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Are vanadium redox flow batteries a good energy storage system?

There are many types of energy storage systems. Among them, one of the most interesting in the last decades has been vanadium redox flow batteries (VRFBs) because of their long lifetime and scalability. The performance of VRFBs is affected by many different parameters, including the electrolyte flow rate.

What is flow rate optimization in a vanadium redox flow battery?

Studies on flow rate optimization in the vanadium redox flow battery are rarely reported in literature. Ma et al. proposed a flow rate step-up strategy which maintains a constant flow rate throughout main operating state-of-charge (SOC) until stepping up the flow rate at the end of charge or discharge .

Do redox flow batteries have a flow factor control strategy?

Abstract: The optimization of vanadium redox flow batteries (VRFBs) is closely related to the flow rate control: a proper regulation of the electrolyte flow rate reduces losses and prolongs battery lifetime. To this end, a flow factor control strategy in VRFBs was proposed in the literature provided with numerical/experimental validations.

What is a redox flow battery?

This type of battery belongs to the family of redox flow batteries. Redox flow batteries differ from conventional batteries by having energy conversion systems separate from the chemical storage. 8 This makes it possible to modularize the design of these batteries, giving them flexibility and scalability.

Why is electrolyte flow control important for large-scale vanadium redox flow battery systems?

Apart from this, the electrolyte flow also plays a key role in removing any accumulated heat in the stack to avoid potential thermal precipitation in the positive half-cell. Therefore, a sophisticated flow control system is valuable for large-scale vanadium redox flow battery systems and is worthy of further investigation and development.

What is mass transport loss in all-vanadium redox flow batteries?

This mass transfer resistance thus contributes to voltage losses, referred to as mass transport losses or concentration overpotential, compared to the reversible potential of cell. In this paper, we derived analytical expressions for estimating the mass transport losses in all-vanadium redox flow batteries.

Can iron-based aqueous flow batteries be used for grid energy storage?

A new iron-based aqueous flow battery shows promise for grid energy storage applications. A commonplace chemical used in water treatment facilities has been repurposed for large-scale energy storage in a new battery design by researchers at the Department of Energy's Pacific Northwest National Laboratory.

What is an iron-based flow battery?

Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available. What makes this battery different is that it stores energy in a unique liquid chemical formula that combines charged iron with a neutral-pH phosphate-based liquid electrolyte, or energy carrier.

What is Iron-Flow batteries?

This unique feature allows for cost-effective scaling, essential for large-scale applications. Developed using an advanced metal complex and membrane, Iron-Flow Batteries is based at the Paris Flow Tech platform – a premier hub for innovation in continuous flow chemistry.

Are iron-based aqueous redox flow batteries the future of energy storage?

The rapid advancement of flow batteries offers a promising pathway to addressing global energy and environmental challenges. Among them, iron-based aqueous redox flow batteries (ARFBs) are a compelling choice for future energy storage systems due to their excellent safety, cost-effectiveness and scalability.

Are all-liquid flow batteries suitable for long-term energy storage?

Among the numerous all-liquid flow batteries, all-liquid iron-based flow batteries with iron complexes redox couples serving as active material are appropriate for long duration energy storage because of the low cost of the iron electrolyte and the flexible design of power and capacity.

Are iron-based batteries a good choice for energy storage?

For comparison, previous studies of similar iron-based batteries reported degradation of the charge capacity two orders of magnitude higher, over fewer charging cycles. Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available.

What is the difference between flow batteries and conventional batteries?

Energy storage is the main differing aspect separating flow batteries and conventional batteries. Flow batteries store energy in a liquid form (electrolyte) compared to being stored in an electrode in conventional batteries. Due to the energy being stored as electrolyte liquid it is easy to increase capacity through adding more fluid to the tank.

Are flow batteries better than lithium ion?

There's no such thing as a flow-battery Tesla. But the companies at the International Flow Battery Forum in Prague in late June were adamant that flow batteries are now cheaper, more reliable, and safer than lithium ion in a growing number of real-world stationary energy applications.

Are flow batteries cheaper than other batteries?

On charging, ions from one electrolyte move through the battery's membrane to the second electrolyte. At large scale, flow batteries are cheaper than other batteries over their lifetimes. Source: Saudi Aramco. Note: The comparison is of the lifetime cost of a 10 MW battery capable of supplying electricity for 4 h at a time.

