Tailoring Energy and Power Density through Controlling the Concentration of Oxygen Vacancies in V<sub>2</sub>O<sub>5</sub>/PEDOT Nanocable-Based Supercapacitors

Bi, Wenchao; Jahrman, Evan P.; Seidler, Gerald T.; Wang, Jichao; Gao, Guohua; Wu, Guangming; Atif, M.; AlSalhi, Mohamad S.; Cao, Guangmin

doi:10.1021/acsami.9b03830

Cited by 65 publications

(38 citation statements)

References 61 publications

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“…The concentration of each oxidation state of vanadium cations was estimated from the corresponding peak area percentage. The overall vanadium oxidation states of the samples were examined by X‐ray absorption near‐edge structure measurements in the vanadium K‐edge using laboratory‐based instrumentation (University of Washington), and analyzed with a reported methodology . Fitting was performed in Mathematica with the energy from 5460 to 5490 eV, using the function NonlinearModelFit through a linear combination of the spectra of reference compounds.…”

Section: Methodsmentioning

confidence: 99%

Interface Engineering V₂O₅ Nanofibers for High‐Energy and Durable Supercapacitors

Wang

Jahrman

et al. 2019

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been made on elaborating the electrode materials with higher energy density for supercapacitors to meeting ever-increasing requirements. The energy density (E) of a supercapacitor is mainly dependent on the specific capacitance (C) and cell potential window (V) of electrode materials according to the equation E = 1/2CV 2 . [3] Thus, developing electrode materials with enhanced specific capacitance is crucial for high-energy supercapacitors. Carbonaceous material based electric double-layer capacitors appear with a low capacitance due to the physical absorption/desorption at the electrode surface. [4] Comparatively, transition metal oxides (TMOs) and conductive polymers (CPs) based pseudocapacitors exhibit higher theoretical storage capacitance because of the reversible faradic reactions on or near the electrode surface. [5] Vanadium pentoxide (V 2 O 5 ), a layer-structured TMO, has prospective applications in electrochemical energy storage due to its high theoretical capacitance (2020 F g −1 ), a broader operating voltage( up to ≈2.8 V), as well as low cost and abundance in nature. [6] However, the poor electrical conductivity of V 2 O 5 (10 −3 to 10 −2 S cm −1 ) limits the electron transfer kinetics for redox reactions. As a result, the pseudocapacitive reactions mainly occur on the surface or near-surface region of V 2 O 5 electrode materials, leading to a low utilization of V 2 O 5 and unsatisfactory specific capacitance. [7] In addition, the vanadium dissolution and structural instability reduces its cycling life. [8] To address these problems, many synthetic methods have been proposed. First, nanostructured V 2 O 5 materials with a large specific surface area are fabricated to provide sufficient contact area for fast Faradic reactions, such nanoribbons, [9] and nanobelts. [10] Second, tailoring the materials with multiple physicochemical properties can effectively enhance the electrochemical performance of V 2 O 5 with diverse functions from components. For instance, layered V 2 O 5 /poly(3,4-ethylenedioxythiophene) (PEDOT)/MnO 2 nanosheets show enhanced energy density (39.2 W h kg −1 ) and cycling stability (93.5% capacitance retention after 3000 cycles) due to the synergistic combination of PEDOT, MnO 2 , and V 2 O 5 . [11] However, V 2 O 5 electrode materials with enhanced electrochemical performance, fabricated in an uncomplicated and low-cost process are still necessary for practical applications. Based on the previous study, both polyaniline (PANI) and PEDOT improve the electrical conductivity as well as the stability of V 2 O 5 by forming a conductive coating, [8,11] A local electric field is induced to engineer the interface of vanadium pentoxide nanofibers (V 2 O 5 -NF) to manipulate the charge transport behavior and obtain high-energy and durable supercapacitors. The interface of V 2 O 5 -NF is modified with oxygen vacancies (Vö) in a one-step polymerization process of polyaniline (PANI). In the charge storage process, the local electric field deriving from the lopsided charge distribution arou...

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Section: Methodsmentioning

confidence: 99%

Interface Engineering V₂O₅ Nanofibers for High‐Energy and Durable Supercapacitors

Wang

Jahrman

et al. 2019

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“…Beyond the atmospheric treatment and doping, surface coatings such as conductive polymers can also introduce gradient oxygen vacancies in V 2 O 5 through in-situ polymerization. [185][186][187][188] The concentration of oxygen vacancies gradually decrease from the highest concentration at the surface, i.e., the interface between V 2 O 5 and poly (3, 4-ethylenedioxythiophene) (PEDOT), to near zero inside. [186] During cycling, a local electric field develops, which is derived from lopsided charge distribution around oxygen vacancies.…”

