____________________Dataset for Glue-assisted Exfoliation of Two-dimensional Sulfur-rich Niobium Thiophosphate (Nb4P2S21) for Sulfur-equivalent Electrode Study in Lithium Storage____________________ Last updated: 2024-06-05 ______Contact______ * Zdeněk Sofer * ORCID: 0000-0002-1391-4448 * Department of Inorganic Chemistry, University of Chemistry and Technology Prague * Technická 5, 166 28 Praha 6 - Dejvice, Česká republika ______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 ______Licence______ *Dataset for Glue-assisted Exfoliation of Two-dimensional Sulfur-rich Niobium Thiophosphate (Nb4P2S21) for Sulfur-equivalent Electrode Study in Lithium Storage © 2024 by Zdeněk Sofer is licensed under CC BY *licence information: https://creativecommons.org/licenses/by/4.0/ ------------------------------------------------------------------------------------------------ ______About the dataset______ Two-dimensional (2D) layered thiophosphates have garnered attention for advanced batteries due to their open ionic diffusion channels, high capacity, and unique catalytic properties. However, their potential in energy storage applications remains largely unexplored. In this study, we report for the first time a 2D transition metal thiophosphate (Nb4P2S21) with high sulfur content. Nb4P2S21, synthesized via chemical vapor transport (CVT), is treated as a sulfur-equivalent material with better conductivity than sulfur, suitable for high-capacity lithium storage. The bulk material can be delaminated into high-quality nanoplates via glue-assisted grinding exfoliation, both displaying a layered quasi-one-dimensional (quasi-1D) morphology, which shortens the ion diffusion path and promises enhanced rate performance compared to larger lateral 2D materials. Density functional theory (DFT) calculations indicate that Nb4P2S21 has a direct bandgap of 1.64 eV (HSE06 method), with exfoliated counterparts showing near-infrared (NIR) photoluminescence at 755 nm, broadening potential applications to NIR-based devices. By tuning the working voltage window for lithium-ion batteries (LIBs) and controlling lithiation product formation, the material exhibits distinct electrochemical characteristics at 0 ~ 2.6 V, 0.5 ~ 2.6 V, 1.0 ~ 2.6 V, and 1.5 ~ 2.6 V. However, sulfur-rich electrodes in carbonate electrolytes demonstrate limited electrochemical potential due to polysulfide formation, leading to detrimental side reactions with carbonate-based electrolytes. Transitioning to ether-based electrolytes improves the initial reversible capacity and Coulombic efficiency of Nb4P2S21 by stabilizing the formed polysulfides. Despite this improvement, the material still mirrors the shuttle effect in lithium-sulfur batteries, diminishing active sulfur and undermining battery integrity. Further EDS and TOF-SIMS analyses of post-cycled electrode materials show significant sulfur loss and precipitation within the electrodes, exacerbating the shuttle effect and causing battery failure. Implementing strategies used in lithium-sulfur batteries, such as introducing polar host catalysts, could enhance the potential of these materials. ______Methods of data collection______ * X-ray diffraction The X-ray diffraction (XRD) pattern was captured using a Bruker D8 X-ray diffractometer, employing Cu Kα radiation (λ = 0.15418 nm, U = 40 kV, I = 40 mA). * X-ray photoelectron spectroscopy High-resolution X-ray photoelectron spectroscopy (XPS) measurements were carried out using Specs spectrometer, equipped with a monochromatic aluminum X-ray source (1486.7 eV) combined with a Phoibos 150 hemispherical analyzer. * Scanning electron microscopy, scanning transmission electron microscopy and energy dispersive spectroscopy Scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive spectroscopy (EDS) analyses were conducted using a Tescan MAIA 