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The different contributions of the interfacial capacitance are identified in the case of passive materials or thin protective coatings deposited on the electrode surface. The method is based on a graphical analysis of the EIS results to determine both the passive-film capacitance in the high-frequency domain and the double-layer capacitance in the low-frequency domain. The proposed analysis is shown to be independent of the physicochemical origins of the frequency dispersion of the interfacial capacitances which results, from an analysis point of view of the experimental results, in the use of a constant-phase element However, for a correct evaluation of the thin-film properties such as its thickness, the high-frequency data must be corrected for the double-layer contribution. In particular, it is shown that if the double-layer capacitance gives a frequency-dispersed response, it is necessary to correct the high-frequency part for the double-layer constant-phase elements. This is first demonstrated on synthetic data and then used for the determination of the thickness of thin oxide film formed on Al in neutral pH solution.
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http://dx.doi.org/10.1002/cphc.202100177 | DOI Listing |
ACS Omega
September 2025
Department of Physics, Birla Institute of Technology and Science, Pilani, Pilani Campus, Vidya Vihar, Pilani, Rajasthan 333031, India.
We report the performance of solid-state ceramic supercapacitors (SSCs) based on a novel composite electrolyte comprising aluminum-doped lithium lanthanum titanate perovskite, LiLaTiAlO (Al-doped LLTO), and the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM BF). Rietveld refinement of X-ray diffraction data confirms the preservation of the tetragonal perovskite phase after Al substitution, indicating structural stability of the host lattice. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy further corroborate the successful incorporation of Al without forming secondary phases.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
Division of Nano Life Science, Kanazawa University, Kakuma-machi, 920-1192 Kanazawa, Japan.
Atomic force microscopy (AFM) imaging of ionic liquid (IL) distribution in electric double-layer (EDL) devices has been actively explored to understand the origin of their excellent performance. However, this has been impeded by insufficient resolution or a poor understanding of the mechanisms of 3D IL imaging. Here, we overcome these difficulties using 3D scanning force microscopy (3D-SFM) with variable tip/sample bias voltages for visualizing 3D ,-diethyl--methyl--(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide (DEME-TFSI) distributions on a Au electrode in EDL capacitors.
View Article and Find Full Text PDFJ Colloid Interface Sci
August 2025
Department of Chemical Engineering and Key Laboratory of Advanced Materials of Ministry of Education, Tsinghua University, Beijing 100084, China. Electronic address:
Reversible electroadhesive polyelectrolyte gels have emerged as promising materials for flexible electronic and soft robotic applications. While current research predominantly emphasizes polymer design and structural optimization to enhance both the reversibility and strength of electroadhesion, fundamental limitations persist in elucidating ion-mediated interfacial mechanisms. Herein, the synergistic effects of ion species selection and interfacial engineering were systematically investigated through the development of distinct polyelectrolyte hydrogel assemblies.
View Article and Find Full Text PDFSci Rep
September 2025
Department of Physics, Amrita School of Physical Sciences Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore, 641 112, India.
Hollow carbon spheres are among the most promising materials for supercapacitor electrodes. Here, N, S, and F-doped hollow carbon spheres have been synthesized, and their electric double layer supercapacitor (EDLC) performances have been investigated in a KOH electrolyte. It is found that the device with electrodes having N, S, and F ternary atom-doped material delivers superior performance and rate capability compared to N-doped and N, S co-doped materials.
View Article and Find Full Text PDFAdv Mater
September 2025
Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
Electrochemical Capacitors (ECs) are considered capable of replacing bulky and low-capacitance aluminum electrolytic capacitors (AECs) in alternative-current filtering, yet regrettably, they have been plagued by slow ion migration and sluggish electrical response. Non-carbon-based electrode materials, while exhibiting significantly higher electric double-layer capacitance (EDLC) compared to carbon-based electrodes, still face the challenge of relatively high interfacial charge transfer resistance (R) that needs to be overcome. Here, a charge-transfer kinetics enhancement strategy is demonstrated by utilizing the lattice oxygen deficiency in molybdenum dioxide (MoO ) to increase metallic electrical conductivity and the number of active sites.
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