Angelo Sarra1,†,‡, Sergio Brutti1,2,3,† , Oriele Palumbo1, Francesco Capitani4, Ferenc Borondics4, Giovanni Battista Appetecchi5, Nicholas Carboni1, Syed Abdul Ahad6, Hugh Geaney6, Kevin Ryan6 and Annalisa Paolone1,*
1Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Piazzale Aldo Moro 5, 00185 Rome, Italy
2Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
3GISEL-Centro di Riferimento Nazionale per i Sistemi di Accumulo Elettrochimico di Energia, INSTM, Via G. Giusti 9, 50121 Firenze, Italy
4Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, BP 48, CEDEX, 91192 Gif-sur-Yvette, France
5Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA), Materials and Physicochemical Processes Technical Unit (SSPT-PROMAS-MATPRO), Via Anguillarese 301, 00123 Rome, Italy
6Department of Chemical Sciences and Bernal Institute, University of Limerick, V94 T9PX Limerick, Ireland
Corresponding Author: Annalisa Paolone (email@example.com)
†These authors contributed equally to this work.
‡Present address: Microscopy Center, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy
Received: 29 November 2022 / Revised: 20 February 2023 / Accepted: 24 February 2023 / Published: 26 February 2023
Link to Paper:
The morphological changes of Si nanowires (Si NWs) cycled in 1:1 ethylene–carbonate (EC)/diethyl–carbonate (DEC) with or without different additives, fluoroethylene carbonate (FEC) or vinylene carbonate (VC), as well as the composition of the deposited solid–electrolyte interphase layer, are investigated by a combination of experimental microscopic and spectroscopic techniques. Scanning electron microscopy and optical spectroscopy highlight that the NW morphology is better preserved in samples cycled in the presence of FEC and VC additives compared to the additive-free electrolyte. However, only the use of FEC is capable of slightly mitigating the amorphization of silicon upon cycling. The solid electrolyte interphase (SEI) formed over the Si NWs cycled in the additive-free electrolyte is richer in organic and inorganic carbonates compared to the SEI grown in the presence of the VC and FEC additives. Furthermore, both additives are able to remarkably limit the degradation of the LiPF6 salt. Overall, the use of the FEC-additive in the carbonate-based electrolyte promotes both morphological and structural resilience of the Si NWs upon cycling thanks to the optimal composition of the SEI layer.
Keywords: silicon; negative electrodes; Li-ion batteries; microscopy; solid electrolyte interphase