Electrolyte preparation. Tetraglyme (4G) (Sigma-Aldrich, ≥99%) was distilled under vacuum over sodium (Sigma-Aldrich, 99.9%) and benzophenone (Sigma-Aldrich, 99%). The distilled solvent was introduced to a N2 glovebox (H2O <0.1ppm, O2 <0.1 ppm) and was dried using freshly activated 4 Å molecular sieves (Sigma-Aldrich) for 72 hours (h). Magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) (Solvionic, 99.5%) was dried in a Buchi oven at 120 o C for 72 h and transferred into the N2 glove-box. The electrolyte was prepared by dissolving 0.5 M Mg(TFSI)2 in tetraglyme at room temperature. The solution was left stirring overnight until a colourless solution was obtained. The water content measured by Karl Fischer titration was found to be <15 ppm. 2 M butyl magnesium chloride (BuMgCl) in tetrahydrofuran (THF, Sigma Aldrich) was used as received.
It has recently been established that 1-octanethiol in the electrolyte can allow iron electrodes to be discharged at higher rates. However, the effect of thiol additives on the air electrode has not yet been studied. The effect of solvated thiols on the surface positive electrode reaction is of prime importance if these are to be used in an iron-air battery. This work shows that the airelectrode catalyst is poisoned by the presence of octanethiol, with the oxygen reduction overpotential at the air electrode increasing with time of exposure to the solution and increased 1-octanethiol concentration in the range 0-0.1 mol dm −3. Postmortem XPS analyses were performed over the used air electrodes suggesting the adsorption of sulphur species over the catalyst surface, reducing its performance. Therefore, although sulphur-based additives may be suitable for nickel-iron batteries, they are not recommended for iron-air batteries except in concentrations well below 10 × 10 −3 mol dm −3 .
Since their discovery, lithium-ion batteries (LIBs) have dominated the energy storage and power market due to their attractive attributes. However, LIBs cannot cope with the ever-growing energy demand and new alternatives must be explored. The low cost, and abundance of sodium, as well as its similar chemical properties to lithium, make the sodium-ion battery (SIB) a promising alternative for the future.1-5 SIBs often suffer from a short cycle lifespan, which is mainly attributed to the formation of an unstable solid electrolyte interphase (SEI) layer on the hard carbon anode surface. During the first cycle, the electrolyte solution is reduced, and its decomposition products form a passivation film (SEI) on the anode. Ideally, the SEI should protect the electrolyte from further decomposition during subsequent cycling, while being permeable to sodium ions. To reach this ideal situation, the employment of film-forming electrolyte additives in small amounts is necessary.6-11 In this study, in-operando electrochemical quartz crystal microbalance is used to monitor how additives affect the mass variation during the sodium intercalation/de-intercalation process. Mass spectrometry is further employed to identify and quantify the generated gaseous species during the initial SEI formation. After cycling, scanning electron microscopy and X-ray photoelectron spectroscopy are used to explore the additives effect on the SEI thickness and composition. A range of additives are considered including 1,3-propane sultone, succinonitrile and sodium-difluoro(oxalato)borate. The results of this study will be presented, along with suggestions for future research. Reference s : [1] P. K. Nayak, L. Yang, W. Brehm, P. Adelhelm, Angew. Chem. Int. Ed. 57 (2018) 102–120. [2] S. Roberts, E. Kendrick, Nanotechnol. Sci. Appl.11 (2018) 23-33. [3] H. Li, X. Zhang, Z. Zhao, Z. Hu, X. Liu, G. Yu, Energy Storage Mater. 26 (2020) 83–104. [4] J. Deng, W. B. Luo, S. L. Chou, H. K. Liu, S. X. Dou, Adv. Energy Mater. 8 (2018) 1–17. [5] L. Li, Y. Zheng, S. Zhang, J. Yang, Z. Shao, Z. Guo, Energy Environ. Sci., 11 (2018) 2310–2340. [6] G. Eshetu, M. Martinez-Ibañez, E. Sánchez-Diez, I. Gracia, L. Chunmei, L. M. Rodriguez-Martinez, T. Rojo, H. Zhang, M. Armand, Chem. Asian J. 13 (2018) 2770-2780. [7] M. Dahbi, T. Nakano, N. Yabuuchi, S. Fujimura, K. Chihara, K. Kubota, J.Y. Son, Y.T. Cui, H. Oji, S. Komaba, ChemElectroChem, 3 (2016) 1856–1867. [8] G. Yan, K. Reeves, D. Foix, Z. Li, C. Cometto, S. Mariyappan, M. Salanne, J.M. Tarascon, Adv. Energy Mater. 4 (2019) 36244–36251. [9] S. Komaba, W. Murata, T. Ishikawa, N. Yabuuchi, T. Ozeki, T. Nakayama, O. Atsushi, G. Kazuma, K. Fujiwara, Adv. Funct. Mater. 21 (2011) 3859-3867. [10] A. Bouibes, N. Takenaka, T. Fujie, K. Kubota, S. Komaba, M. Nagaoka, Appl. Mater. Interfaces. 10 (2018) 28525-28532. [11] M.A. Muñoz-Márquez, D. Saurel, J.L. Gómez-Cámer, M. Casas-Cabanas, E. Castillo-Martínez, T. Rojo, Adv. Energy Mater. 7 (2017) 1-31.
