Fluorine-free electrolytes for all-solid sodium-ion batteries based on percyano-substituted organic salts

• Published in: Scientific reports Vol. 7; no. 1; p. 40036
• Main Authors: Bitner-Michalska, Anna, Nolis, Gene M., Żukowska, Grażyna, Zalewska, Aldona, Poterała, Marcin, Trzeciak, Tomasz, Dranka, Maciej, Kalita, Michał, Jankowski, Piotr, Niedzicki, Leszek, Zachara, Janusz, Marcinek, Marek, Wieczorek, Władysław
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.01.2017; Nature Publishing Group
• Subjects: 119/118; 140/133; 639/638/161/891; 639/638/675; Anions; Electrochemistry; Electrolytes; Ethylene; Fluorine; Humanities and Social Sciences; Ions; multidisciplinary; Polyethylene oxide; Polymers; Salts; Science; Sodium; Thermal stability
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep40036

A new family of fluorine-free solid-polymer electrolytes, for use in sodium-ion battery applications, is presented. Three novel sodium salts withdiffuse negative charges: sodium pentacyanopropenide (NaPCPI), sodium 2,3,4,5-tetracyanopirolate (NaTCP) and sodium 2,4,5-tricyanoimidazolate (NaTIM) were designed andtested in a poly(ethylene oxide) (PEO) matrix as polymer electrolytes for anall-solid sodium-ion battery. Due to unique, non-covalent structural configurations of anions, improved ionic conductivities were observed. As an example, “liquid-like” high conductivities (>1 mS cm −1 ) were obtained above 70 °C for solid-polymer electrolyte with a PEO to NaTCP molar ratio of 16:1. All presented salts showed high thermal stability and suitable windows of electrochemical stability between 3 and 5 V. These new anions open a new class of compounds with non-covalent structure for electrolytes system applications.