Schematic design of a vanadium redox flow battery system1 MW 4 MWh containerized vanadium flow battery owned by Avista Utilities and manufactured by UniEnergy TechnologiesA vanadium redox flow battery located at the University of New South Wales, Sydney, Australia
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.[6] The battery uses vanadium's ability to exist in a solution in four different oxidation states to make a battery with a single electroactive element instead of two.[7] For several reasons, including their relative bulkiness, vanadium batteries are typically used for grid energy storage, i.e., attached to power plants/electrical grids.[8]
Numerous companies and organizations are involved in funding and developing vanadium redox batteries.
History
Pissoort mentioned the possibility of VRFBs in the 1930s.[9] NASA researchers and Pellegri and Spaziante followed suit in the 1970s,[10] but neither was successful. Maria Skyllas-Kazacos presented the first successful demonstration of an All-Vanadium Redox Flow Battery employing dissolved vanadium in a solution of sulfuric acid in the 1980s.[11][12][13] Her design used sulfuric acid electrolytes, and was patented by the University of New South Wales in Australia in 1986.[2]
One of the important breakthroughs achieved by Skyllas-Kazacos and coworkers was the development of a number of processes to produce vanadium electrolytes of over 1.5 M concentration using the lower cost, but insoluble vanadium pentoxide as starting material. These processes involved chemical and electrochemical dissolution and were patented by the University of NSW in 1989. During the 1990s the UNSW group conducted extensive research on membrane selection,[14][15] graphite felt activation,[16][17] conducting plastic bipolar electrode fabrication,[18] electrolyte characterisation and optimisation as well as modelling and simulation. Several 1-5kW VFB prototype batteries were assembled and field tested in a Solar House in Thailand and in an electric golf cart at UNSW.[19]
The UNSW All-Vanadium Redox Flow Battery patents and technology were licensed to Mitsubishi Chemical Corporation and Kashima-Kita Electric Power Corporation in the mid-1990s and subsequently acquired by Sumitomo Electric Industries where extensive field testing was conducted in a wide range of applications in the late 1990s and early 2000s.[20]
In order to extend the operating temperature range of the battery and prevent precipitation of vanadium in the electrolyte at temperatures above 40oC in the case of V(V), or below 10oC in case of the negative half-cell solution, Skyllas-Kazacos and coworkers tested hundreds of organic and inorganic additives as potential precipitation inhibitors. They discovered that inorganic phosphate and ammonium compounds were effective in inhibiting precipitation of 2 M vanadium solutions in both the negative and positive half-cell at temperatures of 5 and 45°C respectively and ammonium phosphate was selected as the most effective stabilising agent. Ammonium and phosphate additives were used to prepare and test a 3 M vanadium electrolyte in a flow cell with excellent results.[20]
Number of patent families and non-patent publications about several types of flow battery chemistries by year.
Advantages and disadvantages
Advantages
VRFBs' main advantages over other types of battery:[22]
energy capacity and power capacity are decoupled and can be scaled separately
energy capacity is obtained from the storage of liquid electrolytes rather than the cell itself
power capacity can be increased by adding more cells
can remain discharged indefinitely without damage
mixing electrolytes causes no permanent damage
single charge state across the electrolytes avoids capacity degradation
safe, non-flammable aqueous electrolyte
no noise or emissions
wide operating temperature range including passive cooling[23][24]
long charge/discharge cycle lives: 15,000-20,000 cycles and 10–20 years.
relatively poor energy-to-volume ratio compared to standard storage batteries
having moving parts in the pumps that produce the flow of electrolyte solution
toxicity of vanadium (V) compounds.
Materials
Schematic of vanadium redox flow battery.Solutions of Vanadium sulfates in four different oxidation states of vanadium.Different types of graphite flow fields are used in vanadium flow batteries. From left to right: rectangular channels, rectangular channels with flow distributor, interdigitated flow field, and serpentine flow field.
