Durability of graphite coated carbon composite bipolar plates for vanadium redox flow batteries

Choe, Jaeheon; Lim, Jun Woo; Kim, Minkook; Kim, Jinwhan; Lee, Dai Gil

doi:10.1016/j.compstruct.2015.08.030

Cited by 26 publications

(16 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7,[23][24][25] Up to date there are several studies dealing with cyclic aging of BPPs for the VRFB. [4][5][6][7]9,10,14,16,18,20,21,26 For example Liu et al showed that carbon-polyethylene composite BPPs were aging when an anodic polarization potential of 2.26 V vs. standard hydrogen electrode (SHE) was applied for 6 h in 2 M VOSO 4 in 2 M H 2 SO 4 . Their results indicate that new oxygen functional groups (C=O and O=C-OH) were formed on the surface of the BPP, delamination processes commenced and material was lost by corrosion.…”

Section: 12mentioning

confidence: 99%

“…5,12 Different composite materials were already investigated for the production of BPPs in the VRFB, including diverse graphite and carbon materials with polyethylene, 12,[14][15][16] polypropylene (elastomer), 6,7 fluoropolymer, 4 polyphenylene sulfide, 5 phenol formaldehyde resin, 17 as well as epoxy resin. 9,10,[18][19][20][21] Looking only at the single components, polymers like polyethylene, polypropylene and polytetrafluoroethylene exhibit high chemical resistance toward concentrated sulfuric * Electrochemical Society Member.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Chemical Stability of Graphite-Polypropylene Bipolar Plates for the Vanadium Redox Flow Battery at Resting State

Satola

Kirchner

Komsiyska

et al. 2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

Current collectors called bipolar plates (BPP) are important elements within the conversion unit of the vanadium redox flow battery (VRFB). They are in direct contact with acidic electrolytes, containing vanadium species in different oxidation states. The influence of the state of charge (SOC) on the calendar aging of BPPs was examined. Graphite-polypropylene BPPs were immersed in positive and negative vanadium electrolytes at 0%, 20%, 80% and 100% SOC for 30, 90 and 190 days. H 2 gas evolution was observed as side reaction on the surface of the BPPs in the negative electrolyte. After electroless aging, scanning electron (SEM) and confocal microscopy measurements showed no significant changes in the surface morphology. The electrical conductivities of the BPPs were not affected significantly. However, contact angle (θ) measurements revealed that the positive electrolyte influenced the wettability of the BPPs. X-ray photoelectron (XP) spectroscopy showed progressing oxidation of the BPP surfaces in the positive electrolyte and adsorption or entrapment of vanadium ions in the pores at high SOC. Cyclic voltammograms (CV) provided evidence that the graphite was oxidized combined with an increase in effective surface area. ATR-FTIR measurements showed slight oxidation of pure polypropylene granulate in the positive electrolyte with 100% SOC. The increasing energy power supply from intermittent renewable energy sources requires a rapid introduction of efficient energy storages. One promising technology is the vanadium redox flow battery (VRFB), as it enables to scale the power and the storage capacity independently according to specific requirements.1,2 In addition the VRFB is characterized by a fast response time and long electrolyte cycle life.3 Each reaction unit in a VRFB stack is composed of two half-cells separated by a membrane consisting of an electrode in contact with a current collector called bipolar plate (BPP).2 In a battery stack the BPPs are "non-active" components that conduct current from one cell to the other. They physically separate adjacent cells from each other while staying in contact with acidic half-cell electrolytes containing vanadium species in different oxidation states on each side. 4 For brevity we call the V 2+ /V 3+ solution "negative electrolyte" and the VO 2+ /VO 2 + solution "positive electrolyte". While vanadium redox reactions mainly occur on the surfaces of the porous electrodes, they could also occur unintentionally on the surfaces of the BPPs. [5][6][7] Therefore, a good BPP should be characterized by a high chemical and mechanical stability, high electrical conductivity and impermeability to preclude leakage. 8 Metallic BPPs are usually not used in VRFB as they corrode in acidic environments and would need a protective layer.5,9,10 Therefore, graphite based BPPs are commonly used as they possess a good electrical conductivity and a better chemical stability. 4 However, pure graphite plates are not favored as BPPs due to their high weight and cost as well as low mechanical stre...

