Issue 48, 2019, Issue in Progress

Dendrite formation in Li-metal anodes: an atomistic molecular dynamics study

Abstract

Lithium-metal is a desired material for anodes of Li-ion and beyond Li-ion batteries because of its large theoretical specific capacity of 3860 mA h gāˆ’1 (the highest known so far), low density, and extremely low potential. Unfortunately, there are several problems that restrict the practical application of lithium-metal anodes, such as the formation of dendrites and reactivity with electrolytes. We present here a study of lithium dendrite formation on a Li-metal anode covered by a cracked solid electrolyte interface (SEI) of LiF in contact with a typical liquid electrolyte composed of 1 M LiPF6 salt solvated in ethylene carbonate. The study uses classical molecular dynamics on a model nanobattery. We tested three ways to charge the nanobattery: (1) constant current at a rate of one Li+ per 0.4 ps, (2) pulse train 10 Li+ per 4 ps, and (3) constant number ions in the electrolyte: one Li+ enters the electrolyte from the cathode as one Li+ exits the electrolyte to the anode. We found that although the SEI does not interfere with the lithiation, the mere presence of a crack in the SEI boosts and guides dendrite formation at temperatures between 325 K and 410.7 K at any C-rate, being more favorable at 325 K than at 410.7 K. On the other hand, we find that a higher C-rate (2.2C) favors the lithium dendrite formation compared to a lower C-rate (1.6C). Thus the battery could store more energy in a safe way at a lower C-rate.

Graphical abstract: Dendrite formation in Li-metal anodes: an atomistic molecular dynamics study

Article information

Article type
Paper
Submitted
04 Jul 2019
Accepted
14 Aug 2019
First published
04 Sep 2019
This article is Open Access
Creative Commons BY license

RSC Adv., 2019,9, 27835-27848

Dendrite formation in Li-metal anodes: an atomistic molecular dynamics study

L. A. Selis and J. M. Seminario, RSC Adv., 2019, 9, 27835 DOI: 10.1039/C9RA05067A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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