Electrode
The electrodes in a VRB cell are carbon based. Several types of carbon electrodes used in VRB cell have been reported such as carbon felt, carbon paper, carbon cloth, and graphite felt.[26][27][28] Carbon-based materials have the advantages of low cost, low resistivity and good stability. Among them, carbon felt and graphite felt are preferred because of their enhanced three-dimensional network structures and higher specific surface areas, as well as good conductivity and chemical and electrochemical stability.[29][30]
The pristine carbon-based electrode exhibits hydrophobicity and limited catalytic activity when interacting with vanadium species. To enhance its catalytic performance and wettability, several approaches have been employed, including thermal treatment, acid treatment, electrochemical modification, and the incorporation of catalysts.[28][31] Carbon felt is typically produced by pyrolyzingpolyacrylonitrile (PAN) or rayon fibers at approximately 1500°C and 1400°C, respectively. Graphite felt, on the other hand, undergoes pyrolysis at a higher temperature of about 2400°C. To thermally activate the felt electrodes, the material is heated to 400°C in an air or oxygen-containing atmosphere. This process significantly increases the surface area of the felt, enhancing it by a factor of 10.[32] The activity towards vanadium species are attribute to the increase in oxygen functional groups such as carbonyl group (C=O) and carboxyl group (C-O) after thermal treatment in air.[33] Many other surface modifications have shown improvement in activity such as graphene oxide and polyaniline.[34] There is currently no consensus regarding the specific functional groups and reaction mechanisms that dictate the interaction of vanadium species on the surface of the electrode. It has been proposed that the V(II)/V(III) reaction follows an inner-sphere mechanism, while the V(IV)/V(V) reaction tends to proceed through an outer-sphere mechanism.[31]
Electrolyte
Both electrolytes are vanadium-based. The electrolyte in the positive half-cells contains VO+2 and VO2+ ions, while the electrolyte in the negative half-cells consists of V3+ and V2+ ions. The electrolytes can be prepared by several processes, including electrolytically dissolving vanadium pentoxide (V2O5) in sulfuric acid (H2SO4).[35] The solution is strongly acidic in use.
Membrane
The membrane should allow protons to cross while keeping electrons and other ions separate. This creates charge separation and thus voltage. The most common membrane material is perfluorinated sulfonic acid (PFSA or Nafion). However, vanadium ions can penetrate a PFSA membrane, a phenomenon known as crossing-over, reducing the energy capacity of the battery.[36][37] A 2021 study found that penetration is reduced with hybrid sheets made by growing tungsten trioxide nanoparticles on the surface of single-layered graphene oxide sheets. These hybrid sheets are then embedded into a sandwich structured PFSA membrane reinforced with polytetrafluoroethylene (Teflon). The nanoparticles also promote proton transport, offering high coulombic efficiency and energy efficiency of more than 98.1 percent and 88.9 percent, respectively.[38]
Flow field
The resistive losses identified by the polarisation curve can be attributed to three main areas: activation loss, ohmic loss, and mass transport loss. Activation loss arises from slow charge transfer kinetics between the surface of the electrode and electrolyte. Ohmic losses are from the ohmic resistance of the electrolyte, electrode, membrane, and current collector. Ohmic losses can be reduced by improved cell design, such as zero-gap cell design and reduced membrane thickness.[39] Mass transport losses are from the lack of active vanadium species being transported to the electrode surface. The flow field design that promotes convective mass transport is crucial to reducing mass transport losses.[40][41] Serpentine and interdigitated flow field designs were produced by machining a bipolar plate adjacent to the porous electrode. The felt electrode can also be cut to create an electrolyte flow channel.[42][43] Both serpentine and interdigitated flow fields have been shown to enhance mass transport, which reduces mass transport polarisation and therefore increases limiting current density and peak power density. Flow dispensers are sometimes placed in the cell to distribute the flow and reduce jets. The flow field must also be designed to provide uniform electrolyte distribution to prevent dead zones in the cell and reduce pressure drop across the cell stack.[43][44]
Operation
Cyclic voltammogram of vanadium (IV) solution in sulfuric acid solution
Other useful properties of vanadium flow batteries are their fast response to changing loads and their overload capacities. They can achieve a response time of under half a millisecond for a 100% load change, and allow overloads of as much as 400% for 10 seconds. Response time is limited mostly by the electrical equipment. Unless specifically designed for colder or warmer climates, most sulfuric acid-based vanadium batteries work between about 10 and 40°C. Below that temperature range, the ion-infused sulfuric acid crystallizes.[48] Round trip efficiency in practical applications is around 70–80%.[49]
