Rethinking Pseudocapacitance: A Way to Harness Charge Storage of Crystalline RuO<sub>2</sub>

Jadon, Ankita; Prabhudev, Sagar; Buvat, Gaëtan; Patnaik, Sai Gourang; Djafari-Rouhani, Mehdi; Estève, Alain; Guay, Daniel; Pech, David

doi:10.1021/acsaem.0c00476

Cited by 16 publications

(6 citation statements)

References 16 publications

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“…These experiments provide clear-cut evidence for the transformation of RuO 2 to hydrous RuO 2 and then to metallic Ru. Upon cathodic polarization in the HER potential region (down to −100 mV SHE ), first the layer spacing of RuO 2 (110) increases (SXRD, l-scan Figure b), a process that is reconciled with proton insertion into the RuO 2 lattice and that may be interesting for charge storage in crystalline RuO 2 . However, both the octahedral coordination of Ru and the connectivity of the Ru–O 6 octahedrons (rutile structure) are still preserved.…”

Section: Critical Discussion Of Selected Model Studiesmentioning

confidence: 99%

“…Upon cathodic polarization in the HER potential region (down to −100 mV SHE ), first the layer spacing of RuO 2 (110) increases (SXRD, l-scan Figure 9b), a process that is reconciled with proton insertion into the RuO 2 lattice and that may be interesting for charge storage in crystalline RuO 2 . 203 However, both the octahedral coordination of Ru and the connectivity of the Ru− O 6 octahedrons (rutile structure) are still preserved. A further increase in the cathodic potential steadily destroys the crystallinity of the RuO 2 (110) layer (Figure 9a,b), likely via the formation of OH and water from lattice O, thereby breaking the connectivity among the Ru−O 6 octahedrons in the rutile RuO 2 structure.…”

Section: Critical Discussion Of Selected Model Studiesmentioning

confidence: 99%

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Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO₂, IrO₂) for Acidic Water Splitting

Over

2021

ACS Catal.

178

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Electrocatalytic water splitting allows storing excess energy from renewable energy sources such as wind and solar in chemical bonds of hydrogen molecules. So far, only polymer electrolyte membrane (PEM) water electrolyzers under acidic conditions can cope with the intermittent supply of energy, requiring, however, noble metals at the cathode for the hydrogen (HER) and precious metal oxides at the anode for the oxygen evolution reaction (OER). Prototypical oxides for the OER under acidic conditions are RuO2 and IrO2 that can meet the stringent requirements for long-term stability and high electrocatalytic activity. While RuO2 is substantially more active than IrO2, RuO2 is significantly less stable than IrO2 due to corrosion under OER conditions. Our microscopic understanding of the underlying processes of corrosion is, however, surprisingly poor, while the rate-determining steps in the OER over RuO2 and IrO2 are still under debate. In this perspective, I will be focusing on the discussion of the electrochemical degradation of ultrathin single-crystalline RuO2(110) and IrO2(110) films in the potential regions of both OER and HER. The single crystallinity of the model electrodes allows for identifying structure–property relationships and for a tight connection to theory. Since stability and activity in the OER are reported to be intimately coupled, I will also include a critical review of our present knowledge on the microscopic steps in the OER on RuO2 and IrO2, both from theory and experiments. Ultimately, from these atomic scale insights, the inherent material properties may be uncovered which underlie the observed electrochemical stability and activity of IrO2 and RuO2. It is the hope that these fundamental insights will aid the search for alternative more abundant electrode material systems for acidic water electrolyzers.

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Section: Critical Discussion Of Selected Model Studiesmentioning

confidence: 99%

Section: Critical Discussion Of Selected Model Studiesmentioning

confidence: 99%

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO₂, IrO₂) for Acidic Water Splitting

Over

2021

ACS Catal.

