Hybrid energy storage: high voltage aqueous supercapacitors based on activated carbon–phosphotungstate hybrid materials

Suárez-Guevara, Jullieth; Ruíz, Vanesa; Gómez‐Romero, Pedro

doi:10.1039/c3ta14455k

Cited by 149 publications

(110 citation statements)

References 53 publications

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“…4a), we observed retention of the double-layer behavior of the carbon matrix without any important modifications. This finding indicates that POM treatment did not result in the matrix oxidation commonly observed in extended reaction times [15,16,40] and did not block accessible pores. However, when the same matrix was treated with a POM/EtOH solution (VC + POM/EtOH, Fig.…”

Section: Electrochemical Characterizationmentioning

confidence: 76%

“…sensors and fuel cells due to their electrocatalytic properties [7][8][9], and more recently, in supercapacitors [10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…POM particles have also been deposited on electrode surfaces and immobilized into or within conducting polymers to modify their properties [11,[22][23][24][25][26]. Furthermore, they have been incorporated in a diversity of carbon matrices such as activated carbon [15,16,27], carbon cloth and fibers [4,5], gels [6] and aerogels [14], pastes [7,8], nanofibers [12], multiwalled carbon nanotubes [9-11, 13, 28-33], and graphene [10,11,[34][35][36][37] and electrodeposited onto vitreous carbon substrates [38,39]. These types of carbon matrices compared to others can strongly immobilize these molecular oxides, showing low solvent desorption due to covalent bonds between the functional groups present on the surfaces of the carbons and oxides [9,11,13,30,32,40].…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

Cuentas-Gallegos

López-Cortina

Brousse

et al. 2015

J Solid State Electrochem

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In this work, we show a comparative study based on the effects of specific chemical functional groups (-OH, -NH 2 ), grafted on Vulcan carbon (VC) with the incorporation of a specific polyoxometalate (POM), PMo 12 (H 3 PMo 12 O 40 ), to improve electrochemical performance. We observed a decrease in the specific surface area of the grafted matrices (VC-OH and VC-NH 2 ) [1], and the same trend was observed for PMo 12 (POM) incorporation. Our electrochemical studies showed low concentrations of POM in unmodified VCs and higher POM concentrations for grafted matrices (VC-OH and VC-NH 2 ) after 500 voltammetric cycles, especially for the VC grafted with -OH groups (VC-OH-POM). Mechanisms have been proposed for POM interaction with the grafted groups in carbon, emphasizing the role of aqueous medium and redox activity of POM. Cyclic voltammograms suggested the POM anchoring through -OH groups with a strong interaction as a covalent bond, resulting in a surface coverage of 1.66 × 10 −11 mol cm −2. Surface modifications could be extrapolated to other carbons, and the materials could be employed for different potential applications such as photocatalysis, amperometric sensors, fuel cells, and supercapacitors.

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Section: Electrochemical Characterizationmentioning

confidence: 76%

“…sensors and fuel cells due to their electrocatalytic properties [7][8][9], and more recently, in supercapacitors [10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

Cuentas-Gallegos

López-Cortina

Brousse

et al. 2015

J Solid State Electrochem

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“…Moreover, they are so small and heavily charged that they are soluble in many solvents and, in principle, useless as active electrochemical electrode materials by themselves. However, POMs contribute their water solubility and faradaic charge-storage mechanisms to well-known varied redox potentials leading to robust electrodes and electroanalytical platforms [41]. Therefore, integration of POMs with graphene will lead to the development of new concept hybrid materials where surface functional moieties on GO and rGO serve as chemical linkers and POMs clusters as molecular spacers for graphene sheets that allow excess to large specific surface enabling higher storage capacity otherwise inaccessible for ion adsorption due to self-aggregation.…”

Section: Introductionmentioning

confidence: 99%

Functionalized Graphene–Polyoxometalate Nanodots Assembly as “Organic–Inorganic” Hybrid Supercapacitors and Insights into Electrode/Electrolyte Interfacial Processes

Gupta

Aberg

Carrizosa

2017

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Abstract:The stable high-performance electrochemical electrodes consisting of supercapacitive reduced graphene oxide (rGO) nanosheets decorated with pseudocapacitive polyoxometalates (phosphomolybdate acid-H 3 PMo 12 O 40 (POM) and phosphotungstic acid-H 3 PW 12 O 40 (POW)) nanodots/nanoclusters are hydrothermally synthesized. The interactions between rGO and POM (and POW) components create emergent "organic-inorganic" hybrids with desirable physicochemical properties (specific surface area, mechanical strength, diffusion, facile electron and ion transport) enabled by molecularly bridged (covalently and electrostatically) tailored interfaces for electrical energy storage. The synergistic hybridization between two electrochemical energy storage mechanisms, electrochemical double-layer from rGO and redox activity (faradaic) of nanoscale POM (and POW) nanodots, and the superior operating voltage due to high overpotential yielded converge yielding a significantly improved electrochemical performance. They include increase in specific capacitance from 70 F·g −1 for rGO to 350 F·g −1 for hybrid material with aqueous electrolyte (0.4 M sodium sulfate), higher current carrying capacity (>10 A·g −1 ) and excellent retention (94%) resulting higher specific energy and specific power density. We performed scanning electrochemical microscopy to gain insights into physicochemical processes and quantitatively determine associated parameters (diffusion coefficient (D) and heterogeneous electron transfer rate (k ET )) at electrode/electrolyte interface besides mapping electrochemical (re)activity and electro-active site distribution. The experimental findings are attributed to: (1) mesoporous network and topologically multiplexed conductive pathways; (2) higher density of graphene edge plane sites; and (3) localized pockets of re-hybridized orbital engineered modulated band structure provided by polyoxometalates anchored chemically on functionalized graphene nanosheets, contribute toward higher interfacial charge transfer, rapid ion conduction, enhanced storage capacity and improved electroactivity.