What are the advantages and disadvantages of flow batteries?

One advantage of flow batteries is that they can also be immediately “recharged” by replacing the spent liquids in the tank with energised liquid. The volume of liquid electrolyte determines the battery energy capacity, with the surface area of the electrodes determining the battery power – so typically flow batteries are quite large and heavy!

Are redox flow batteries better than lithium ion batteries?

Redox flow batteries have a reputation of being second best. Less energy intensive and slower to charge and discharge than their lithium-ion cousins, they fail to meet the performance requirements of snazzy, mainstream applications, such as cars and cell phones. There's no such thing as a flow-battery Tesla.

Are vanadium redox flow batteries expensive?

Vanadium Redox Flow Batteries (VRFBs) are proven technologies that are known to be durable and long lasting. They are the work horses and long-haul trucks of the battery world compared to the sports car, like fast Lithium-Ion (Li-Ion) batteries. However, VRFBs have developed a reputation for being notoriously expensive.

How many kilowatts can a chromium flow battery store?

Thanks to the chemical characteristics of the iron and chromium ions in the electrolyte, the battery can store 6,000 kilowatt-hours of electricity for six hours. A company statement says that iron-chromium flow batteries can be recharged using renewable energy sources like wind and solar energy and discharged during high energy demand.

What is China's first megawatt iron-chromium flow battery energy storage project?

China's first megawatt iron-chromium flow battery energy storage demonstration project, which can store 6,000 kWh of electricity for 6 hours, was successfully tested and was approved for commercial use on February 28, 2023, making it the largest of its kind in the world.

Can iron-chromium flow batteries be recharged?

A company statement says that iron-chromium flow batteries can be recharged using renewable energy sources like wind and solar energy and discharged during high energy demand. Although pumped-hydro storage is the most widely used technology right now, it cannot fully satisfy China's expanding demand for energy storage, noted the China Daily report.

Which electrolyte is a carrier of energy storage in iron-chromium redox flow batteries (icrfb)?

The electrolyte in the flow battery is the carrier of energy storage, however, there are few studies on electrolyte for iron-chromium redox flow batteries (ICRFB). The low utilization rate and rapid capacity decay of ICRFB electrolyte have always been a challenging problem.

What are the advantages of iron chromium redox flow battery (icrfb)?

Its advantages include long cycle life, modular design, and high safety [7, 8]. The iron-chromium redox flow battery (ICRFB) is a type of redox flow battery that uses the redox reaction between iron and chromium to store and release energy . ICRFBs use relatively inexpensive materials (iron and chromium) to reduce system costs .

How many kilowatts can a battery store?

The battery can store 6,000 kilowatt-hours of electricity for six hours. Tectonics? Nope. Drought is causing parts of South Africa to rise from the ocean Representational image: The "most powerful" iron-chromium flow battery cell in the world.

What are iron flow batteries?

They were first introduced in 1981. Iron flow batteries are a type of energy storage technology that uses iron ions in an electrolyte solution to store and release energy. They are a relatively new technology, but they have a number of advantages over other types of energy storage, such as lithium-ion batteries.

Are iron flow batteries safe?

Iron flow batteries (IFBs) are a type of energy storage device that has a number of advantages over other types of energy storage, such as lithium-ion batteries. IRFBs are safe, non-toxic, have a long lifespan, and are versatile. ESS is a company that is working to make IRFBs better and cheaper.

Can iron-based aqueous flow batteries be used for grid energy storage?

A new iron-based aqueous flow battery shows promise for grid energy storage applications. A commonplace chemical used in water treatment facilities has been repurposed for large-scale energy storage in a new battery design by researchers at the Department of Energy's Pacific Northwest National Laboratory.

Are iron flow batteries a good alternative to lithium-ion batteries?

However, they have inherent limitations when used for long-duration energy storage, including low recyclability and a reliance on “conflict minerals” such as cobalt. Iron flow batteries (IRB) or redux flow batteries (IRFBs) or Iron salt batteries (ISB) are a promising alternative to lithium-ion batteries for stationary energy storage projects.

Are iron-based batteries a good choice for energy storage?

