____________________Dataset for "Wide electrochemical stability window of boron-doped microcrystalline diamond electrode in NaNO3 water-in-salt electrolytes" ____________________ Last updated: 2024-12-04 ______Contact______ * Egor Ukraintsev * ORCID: 0000-0002-9768-5119 * Faculty of Electrical Engineering, Czech Technical University in Prague, Prague * Technická 2, 16227 Prague, Czech Republic ______Principal Investigator______ * Karel Bouzek * ORCID: 0000-0002-0394-0634 * Dept. of Inorganic Technology, Faculty of Chemical Technology, University of chemistry and Technology, Prague * Technicka 5, 166 28, Prague 6, Czech Republic ______Data manager or custodian______ * Šárka Paušová * ORCID: 0000-0003-2494-1510 * Dept. of Inorganic Technology, Faculty of Chemical Technology, University of chemistry and Technology, Prague * Technicka 5, 166 28, Prague 6, Czech Republic ______License______ *Wide electrochemical stability window of boron-doped microcrystalline diamond electrode in NaNO3 water-in-salt electrolytes © 2024 by Egor Ukraintsev is licensed under CC BY *license information: https://creativecommons.org/licenses/by/4.0/ ------------------------------------------------------------------------------------------------ ______About the dataset______ Expanding the electrochemical stability window (ESW) of aqueous electrolytes can contribute to the high energy density of electrochemical energy storage devices and supercapacitors (SC). Here we demonstrate unique electrochemical interaction in two and three-electrode configurations of sodium nitrate (NaNO3) water-in-salt (WiS) electrolyte in a wide range of concentrations (1-12 m) with an electrode made of boron-doped microcrystalline diamond (B-MCDE, grain size ~ 1 m) deposited by a microwave plasma Chemical Vapor Deposition (CVD) process. Compared to a commercial glassy carbon electrode (C-GCE), the extension of ESW up to ~ 3 V was obtained. In the frequency range of 10 mHz - 100 kHz, the B-MCDE also demonstrated better conductive (down to Rct of 50 Ω) and capacitive (up to Cdl 3.2 µF) properties compared to C-GCE for all investigated electrolyte concentrations, where the appropriate equivalent circuit was identified. The best performance was obtained for 8 m WiS concentration at neutral pH and room temperature, whereas 12 m WiS was unstable, as confirmed by Raman spectroscopy. The expanded ESW and superior performance of B MCDE are explained by its high quality material properties and nanostructured, almost nanoporous surface (feature size < 100 nm) formed in the WiS electrolyte. The results reveal that, with a well-controlled quality, boron-doped diamond electrodes provide apparent advantages for water-in-salt SCs. Dataset contains PowerPoint presentation with several images, opj file with the raman data, SEM crossection image and zip with the SEM data. ______Methods of data collection______ SEM images were obtained using MAIA3, Tescan SEM. Raman spectra were obtained using Renishaw In Via Reflex Raman. The pH and conductivity of all NaNO3 electrolytes were measured by a pH meter (HANNA Laboratory EDGE pH) and a conductometer (Cond 3310 SET 1). To evaluate the transport kinetics during the electrochemical reaction, EIS measurements of aqueous NaNO3 solutions (concentrations 1-12 m) were performed. ______Methods of data processing______ The ESW was evaluated from the CV curves considering an onset at the current density of +0.1 mA/cm2 on the positive potential side and -0.1 mA/cm2 on the negative potential side. Since the electrodes had different areas: AB-MCDE=0.023 cm2 and AС-BDDE=0.071 сm2, the onset current values were taken at +2.3 µA і -2.3 µA for B-MCDE and +7.1 µA і -7.1 µA for C-GCE, respectively. ------------------------------------------------------------------------------------------------ ______File name structure_____ * VZ3_019_021_CVUT_D_0001_v1 VZ4 – research proposal (3 characters) 019 – order of the publication in the research proposal (3 char.) 021 – last 3 numerals of the superior indicator (3 char.) VSCHT – institution abbreviation (max. 5 char.) VSCHT - University of chemistry and technology, Prague CVUT - Czech Technical University UFCH - Institute of Physical Chemistry, Czech Academy of Sciences UK - Charles University VUT - Brno University of Technology Y – file type (1 char.): M – manuscript D – data S – supplementary information P – published version of the article 0000 – order of the files in the dataset (4 char.) v1 – versioning (v + version number) ______File formats______ * inp = input files for DFT simulations. ------------------------------------------------------------------------------------------------ ______List of files______ VZ3_019_021_CVUT_D_0001_v1.xlsx - Excel file with the raman data, Figure 4. VZ3_019_021_CVUT_D_0002_v1.tif - SEM crossection image, Figure 1. VZ3_019_021_CVUT_D_0003-17_v1.jpg - SEM RAW data. Other data were measured at partner institution outside the project.