Proposed improvements
The original VRFB design by Skyllas-Kazacos employed sulfate (added as vanadium sulfate(s) and sulfuric acid) as the only anion in VRFB solutions, which limited the maximum vanadium concentration to 1.7 M of vanadium ions.[50] In the 1990s, Skyllas-Kazacos discovered the use of ammonium phosphate and other inorganic compounds as precipitation inhibitors to stabilise 2 M vanadium solutions over a temperature range of 5 to 45 oC and a Stabilising Agent patent was filed by UNSW in 1993. This discovery was largely overlooked however and in around 2010 a team from Pacific Northwest National Laboratory proposed a mixed sulfate-chloride electrolyte, that allowed for the use in VRFBs solutions with the vanadium concentration of 2.5 M over a whole temperature range between −20 and +50°C.[51][52] Based on the standard equilibrium potential of the V5+/V4+ couple it is expected to oxidize chloride, and for this reason chloride solutions were avoided in earlier VRFB studies. The surprising oxidative stability (albeit only at the state of charge below ca. 80%) of V5+ solutions in the presence of chloride was explained on the basis of activity coefficients.[53] Many researchers explain the increased stability of V(V) at elevated temperatures by the higher proton concentration in the mixed acid electrolyte that shifts the thermal precipitation equilibrium of V(V) away from V2O5. Nevertheless, because of a high vapor pressure of HCl solutions and the possibility of chlorine generation during charging, such mixed electrolytes have not been widely adopted.[54]
Another variation is the use of vanadium bromide salts. Since the redox potential of Br2/2Br− couple is more negative than that of V5+/V4+, the positive electrode operates via the bromine process.[55] However, due to problems with volatility and corrosivity of Br2, they did not gain much popularity (see zinc-bromine battery for a similar problem). A vanadium/cerium flow battery has also been proposed .[56]
Specific energy and energy density
VRBs achieve a specific energy of about 20Wh/kg (72 kJ/kg) of electrolyte. Precipitation inhibitors can increase the density to about 35Wh/kg (126 kJ/kg), with higher densities possible by controlling the electrolyte temperature. The specific energy is low compared to other rechargeable battery types (e.g., lead–acid, 30–40Wh/kg (108–144 kJ/kg); and lithium ion, 80–200Wh/kg (288–720 kJ/kg)).[citation needed]
Applications
VRFBs' large potential capacity may be best-suited to buffer the irregular output of utility-scale wind and solar systems.[22]
Their reduced self-discharge makes them potentially appropriate in applications that require long-term energy storage with little maintenance—as in military equipment, such as the sensor components of the GATOR mine system.[57][22]
Companies funding or developing vanadium redox batteries
Companies funding or developing vanadium redox batteries include Sumitomo Electric Industries,[72] CellCube (Enerox),[73]UniEnergy Technologies,[74] StorEn Technologies[75][76] in Australia, Largo Energy[77] and Ashlawn Energy[78] in the United States; H2 in Gyeryong-si, South Korea;[79] Renewable Energy Dynamics Technology,[80] Invinity Energy Systems[81] in the United Kingdom, VoltStorage[82] and Schmalz[83][84] in Europe; Prudent Energy[85] in China; Australian Vanadium, CellCube and North Harbour Clean Energy[86][87] in Australia; Yadlamalka Energy Trust and Invinity Energy Systems[88][89] in Australia; EverFlow Energy JV SABIC SCHMID Group in Saudi Arabia[90] and Bushveld Minerals in South Africa.[91]
↑ Chieng, S.C.; Kazacos, M.; Skyllas-Kazacos, M. (1992). "Preparation and evaluation of composite membrane for vanadium redox battery applications". Journal of Power Sources. 39 (1): 11–19. Bibcode:1992JPS....39...11C. doi:10.1016/0378-7753(92)85002-R.
↑ Chieng, S.C.; Kazacos, M.; Skyllas-Kazacos, M. (16 December 1992). "Modification of Daramic, microporous separator, for redox flow battery applications". Journal of Membrane Science. 75 (1–2): 81–91. doi:10.1016/0376-7388(92)80008-8.
↑ Sun, B.; Skyllas-Kazacos, M. (June 1992). "Modification of graphite electrode materials for vanadium redox flow battery application—I. Thermal treatment". Electrochimica Acta. 37 (7): 1253–1260. doi:10.1016/0013-4686(92)85064-R.
↑ Sun, Bianting; Skyllas-Kazacos, Maria (October 1992). "Chemical modification of graphite electrode materials for vanadium redox flow battery application—part II. Acid treatments". Electrochimica Acta. 37 (13): 2459–2465. doi:10.1016/0013-4686(92)87084-D.
↑ Zhong, S.; Kazacos, M.; Burford, R.P.; Skyllas-Kazacos, M. (October 1991). "Fabrication and activation studies of conducting plastic composite electrodes for redox cells". Journal of Power Sources. 36 (1): 29–43. Bibcode:1991JPS....36...29Z. doi:10.1016/0378-7753(91)80042-V.
↑ Tang, Ao; McCann, John; Bao, Jie; Skyllas-Kazacos, Maria (November 2013). "Investigation of the effect of shunt current on battery efficiency and stack temperature in vanadium redox flow battery". Journal of Power Sources. 242: 349–356. Bibcode:2013JPS...242..349T. doi:10.1016/j.jpowsour.2013.05.079.
