Pyrolysis temperature dependence of sodium storage mechanism in non-graphitizing carbons. (May 2023)

• Record Type: Journal Article
• Authors: Tonnoir, Hélène; Huo, Da; Davoisne, Carine; Celzard, Alain; Fierro, Vanessa; Saurel, Damien; El Marssi, Mimoun; Benyoussef, Manal; Meunier, Philippe; Janot, Raphaël
• Is Part Of: Carbon. Volume 208(2023)
• Page Start: 216
• Page End: 226
• Publication Date: 2023-05
• Subjects: Hard carbon -- Sodium-ion battery -- SAXS -- Porosity -- In situ Raman spectroscopy; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2023.03.055
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Hard carbons are the most investigated materials as negative electrode for Na-ion batteries, although the exact mechanism of sodium storage remains under debate. This work is focused on the study of the sodiation mechanism of non-graphitizing carbons (NGC) prepared in a wide range of pyrolysis temperatures (1000 °C–2500 °C), thus covering the whole range from hard carbons (HC) to glassy carbons (GC). Structural and textural characterizations show that increasing the pyrolysis temperature leads to NGCs with a more ordered structure, containing fewer heteroatoms and structural defects, and particularly leads to a developed closed microporosity. In this work, in situ Raman spectroscopy at different excitation wavelengths is used to clarify the mechanism of electrochemical sodiation: it is revealed that the intercalation of Na + between the graphene layers occurs mainly during the sloping part of the galvanostatic profile, whereas the plateau at low voltage (below 0.1 V vs. Na + /Na) can be associated with the filling of micropores with sodium. Graphical abstract: Image 1 Highlights: Hard and glassy carbons are synthesized at four different pyrolysis temperatures. Materials characterizations are structural, textural and electrochemical. Pyrolysis temperature dependence of structure, performance and Na storage mechanism. Multi-wavelength Raman spectroscopy is used for structural and mechanistic studies. In situ Raman spectroscopy shows intercalation-pore filling mechanism.