Transition from Battery to Pseudocapacitor Behavior via Structural Water in Tungsten Oxide

Mitchell, James B.; Lo, William Chung Hei; Genç, Arda; LeBeau, James M.; Augustyn, Veronica

doi:10.1021/acs.chemmater.6b05485

Cited by 186 publications

(194 citation statements)

References 52 publications

(77 reference statements)

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“…A distribution of hexagonal window sites along the nanorod length could be more beneficial if an interfacial electric field at the step edge promotes the electrochemical reaction . Surface adsorbed or structural water present in larger quantities on longer nanorods could also improve kinetics . Regardless of the origin of the length‐dependent effect, we conclude that these hexagonal nanorods due not exhibit intercalation pseudocapacitance.…”

Section: Resultsmentioning

confidence: 87%

“…[26,37] Surface adsorbed or structural water present in larger quantities on longer nanorods could also improve kinetics. [34,38] Regardless of the origin of the lengthdependent effect, we conclude that these hexagonal nanorods due not exhibit intercalation pseudocapacitance. While it is possible that our calculations underestimate the total number of surface sites because we assume a perfect hexagonal prism morphology, that underestimation would still lead us to conclude that less sub-surface sites participate in pseudocapacitive charge storage.…”

Section: Quantifying Pseudocapacitive Charge Storage At Surface and Smentioning

confidence: 77%

“…The OD onset could occur at more negative potentials for those particles with a significant contact resistance. Another possible explanation is that varying amounts of structural or surface adsorbed water in these nanorods influences the Li‐ion binding energetics at the WO 3 /electrolyte interface, and diffusion behavior within the nanorod bulk …”

Section: Resultsmentioning

confidence: 99%

“…Another possible explanation is that varying amounts of structural or surface adsorbed water in these nanorods influences the Li-ion binding energetics at the WO 3 / electrolyte interface, and diffusion behavior within the nanorod bulk. [34][35][36]…”

Section: Single Nanoparticle Charge Storage Behaviormentioning

confidence: 99%

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Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

et al. 2020

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Pseudocapacitors promise to combine the high‐rate capability of electrochemical capacitors with the high energy‐density of batteries. A major challenge in the field is to demonstrate that pseudocapacitors behave electrochemically like a capacitor and the charge storage process is faradaic in nature. It is challenging to do so because pseudocapacitive charging has the same electrical signatures as non‐faradaic electrical double‐layer charging. Here we use electro‐optical imaging to measure Li‐ion insertion reactions in single WO3 nanoparticles. On average, these WO3 particles exhibit a hybrid charge storage mechanism: both diffusion‐limited (battery‐like) and pseudocapacitive (capacitor‐like) mechanisms contribute to the total charge stored. Individual particles exhibit different charge storage mechanisms at the same applied potential. Longer nanorods store more pseudocapacitive charge than shorter nanorods, presumably due to 1) a surface step edge gradient that exposes large hexagonal window Li‐ion binding sites along the nanorod length and/or 2) higher structural water content that influences the Li‐ion binding energetics and diffusion behavior. Importantly, we quantified the penetration depth of Li‐ion insertion and concluded that Li ions insert as deep as two‐unit cells below the surface. The methodology presented herein can be applied to a wide range of solid‐state ion‐insertion materials.

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Section: Resultsmentioning

confidence: 87%

Section: Quantifying Pseudocapacitive Charge Storage At Surface and Smentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Section: Single Nanoparticle Charge Storage Behaviormentioning

confidence: 99%

See 2 more Smart Citations

Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

et al. 2020

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“…[72] The diffusion control process of the electrode was fitted with a Warburg element Z w and determined the diffusion resistance (W R ) of the AVO, KVO, and NVO devices are 22.2, 25.6, and 24.2 Ω cm −2 . [75] Comparing 1D and 2D morphological structures, the 2D materials have more electroactive sites and the probability of electrolytic ions' interaction with the electroactive material is more [76] than the 1D nanostructure. Figure S10b (Supporting Information) presented the Nyquist plots of heattreated HAVO, HKVO and HNVO samples and the resultant plots were well fitted with the same equivalent circuit.…”

Section: Wwwadvmatinterfacesdementioning

confidence: 99%

Vanadium Pentoxide with H₂O, K⁺, and Na⁺ Spacer between Layered Nanostructures for High‐Performance Symmetric Electrochemical Capacitors

