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[HAX-PES_Li metal_Fin.docx](https://mdr.nims.go.jp/filesets/881ea0cb-856f-454d-afad-c0baffc37188/download)

## Creator

[Hideyuki Yasufuku](https://orcid.org/0000-0001-5600-8958), [Tsuyoshi Ohnishi](https://orcid.org/0000-0002-2333-7752), [Shigenori Ueda](https://orcid.org/0000-0001-9425-0614), [Yoshiyuki Yamashita](https://orcid.org/0000-0003-0994-8095), [Hiroshi Shinotsuka](https://orcid.org/0000-0001-5147-1396), [Hideki Yoshikawa](https://orcid.org/0000-0002-7389-8865), [Shigeo Tanuma](https://orcid.org/0000-0003-2628-9941), [Satoshi Kawada](https://orcid.org/0000-0003-4618-2746), [Yoshitaka Matsushita](https://orcid.org/0000-0002-4968-8905)

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[Creative Commons BY Attribution 4.0 International](https://creativecommons.org/licenses/by/4.0/)

## Other metadata

[Hard x-ray photoelectron spectroscopy (HAXPES) Cr                    <i>Kα</i>                    and XPS Al                    <i>K</i>                    <i>α</i>                    measurements of bulk lithium metal](https://mdr.nims.go.jp/datasets/0d9a658d-b6b5-4b19-b4bc-6d0a54446e5f)

## Fulltext

Hard X-ray Photoelectron Spectroscopy (HAXPES) Cr Kα and XPS Al Kα measurements of bulk Lithium metalHideyuki Yasufuku, Tsuyoshi Ohnishi, Shigenori Ueda, Yoshiyuki Yamashita, Hiroshi Shinotsuka, Hideki Yoshikawa, Shigeo Tanuma, Satoshi Kawada, and Yoshitaka MatsushitaNational Institute for Materials Science, 1-1, Namiki, Tsukuba, Ibaraki 305-0044, Japan.(Received day Month year; accepted day Month year; published day Month year)Electronic states of bulk lithium were measured by hard X-ray photoelectron spectroscopy (HAXPES) and XPS. The samples were measured using Cr Kα and Al Kα excitation sources at 5414.8 eV and 1486.6 eV, respectively, including survey, Li 1s, O 1s and F 1s spectra were obtained.Keywords: Lithium, HAXPES, Cr Kα, Al Kα Accession#: Enter Accession Number. Technique: XPSSpecimen: LithiumInstrument: ULVAC-PHI QuantesMajor Elements in Spectra: Li Minor Elements in Spectra: O, F, ArPublished Spectra: 9Spectral Category: Referencea)Electronic mail: yasufuku.hideyuki@nims.go.jpINTRODUCTIONWith the launch of hard X-ray photoelectron spectroscopy (HAXPES) using Cr Kα excitation sources (Ref. 1), XPS measurements using hard X-rays became more accessible. Reference spectra of various elements and compounds are vigorously published. How ever, the spectra using Cr Kα excitation sources of alkali metals and alkaline earth metals and their compounds are still largely unpublished, even they are hot and important materials for the application such as for secondary battery (Ref. 2), caused by their high chemical reactivities.In this work, we present the results of measurements of bulk lithium metal using a laboratory-based HAXPES (Excitation source: monochromatic Cr Kα, 5414.8 eV) / XPS (monochromatic Al Kα, 1486.6 eV) equipment, as reference data. The results shown here include the survey spectrum as well as high resolution spectra of Li 1s, O 1s and F 1s.SPECIMEN DESCRIPTION (ACCESSION # Enter Accession Number.) Specimen: Lithium, LiCAS Registry #: 7439-93-2Specimen Characteristics: unknown homogeneity;  solid;  unknown crystallinity;  conductor;  metal;  - Chemical Name:  LithiumSource: Honjo Metal Co., Ltd.Composition: LithiumForm: Foil, approximately 15 mm x 10 mm x t0.5 mmStructure: LiHistory & Significance: Metal foil, 99.9% in metal basisAs Received Condition: Lithium stored in an argon atmosphere.Analyzed Region: Rectangular region (Raster size of the X-rays: 400 µm x 100 µm) approximately in the center of the sputtered area.Ex Situ Preparation/Mounting: Li samples were cut