show abstract

Section: 12mentioning

confidence: 99%

mentioning

confidence: 99%

Chemical Stability of Graphite-Polypropylene Bipolar Plates for the Vanadium Redox Flow Battery at Resting State

Satola

Kirchner

Komsiyska

et al. 2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…The gas permeability of the BP could then be calculated. Choe et al also measured the permeability of various graphite foils via water vapor instead of air. The following standard equation was used to calculate the permeability:

italicPermeability coefficient = \frac{WVTR}{P_{w}} b,

where WVTR is the water vapor transmission rate, P w is the pressure difference across the specimen, and b is the thickness of the specimen.…”

Section: Degradation Of Vrfb Componentsmentioning

confidence: 99%

“…To reduce the interfacial resistance of composite BPs, Choe et al coated composite BPs with pyrolytic graphite and expanded flake‐type graphite. It was found that the pyrolytic graphite had higher durability, likely because its graphene sheets were highly oriented in structure due to being crystallized in a planar direction.…”

Section: Degradation Of Vrfb Componentsmentioning

confidence: 99%

A review of all‐vanadium redox flow battery durability: Degradation mechanisms and mitigation strategies

et al. 2019

View full text Add to dashboard Cite

Summary The all‐vanadium redox flow battery (VRFB) is emerging as a promising technology for large‐scale energy storage systems due to its scalability and flexibility, high round‐trip efficiency, long durability, and little environmental impact. As the degradation rate of the VRFB components is relatively low, less attention has been paid in terms of VRFB durability in comparison with studies on performance improvement and cost reduction. This paper reviews publications on performance degradation mechanisms and mitigation strategies for VRFBs in an attempt to achieve a systematic understanding of VRFB durability. Durability studies of individual VRFB components, including electrolyte, membrane, electrode, and bipolar plate, are introduced. Various degradation mechanisms at both cell and component levels are examined. Following these, applicable strategies for mitigating degradation of each component are compiled. In addition, this paper summarizes various diagnostic tools to evaluate component degradation, followed by accelerated stress tests and models for aging prediction that can help reduce the duration and cost associated with real lifetime tests. Finally, future research areas on the degradation and accelerated lifetime testing for VRFBs are proposed.

show abstract

“…Because BPs need to operate in an acidic environment, their chemical stability is critical in the selection of BP materials; however, BPs for VRB applications have not been extensively studied to date. Lee et al [10,11] developed composite BPs with different polymers and investigated the durability of graphite-coated carbon composite BPs [12]. Caglar et al [13] used titanate-based coupling agents and carbon nanotubes for bridging graphite particles.…”

Section: Introductionmentioning

confidence: 99%

Development of Integrally Molded Bipolar Plates for All-Vanadium Redox Flow Batteries

et al. 2016

View full text Add to dashboard Cite

All-vanadium redox flow batteries (VRBs) are potential energy storage systems for renewable power sources because of their flexible design, deep discharge capacity, quick response time, and long cycle life. To minimize the energy loss due to the shunt current, in a traditional design, a flow field is machined on two electrically insulated frames with a graphite plate in between. A traditional bipolar plate (BP) of a VRB consists of many components, and thus, the assembly process is time consuming. In this study, an integrally molded BP is designed and fabricated to minimize the manufacturing cost. First, the effects of the mold design and injection parameters on frame formability were analyzed by simulation. Second, a new graphite plate design for integral molding was proposed, and finally, two integrally molded BPs were fabricated and compared. Results show that gate position significantly affects air traps and the maximum volume shrinkage occurs at the corners of a BP. The volume shrinkage can be reduced using a large graphite plate embedded within the frame.

show abstract

Durability of graphite coated carbon composite bipolar plates for vanadium redox flow batteries

Cited by 26 publications

References 10 publications

Chemical Stability of Graphite-Polypropylene Bipolar Plates for the Vanadium Redox Flow Battery at Resting State

Chemical Stability of Graphite-Polypropylene Bipolar Plates for the Vanadium Redox Flow Battery at Resting State

A review of all‐vanadium redox flow battery durability: Degradation mechanisms and mitigation strategies

Development of Integrally Molded Bipolar Plates for All-Vanadium Redox Flow Batteries

Contact Info

Product

Resources

About