Towards safer sodium-ion batteries via organic solvent/ionic liquid based hybrid electrolytes
Artikel i vetenskaplig tidskrift, 2016

Hybrid electrolytes aimed at application in sodium-ion batteries (SIB) consisting of an organic solvent mixture (EC:PC) and different ionic liquids (ILs); EMImTFSI, BMImTFSI, and Pyr13TFSI, and with the NaTFSI salt providing the Na+ charge carriers have here been extensively studied. The physico-chemical and electrochemical characterisation includes ionic conductivity, viscosity, density, cation coordination and solvation, various safety measures, and electrochemical stability window (ESW). Hybrid electrolytes with 10-50% of IL content were found to have ionic conductivities on par with comparable organic solvent based electrolytes, but with highly enhanced safety properties. A systematic Raman spectroscopy study of the cation coordination and solvation before and after electrolyte safety tests by ignition suggest that IL cations and TFSI remain stable when ignited while organic solvents are consumed. Finally, the solid electrolyte interphase (SEI) formed when using hybrid electrolytes has both better mechanical and electrochemical stability than the SEI derived from pure IL based electrolytes. For a half-cell with a hard carbon (HC) electrode and a hybrid electrolyte with a composition of 0.8 m NaTFSI in EC0.45:PC0.45:Pyr13TFSI0.10 encouraging results were obtained for IL based electrolytes - ca. 182 mAhg-1 at C/10 over 40 cycles.

Imidazolium

Sodium-ion battery

Pyrrolidinium

Ionic liquid

Hybrid electrolytes

Safety

Författare

Damien Monti

Chalmers, Fysik, Kondenserade materiens fysik

A. Ponrouch

ALISTORE-ERI European Research Institute

CSIC - Instituto de Ciencia de Materiales de Barcelona (ICMAB)

M. R. Palacin

CSIC - Instituto de Ciencia de Materiales de Barcelona (ICMAB)

ALISTORE-ERI European Research Institute

Patrik Johansson

Chalmers, Fysik, Kondenserade materiens fysik

Journal of Power Sources

0378-7753 (ISSN)

Vol. 324 712-721

Styrkeområden

Transport

Energi

Materialvetenskap

Ämneskategorier

Den kondenserade materiens fysik

DOI

10.1016/j.jpowsour.2016.06.003