For comparison, previous studies of similar iron-based batteries reported degradation of the charge capacity two orders of magnitude higher, over fewer charging cycles. Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available.

Are iron-based aqueous redox flow batteries the future of energy storage?

The rapid advancement of flow batteries offers a promising pathway to addressing global energy and environmental challenges. Among them, iron-based aqueous redox flow batteries (ARFBs) are a compelling choice for future energy storage systems due to their excellent safety, cost-effectiveness and scalability.

What are the advantages and disadvantages of flow batteries?

At present, the biggest advantage of flow batteries is the number of cycles, which can reach 15,000-20,000 cycles, far ahead of other energy storage technologies. However, flow batteries also have very obvious shortcomings, that is, the self-discharge rate is relatively high, resulting in relatively low efficiency.

Are aqueous iron-based flow batteries suitable for large-scale energy storage applications?

Thus, the cost-effective aqueous iron-based flow batteries hold the greatest potential for large-scale energy storage application.

Do Iron Flow batteries corrode?

They also corrode in the air, while iron is non-toxic and only slightly reactive with water and air. Theoretically, the iron flow batteries have unlimited cycle life, and their store change does not degrade, even after multiple years of charging and discharging.

What are iron flow battery-based storage solutions?

Iron flow battery-based storage solutions have recently made a historical breakthrough to counter some of the disadvantages of lithium-ion battery solutions. They offer a safe, non-flammable, non-explosive, high power density, and cost-effective energy storage solution.

What causes the capacity decay of iron-vanadium flow batteries?

Thus, the capacity decay of Iron-vanadium flow batteries can be mainly attributed to the ion diffusions across the membrane. In the main, the capacity retention ability of VFB is superior to that of IVFB, because the VFB capacity is not only higher after 500 cycles, but also without unexpected fluctuation during the whole testing.

Are iron-based flow batteries a viable alternative?

In contrast, iron-based flow batteries offer a more economically viable alternative, benefiting from the natural abundance, low cost and low toxicity of iron—features that make them particularly appealing for grid-scale deployment.

Why is graphite felt a good electrode material?

Graphite felt (GF) has become main electrode material due to its low cost, good stability, and strong corrosion resistance . However, its poor hydrophilicity and insufficient active sites result in slow redox kinetics and restrict the battery efficiency, , .

What are sigracell® carbon and graphite felts used for?

SIGRACELL® carbon and graphite felts offer ideal properties for an efficient charge exchange in high-temperature batteries like redox flow batteries.

What size battery felt do you supply?

We supply battery felts in standard sizes up to 1350 mm (53") in width in 25 m (82 ft) rolls. Beyond that, we produce carbon and graphite felts in customer- specific dimensions. The entire in-house value chain ensures the quality of SIGRACELL ® battery felts from SGL Carbon and thus contributes to optimizing battery performance.

Are gf@fe-n/s-CNF batteries efficient?

At 200 mA cm −2, energy efficiency and voltage efficiency of the battery using GF@Fe-N/S-CNFs are 9.7 % and 10.6 % higher than those of blank battery, and efficiency displays no decay during 350 charge–discharge cycles at 150 mA cm −2. This study improves poor stability on the electrode and insufficient active sites for carbon-based catalysts.

Why do we use felts for anodes & cathodes?

Our felts are used for anodes as well as cathodes. Thanks to a unique combination of electrical conductivity, electrochemical stability, high porosity and good elasticity, they facilitate an efficient charge exchange between the electrolyte and the bipolar plate.

What is a vanadium flow battery?

It can provide sustainable and reliable energy supply solutions, particularly for renewable energy sources such as solar and wind. Vanadium flow batteries consist of two tanks containing vanadium electrolyte, a pump system to circulate the electrolyte, and a fuel cell stack where the electrochemical reactions occur.

How do electrolytes work in vanadium flow batteries?

Electrolytes operate within vanadium flow batteries by facilitating ion transfer and enabling efficient energy storage and release during the charging and discharging processes. Vanadium flow batteries utilize vanadium ions in two different oxidation states, which allows for effective energy storage.

What are the advantages of using vanadium flow batteries for energy storage?