↑ Chakrabarti, M.H.; Brandon, N.P.; Hajimolana, S.A.; Tariq, F.; Yufit, V.; Hashim, M.A.; Hussain, M.A.; Low, C.T.J.; Aravind, P.V. (May 2014). "Application of carbon materials in redox flow batteries". Journal of Power Sources. 253: 150–166. Bibcode:2014JPS...253..150C. doi:10.1016/j.jpowsour.2013.12.038.
↑ Singh, Manoj K.; Kapoor, Manshu; Verma, Anil (May 2021). "Recent progress on carbon and metal based electrocatalysts for vanadium redox flow battery". WIREs Energy and Environment. 10 (3). Bibcode:2021WIREE..10E.393S. doi:10.1002/wene.393.
1 2 Bourke, Andrea; Oboroceanu, Daniela; Quill, Nathan; Lenihan, Catherine; Safi, Maria Alhajji; Miller, Mallory A.; Savinell, Robert F.; Wainright, Jesse S.; SasikumarSP, Varsha; Rybalchenko, Maria; Amini, Pupak; Dalton, Niall; Lynch, Robert P.; Buckley, D. Noel (1 March 2023). "Review—Electrode Kinetics and Electrolyte Stability in Vanadium Flow Batteries". Journal of the Electrochemical Society. 170 (3): 030504. Bibcode:2023JElS..170c0504B. doi:10.1149/1945-7111/acbc99.
↑ Parasuraman, Aishwarya; Lim, Tuti Mariana; Menictas, Chris; Skyllas-Kazacos, Maria (July 2013). "Review of material research and development for vanadium redox flow battery applications". Electrochimica Acta. 101: 27–40. doi:10.1016/j.electacta.2012.09.067.
↑ Revankar, Shripad T. (2019). "Chapter 6. Chemical Energy Storage". In Bindra, Hitesh & Revankar, Shripad (eds.). Storage and Hybridization of Nuclear Energy – Techno-economic Integration of Renewable and Nuclear Energy. London: Academic Press. pp.177–227. doi:10.1016/B978-0-12-813975-2.00006-5. ISBN9780128139752. S2CID189154686.
↑ M. Skyllas-Kazacos, M. Rychcik and G. Robins Robert, "All vanadium redox battery." 1986AU-0055562 1986-04-02. M. Skyllas-Kazacos, "All-vanadium redox battery and additives." 1988WO-AU00472 1988-12-091989AU-0028153 1989-12-09. M. Skyllas-Kazacos, M. Kazacos and C. Mcdermott Rodney John, "Vanadium charging cell and vanadium dual battery system." 1989AU-0028152 1989-12-09. M. Kazacos and S. Kazacos Maria, "High energy density vanadium electrolyte solutions, methods of preparation thereof and all-vanadium redox cells and batteries containing high energy vanadium electrolyte solutions." 1996AT-0911853T 1996-05-031996AU-0054914 1996-05-031996US-08945869 1996-05-031996WO-AU00268 1996-05-031996NZ-0306364 1996-05-031996ES-0911853T 1996-05-031996EP-0911853 1996-05-031996DE-6030298 1996-05-031996CA-2220075 1996-05-031998HK-0110321 1998-08-312002US-10226751 2002-08-22
↑ Li, L.; Kim, S.; Wang, W.; Vijayakumar, M.; Nie, Z.; Chen, B.; Zhang, J.; Xia, G.; Hu, J.; Graff, G.; Liu, J.; Yang, Z. (2011). "A stable vanadium redox-flow battery with high energy density for large-scale energy storage". Advanced Energy Materials. 1 (3): 394–400. Bibcode:2011AdEnM...1..394L. doi:10.1002/aenm.201100008. S2CID33277301.
↑ Yang, Y.; Zhang, Y.; Tang, L.; Liu, T.; Huang, J.; Peng, S.; Yang, X. (September 2019). "Investigations on physicochemical properties and electrochemical performance of sulfate-chloride mixed acid electrolyte for vanadium redox flow battery". Journal of Power Sources. 434: Article 226719. Bibcode:2019JPS...43426719Y. doi:10.1016/j.jpowsour.2019.226719. S2CID197352614.
↑ Vafiadis, Helen; Skyllas-Kazacos, Maria (2006). "Evaluation of membranes for the novel vanadium bromine redox flow cell". Journal of Membrane Science. 279 (1–2): 394–402. doi:10.1016/j.memsci.2005.12.028.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.