178

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“…The above results proved that the pseudocapacitance of RuO 2 came from the surface redox reaction, not the bulk reaction of RuO 2 . In order to better understand the charge storage mechanism of RuO 2 in acidic media, more and more researchers have begun to use theoretical calculation methods to analyze the thermodynamic and kinetic behavior of RuO 2 on the atomic scale [ 46 – 49 ]. The results of first-principles density-functional theory (DFT) showed that the intercalation of protons would lead to the formation of O–H covalent bonds and the formation of an electronic delocalization state for only 0.3 electrons transferring to the Ru atom center.…”

Section: Electrochemical Proton Storage Materials and Mechanismsmentioning

confidence: 99%

Electrochemical Proton Storage: From Fundamental Understanding to Materials to Devices

Wang

et al. 2022

Nano-Micro Lett.

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Simultaneously improving the energy density and power density of electrochemical energy storage systems is the ultimate goal of electrochemical energy storage technology. An effective strategy to achieve this goal is to take advantage of the high capacity and rapid kinetics of electrochemical proton storage to break through the power limit of batteries and the energy limit of capacitors. This article aims to review the research progress on the physicochemical properties, electrochemical performance, and reaction mechanisms of electrode materials for electrochemical proton storage. According to the different charge storage mechanisms, the surface redox, intercalation, and conversion materials are classified and introduced in detail, where the influence of crystal water and other nanostructures on the migration kinetics of protons is clarified. Several reported advanced full cell devices are summarized to promote the commercialization of electrochemical proton storage. Finally, this review provides a framework for research directions of charge storage mechanism, basic principles of material structure design, construction strategies of full cell device, and goals of practical application for electrochemical proton storage.

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“…Numerous studies, however, serve to demonstrate this pseudocapacitive behavior (Figure S1, Supporting Information). [ 2,4,11–44 ] This thus leads one to consider the possible reasons for a redox reaction, which is essentially a Faradaic occurrence, deviating so far from the ideal peak response (as illustrated in Figure 1 ).…”

Section: Introductionmentioning

confidence: 99%

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

Zhu,

Deebansok,

Deng

et al. 2024

Advanced Energy Materials

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Electrochemical energy storage devices are built upon the foudations of batteries and supercapacitors. In the past decade, new pseudocapacitor‐like electrodes are intensively developed to obtain superior energy storage performance. Pseudocapacitive matarials store charge through Faradaic processes, while the electrochemical signal remains like electrochemical double‐layer capacitors (EDLCs). To address this controversy, an analytical model is introduced for evaluating the voltammograms of electrode materials. Given this, the work focuses on understanding the origin of the pseudocapacitive phenomena in the cyclic voltammetry (CV) electrochemical signal. Based on electron transfer mechanism and tunnelling effect within the atomic structure, pseudocapacitive matarials possess a high electron delocalization possibility related to the redox centers number and initiates the electrochemical potential distribution among neighboring redox sites, which is consequently observed in the electrochemical signal as the plateau feature in CV, like EDLC. First, the determination of the capacitive tendency of various electrode materials is proposed, which turns out to be relative to the redox centers number (n) and total charge (Z). Here, when this number is large, electron hopping will very likely happen. The developed model is versatile to predict rate/potential regimes for the maximum faradaic storage, and then well differentiates the pseudocapacitive and battery materials.

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Rethinking Pseudocapacitance: A Way to Harness Charge Storage of Crystalline RuO₂

Cited by 16 publications

References 16 publications

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO₂, IrO₂) for Acidic Water Splitting

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO₂, IrO₂) for Acidic Water Splitting

Electrochemical Proton Storage: From Fundamental Understanding to Materials to Devices

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

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Rethinking Pseudocapacitance: A Way to Harness Charge Storage of Crystalline RuO2

Cited by 16 publications

References 16 publications

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO2, IrO2) for Acidic Water Splitting

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO2, IrO2) for Acidic Water Splitting

Electrochemical Proton Storage: From Fundamental Understanding to Materials to Devices

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

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Product

Resources

About

Rethinking Pseudocapacitance: A Way to Harness Charge Storage of Crystalline RuO₂

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO₂, IrO₂) for Acidic Water Splitting

Fundamental Studies of Planar Single-Crystalline Oxide Model Electrodes (RuO₂, IrO₂) for Acidic Water Splitting