The key advantages of using vanadium flow batteries for energy storage include their longevity, scalability, safety, and efficiency. Longevity: Vanadium flow batteries have a long operational life, often exceeding 20 years. Scalability: These batteries can be easily scaled to accommodate various energy storage needs.

What factors contribute to the adoption of vanadium flow batteries?

Several factors contribute to the adoption of vanadium flow batteries, including the need for energy storage in renewable energy integration, reductions in energy costs, and technological advancements in battery components. The scalability of these systems also impacts their deployment.

What are vanadium redox flow batteries (VRFB)?

Interest in the advancement of energy storage methods have risen as energy production trends toward renewable energy sources. Vanadium redox flow batteries (VRFB) are one of the emerging energy storage techniques being developed with the purpose of effectively storing renewable energy.

How long do vanadium flow batteries last?

While vanadium flow batteries can cycle through charge and discharge many times, issues such as membrane degradation can shorten their effective life. A lifespan of around 10,000 cycles is common, unlike lithium-ion batteries, which can offer around 3,000 to 5,000 cycles.

What is a vanadium flow battery?

Vanadium flow batteries employ all-vanadium electrolytes that are stored in external tanks feeding stack cells through dedicated pumps. These batteries can possess near limitless capacity, which makes them instrumental both in grid-connected applications and in remote areas.

What is a single vanadium element battery?

Their single vanadium element system avoids capacity fading caused by crossover contamination in iron-chromium flow batteries (ICFBs) . Additionally, VRFBs use an aqueous electrolyte, eliminating the safety risks associated with bromine vapor corrosion in zinc-bromine flow batteries (ZBFBs) .

What is a single cell vanadium redox flow battery (VRFB)?

A laboratory-scale single cell vanadium redox flow battery (VRFB) was constructed with an active area of 64 cm 2. The electrolyte was produced by dissolving vanadium pentoxide in sulphuric acid.

What is a vanadium redox flow battery?

Vanadium redox flow battery is one of the most promising devices for a large energy storage system to substitute the fossil fuel and nuclear energy with renewable energy. The VRFB is a complicated device that combines all the technologies of electrochemistry, mechanical engineering, polymer science, and materials science similar to the fuel cell.

What is the ideal electrolyte for vanadium batteries?

The ideal electrolyte for vanadium batteries needs to ensure the stability of high-concentration vanadium ions in different oxidation states over a wide temperature range. A key issue to be resolved is to improve the stability of V 5+ at high temperatures (50 °C) and V 3+ at low temperatures (−5 °C).

Can ion transport improve vanadium redox flow battery electrolytes?

Furthermore, research progress in other battery fields shows that optimizing electrolyte formulations [21, 22] and ion transport [23, 24] can significantly enhance energy density and cycling stability, providing valuable insights for improving vanadium redox flow battery electrolytes. Table 1.

Can iron-based aqueous flow batteries be used for grid energy storage?

A new iron-based aqueous flow battery shows promise for grid energy storage applications. A commonplace chemical used in water treatment facilities has been repurposed for large-scale energy storage in a new battery design by researchers at the Department of Energy's Pacific Northwest National Laboratory.

Are iron-based aqueous redox flow batteries the future of energy storage?

The rapid advancement of flow batteries offers a promising pathway to addressing global energy and environmental challenges. Among them, iron-based aqueous redox flow batteries (ARFBs) are a compelling choice for future energy storage systems due to their excellent safety, cost-effectiveness and scalability.

What is an iron-based flow battery?

Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available. What makes this battery different is that it stores energy in a unique liquid chemical formula that combines charged iron with a neutral-pH phosphate-based liquid electrolyte, or energy carrier.

Are iron-based batteries a good choice for energy storage?

For comparison, previous studies of similar iron-based batteries reported degradation of the charge capacity two orders of magnitude higher, over fewer charging cycles. Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available.

Are aqueous redox flow batteries a reliable energy storage system?

To address the inherent volatility of renewable energy, the development of reliable electricity energy storage systems is essential . Cost-effective aqueous redox flow batteries (ARFBs) have emerged as a promising option for long-term grid-scale energy storage, enabling stable energy storage and release.

What is a flow battery?

The larger the electrolyte supply tank, the more energy the flow battery can store. Flow batteries can serve as backup generators for the electric grid. Flow batteries are one of the key pillars of a decarbonization strategy to store energy from renewable energy resources.

