Structural and chemical analysis of hard carbon negative electrode for Na-ion battery with X-ray Raman scattering and solid-state NMR spectroscopy

Rajh, Ava (author), Gabrijelčič, Matej (author), Tratnik, Blaž (author), Bučar, Klemen (author), Arčon, Iztok (author), Petric, Marko (author), Dominko, Robert (author), Vižintin, Alen (author), Kavčič, Matjaž (author)

This study explores the structural changes of hard carbon (HC) negative electrodes in sodium-ion batteries induced by insertion of Na ions during sodiation. X-ray Raman spectroscopy (XRS) was used to record both C and Na K-edge absorption spectra from bulk HC anodes carbonized at different temperatures and at several points during sodiation and desodiation. Comparing the $\pi ^∗/\sigma ^∗$ regions in the C K-edge spectra sp$^2$/sp$^3$ hybridization ratio of material was determined. Higher carbonization temperatures led to increased order in graphitic structure and shorter C–C bond lengths. Sodiation caused a decrease in graphitic layer order due to inserted Na ions. Complementary operando solid state $^{23}$Na nuclear magnetic resonance (ssNMR) studies confirmed the structural changes, while showing pore filling mechanism, which is not observed in ex situ measurements, primarily at higher carbonization temperatures. XRS analysis of Na K-edge spectra revealed systematic variations in the solid electrolyte interface (SEI) composition during cycling. Changes in XRS spectra were attributed to both SEI composition alterations, accompanied by the insertion/adsorption of Na ions at defect sites within the carbon structure.

• Language: English
• Keywords: hard carbons, X-ray Raman scattering, ssNMR, Na-ion batteries
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 14 str.
• Numbering: Vol. 228, art. 119398
• PID: 20.500.12556/RUL-159399
• UDC: 544.5/.6
• ISSN on article: 1873-3891
• DOI: 10.1016/j.carbon.2024.119398
• COBISS.SI-ID: 201116419
• Publication date in RUL: 09.07.2024

Record is a part of a journal

• Title: Carbon
• Publisher: Elsevier
• ISSN: 1873-3891
• COBISS.SI-ID: 22990853

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: trdi ogljik, Ramanova spektroskopija, baterije, elektrotehnika, ogljik