Ava Rajh , Matej Gabrijelčič , Blaž Tratnik , Klemen Bučar , Iztok Arčon , Marko Petric , Robert Dominko , Alen Vizintin , Matjaž Kavčič
{"title":"Structural and chemical analysis of hard carbon negative electrode for Na-ion battery with X-ray Raman scattering and solid-state NMR spectroscopy","authors":"Ava Rajh , Matej Gabrijelčič , Blaž Tratnik , Klemen Bučar , Iztok Arčon , Marko Petric , Robert Dominko , Alen Vizintin , Matjaž Kavčič","doi":"10.1016/j.carbon.2024.119398","DOIUrl":null,"url":null,"abstract":"<div><p>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 <span><math><msup><mrow><mi>π</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>/<span><math><msup><mrow><mi>σ</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> regions in the C K-edge spectra <span><math><msup><mrow><mi>sp</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>/<span><math><msup><mrow><mi>sp</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span> hybridization ratio of material was determined. Higher carbonization temperatures led to increased order in graphitic structure and shorter <figure><img></figure>\nbond lengths. Sodiation caused a decrease in graphitic layer order due to inserted Na ions. Complementary <em>operando</em> solid state <span><math><mrow><msup><mrow></mrow><mrow><mn>23</mn></mrow></msup><mi>Na</mi></mrow></math></span> nuclear magnetic resonance (ssNMR) studies confirmed the structural changes, while showing pore filling mechanism, which is not observed in <em>ex situ</em> 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.</p></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":null,"pages":null},"PeriodicalIF":10.5000,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008622324006171/pdfft?md5=6d1bc89468f5f97956c0d3e489a441d7&pid=1-s2.0-S0008622324006171-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Carbon","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008622324006171","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
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 / regions in the C K-edge spectra / hybridization ratio of material was determined. Higher carbonization temperatures led to increased order in graphitic structure and shorter
bond lengths. Sodiation caused a decrease in graphitic layer order due to inserted Na ions. Complementary operando solid state 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.
本研究探讨了钠离子电池中的硬碳(HC)负极在钠化过程中由于 Na 离子的插入而引起的结构变化。研究人员使用 X 射线拉曼光谱 (XRS) 记录了在不同温度下碳化的块状碳氢化合物阳极的 C 和 Na K 边吸收光谱。通过比较 C K 边光谱中的π∗π∗/σ∗σ∗区域,确定了材料的 sp2sp2/sp3sp3 杂化率。碳化温度越高,石墨结构的有序性越强,键长越短。由于 Na 离子的插入,钠化导致石墨层的有序性降低。互补操作态固态 23Na23Na 核磁共振(ssNMR)研究证实了结构的变化,同时显示了孔隙填充机制,这在原位测量中没有观察到,主要是在较高的碳化温度下。对 Na K-edge 光谱进行的 XRS 分析表明,在循环过程中,固体电解质界面 (SEI) 的成分发生了系统性变化。XRS 光谱的变化可归因于 SEI 成分的改变,以及 Na 离子在碳结构缺陷位置的插入/吸附。
期刊介绍:
The journal Carbon is an international multidisciplinary forum for communicating scientific advances in the field of carbon materials. It reports new findings related to the formation, structure, properties, behaviors, and technological applications of carbons. Carbons are a broad class of ordered or disordered solid phases composed primarily of elemental carbon, including but not limited to carbon black, carbon fibers and filaments, carbon nanotubes, diamond and diamond-like carbon, fullerenes, glassy carbon, graphite, graphene, graphene-oxide, porous carbons, pyrolytic carbon, and other sp2 and non-sp2 hybridized carbon systems. Carbon is the companion title to the open access journal Carbon Trends. Relevant application areas for carbon materials include biology and medicine, catalysis, electronic, optoelectronic, spintronic, high-frequency, and photonic devices, energy storage and conversion systems, environmental applications and water treatment, smart materials and systems, and structural and thermal applications.