Lithium intercalation into disordered carbon/SiCN composite. Part 2: Raman spectroscopy and 7Li MAS NMR investigation of lithium storage sites
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- 作者：Magdalena Graczyk-Zajac ; Maximilian Wimmer…
- 刊名：Journal of Solid State Electrochemistry
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：21
- 期：1
- 页码：47-55
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Physical Chemistry; Electrochemistry; Energy Storage; Characterization and Evaluation of Materials; Analytical Chemistry; Condensed Matter Physics;
- 出版者：Springer Berlin Heidelberg
- ISSN：1433-0768
- 卷排序：21
文摘
Within this work, we analyze the lithium storage sites within carbon/silicon carbonitride (SiCN) composites. Commercial carbons, HD3 (hard carbon) and LD1N and LD2N (soft carbons), of varying porosity are impregnated with polysilazane (HTT 1800) and pyrolysed at 1100 °C. It is found in the first part of this study (Graczyk-Zajac et al. J Solid State Electrochem 19:2763–2769, 2015) that the initial porosity of the carbon phase plays an important role in determining the lithium insertion capacity and rate capability of the composite material. By applying Raman spectroscopy and solid-state 7Li MAS NMR on pristine, lithiated, and delithiated samples, we investigate the lithium storage sites within the composite materials. By means of Raman spectroscopy, it has been found that lithium storage in hard carbon-derived composites occurs in a significant extent via adsorption-like process within unorganized carbon, whereas for the soft carbon composites, storage in turbostratic carbon is identified. 7Li solid-state NMR confirms these findings revealing that more than 33 % of lithium stored in HD3/SiCN is adsorbed in ionic form at the surface and in pores of the composite, while around 38 % is stored between carbon layers. LD1N and LD2N composites store more than 50 % of lithium in the intercalation-type sites.