3 system, integrated with an Oxford EDS detector and operated via Aztec software. * Atomic force microscopy Thickness measurements of exfoliated nanoplates were performed using Atomic Force Microscopy (AFM) with an Ntegra Spectra instrument from NT-MDT. * Raman spectroscopy Raman spectra were obtained using a Renishaw inVia Raman Microscope, featuring backscattering geometry, a CCD camera detector, and a 532 nm, 50 mW DPSS laser at full power. A 20× objective lens was used for sample focusing. Photoluminescence spectra were acquired using a Renishaw InVia Raman confocal microscope, employing a 532 nm excitation, 50 mW Nd-YAG laser. Both bulk and exfoliated suspension were drop-casted onto nickel support for drying. * Transmission electron microscopy Transmission electron microscopy (TEM) analysis, using a Jeol 2200 FS microscope (Japan) with an attached Oxford Instrument energy dispersive spectroscopy (EDS) system (England), was employed to characterize the crystal structure, morphology, and elemental composition. TF Helios 5 FX dual-beam microscope equipped with a compustage holder and a 256x256 px Timepix detector was utilized for a cross-sectional lamella preparation and subsequent electron diffraction analysis. The lamella was prepared in a standard lift-out procedure using ion beam voltages ranging from 30 kV to 2 kV and ion beam currents ranging from 20 nA to 20 pA. The electron diffraction pattern was recorded with the Timepix detector in a spot mode using an electron beam current of 25 pA and electron beam accelerating voltage of 30 kV. * In-situ Raman measurements The in-situ Raman of the battery during charge and discharge was characterized using a two-electrode cell with an optical window. The Raman spectra were collected using a Renishaw inVia Raman Microscope, featuring backscattering geometry, a CCD camera detector, and a 785 nm. an AutoLab PGSTAT204 (Eco Chemie, Utrecht, Netherlands) with NOVA Version 2.1.7 software was employed to perform the discharge/charge process of two electrode cell systems. * DFT Calculations The ground state calculations were conducted using the Vienna Ab initio Simulation Package (VASP). The Perdew-Burke-Ernzerhof (PBE) functional was employed for the exchange-correlation interaction, except for specific band structure calculations, where the HSE06 functional was utilized. The electron-ion interaction was described using the projector-augmented wave method. For geometry optimization and electronic structure calculations, we applied an energy cutoff of 500 eV and utilized a Monkhorst-Pack 3x3x3 k-mesh grid. The lattice constants and atomic positions underwent full relaxation until atomic forces reached magnitudes smaller than 0.01 eV Å-1. The convergence criterion for electron relaxation was set at 10-6 eV. This methodology ensures accurate and reliable results in accordance with the specified requirements of the experimental study. * Electrochemical testing Electrochemical testing included discharge/charge performance analysis using a Neware battery test system (Neware BTS 8.0, Shenzhen, China). Additionally, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were conducted at room temperature, employing a CorrTest CS Studio electrochemical workstation (Wuhan CorrTest Instrument Corp). ______Methods of data processing______ * X-ray photoelectron spectroscopy XPS data fitting was performed in CasaXPS software. Original .vms data format was converted to .csv. * Tauc Plot Tauc plots were processed from UV-VIS absorption spectra using the Tauc equation. * X-ray diffraction X-ray diffraction data were collected as .raw and then converted to .csv. * Other data processing All other data were unprocessed and obtained directly as .csv files. ------------------------------------------------------------------------------------------------ ______File