Are vanadium redox flow batteries sustainable?

In the pursuit of sustainable and reliable energy storage solutions, Vanadium Redox Flow Batteries offer a compelling combination of safety, longevity, and recyclability - key attributes of any truly environmentally friendly and long-duration energy storage technology.

When were vanadium flow batteries invented?

In the 1980s, the University of New South Wales in Australia started to develop vanadium flow batteries (VFBs). Soon after, Zn-based RFBs were widely reported to be in use due to the high adaptability of Zn-metal anodes to aqueous systems, with Zn/Br2 systems being among the first to be reported.

What is a vanadium redox flow battery (VRFB)?

In contrast, technologies like vanadium redox flow batteries (VRFBs) rely on reusable liquid electrolytes and recyclable hardware, enabling a more robust and predictable pathway toward circular energy storage.

How long do flow batteries last?

Valuation of Long-Duration Storage: Flow batteries are ideally suited for longer duration (8+ hours) applications; however, existing wholesale electricity market rules assign minimal incremental value to longer durations.

Why do flow battery developers need a longer duration system?

Flow battery developers must balance meeting current market needs while trying to develop longer duration systems because most of their income will come from the shorter discharge durations. Currently, adding additional energy capacity just adds to the cost of the system.

Do flow batteries degrade?

That arrangement addresses the two major challenges with flow batteries. First, vanadium doesn't degrade. “If you put 100 grams of vanadium into your battery and you come back in 100 years, you should be able to recover 100 grams of that vanadium—as long as the battery doesn't have some sort of a physical leak,” says Brushett.

What is all vanadium redox flow battery (VRFB)?

The all vanadium redox flow battery (VRFB) is an electrochemical energy storage system invented by Maria Skyllas-Kazacos in 1984. It consists of two electrochemical half cells, separated by an ion exchange membrane (Fig. 13.4). 13.4. Overview of a vanadium redox flow battery.

What is a vanadium redox battery (VRB)?

The vanadium redox battery (VRB), also known as the vanadium flow battery (VFB) or vanadium redox flow battery (VRFB), is a type of rechargeable flow battery. It employs vanadium ions as charge carriers.

Can a vanadium redox flow battery be used as an electrocatalyst?

Yuke Su, in Journal of Power Sources, 2021 The vanadium redox flow battery (VRFB) is promising for large-scale energy storage, but commercial electrodes, such as graphite felt (GF), suffer from poor electrochemical activity caused by sluggish kinetics and high polarization, leading to a need for high performance and cost-effective electrocatalysts.

What is a redox flow battery?

Although there are many different flow battery chemistries, vanadium redox flow batteries (VRFBs) are the most widely deployed type of flow battery because of decades of research, development, and testing. VRFBs use electrolyte solutions with vanadium ions in four different oxidation states to carry charge as Figure 2 shows.

What are vanadium redox batteries used for?

For several reasons, including their relative bulkiness, vanadium batteries are typically used for grid energy storage, i.e., attached to power plants/electrical grids. Numerous companies and organizations are involved in funding and developing vanadium redox batteries. Pissoort mentioned the possibility of VRFBs in the 1930s.

How important is safety advice for a vanadium flow battery?

As the global installed energy capacity of vanadium flow battery systems increases, it becomes increasingly important to have tailored standards offering specific safety advice.

What is a soluble lead-acid flow battery?

A scaled-up soluble lead-acid flow battery has been demonstrated, operating both as a single cell and as a bipolar, two-cell stack. Using short charge times (900 s at ≤20 mA cm −2) the battery successfully runs for numerous charge/discharge cycles.

What causes a soluble lead-acid flow battery to fail?

Following a large number of charge/discharge cycles, a soluble lead-acid flow battery could fail due to cell shorting caused by the growth of lead and lead dioxide deposition the negative and positive electrode, respectively.

What is a soluble lead acid battery?

As a flow battery, the soluble lead acid battery is also unique in that no microporous separator (typically a cation-exchange membrane such as Nafion) is required and a single reservoir is used for the electrolyte, allowing for a simpler design and a substantial reduction in cost.

What is the difference between soluble and Static lead-acid battery?

