust Polyaniline-silica@polypropylene for High-Performance, High-Capacity Retention All-Vanadium Redox Flow Battery

Robust Polyaniline-silica@polypropylene for High-Performance, High-Capacity Retention All-Vanadium Redox Flow Battery

Synchronized dual-modified graphite felt electrodes for all-vanadium redox flow batteries with high power density and ultra-long lifespan

All-vanadium redox flow battery (VRFB) with high safety and long lifespan is recognized as promising large-scale energy storage system for intermittent renewable energy sources. However, the large-scale development of VRFBs is still hindered by untreated graphite felt electrodes with poor electrocatalytic performance. In this work, we report a modified GF electrode with synchronous etching of the electrode surface and loading of nitrogen-rich biomass carbon, which allows the formation of pores on the GF electrode surface while introducing enriched nitrogen as active sites. The obtained electrode N-EGF exhibits superior wettability, and the structural modification also contributes to the catalytic activity and reversibility of the vanadium redox reaction. The voltage efficiency (VE), energy efficiency (EE) and discharge capacity of the VRFB single cell with N-EGF are improved at current densities from 80 to 280 mA cm−2. Significantly, the power density of the VRFB achieves a peak value of 804.6 mW cm−2. In addition, the N-EGF exhibits excellent stability and ultra-low EE decay rate (0.0018 %) after long-term cycling operation (1285 cycles) at a current density of 200 mA cm−2.