Manikandan

Raj

Rajesh

et al. 2018

Adv Materials Inter

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batteries and the power density similar to the electric double-layer capacitors. [1][2][3][4] Generally, the transition metal oxides and conducting polymers are used as the pseudocapacitor electrode materials, [3] since it stores electric charges based on the Faradaic and non-Faradaic reactions arising at the interface of electrode/electrolyte. [5] Several transition metal oxides, metal sulfides, and metal hydroxides have been displayed to be appropriate for the electrodes of supercapacitors. [6] Mostly, transition metal oxides (e.g., RuO 2 , MnO 2 , NiO, and V 2 O 5 ) are widely utilized as the electrode material to attain pseudocapacitive energy storage property due to their multivalence oxidation states. [7] Among the various metal oxides, vanadium pentoxide (V 2 O 5 ) is reflected to be the most capable candidate for pseudocapacitor owing to its natural abundance and existence of variable oxidation states from +2 to +5 (VO, V 2 O 3 , VO 2 , and V 2 O 5 ). [8] In addition, V 2 O 5 possess a higher theoretical capacitance value of ≈2120 F g −1 under a considerable potential window of 1 V, and this is recognized to the higher oxidation state of vanadium to transfer more than one electron instantly. [9,10] So, vanadium pentoxide nanostructures have been the most regarded materials in various applications, [11] such as batteries, [12][13][14] supercapacitors, [15,16] catalyst, [17] optical switching, [18] and energy-saving devices. [19] In supercapacitors, apart from the electrical/electrochemical properties, the specific capacitance of vanadium oxide also depends upon the morphology and synthesis techniques. [20] Recently, different types of nanostructured V 2 O 5 such as nanowires, [21] nanoribbons, [22] nanorods, [23] nanoplatelets, [24] and nanobelts [25] have been applied for supercapacitor electrodes. [26] Moreover, various synthetic methods such as hydrothermal/solvothermal, thermal decomposition, chemical vapor deposition, microwave-assisted synthesis, and sol-gel [27,28] methods have been adopted for the fabrication of different forms of vanadium oxide nanostructures. Among various synthesis techniques, the hydrothermal method is a low-cost, environmentally friendly, and widely used technique for the development of inorganic nanostructures. The hydrothermal method is a scalable and simple method, retaining autoclaves at lower operational temperatures with Vanadium oxide 2D layered nanostructures with the hydrous form of potassium (K + ) and sodium (Na + ) are synthesized via hydrothermal reaction between VOSO 4 · xH 2 O and different persulfate oxidants ((NH 4 ) 2 S 2 O 8 , K 2 S 2 O 8 , and Na 2 S 2 O 8 ). The physicochemical characterization suggests that the synthesized V 2 O 5 · 3H 2 O nanostructures possess layered morphology with considerable amount of water molecules accommodated between the interlayer spacing of nanostructures. Moreover, samples obtained using K 2 S 2 O 8 and Na 2 S 2 O 8 oxidants have K + (6.41%) and Na + (0.38%) ions intercalated on the 2D nanostructure along with the water mole...

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Methods and Instrumentation in Energy Storage

Mishra

Gossage

Sarbapalli

et al. 2021

Encyclopedia of Electrochemistry

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Electrochemical energy storage systems (EESS), such as batteries, rely on a plethora of dynamic processes including electron and ion transfer, phase transformations, and side reactions, that make their characterization critical toward improving device performance. Both traditional and advanced electroanalytical methods are applied to investigate and evaluate phenomena from the bulk electrode behavior to key interfacial processes, and beyond. Understanding the complexity of energy storage chemistry involves measurements across wide timescales and different spatial dimensions, with high chemical resolution. These demanding characteristics continue to push the development of new analytical instrumentation and methods for better assessment and further improvement of EESS. We discuss the working principles, methods, and instruments needed to evaluate their characteristics and performance. We provide a broad coverage of the electroanalytical principles (e.g. equations, instrumental design, etc.) available for evaluating Li‐ion, redox flow, and other popular EESS. Classical techniques covered include galvanostatic and potentiostatic (dis)charge, cyclic voltammetry, and impedance spectroscopy. We discuss traditional and advanced tools for in situ , operando , and coupled methods to evaluate energy storage materials and the interfacial chemistry under real operating conditions. These include electrochemical methods coupled to nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), neutron‐based methods, X‐ray methods, atomic force microscopy (AFM), and scanning electrochemical microscopy (SECM) to name a few. We hope this introduction to instrumental analysis of EESS is didactical to the novice practitioner and informative to those wishing to expand their knowledge of energy storage.

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Transition from Battery to Pseudocapacitor Behavior via Structural Water in Tungsten Oxide

Cited by 186 publications

References 52 publications

Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

Vanadium Pentoxide with H₂O, K⁺, and Na⁺ Spacer between Layered Nanostructures for High‐Performance Symmetric Electrochemical Capacitors

Methods and Instrumentation in Energy Storage

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Transition from Battery to Pseudocapacitor Behavior via Structural Water in Tungsten Oxide

Cited by 186 publications

References 52 publications

Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

Vanadium Pentoxide with H2O, K+, and Na+ Spacer between Layered Nanostructures for High‐Performance Symmetric Electrochemical Capacitors

Methods and Instrumentation in Energy Storage

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Product

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Vanadium Pentoxide with H₂O, K⁺, and Na⁺ Spacer between Layered Nanostructures for High‐Performance Symmetric Electrochemical Capacitors