Section: Interface Defects and Surface Energymentioning

confidence: 99%

“…[186] DFT calculations showed that migration of oxygen vacancies from the surface of V 2 O 5 inward was thermodynamically favorable, as the Gibbs free energy of formation for vacancies was lower for the inner layers (-306.88 eV) of V 2 O 5 than outer layers (-306.58 eV). [187] Surface defects introduced by atmospheric treatment and polymeric reduction are effective approaches to modify the surface chemistry of electrode materials. The increased surface energy and enhanced electrical conductivity promote the redox kinetics for energy storage.…”

Section: Interface Defects and Surface Energymentioning

confidence: 99%

“…The result is more V 5+ are available for redox reactions and the specific capacitance increased 186. DFT calculations showed that migration of oxygen vacancies from the surface of V 2 O 5 inward was thermodynamically favorable, as the Gibbs free energy of formation for vacancies was lower for the inner layers (−306.88 eV) of V 2 O 5 than outer layers (−306.58 eV) 187…”

Section: Concerns and Strategies In Rbsmentioning

confidence: 99%

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Interphases, Interfaces, and Surfaces of Active Materials in Rechargeable Batteries and Perovskite Solar Cells

et al. 2020

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“…[ 27,28 ] The latter capacity fading commonly stems from a combination of structural changes [ 29 ] and dissolution of vanadium in the electrolyte, especially, in aqueous electrolytes. [ 30 ] Many authors have, therefore, proposed possible solutions to the conductivity problem based on composite electrodes containing conducting polymers [ 31 ] or carbon additives, such as graphene, [ 32 ] carbon nanotubes (CNTs), [ 33 ] or carbon dots. [ 34 ] Likewise, some other nanostructured vanadium oxide and hydroxide materials were also encapsulated in carbonaceous network and showed good electrochemical performance.…”

Section: Introductionmentioning

confidence: 99%

On the Capacities of Freestanding Vanadium Pentoxide–Carbon Nanotube–Nanocellulose Paper Electrodes for Charge Storage Applications

et al. 2020

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Herein, a one‐step protocol for synthesizing freestanding 20 μm thick cellulose paper electrodes composed of V2O5 ⋅ H2O nanosheets (VOx), carbon nanotubes (CNTs), and Cladophora cellulose (CC) is reported. In 1.0 m Na2SO4, the VOx–CNT–CC electrodes deliver capacities of about 200 and 50 C g−1 at scan rates of 20 and 500 mV s−1, respectively. The obtained capacities are compared with the theoretical capacities and are discussed based on the electrochemical reactions and the mass loadings of the electrodes. It is shown that the capacities are diffusion rate limited and, consequently, depend on the distribution and thickness of the V2O5 ⋅ H2O nanosheets, whereas the long‐term cycling stabilities depend on vanadium species dissolving in the electrolyte. The electrodes feature high mass loadings (2 mg cm−2), good rate performances (25% capacity retention at 500 mV s−1), and capacity retentions of 85% after 8000 cycles. A symmetric VOx–CNT–CC energy storage device with a potential window of about 1 V exhibits a capacity of 40 C g−1 at a scan rate of 2 mV s−1.

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Tailoring Energy and Power Density through Controlling the Concentration of Oxygen Vacancies in V₂O₅/PEDOT Nanocable-Based Supercapacitors

Cited by 65 publications

References 61 publications

Interface Engineering V₂O₅ Nanofibers for High‐Energy and Durable Supercapacitors

Interface Engineering V₂O₅ Nanofibers for High‐Energy and Durable Supercapacitors

Interphases, Interfaces, and Surfaces of Active Materials in Rechargeable Batteries and Perovskite Solar Cells

On the Capacities of Freestanding Vanadium Pentoxide–Carbon Nanotube–Nanocellulose Paper Electrodes for Charge Storage Applications

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Tailoring Energy and Power Density through Controlling the Concentration of Oxygen Vacancies in V2O5/PEDOT Nanocable-Based Supercapacitors

Cited by 65 publications

References 61 publications

Interface Engineering V2O5 Nanofibers for High‐Energy and Durable Supercapacitors

Interface Engineering V2O5 Nanofibers for High‐Energy and Durable Supercapacitors

Interphases, Interfaces, and Surfaces of Active Materials in Rechargeable Batteries and Perovskite Solar Cells

On the Capacities of Freestanding Vanadium Pentoxide–Carbon Nanotube–Nanocellulose Paper Electrodes for Charge Storage Applications

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Product

Resources

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Tailoring Energy and Power Density through Controlling the Concentration of Oxygen Vacancies in V₂O₅/PEDOT Nanocable-Based Supercapacitors

Interface Engineering V₂O₅ Nanofibers for High‐Energy and Durable Supercapacitors

Interface Engineering V₂O₅ Nanofibers for High‐Energy and Durable Supercapacitors