Fabrication of nitrogen-doped graphite felts as positive electrodes using polypyrrole as a coating agent in vanadium redox flow batteries

Park, Gwan Soo; Kim, Han Sung

doi:10.1039/c5ta02674a

Cited by 87 publications

(50 citation statements)

References 40 publications

(44 reference statements)

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“…11 Therefore, selecting suitable electrode materials is crucial in VRFB design. 5 Carbonaceous materials such as carbon paper, graphite felt, carbon cloth, and graphite powder have been investigated as electrode materials for VRFBs. 12,13 Among them, graphite felts (GFs) are the most widely used because of their porous threedimensional network structure; low cost; high electrical conductivity, chemical and mechanical stability, and specific surface area; resistance of corrosion in acidic solutions, and a wide operating potential range.…”

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confidence: 99%

Electrocatalytic activity of Nb-doped hexagonal WO₃ nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

et al. 2016

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In this paper, we report a facile hydrothermal method to synthesize low-cost, high-catalytic-activity, and stable niobiumdoped hexagonal tungsten trioxide nanowires (Nb-doped h-WO3 NWs); these NWs were employed as catalysts to improve the electrocatalytic activity of graphite felt (GF) electrodes for use as positive electrodes in an all-vanadium redox flow battery (VRFB). The effect of Nb doping and its composition on the electrochemical performance of GF electrodes for a VRFB was investigated. Cyclic voltammetry and electrochemical impedance spectroscopy results showed that Nb-doped h-WO3 NWs with a Nb/W atomic ratio of 0.03 exhibited the highest electrocatalytic activities for VO 2+ /VO2 + couples among all the tested electrodes. This observation was attributed to the optimal Nb-doping concentration producing moderate defect states, thereby creating structural disorders, such as oxygen vacancies, in WO3 and leading to the generation of more active sites for the VO 2+ /VO2 + redox reaction on the electrode. Moreover, in charge-discharge tests, a VRFB single cell using the Nb-doped h-WO3 NWs (Nb/W = 0.03) catalyst demonstrated an excellent energy efficiency of 78.10% with a current density of 80 mA cm −2 . This efficiency is much higher than that demonstrated by VRFB cells with untreated GF (67.12%) and heat-treated GF obtained through conventional method (72.01%). Furthermore, in the stability test of a VRFB single cell with the Nb-doped h-WO3 NWs (Nb/W = 0.03) catalyst, almost no decay of the cell was observed even after 30 cycles. This observation indicates the outstanding stability of the cell during the redox reaction of vanadium ions under highly acidic conditions.

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Electrocatalytic activity of Nb-doped hexagonal WO₃ nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

et al. 2016

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“…Recently, nitrogen‐doped carbon materials have been investigated as electrode materials for VRFBs because doped nitrogen atoms in carbon materials can act as effective electrocatalysts for the electrochemical reaction of vanadium ion redox couples . By improving the charge transfer kinetics for redox reactions of vanadium ions, Park et al .…”

Section: Introductionmentioning

confidence: 99%

“…Park et al . reported that cobalt impregnated nitrogen‐doped graphite felt using in situ polymerization of polypyrrole exhibited fast electrochemical kinetics of vanadium redox reactions . Shao et al .…”

Section: Introductionmentioning

confidence: 99%

“…Recently, nitrogen-doped carbon materials have been investigated as electrode materials for VRFBs because doped nitrogen atoms in carbon materials can act as effective electrocatalysts for the electrochemical reaction of vanadium ion redox couples. [25][26][27][28][29][30][31][32][33][34] By improving the charge transfer kinetics for redox reactions of vanadium ions, Park et al demonstrated that corn protein-derived nitrogendoped carbon black coated graphite felt showed excellent catalytic activity. 25 Wu et al reported that PAN-based graphite felt prepared by the hydrothermal method in ammonia solution showed enhancement of electrochemical performance in a VRFB.…”

Section: Introductionmentioning

confidence: 99%

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Direct Nitradated Graphite Felt as an Electrode Material for the Vanadium Redox Flow Battery

