title: Comprehensive Insights into the Reactivity of Electrolytes Based on Sodium Ions.
abstract: We report a systematic investigation of Na-based electrolytes that comprise various NaX [X=hexafluorophosphate (PF6 ), perchlorate (ClO4 ), bis(trifluoromethanesulfonyl)imide (TFSI), fluorosulfonyl-(trifluoromethanesulfonyl)imide (FTFSI), and bis(fluorosulfonyl)imide (FSI)] salts and solvent mixtures [ethylene carbonate (EC)/dimethyl carbonate (DMC), EC/diethyl carbonate (DEC), and EC/propylene carbonate (PC)] with respect to the Al current collector stability, formation of soluble degradation compounds, reactivity towards sodiated hard carbon (Nax -HC), and solid-electrolyte interphase (SEI) layer formation. Cyclic voltammetry demonstrates that the stability of Al is highly influenced by the nature of the anions, solvents, and additives. GC-MS analysis reveals that the formation of SEI telltales depends on the nature of the linear alkyl carbonates and the battery chemistry (Li(+) vs. Na(+) ). FTIR spectroscopy shows that double alkyl carbonates are the main components of the SEI layer on Nax -HC. In the presence of Na salts, EC/DMC and EC/DEC presented a higher reactivity towards Nax -HC than EC/PC. For a fixed solvent mixture, the onset temperature follows the sequence NaClO4 <NaFTFSI<NaPF6 <NaTFSI<NaFSI, and the total heat generated increases in the order NaFSI<NaTFSI<NaClO4 <NaPF6 <NaFTFSI.
authors.affiliation: Helmholtz Institute of Ulm (HIU), Helmholtz Str.11, 89081, Ulm, Germany.|Karlsruhe Institute of Technology (KIT), P.O.Box 3640, 76021, Karlsruhe, Germany.
authors.forename: Gebrekidan Gebresilassie
authors.initials: GG
authors.lastname: Eshetu
authors.affiliation: Laboratoire de Réactivité et Chimie des Solide (LRCS), CNRS UMR 7314 Université de Picardie Jules Verne, 33 rue Saint Leu, 80039, Amiens, France.|Réseau sur le Stockage Electrochimique de l'Energie, CNRS RS2E, FR3459, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Grugeon
authors.affiliation: Laboratoire de Réactivité et Chimie des Solide (LRCS), CNRS UMR 7314 Université de Picardie Jules Verne, 33 rue Saint Leu, 80039, Amiens, France.|Renault, DEA-IREB, Renault, Technocentre, 1 avenue du Golf, 78084, Guyancourt, France.
authors.forename: Huikyong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Helmholtz Institute of Ulm (HIU), Helmholtz Str.11, 89081, Ulm, Germany.|Karlsruhe Institute of Technology (KIT), P.O.Box 3640, 76021, Karlsruhe, Germany.
authors.forename: Sangsik
authors.initials: S
authors.lastname: Jeong
authors.affiliation: Helmholtz Institute of Ulm (HIU), Helmholtz Str.11, 89081, Ulm, Germany.|Karlsruhe Institute of Technology (KIT), P.O.Box 3640, 76021, Karlsruhe, Germany.
authors.forename: Liming
authors.initials: L
authors.lastname: Wu
authors.affiliation: Laboratoire de Réactivité et Chimie des Solide (LRCS), CNRS UMR 7314 Université de Picardie Jules Verne, 33 rue Saint Leu, 80039, Amiens, France.|Réseau sur le Stockage Electrochimique de l'Energie, CNRS RS2E, FR3459, France.
authors.forename: Gregory
authors.initials: G
authors.lastname: Gachot
authors.affiliation: Laboratoire de Réactivité et Chimie des Solide (LRCS), CNRS UMR 7314 Université de Picardie Jules Verne, 33 rue Saint Leu, 80039, Amiens, France.|Réseau sur le Stockage Electrochimique de l'Energie, CNRS RS2E, FR3459, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Laruelle
authors.affiliation: CIC Energigune, Parque Tecnologico de Alava, Albert Einstein 48, ED. CIC, 01510, Minano, Spain.
authors.forename: Michel
authors.initials: M
authors.lastname: Armand
authors.affiliation: Helmholtz Institute of Ulm (HIU), Helmholtz Str.11, 89081, Ulm, Germany. gebrekidan.eshetu@kit.edu, stefano.passerini@kit.edu.|Karlsruhe Institute of Technology (KIT), P.O.Box 3640, 76021, Karlsruhe, Germany. gebrekidan.eshetu@kit.edu, stefano.passerini@kit.edu.
authors.forename: Stefano
authors.identifier: http://orcid.org/0000-0002-6606-5304
authors.initials: S
authors.lastname: Passerini
mesh_terms: D002152:Calorimetry, Differential Scanning; D004573:Electrolytes / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D007477:Ions; D012964:Sodium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
chemical_list: D004573:Electrolytes; D007477:Ions; D012964:Sodium
keywords: carbon; electrochemistry; ionic liquids; lithium; sodium