Understanding the charging of supercapacitors by electrochemical quartz crystal microbalance

Niu, Liang; Yang, Lulu; Yang, Jing; Chen, Ming; Zeng, Liang; Duan, Pan; Wu, Tai zheng; Pameté, Emmanuel; Presser, Volker; Feng, Guang

doi:10.1039/d2im00038e

Cited by 7 publications

(6 citation statements)

References 71 publications

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“…The second stage (|σ| = 30–60 μC·cm –2 ), termed the fluctuation stage, features continuous energy fluctuations and more complex ion number changes. The stage characteristics of the composite electrode’s charging process are also reflected in the experimental study . For example, as current density increases, the specific capacitance of the electrode often shows a rapid decline in the first stage followed by a slower decline and a plateau in the second stage, , which is consistent with the overall decline trend of electrode energy in this work.…”

Section: Resultssupporting

confidence: 83%

Revealing the Two-Stage Charging Process in Sulfuric Acid Electrolyte by Molecular Dynamics Simulation

Sun,

Ying,

Fang

et al. 2024

Langmuir

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Two-dimensional MXene materials perform excellently in supercapacitor applications, but self-stacking and overlap limit their applications. Constructing a reasonable layered structure by combining MXene and graphene can effectively inhibit the restacking and overlap of MXene and improve the performance of supercapacitors. In this work, we studied the energy storage performance of a conventional MXene electrode and MXene/graphene composite electrode in sulfuric acid aqueous electrolyte by molecular dynamics (MD) simulation and analyzed their energy storage mechanisms. The simulation results reveal that the MXene/ graphene composite electrode showed faster charge−discharge speed and larger capacity and had more obvious advantages as a cathode. The charging process of the composite cathode can be divided into two stages. In the first stage, SO 4 2− and H 3 O + enter the electrode as a whole in a nearly 1:2 ratio, and a unique three-layer structure is formed in the graphene area, while a large number of HSO 4− leaves the electrode. In the second stage, SO 4 2− with a part of H 3 O + (ratio of 2:2 to 2:3) leave the electrode, and the threelayer structure is gradually destroyed. The cooperation of these two stages leads to a particular "concave" in the total energy change of the composite cathode. The introduction of graphene has brought about changes in ion distribution, migration mechanism, and energy change, making the MXene/graphene cathode show significant advantages in energy storage. This work is of great significance for understanding the microscopic energy storage mechanism of MXene/graphene-based electrodes.

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Section: Resultssupporting

confidence: 83%

Revealing the Two-Stage Charging Process in Sulfuric Acid Electrolyte by Molecular Dynamics Simulation

Sun,

Ying,

Fang

et al. 2024

Langmuir

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“…[63] Besides, ion transport coefficient was calculated to describe the position and migration rate of ions during transport process by molecular dynamics (MD), thus revealing the ion transport mechanism. [64] At present, researchers have analyzed the mass and chemical composition changes of EDL in electrochemical operations by many advanced characterization technology, such as electrochemical quartz crystal microbalances (EQCM), [65] in situ heating X-ray photoelectron spectroscopy, [66] time-of-flight secondary ion mass spectrometry (TOF-SIMS) [67] and electrochemical surface-enhanced Raman spectroscopy (EC-SERS) [33] and so on. The effects of temperature, potential and electric field on evolution of the EDL and SEI are expected to further research.…”

Section: Discussionmentioning

confidence: 99%

Interface Regulation via Electric Double Layer for Rechargeable Batteries

Du,

Song,

Yang

et al. 2023

ChemSusChem

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Interface, especially the electrochemically formed solid electrolyte interphase (SEI), is significantly important for cycling stability, reaction kinetics and safety of rechargeable batteries. The structure and composition of the electric double layer (EDL) greatly affect the formation of SEI and the performance of electrodes. However, as far as we know, there isn’t review to demonstrate the theme specially. Herein, the recent substantial progress for EDL and its impact on the formation of SEI in rechargeable batteries are reviewed and discussed. Firstly, the specific adsorption of electrolyte components on electrodes’ surface and the ionic solvation structure is introduced. Furthermore, various methods for controlling EDL in different electrode systems are described. Finally, the future development of SEI via EDL is presented for improvements and breakthroughs in electrochemical performance of rechargeable batteries.

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“…By monitoring this mass change as the electrode is charged and discharged for a capacitive system, ion fluxes can be determined. This has been used to investigate the ion electrosorption process in supercapacitors, and the charge storage mechanisms in batteries. − However, no studies have used EQCM to look at the double-layer charging of layered MOFs. ,,, Employing this technique to study the charge storage mechanisms of MOF-based devices alongside measurements of their electrochemical performance would allow the link between charging mechanisms and performance to be better understood.…”

Section: Introductionmentioning

confidence: 99%

Understanding Electrolyte Ion Size Effects on the Performance of Conducting Metal–Organic Framework Supercapacitors

Gittins,

Ge,

Balhatchet

et al. 2024

J. Am. Chem. Soc.

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Layered metal−organic frameworks (MOFs) have emerged as promising materials for next-generation supercapacitors. Understanding how and why electrolyte ion size impacts electrochemical performance is crucial for developing improved MOF-based devices. To address this, we investigate the energy storage performance of Cu 3 (HHTP) 2 (HHTP = 2,3,6,7,10, with a series of 1 M tetraalkylammonium tetrafluoroborate (TAABF 4 ) electrolytes with different cation sizes. Three-electrode experiments show that Cu 3 (HHTP) 2 exhibits an asymmetric charging response with all ion sizes, with higher energy storage upon positive charging and a greater charging asymmetry with larger TAA + cations. The results further show that smaller TAA + cations demonstrate superior capacitive performances upon both positive and negative charging compared to larger TAA + cations. To gain further insights, electrochemical quartz crystal microbalance measurements were performed to probe ion electrosorption during charging and discharging. These reveal that Cu 3 (HHTP) 2 has a cation-dominated charging mechanism, but interestingly indicate that the solvent also participates in the charging process with larger cations. Overall, the results of this study suggest that larger TAA + cations saturate the pores of the Cu 3 (HHTP) 2 -based electrodes. This leads to more asymmetric charging behavior and forces solvent molecules to play a role in the charge storage mechanism. These findings significantly enhance our understanding of ion electrosorption in layered MOFs, and they will guide the design of improved MOF-based supercapacitors.

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Understanding the charging of supercapacitors by electrochemical quartz crystal microbalance

Abstract: Supercapacitors are highly valued energy storage devices with high power density, fast charging ability, and exceptional cycling stability. A profound understanding of their charging mechanisms is crucial for continuous performance...

Cited by 7 publications

References 71 publications

Revealing the Two-Stage Charging Process in Sulfuric Acid Electrolyte by Molecular Dynamics Simulation

Revealing the Two-Stage Charging Process in Sulfuric Acid Electrolyte by Molecular Dynamics Simulation

Interface Regulation via Electric Double Layer for Rechargeable Batteries

Understanding Electrolyte Ion Size Effects on the Performance of Conducting Metal–Organic Framework Supercapacitors

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