Novel Na+ Ion Diffusion Mechanism in Mixed Organic–Inorganic Ionic Liquid Electrolyte Leading to High Na+ Transference Number and Stable, High Rate Electrochemical Cycling of Sodium Cells.

Ambient temperature sodium batteries hold the promise of a new generation of high energy density, low-cost energy storage technologies. Particularly challenging in sodium electrochemistry is achieving high stability at high charge/discharge rates. We report here mixtures of inorganic/organic cation fluorosulfonamide (FSI) ionic liquids that exhibit unexpectedly high Na+ transference numbers due to a structural diffusion mechanism not previously observed in this type of electrolyte. The electrolyte can therefore support high current density cycling of sodium. We investigate the effect of NaFSI salt concentration in methylpropylpyrrolidinium (C3mpyr) FSI ionic liquid (IL) on the reversible plating and dissolution of sodium metal, both on a copper electrode and in a symmetric Na/Na metal cell. NaFSI is highly soluble in the IL allowing the preparation of mixtures that contain very high Na contents, greater than 3.2 mol/kg (50 mol %) at room temperature. Despite the fact that overall ion diffusivity decreases...

[1]  M. Forsyth,et al.  Insights into the Transport of Alkali Metal Ions Doped into a Plastic Crystal Electrolyte , 2015 .

[2]  R. Hagiwara,et al.  Thermal and Transport Properties of Na[N(SO2F)2]–[N-Methyl-N-propylpyrrolidinium][N(SO2F)2] Ionic Liquids for Na Secondary Batteries , 2015 .

[3]  D. Macfarlane,et al.  Physical properties of high Li-ion content N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide based ionic liquid electrolytes. , 2015, Physical chemistry chemical physics : PCCP.

[4]  Chung‐Jen Tseng,et al.  Rechargeable Na/Na0.44MnO2 cells with ionic liquid electrolytes containing various sodium solutes , 2015 .

[5]  R. Hagiwara,et al.  Na[FSA]-[C 3 C 1 pyrr][FSA] ionic liquids as electrolytes for sodium secondary batteries: Effects of Na ion concentration and operation temperature , 2014 .

[6]  Jeng‐Kuei Chang,et al.  Ionic liquid electrolytes with various sodium solutes for rechargeable Na/NaFePO4 batteries operated at elevated temperatures. , 2014, ACS applied materials & interfaces.

[7]  M. Armand,et al.  Physicochemical properties of N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide for sodium metal battery applications. , 2014, Physical chemistry chemical physics : PCCP.

[8]  S. Passerini,et al.  Unexpected performance of layered sodium-ion cathode material in ionic liquid-based electrolyte , 2014 .

[9]  Yuki Yamada,et al.  A superconcentrated ether electrolyte for fast-charging Li-ion batteries. , 2013, Chemical communications.

[10]  Shinji Inazawa,et al.  NaFSA–C1C3pyrFSA ionic liquids for sodium secondary battery operating over a wide temperature range , 2013 .

[11]  John B Goodenough,et al.  Evolution of strategies for modern rechargeable batteries. , 2013, Accounts of chemical research.

[12]  Donghan Kim,et al.  Sodium‐Ion Batteries , 2013 .

[13]  Yang‐Kook Sun,et al.  Reversible NaFePO4 electrode for sodium secondary batteries , 2012 .

[14]  R. Hagiwara,et al.  Intermediate-temperature ionic liquid NaFSA-KFSA and its application to sodium secondary batteries , 2012 .

[15]  A. Pádua,et al.  CL&P: A generic and systematic force field for ionic liquids modeling , 2012, Theoretical Chemistry Accounts.

[16]  Kazuma Gotoh,et al.  Electrochemical Na Insertion and Solid Electrolyte Interphase for Hard‐Carbon Electrodes and Application to Na‐Ion Batteries , 2011 .

[17]  Anubhav Jain,et al.  Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials , 2011 .

[18]  S. Seki,et al.  Liquid structure and conformation of a low-viscosity ionic liquid, N-methyl-N-propyl-pyrrolidinium bis(fluorosulfonyl) imide studied by high-energy X-ray scattering , 2008 .

[19]  R. Norton,et al.  Protein effective rotational correlation times from translational self-diffusion coefficients measured by PFG-NMR. , 2008, Biophysical chemistry.

[20]  W Smith,et al.  DL_POLY_2.0: a general-purpose parallel molecular dynamics simulation package. , 1996, Journal of molecular graphics.

[21]  P. Bruce,et al.  Electrochemical measurement of transference numbers in polymer electrolytes , 1987 .

[22]  A. L. V. Geet.  Calibration of methanol nuclear magnetic resonance thermometer at low temperature , 1970 .

[23]  J. E. Tanner,et al.  Restricted Self‐Diffusion of Protons in Colloidal Systems by the Pulsed‐Gradient, Spin‐Echo Method , 1968 .

[24]  M. Eigen,et al.  Self-dissociation and protonic charge transport in water and , 1958, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[25]  E. Purcell,et al.  Relaxation Effects in Nuclear Magnetic Resonance Absorption , 1948 .

[26]  Patrik Johansson,et al.  Ionic liquid based electrolytes for sodium-ion batteries: Na+ solvation and ionic conductivity , 2014 .

[27]  D. Macfarlane,et al.  Fast Charge/Discharge of Li Metal Batteries Using an Ionic Liquid Electrolyte , 2013 .