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“…[15][16][17] All these different mechanisms for charge storage have been traditionally exploited separately.…”

mentioning

confidence: 99%

Capacitive vs Faradaic Energy Storage in a Hybrid Cell with LiFePO₄/RGO Positive Electrode and Nanocarbon Negative Electrode

Cabán-Huertas

Dubal

Ayyad

et al. 2016

J. Electrochem. Soc.

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We report an advanced device based on a Nitrogen-doped Carbon Nanopipes (N-CNP) negative electrode and a lithium iron phosphate (LiFePO 4 ) positive electrode. We carefully balanced the cell composition (charge balance) and suppressed the initial irreversible capacity of the anode in the round of few cycles. We demonstrated an optimal performance in terms of specific capacity 170 mAh/g of LiFePO 4 with energy density of about 203 Wh kg −1 and a stable operation for over 100 charge−discharge cycles. Lithium ion batteries (LIBs) are presently struggling to meet very demanding standards in terms of cost, charge/discharge rate, power and energy densities, and safety in order to enter new emerging markets such as those of electric vehicles and the storage of renewable electrical energy. 1Batteries exhibit relatively high energy densities as a result of faradaic reactions in the bulk of active particles, but are rate-limited. A remarkable example of a well-known material that undergoes a redox process during the battery charge and discharge process is Lithium iron phosphate (LiFePO 4 ). After two decades of the seminal work by Goodenough and col., 2 LiFePO 4 has been established as one of the most widely used positive electrode materials for LIBs thanks to its low cost, abundant raw materials, safety, low toxicity, structural stability and excellent electrochemical properties. The active material can be reversibly charged and discharged with a stable voltage of 3.45 V vs Li + /Li with a very small change in unit cell parameters during the LiFePO 4 /FePO 4 phase transition. On the other hand, for the development of high power batteries based on this material, it is essential to understand and overcome the factors limiting lithium transport through the electrode. Indeed, despite its relatively high theoretical specific capacity (170 mAh/g) and long cycling life, the high-rate performance of pure LiFePO 4 is restricted by its poor electronic conductivity (10 −9 S/cm) and slow lithium diffusion. 3 Many different approaches involving surface coating have been tried to improve the capacity and rate performance of LiFePO 4 as cathode for LIBs. Increasing the conductivity by coating the LiFePO 4 surface with carbon 4,5 or conducting polymers 6,7 have been two of the most popular. In comparison to these carbon materials, graphene can offer an improved interfacial contact because of its superior conductivity, flexible two-dimensional structure, and high surface area. 8 However, due to the thermodynamic instable structure of graphene, it tends to aggregate. Among various graphene derivatives, reduced Graphene Oxide is more polar and hydrophilic than graphene and better conducting that Graphene Oxide and therefore constitutes an optimal choice among graphenes. A critical issue of LIBs technology is the relatively low theoretical specific capacity of conventional graphite anodes, limited to 372 mAh/g. 9 * Electrochemical Society Student Member. z E-mail: pedro.gomez@icn2.cat Electrochemical capacitors 10 can deliver high power at ...

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Hybrid energy storage: high voltage aqueous supercapacitors based on activated carbon–phosphotungstate hybrid materials

Cited by 149 publications

References 53 publications

Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

Functionalized Graphene–Polyoxometalate Nanodots Assembly as “Organic–Inorganic” Hybrid Supercapacitors and Insights into Electrode/Electrolyte Interfacial Processes

Capacitive vs Faradaic Energy Storage in a Hybrid Cell with LiFePO₄/RGO Positive Electrode and Nanocarbon Negative Electrode

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Hybrid energy storage: high voltage aqueous supercapacitors based on activated carbon–phosphotungstate hybrid materials

Cited by 149 publications

References 53 publications

Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

Functionalized Graphene–Polyoxometalate Nanodots Assembly as “Organic–Inorganic” Hybrid Supercapacitors and Insights into Electrode/Electrolyte Interfacial Processes

Capacitive vs Faradaic Energy Storage in a Hybrid Cell with LiFePO4/RGO Positive Electrode and Nanocarbon Negative Electrode

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Capacitive vs Faradaic Energy Storage in a Hybrid Cell with LiFePO₄/RGO Positive Electrode and Nanocarbon Negative Electrode