into a lateral size of 15 mm x 10 mm in a glove box under an Ar atmosphere, adhered to a sample holder with using a jig with a 40˚ inclination angle. The jig was fixed to the sample holder with double-sided carbon tape, and the Li sample was pressure-bonded to the jig. Then the sample was introduced into the HAXPES/XPS equipment using a transfer vessel. The vessel was filled with Ar gas (positive pressure <0.4 Pa), maintaining the same environment as was in the glovebox. In Situ Preparation: Ar ion sputtering was performed with an ion beam incidence angle of 85˚ (5˚ with respect to the sample surface), with an acceleration voltage of 4 kV. Therefore, the footprint of the sputtered area becomes large. The ion beam was scanned linearly with a width of 3 mm in order to make the sputtered area rectangular. The estimated sputtered area on the sample surface was approximately 3 mm x 2 mm. The geometry and the sputtered area size during sputtering were the same throughout the HAXPES/XPS measurements. To prevent oxidation of the Li surface, the spectra were accumulated by repeating sputtering and short-time measurements at the same sample position. Regarding the O 1s and F 1s spectra using Cr Kα, measurements were conducted sequentially, one sweep at a time, following a 5 minutes Ar sputtering process, and this procedure was repeated. To avoid surface oxidation during the measurement, the survey spectral measurement was split into two energy regions, separated by a binding energy of 1500 eV, and each spectrum was measured by repeating one sweep after 5 minutes of Ar ion sputtering. The spectra were measured at X-ray incident angle of 84˚ for both Cr Kα and Al Kα. Charge Control: NoneTemp. During Analysis: 298KPressure During Analysis: 5 x 10-7 PaPre-analysis Beam Exposure: 330sINSTRUMENT DESCRIPTIONManufacturer and Model: ULVAC-PHI QuantesAnalyzer Type: spherical sectorDetector: multichannel resistive plateNumber of Detector Elements: 32INSTRUMENT PARAMETERS COMMON TO ALL SPECTRA■SpectrometerAnalyzer Mode: constant pass energyThroughput (T=EN): Choose an item. a polynomial function (The manufacturer does not disclose information.)Excitation Source Window: AlExcitation Source: Cr Ka monochromaticSource Energy: 5414.8 eVSource Strength: 50 W Source Beam Size: 100 m x 100 mSignal Mode: multichannel direct■GeometryIncident Angle: 84 ˚ (Cr Kα), 84˚ (Al Kα)Source-to-Analyzer Angle: 46 ˚ (Cr Kα), 45˚ (Al Kα)Emission Angle: 38 ˚ (Cr Kα), 39˚ (Al Kα)Specimen Azimuthal Angle: 148.8 ˚ (Cr Kα), 180˚ (Al Kα)Acceptance Angle from Analyzer Axis: 0 ˚Analyzer Angular Acceptance Width: 20 ˚ x 20 ˚■Ion GunManufacturer and Model: ULVAC-PHIEnergy: 4000 eVCurrent: 0.0025 mACurrent Measurement Method: biased stageSputtering Species and Charge: Ar+Spot Size (unrastered): approximately 200 mRaster Size: 3000 m x 2000 m (indicate approximate sputtered area size)Incident Angle: 85 ˚Polar Angle: 60 ˚Azimuthal Angle: 86 ˚ (Cr Kα), 54.7˚ (Al Kα)Comment: A differentially pumped ion gun was used for surface cleaning and the Ar ion sputtering was done between the cycles of spectrum measurement to prevent re-oxidation during XPS analysis.DATA ANALYSIS METHODEnergy Scale Correction: The binding energy of the spectra was referred to the Au 4f7/2 peak (84.00 eV). Recommended Energy Scale Shift: 0 eV for Cr Kα and Al Kα.Peak Shape and Background Method: Shirley background was used for the determination of the peak area.Quantitation Method: PHI MULTIPAK software version 9.9.3 was used to perform quantification. Empirically determined relative sensitivity factors (RSFs) were provided by the software. The RSFs were derived according to ISO 18118 equation (A7) (Ref. 4).ACKNOWLEDGMENTSThis