Lithium metal batteries are gaining increasing attention due to their potential for significantly higher theoretical energy density than conventional lithium ion batteries. *
In the article “Effective Solid Electrolyte Interphase Formation on Lithium Metal Anodes by Mechanochemical Modification” Julia Wellmann, Jan-Paul Brinkmann, Björn Wankmiller, Kerstin Neuhaus, Uta Rodehorst, Michael R. Hansen, Martin Winter and Elie Paillard present a novel mechanochemical modification method for lithium metal anodes, involving roll-pressing the lithium metal foil in contact with ionic liquid-based solutions, enabling the formation of an artificial solid electrolyte interphase with favorable properties such as an improved lithium ion transport and, most importantly, the suppression of dendrite growth, allowing homogeneous electrodeposition/-dissolution using conventional and highly conductive room temperature alkyl carbonate-based electrolytes.*
As a result, stable cycling in symmetrical Li∥Li cells is achieved even at a high current density of
10 A cm–2. Furthermore, the rate capability and the capacity retention in NMC∥Li cells are significantly improved. *
The surface roughness of the lithium metal after applying different modification methods was compared by Atomic Force Microscopy (AFM).*
The Atomic force microscopy (AFM) measurements were performed using a NANOSENSORS™ PointProbe® Plus PPP-ZEILR AFM probe. (Contact Mode Low Force Constant – typical force constant 1.6 N/m – typical resonance frequency 27 kHz – Aluminum Reflex Coating).
All images were recorded in the intermittent contact mode with constant force. The experiments were performed in a glovebox with argon flow to minimize contact to air. An area of 5 μm × 5 μm was chosen for all measurements. *
The calculation of the arithmetic mean deviation of the surface roughness (called average surface roughness, Sa, for simplicity) was done according to EUR 15178N. The maximal surface roughness (Sm) is the difference between the highest and the lowest point on the sample surface within the region of interest. *
Figure 6. from Julia Wellmann et al. “Effective Solid Electrolyte Interphase Formation on Lithium Metal Anodes by Mechanochemical Modification”:
SEM images of lithium electrodes after cycling in symmetric Li∥Li cells with liquid carbonate-based electrolytes (1 M LiPF6 in EC:EMC (3:7)) (a, f) without modification, (b, g) after mechanical modification, (c, h) after mechanochemical modification, and (d, i) after roll-pressing and immersion for 1 day and (e, j) for 7 days after (a–e) one electrodeposition step (1 mAh, 1 mA cm–2) and (f–j) after 50 cycles (1 mAh, 1 mA cm–2). AFM topography images of (k) pristine lithium, (l) mechanically modified lithium, (m) mechanochemically modified lithium, and (n) lithium immersed for 1 day and (o) for 7 days.
*Julia Wellmann, Jan-Paul Brinkmann, Björn Wankmiller, Kerstin Neuhaus, Uta Rodehorst, Michael R. Hansen, Martin Winter, and Elie Paillard
Effective Solid Electrolyte Interphase Formation on Lithium Metal Anodes by Mechanochemical Modification
ACS Applied Materials & Interfaces 2021, 13, 34227−34237
DOI: https://doi.org/10.1021/acsami.1c07490
Open Access: The article “Effective Solid Electrolyte Interphase Formation on Lithium Metal Anodes by Mechanochemical Modification” by Julia Wellmann, Jan-Paul Brinkmann, Björn Wankmiller, Kerstin Neuhaus, Uta Rodehorst, Michael R. Hansen, Martin Winter and Elie Paillard is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.