Conclusions 1. The electrochemistries of the soluble lead-acid flow battery and the static lead-acid battery are distinctly different; in the soluble lead acid battery lead is highly soluble in the electrolyte of methanesulfonic acid, while lead is a solid paste in the static lead-acid battery.

Does soluble lead-acid flow battery self-discharge?

Self-discharge was also observed in the case of the soluble lead-acid flow battery when it was left open-circuit for a long time period. To test the self-discharge characteristic of a soluble lead-acid flow battery, a series of charge/discharge cycles were performed.

How do lead-acid batteries work?

Traditional lead-acid batteries (e.g., SLI, starting lighting ignition) batteries for automotive applications) operate with an electrolyte, typically sulphuric acid, in which lead compounds are only sparingly soluble. Consequently, an insoluble paste containing the active materials is normally applied to each of the electrodes.

Are vanadium redox flow battery electrolytes stable at high temperatures?

Insufficient thermal stability of vanadium redox flow battery (VRFB) electrolytes at elevated temperatures (>40 °C) remains a challenge in the development and commercialization of this technology, which otherwise presents a broad range of technological advantages for the long-term storage of intermittent renewable energy.

What is a vanadium flow battery?

A schematic of a vanadium flow battery is depicted in Figure 1, in which two external tanks are used to carry vanadium ions in their various oxidation states (V 2+, V 3+, VO 2+, and VO 2+) with one redox pair present in each tank.

What is the temperature range of a vanadium flow battery?

Xi J, Jiang B, Yu L, Liu L (2017) Membrane evaluation for vanadium flow batteries in a temperature range of −20–50 °C. J Membrane Sci 522:45–55 Ye Q, Shan TX, Cheng P (2017) Thermally induced evolution of dissolved gas in water flowing through a carbon felt sample. Int J Heat Mass Transf 108:2451–2461

How stable is a vanadium electrolyte?

The stability of the vanadium electrolyte is also highly dependent on the temperature. Temperatures above 40 °C in the positive electrolyte and below 10 °C in the negative electrolyte commonly induce formation of solid V 2 O 5 and VSO 4 precipitates, respectively. [ 2]

Why does the concentration of vanadium vary during battery operation?

This dependence is of critical importance during battery operation; since the SOC of the solution for each half-cell electrolyte could be changed, the vanadium concentrations may differ accordingly because of the ionic diffusion processes across the membrane and thus the solution conductivities vary.

Can vanadium flow batteries avoid cross-contamination?

Authors to whom correspondence should be addressed. These authors contributed equally to this work. The vanadium flow batteries that employ the vanadium element as active couples for both half-cells, thus avoiding cross-contamination, are promising large-scale energy storage devices.

What are vanadium redox flow batteries (VRFB)?

The vanadium redox flow batteries (VRFB) seem to have several advantages among the existing types of flow batteries as they use the same material (in liquid form) in both half-cells, eliminating the risk of cross contamination and resulting in electrolytes with a potentially unlimited life.

Why do vanadium flow batteries use only one element?

Vanadium flow batteries use only a single element in both half -cells Eliminates the problem of cross-contamination across the membrane K. Webb ESE 471 21 VRB Reactions At the anode (charging to the right):

Which chemistry is best for redox flow batteries?

The most commercially developed chemistry for redox flow batteries is the all-vanadium system, which has the advantage of reduced effects of species crossover as it utilizes four stable redox states of vanadium. This chapter reviews the state of the art, challenges, and future outlook for all-vanadium redox flow batteries. 1.

What membranes are used in vanadium flow batteries?

The membranes employed in vanadium flow batteries can be grouped into ion exchange membranes and physical separators; however, this topic will only focus on ion exchange membranes .

What are all-vanadium redox flow batteries?

All-vanadium redox flow batteries use V (II), V (III), V (IV), and V (V) species in acidic media. This formulation was pioneered in the late eighties by the research group of Dr Maria Skyllas-Kazacos as an alternative to the Fe/Cr chemistry originally proposed by NASA.

Who invented all-vanadium redox flow batteries?

Skyllas-Kazacos et al. developed the all-vanadium redox flow batteries (VRFBs) concept in the 1980s . Over the years, the team has conducted in-depth research and experiments on the reaction mechanism and electrode materials of VRFB, which contributed significantly to the development of VRFB going forward, , .