work was supported by "Advanced Research Infrastructure for Materials and Nanotechnology in Japan (ARIM)" of the Ministry of Education, Culture, Sports, Science and Technology (MEXT). Proposal Number JPMXP1225NM2201.AUTHOR DECLARATIONSConflicts of Interest (required)The authors have no conflicts of interest to declare.Author Contributions (if applicable)H. Yausfuku: Methodology (equal); Investigation (lead); Validation (lead); Writing – original draft (lead); Writing – review & editing (equal).T. Ohnishi: Sample provision (lead); Sample preparation (lead).S. Ueda: Writing – review & editing (lead).Y. Yamashita: Writing – review & editing (equal).H. Shinotsuka: Software (lead).H. Yoshikawa: Methodology (lead); Validation (equal); Software (equal); Writing – review & editing (equal).S. Tanuma: Methodology (equal); Validation (equal); Software (equal).S. Kawada: Funding acquisition (lead); Writing – review & editing (equal).Y. Matsushita: Sample preparation (equal); Writing – original draft (equal); Conceptualization (lead); Supervision (lead); Writing – review & editing (equal).DATA AVAILABILITY STATEMENTThe data that support the findings of this study are available within the article and its supplementary material. REFERENCES1. K. Artyushikova, S. R. Leadley, and A. G. Shard, J. Vac. Sci. Technol. A 42, 052801 (2024); Surf. Sci. Spectra, 31, (2024), and “HAXPES Database” by Furukawa Electric Co., Ltd. and ULVAC-PHI, Inc. (https://www.ulvac-phi.com/ja/club-phi/database/haxpes_notices/).2. "Materials and Working Mechanisms of Secondary Batteries" Ed. C. -z. Yang, Y. Lou, J. Zhang, X. Xie, and B. \Xia, Springer-Nature (2023).3. Y. Takata, Y.  Kayanuma, M. Yabashi, K, Tamasaku, Y. Nishino, D. Miwa, Y.Harada, K.Horiba, S. Shin, S. Tanaka, E. Ikenaga, K Kobayashi, Y. Senba, H. Ohashi, and T. Ishikawa, Phys. Rev. B, 75, 233404 (2007)4. ISO 18118:2015, Surface Chemical Analysis—Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy—Guide to the Use of Experimentally Determined Relative Sensitivity Factors for the Quantitative Analysis of Homogeneous Materials (International Organization for Standardization, Geneva, Switzerland, 2015).5. W. Smekal, W. S. M. Werner1 and C. J. Powell, Surf. Interface Anal., 37, 1059 (2005) SPECTRAL FEATURES TABLE Spectrum ID # Element/ Transition Peak Energy (eV) Peak Width FWHM (eV) Peak Area(eV x cts/s) Sensitivity Factor Concentration (at. %) Peak Assignment Li1s (Cr Kα) Li 1s 55.47 1.38 41 0.009 100 Li Li1s (Cr Kα) Li loss 63.01 2.94 32 … … Li O1s (Cr Kα) O 1s … … … … … No peak F1s (Cr Kα) F 1s … … … … … No peak Li1s (Al Kα) Li 1s 55.07 0.67 5098 0.028 99.78 Li Li1s (Al Kα) Li loss 62.53 2.04 3020 … … Li O1s (Al Kα) O 1s 531.1 1.95 398 0.733 0.22 Surface oxidation F1s (Al Kα) F 1s … … … … … No peakComment to Spectral Features Table: The peak position of Li 1s measured with the Cr Kα is 0.40 eV higher in the binding energy compared to that measured with the Al Kα. This difference is considered to be the recoil effect in photoelectron emission (Ref. 3). The calculated recoil energy of photoelectrons emitted from the isolated Li atom for the 1s core level using the Cr Kα is 0.42 eV, while that using the Al Kα is 0.11 eV. Therefore, the difference in the calculated peak shift due to the recoil effect is 0.31 eV. This calculated recoil difference (0.31 eV) is the same order as the difference in the experimental Li 1s peak positions of 0.40 eV between the Cr Kα and Al Kα. ANALYZER CALIBRATION TABLE Spectrum ID # Element/ Transition Peak Energy (eV) Peak Width FWHM (eV) Peak Area (eV x cts/s) Sensitivity Factor Concentration (at. %) Peak Assignment … Au 4f7/2 84.00 0.84 235574 ... ... Au (Al Kα) … Ag 3d5/2 368.29 0.75 292514 ... ... Ag (Al Kα)  Cu 2p3/2 932.72 1.04 276369 ... ... Cu (Al Kα)  Au 4f7/2 84.00 1.39 2698.7 ... ... Au (Cr Kα)  Ag 3d5/2 368.30 1.43 5012 ... ... Ag (Cr Kα) … Cu 2p3/2 932.77 1.63 12555 ... ... Cu (Cr Kα)Comment to Analyzer Calibration Table: In the calibration table, the top three peak energies are obtained with the Al Kα, and the bottom three peak energies are obtained with the Cr Kα. The pass energies were 55 and 112 eV for Al Kα and Cr Kα, respectively. GUIDE TO FIGURES Spectrum (Accession) # Spectral Region Voltage Shift* Multiplier Baseline Comment # Survey (Al Kα) Survey 0 eV 1 0 … Survey (Cr Kα) Lower Survey 0 eV 1 0 … Survey (Cr Kα) Higher Survey 0 eV 1 0 … Li1s (Cr Kα) Li 1s 0 eV 1 0 … O1s (Cr Kα) O1s 0 eV 1 0 … F1s (Cr Kα) F1s 0 eV 1 0 … Li1s (Al Kα) Li 1s 0 eV 1 0 … O1s (Al Kα) O1s 0 eV 1 0 … F1s (Al Kα) F1s 0 eV 1 0 …   Publish in Surface Science Spectra: Yes ☒ No ☐ Accession # Survey (Al Kα) ■ Specimen Li ■ Technique XPS ■ Spectral Region survey Instrument ULVAC-PHI Quantes Excitation Source Al Ka monochromatic Source Energy 1486.6 eV Source Strength 25 W Source Size 0.1 mm x 0.1 mm Analyzer Type spherical sector analyzer Incident Angle 84˚ Emission Angle 39˚ Analyzer Pass Energy 280 eV Analyzer Resolution 1.69 eV Total Signal Accumulation Time 456 s Total Elapsed Time 504 s Number of Scans 8 Effective Detector Width 32 eV Comments The survey spectrum was obtained after a long period of Ar sputter cleaning. In the spectrum, no Ar 2p and 2s peaks were detected.   Publish in Surface Science Spectra: Yes ☒ No ☐ Accession # Survey (Cr Kα) Lower ■ Specimen Li ■ Technique XPS ■ Spectral Region survey Instrument ULVAC-PHI Quantes Excitation Source Cr Ka monochromatic Source Energy 5414.8 eV Source Strength 50 W Source Size 0.1 mm x 0.1 mm Analyzer Type spherical sector analyzer Incident Angle 84˚ Emission Angle 38˚ Analyzer Pass Energy 280 eV Analyzer Resolution 2.32 eV Total Signal Accumulation Time 4932 s Total Elapsed Time 5424 s Number of Scans 8 Effective Detector Width 32 eV Comments The survey spectrum shown here is the lower part of the spectrum, which was measured separately from the higher part by dividing the spectrum at a binding energy of 1500 eV. This division was made to shorten the measurement time and prevent surface oxidation. This spectrum was obtained by repeating the spectral measurement (11 minutes) and Ar sputtering (5 minutes).   Publish in Surface Science Spectra: Yes ☒ No ☐ Accession # Survey (Cr Kα) Higher ■ Specimen Li ■ Technique XPS ■ Spectral Region survey Instrument ULVAC-PHI Quantes Excitation Source Cr Ka monochromatic Source Energy 5414.8 eV Source Strength 50 W Source Size 0.1 mm x 0.1 mm Analyzer Type spherical sector analyzer Incident Angle 84˚ Emission Angle 38˚ Analyzer Pass Energy 280 eV Analyzer Resolution 2.32 eV Total Signal Accumulation Time 4902 s Total Elapsed Time 5394 s Number of Scans 8 Effective Detector Width 32 eV Comments The survey spectrum shown here is the higher part of the spectrum, which was measured separately from the lower part by dividing the spectrum at a binding energy of 1500 eV.  The broad peak detected in the binding energy region above 2700 eV was assigned as Ar KLL Auger peaks due to small amount of Ar atoms deeply buried in Li specimen, based on simulations using SESSA package (Ref. 5).  Publish in SSS: Yes ☒ No ☐  ■ Accession #:  Li 1s (Cr Kα)  ■ Specimen: Li  ■ Technique: XPS  ■ Spectral Region: Li 1s  Instrument: ULVAC-PHI Quantes   Excitation Source: Cr Ka monochromatic  Source Energy: 5414.8 eV  Source Strength: 50 W  Source Size: 0.1 mm x 0.1 mm   Analyzer Type: spherical sector   Incident Angle: 84 ˚  Emission Angle: 38 ˚  Analyzer Pass Energy 112 eV  Analyzer Resolution: 1.42 eV  Total Signal Accumulation Time: 95742 s  Total Elapsed Time: 105414 s  Number of Scans: 320  Effective Detector Width: 12.8 eV  Comments: The Li 1s spectrum was obtained by repeating the spectral measurement (11 minutes) and Ar sputtering (5 minutes).    