Anode-Electrolyte Interfaces in Secondary Magnesium Batteries Ran Attias, Michael Salama, Baruch Hirsch, Yosef Goffer, Doron Aurbach  Joule  Volume 3, Issue 1, Pages 27-52 (January 2019) DOI: 10.1016/j.joule.2018.10.028 Copyright © 2018 Elsevier Inc. Terms and Conditions

Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 1 Comparative Steady-State Cyclic Voltammograms Related to Several Mg-Based Electrolyte Solutions with THF as the Solvent Pt Working Electrodes, Mg Metal as Reference and Counter Electrodes (A) Comparison among aluminate, Grignard, and borate-based electrolyte solutions at various concentrations. Reprinted with permission from Aurbach et al.,4 copyright 2002. (B) APC electrolyte solutions at different concentrations, emphasizing the effect on anodic stability. The inset presents the entire voltammetric response of the solutions. Reproduced with permission from Pour et al.,21 copyright American Chemical Society. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 2 Electrochemical Performance of Boron-Based Electrolyte Materials (A) Typical steady-state voltammograms of Pt electrodes in different electrolytes: (A) 0.4 M Mes3B-PhMgCl and (B) 0.5 M Mes3B-(PhMgCl)2. The inset is a zoom-in of the 1.5–4-V region. Reprinted with permission from Guo et al.,12 copyright 2012 Royal Society of Chemistry. (B) Selected cyclic voltammograms of 0.75 M MMC/G4 electrolyte on Pt electrode collected within the potential range 0.6–3.0 V versus Mg at 5 mV/s. Inset: cycling efficiencies of Mg deposition and dissolution. Reprinted with permission from Tutusaus et al.,29 copyright 2015, Wiley-VCH, Angew. Chem. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 3 Cyclic Voltammetry Measurements of Nitrogen-Containing Electrolytes (A) Cyclic voltammograms and linear sweep voltammetry (inset) of 0.25 M MACC 2:1 solution in DME. The working electrode is Pt, while the counter and reference electrodes are Mg metal. Measurements were obtained at 25 mV s−1 and ambient conditions. Reprinted with permission from Doe et al.,35 copyright 2014 Royal Society of Chemistry. (B–D) Typical cyclic voltammograms with Pt electrodes of 0.5 M THF solutions are shown for different ratios of Mg(HMDS)2 and MgCl2, respectively: (B) 2:1, (C) 1:2, and (D) 1:4. The scan rate was 100 mV/s with Pt working electrode and Mg ribbons as both reference and counter electrodes. Rreprinted with permission from Liao et al.,14 copyright 2012 Royal Society of Chemistry. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 4 MgTFSI2 -MgCl2 Electrochemical Conditioning Process (A) Typical cyclic voltammetry (CV) of Pt working electrodes (WE) in (A) MgTFSI2 0.5 M in DME solution, scanned at 25 mV/s. The inset shows a CV of a Pt electrode in MgTFSI2 0.5 M solution in diglyme. (B) MgTFSI2 0.25 M with MgCl2 0.5 M in DME, scanned at 25 mV/s. Mg foils served as reference and counter electrodes (RE and CE). Addition of MgCl2 significantly reduces the overpotential for both deposition and dissolution processes. (C) Selected CV cycles during the conditioning procedure of MgTFSI2 0.25 M with MgCl2 0.5 M in DME solution, scanned at 1 mV/s. Pt served as WE and Mg as both RE and CE. (D) Typical CV of Pt WE in conditioned MgTFSI2 0.25 M + MgCl2 0.5 M DME solution, scanned at 25 mV/s, with Mg foils as both RE and CE. Reprinted with permission from Shterenberg et al.,38 copyright 2015. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 5 Impact of Artificial SEI on the Overall Electrochemical Performance (A and B) Voltage responses of symmetric Mg cells under repeated polarization with and without artificial interphase in different electrolyte systems at a current density of 0.01 mA cm−2 showing reversible Mg deposition/stripping in (A) APC electrolyte, where each deposition/stripping cycle lasts for 1 hr, and (B) 0.5 M Mg(TFSI)2/PC electrolyte, where each deposition/stripping cycle lasts 30 min. The cell made with pristine Mg electrodes shows huge overpotential at the beginning and fails after 135 cycles, whereas the cell made with the Mg2+-conducting interphase-protected Mg electrodes performs prolonged cycles in carbonate-based electrolytes. The reversibility is conspicuous in the latter, as proven over 1,000 cycles. (C) Voltage hysteresis versus cycle numbers for symmetric Mg electrodes with 0.5 M Mg(TFSI)2/PC electrolyte. Lower voltage hysteresis is observed for interphase-protected Mg electrode, where the artificial interphase prevents reductive decomposition of PC. Reprinted with permission from Son et al.,48 copyright 2018 Nature. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 6 Electrochemical Performance for Magnesium-Bismuth Alloy as Anode Materials (A) Cyclic voltammograms of Mg insertion/deinsertion in bismuth. (B) Discharge/charge profile of an Mg-Bicell. (C) Rate performance of an Mg-Bicell. (D) Cycling stability and Coulombic efficiency of bismuth electrode for reversible Mg insertion/deinsertion. Cell configuration: Mg/0.1 M Mg(BH4)2-1.5 M LiBH4-diglyme/Bi. Reproduced with permission from Shao et al.,58 copyright American Chemical Society. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 7 Galvanostatic Curve Obtained at 2C, after Initial Activation Sweeps Inset: evolution of discharge and charge capacities and Coulombic efficiency. Reprinted with permission from Murgia et al.,55 copyright 2015 Royal Society of Chemistry. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 8 Comparative Analysis of Magnesium-Tin and Magnesium-Bismuth Anode Materials First cycle galvanostatic magnesiation/de-magnesiation curves for Sn/Mg (black) and Bi/Mg (red) half-cells (using organohaloaluminate electrolyte) highlighting their achievable theoretical capacities. Inset: XRD spectra for (1) as-fabricated Sn, (2) magnesiated Sn (or Mg2Sn––peak positions marked with arrows), and (3) de-magnesiated Mg2Sn. Reprinted with permission from Singh et al.,63 copyright 2013 Royal Society of Chemistry. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 9 Comparison of Electrochemical Behavior of SnSb and Sn for Mg Magnesiation-Demagnesiation (A and B) CV acquired at 0.05 mV/s (A) and charge-discharge profiles acquired at 50 mA/g (B). (C and D) Specific capacity for SnSb at different current densities (in mA/g) as noted (C) and cycling stability of SnSb, at 500 mA/g (D). Reprinted with permission from Cheng et al.,65 copyright 2015, Wiley-VCH Adv. Mater. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 10 Galvanostatic Cycling of In-Based Formulated Electrode at C/50 and Corresponding Capacity Evolution at C/50 Inset: corresponding charge and discharge capacities evolution. Reprinted with permission from Murgia et al.67 Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 11 Cycling Performance of LTO (A) Comparison of the rate capabilities of the cell cycled at different current densities. (B) Cycling performance of the cells using LTO electrodes cycled at a current density of 300 mA/g. Reprinted with permission from Wu et al.,69 copyright 2014 Nature. Joule 2019 3, 27-52DOI: (10.1016/j.joule.2018.10.028) Copyright © 2018 Elsevier Inc. Terms and Conditions