name structure_____ * VZx_000_111_XXXXX_Y_0000_v1 VZx – research proposal (3 characters) 000 – order of the publication in the research proposal (3 char.) 111 – last 3 numerals of the superior indicator (3 char.) XXXXX – 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 arctile 0000 – order of the files in the dataset (4 char.) v1 – versioning (v + version number) * example: VZ1_001_023_VSCHT_D_0001_v1.csv ______File formats______ * All data are in .csv format. ______Date formats______ * No date formats in the dataset. ______Units and abbreviations______ * XRD: 2Theta(°) vs Intesity (a.u.) * DFT: Position ( ) vs Energy (eV) * CV: Potential (V) vs Current (mA/g) * Charge-discharge: Voltage (V) vs Specific capacity (mAh/g) * Cycling stability: Cycle number (n) vs Specific capacity (mAh/g) * Electrochemical impedance spectroscopy: Impedance real (ohm) vs Impedance imaginary ( ) * Photoluminiscence: Wavelength (nm) vs Intensity (counts) * Raman spectroscopy: Raman shift (cm-1) vs Intensity (counts) * SIMS: Depth ( ) vs intensity (counts) * UV-VIS: Wavelength (nm) vs absorbance ( ) * Tauc plot: Energy (eV) vs Intensity (counts) * XPS: Binding energy (eV) vs intensity (counts) ------------------------------------------------------------------------------------------------ ______List of files______ * Figure 1h - band structure with HSE06, Figure 1h - band structure with PBE, Figure 1h - DOS with HSE06, Figure 1h - DOS with PBE VZ1_007_021_VSCHT_D_0001_v1.csv VZ1_007_021_VSCHT_D_0002_v1.csv VZ1_007_021_VSCHT_D_0003_v1.csv VZ1_007_021_VSCHT_D_0004_v1.csv * Figure 4a-i - CV of Nb4P2S21 at 0-2.6V, Figure 4a-ii - CV of Nb4P2S21 at 1.5-2.6V, Figure 4a-ii CV of Nb4P2S21 at 1.0-2.6V, Figure 4a-ii CV of Nb4P2S21 at 0.5-2.6V, Figure 4b - proportion of Li in Nb4P2S21, Figure 5a - charge-discharge curves of Nb4P2S21 at 0-2.6V , Figure 5b - charge-discharge curves of Nb4P2S21 at 0.5-21.6V , Figure 5c - charge-discharge curves of Nb4P2S21 at 1-2.6V , Figure 5d - charge-discharge curves of Nb4P2S21 at 1.5-2.6V, Figure 5e - cycling stability of Nb4P2S21 at various voltages, Figure 5f charge-discharge curves of Nb4p2S21 at 1-2.6V in ether electrolyte, Figure S8a - CV cycling for EIS, Figure S8b - Nyquist plots at various cutoff voltage VZ1_007_021_VSCHT_D_0005_v1.csv VZ1_007_021_VSCHT_D_0006_v1.csv VZ1_007_021_VSCHT_D_0007_v1.csv VZ1_007_021_VSCHT_D_0008_v1.csv VZ1_007_021_VSCHT_D_0009_v1.csv VZ1_007_021_VSCHT_D_0010_v1.csv VZ1_007_021_VSCHT_D_0011_v1.csv VZ1_007_021_VSCHT_D_0012_v1.csv VZ1_007_021_VSCHT_D_0013_v1.csv VZ1_007_021_VSCHT_D_0014_v1.csv VZ1_007_021_VSCHT_D_0015_v1.csv VZ1_007_021_VSCHT_D_0016_v1.csv VZ1_007_021_VSCHT_D_0017_v1.csv * Figure 2j - Photoluminiscence spectra * Figure 1d Raman spectrum of bulk Nb4P2S21, Figure 2k - Raman spectra of bulk powder vs exfoliated material, Figure 4c - In-situ Raman at initial cycling under 0-2.6 V. VZ1_007_021_VSCHT_D_0018_v1.csv VZ1_007_021_VSCHT_D_0019_v1.csv VZ1_007_021_VSCHT_D_0020_v1.csv * Figure 6e - SIMS total intensity with the etching depth of Nb4P2S21 in ether electrolyte, Figure 6f - SIMS total intensity with the etching depth of Nb4P2S21 in carbonate electrolyte VZ1_007_021_VSCHT_D_0021_v1.csv VZ1_007_021_VSCHT_D_0022_v1.csv * Figure 2i - UV-Vis spectra, Figure 2i - Tauc plots VZ1_007_021_VSCHT_D_0023_v1.csv VZ1_007_021_VSCHT_D_0024_v1.csv * Figure 3i - XRD of bulk powder, Figure 3j - XRD of exfoliated nanoplates, Figure S7 - XRD-of Nb4P2S21 at different cutoff voltage VZ1_007_021_VSCHT_D_0025_v1.csv VZ1_007_021_VSCHT_D_0026_v1.csv VZ1_007_021_VSCHT_D_0027_v1.csv * Figure 1e - XPS spectrum of Nb 3d, Figure 1f - XPS spectrum of P 2p, Figure 1g - XPS spectrum of S 2p, Figure 4d - XPS of Nb 3d at various voltages VZ1_007_021_VSCHT_D_0028_v1.csv VZ1_007_021_VSCHT_D_0029_v1.csv VZ1_007_021_VSCHT_D_0030_v1.csv VZ1_007_021_VSCHT_D_0031_v1.csv