Publish in SSS: Yes ☒ No ☐  ■ Accession #:  O 1s (Cr Kα)  ■ Specimen: Li  ■ Technique: XPS  ■ Spectral Region: O 1s  Instrument: ULVAC-PHI Quantes   Excitation Source: Cr Ka monochromatic  Source Energy: 5414.8 eV  Source Strength: 50 W  Source Size: 0.1 mm x 0.1 mm   Analyzer Type: spherical sector   Incident Angle: 84 ˚  Emission Angle: 38 ˚  Analyzer Pass Energy 112 eV  Analyzer Resolution: 1.42 eV  Total Signal Accumulation Time: 3894 s  Total Elapsed Time: 4284 s  Number of Scans: 16  Effective Detector Width: 12.8 eV  Comments: The spectrum was acquired by repeating the spectral measurement (4.5 minutes) and Ar sputtering (5 minutes).   I Publish in SSS: Yes ☒ No ☐  ■ Accession #:  F 1s (Cr Kα)  ■ Specimen: Li  ■ Technique: XPS  ■ Spectral Region: F 1s  Instrument: ULVAC-PHI Quantes   Excitation Source: Cr Ka monochromatic  Source Energy: 5414.8 eV  Source Strength: 50 W  Source Size: 0.1 mm x 0.1 mm   Analyzer Type: spherical sector   Incident Angle: 84 ˚  Emission Angle: 38 ˚  Analyzer Pass Energy 112 eV  Analyzer Resolution: 1.42 eV  Total Signal Accumulation Time: 3894 s  Total Elapsed Time: 4284 s  Number of Scans: 16  Effective Detector Width: 12.8 eV  Comments: The spectrum was acquired after the O1s measurement.    Publish in SSS: Yes ☒ No ☐  ■ Accession #:  Li 1s (Al Kα)  ■ Specimen: Li  ■ Technique: XPS  ■ Spectral Region: Li 1s  Instrument: ULVAC-PHI Quantes   Excitation Source: Al Ka monochromatic  Source Energy: 1486.6 eV  Source Strength: 25 W  Source Size: 0.1 mm x 0.1 mm   Analyzer Type: spherical sector   Incident Angle: 84 ˚  Emission Angle: 39 ˚  Analyzer Pass Energy 55 eV  Analyzer Resolution: 0.8 eV  Total Signal Accumulation Time: 1512 s  Total Elapsed Time: 1674 s  Number of Scans: 48  Effective Detector Width: 6.4 eV  Comments: The spectrum was obtained by repeating a 5 minutes Ar ion sputtering followed by O 1s (0.5 minutes), Li 1s (2 minutes) and F 1s (0.5 minutes) measurements.    Publish in SSS: Yes ☒ No ☐  ■ Accession #:  O 1s (Al Kα)  ■ Specimen: Li  ■ Technique: XPS  ■ Spectral Region: O 1s  Instrument: ULVAC-PHI Quantes   Excitation Source: Al Ka monochromatic  Source Energy: 1486.6 eV  Source Strength: 25 W  Source Size: 0.1 mm x 0.1 mm   Analyzer Type: spherical sector   Incident Angle: 84 ˚  Emission Angle: 39 ˚  Analyzer Pass Energy 55 eV  Analyzer Resolution: 0.8 eV  Total Signal Accumulation Time: 462 s  Total Elapsed Time: 516 s  Number of Scans: 16  Effective Detector Width: 6.4 eV  Comments: Comments: The spectrum was obtained by repeating a 5 minutes Ar ion sputtering followed by O 1s (0.5 minutes), Li 1s (2 minutes) and F 1s (0.5 minutes) measurements.    Publish in SSS: Yes ☒ No ☐  ■ Accession #:  F 1s (Al Kα)  ■ Specimen: Li  ■ Technique: XPS  ■ Spectral Region: F 1s  Instrument: ULVAC-PHI Quantes   Excitation Source: Al Ka monochromatic  Source Energy: 1486.6 eV  Source Strength: 25 W  Source Size: 0.1 mm x 0.1 mm   Analyzer Type: spherical sector   Incident Angle: 84 ˚  Emission Angle: 39 ˚  Analyzer Pass Energy 55 eV  Analyzer Resolution: 0.8 eV  Total Signal Accumulation Time: 462 s  Total Elapsed Time: 516 s  Number of Scans: 16  Effective Detector Width: 6.4 eV  Comments: The spectrum was obtained by repeating a 5 minutes Ar ion sputtering followed by O 1s (0.5 minutes), Li 1s (2 minutes) and F 1s (0.5 minutes) measurements.  image1.pngimage2.pngimage3.pngimage4.pngimage5.pngimage6.pngimage7.pngimage8.pngimage9.png