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Engineering High Energy Density Sodium Battery Anodes for Improved Cycling with Superconcentrated Ionic Liquid Electrolytes

preprint
revised on 30.01.2020, 01:06 and posted on 30.01.2020, 11:20 by Dmitrii A. Rakov, Fangfang Chen, Shammi A. Ferdousi, Hua Li, Thushan Pathirana, Alexandr Simonov, Patrick C. Howlett, Rob Atkin, Maria Forsyth

Non-uniform metal deposition and dendrite formation in high density energy storage devices reduces the efficiency, safety, and life of batteries with metal anodes. Superconcentrated ionic liquid (IL) electrolytes (e.g. 1:1 IL:alkali ion) coupled with anode preconditioning at more negative potentials can completely mitigate these issues, and therefore revolutionize high density energy storage devices. However, the mechanisms by which very high salt concentration and preconditioning potential enable uniform metal deposition and prevent dendrite formation at the metal anode during cycling are poorly understood, and therefore not optimized. Here, we use

atomic-force microscopy and molecular dynamics simulations to unravel the influence of these factors on the interface chemistry in a sodium electrolyte, demonstrating how a molten salt like structure at the electrode surface results in dendrite free metal cycling at higher rates. Such a structure will support the formation of a more favorable solid electrolyte interphase (SEI) accepted as being a critical factor in stable battery cycling. This new understanding will enable engineering of efficient anode electrodes by tuning interfacial nanostructure via salt concentration and high voltage preconditioning.

Funding

CE140100012

DP160101178

National Computational Merit Allocation Scheme

History

Email Address of Submitting Author

chenf@deakin.edu.au

Institution

Deakin University

Country

Australia

ORCID For Submitting Author

0000-0002-8004-1720

Declaration of Conflict of Interest

No conflict of interest

Version Notes

Version-1, the wrong additional information part was removed.