The Magnesium battery is considered a potential a high energy, sustainable successor to the lithium-ion battery, due to an almost two-fold increase in the volumetric capacity of magnesium compared to lithium (Li), decreased probability of dendritic growth, cheaper raw material costs, and high natural abundance.[1]–[3] Current electrolytes have been found to be insufficiently stable towards the Mg electrode, leading to reduction of the electrolyte and formation of a solid electrolyte interphase (SEI), which is believed to be detrimental to performance.[4]–[6] Our previous study [7] indicated a cycling mechanism at Mg surface in a Mg(TFSI)2-based electrolyte occurring through Mg deposits and an evolution of interphase chemistry during conditioning that is critical for stable cycling in the Mg(TFSI)2-glyme electrolyte. However, unlike Li metal batteries,[8], [9] where the Li plating and nucleation mechanism has been studied in depth, this is not the case for Mg batteries. In this study, we have combined electrochemical analysis with state-of-the-art cryo-focus ion beam scanning electron microscopy (FIB-SEM) and energy-dispersive X-ray spectroscopy (EDX), aiming to give insight into the Mg nucleation & growth mechanism. In doing so, we are able to reveal the detailed chemical and structural composition of the Mg deposits for the first time. Our studies are performed in Mg(TFSI)2-tetraglyme electrolyte as the leading base electrolyte for the battery. By linking the structure of Mg deposits to their state of charge and cycling performance, we can conclusively demonstrate the origin of the high overpotential in the battery. In addition, we show how Mg is reversibly plated and stripped within the deposit and demonstrate how the structure and size of the Mg deposit fluctuates to accommodate this process. Image caption: Electron microscopy images of the cross -section of a Mg particle after discharge etched using cryo-FIB-SEM, showing. a) secondary electron images of the exposed cross-section and b) In lens secondary electron images highlighting the distinct regions of the particle: Mg-rich inner core, MgO-rich outer core and interphase. References: [1] G. N. Newton, L. R. Johnson, D. A. Walsh, B. J. Hwang, and H. Han, ACS Sustain. Chem. Eng., vol. 9, no. 19, pp. 6507–6509, May 2021 [2] M. Fichtner, Magnesium Batteries: Research and Applications, vol. 2020, no. 23. Royal Society of Chemistry, 2019 [3] J. W. Choi and D. Aurbach, Nat. Rev. Mater., vol. 1, no. 4, p. 16013, 2016 [4] J. Muldoon, C. B. Bucur, and T. Gregory, Chem. Rev., vol. 114, no. 23, pp. 11683–11720, Dec. 2014 [5] A. Ponrouch, J. Bitenc, R. Dominko, N. Lindahl, P. Johansson, and M. R. Palacin, Energy Storage Mater., vol. 20, no. pp. 253–262, Feb. 2019 [6] R. Attias, M. Salama, B. Hirsch, Y. Goffer, and D. Aurbach, Joule, vol. 3, no. 1, pp. 27–52, 2019 [7] C. Holc, K. Dimogiannis, E. Hopkinson, and L. R. Johnson, ACS Appl. Mater. Interfaces, vol. 13, no. 25, pp. 29708–29713, Jun. 2021 [8] Z. Yu et al. Nat Energy, vol 5, pp.526–533 Jun. 2020 [9] B. Liu, J. G. Zhang and W. Xu, Joule, vol 2, no. 16, pp. 833-845, May 2018 Figure 1
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.