Poly(vinyl chloride) ionic liquid polymer electrolyte based on bis(fluorosulfonyl)amide for sodium secondary batteries

• Main Authors: Ab Rani, M.A (Author), Hagiwara, R. (Author), Hwang, J. (Author), Matsumoto, K. (Author)
• Format: Article
• Language: English
• Published: Electrochemical Society Inc. 2017
• Subjects: Amides; Anodic stabilities; Bis(fluorosulfonyl)amide; Chlorine compounds; Electric batteries; Electrochemical window; Electrodes; Electrolytes; Ionic liquids; Iron compounds; Liquids; Metal electrodeposition; Polyelectrolytes; Polymers; Polyvinyl chlorides; Positive electrodes; Reversible capacity; Secondary batteries; Sodium; Sodium compounds; Sodium secondary batteries; Theoretical capacity
• Online Access: View Fulltext in Publisher; View in Scopus
• ISBN: 00134651 (ISSN)
• ISSN: 00134651 (ISSN)
• DOI: 10.1149/2.0221708jes

Non-flammable electrolytes have been extensively studied to improve the safety of energy storage devices. In this study, a new ionic liquid polymer electrolyte (ILPE) prepared by a cast technique using poly(vinyl chloride) (PVC) as the host polymer was examined for sodium secondary batteries. The ILPE containing 50 wt% of 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide [C2C1im][FSA] ionic liquid showed an ionic conductivity of 5.6 mS cm−1 at 318 K. It remains stable up to 517 K based on 5 wt% loss. Stable sodium metal electrodeposition/dissolution was observed at the cathodic limit of the electrochemical window for the ILPE containing Na[FSA] ([C2C1im][FSA]:Na[FSA]:PVC = 2.0:1.0:1.0 w/w). The anodic limit was observed at around 4.7 V vs. Na+/Na on a Pt working electrode, while on an Al working electrode a higher anodic stability owing to passivation was observed. In the Na/[C2C1im][FSA]-Na[FSA]-PVC/-Na2FeP2O7-cell with the theoretical capacity of 97 mAh g−1, a reversible capacity of 92 mAh g−1 was obtained at 363 K for the Na2FeP2O7 positive electrode. These results suggest great potential of this PVC-based ILPE for constructing very safe sodium secondary batteries. © The Author(s) 2017. Published by ECS. All rights reserved.