Kim

Chung

Park

et al. 2018

Bulletin Korean Chem Soc

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The vanadium redox flow battery (VRFB) is one of the most promising electrochemical energy storage systems for grid support. However, the electrochemical performance of the VRFB should be further improved for successful penetration into the large‐scale energy storage system market. Among all the components of the VRFB, the electrode, which provides an active site for the vanadium ion redox reaction, plays an important role in determining the electrochemical properties of the VRFB. In this work, nitrogen‐doped graphite felts prepared via a direct nitridation route using NH3 were investigated as electrode materials for the VRFB. The resulting N‐doped graphite felt electrode showed much improved voltage efficiency and energy efficiency of 87.1 and 85.0%, respectively, compared to those of pristine graphite felt (82.13 and 79.6%, respectively). These improvements can be attributed to doped nitrogen atoms in the graphite felt electrode acting as an efficient electrocatalyst for the vanadium redox reaction in a VRFB system.

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“…While not involved in direct energy storage, electrode materials play a crucial role in the overall power density and energy efficiency as the electrodes must provide sites for reactions and efficiently transport charge to and from the active species [13]. Thus, potential VRFB electrode materials must have high electrical conductivity, mechanical strength, large specific surface area, good stability in (acidic) electrolytes, and electrochemical activity [14].…”

Section: Introductionmentioning

confidence: 99%

Properties of mesoporous carbon modified carbon felt for anode of all-vanadium redox flow battery

Schmidt

Cao

2016

Sci. China Mater.

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A novel anode material for all-vanadium redox flow battery was synthesized by dispersion coating of sol-gel processed (resorcinol-furaldehyde) mesoporous carbon (MPC) onto the surface of polyacrylonitrile carbon felt (CF). The coated samples were then annealed at 900°C and 1100°C and the subsequent morphology, surface chemistry, and electrochemical properties of the MPC coated CF were characterized and compared with an uncoated CF. Addition of the MPC coating is shown to dramatically increase surface area while also increasing the number of active surface oxygen groups particularly for samples annealed at 1100°C. MPC coating shows a mixed effect on electrochemical properties. Characterization with cyclic voltammetry reveals the introduction of MPC coating provides roughly 30% increase in peak current density for the oxidation and reduction reactions of the V(IV)/V(V ) redox couple, which is attributed to the significantly increased number of active reaction sites. However, MPC coating seems to be accompanied by a reduction in conductivity as demonstrated by increased redox peak separation and charge transfer resistance. This negative effect on conductivity can be mitigated by heat treatment (at or above 1100°C) which improves surface graphitization reducing redox peak separation and charge transfer resistance such that it is comparable with uncoated samples.

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Fabrication of nitrogen-doped graphite felts as positive electrodes using polypyrrole as a coating agent in vanadium redox flow batteries

Cited by 87 publications

References 40 publications

Electrocatalytic activity of Nb-doped hexagonal WO₃ nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

Electrocatalytic activity of Nb-doped hexagonal WO₃ nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

Direct Nitradated Graphite Felt as an Electrode Material for the Vanadium Redox Flow Battery

Properties of mesoporous carbon modified carbon felt for anode of all-vanadium redox flow battery

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Fabrication of nitrogen-doped graphite felts as positive electrodes using polypyrrole as a coating agent in vanadium redox flow batteries

Cited by 87 publications

References 40 publications

Electrocatalytic activity of Nb-doped hexagonal WO3 nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

Electrocatalytic activity of Nb-doped hexagonal WO3 nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

Direct Nitradated Graphite Felt as an Electrode Material for the Vanadium Redox Flow Battery

Properties of mesoporous carbon modified carbon felt for anode of all-vanadium redox flow battery

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Electrocatalytic activity of Nb-doped hexagonal WO₃ nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries

Electrocatalytic activity of Nb-doped hexagonal WO₃ nanowire-modified graphite felt as a positive electrode for vanadium redox flow batteries