Unexplored Class of Eutectic Electrolytes for Rechargeable Magnesium Batteries

Abstract

Lithium-ion batteries have had huge success in the last three decades. Although their chemistry has matured along with commercial acceptance, there is a strong incentive to design battery materials from abundant resources; yet they can deliver high energy and power density with enhanced safety parameters competitively. Magnesium-metal rechargeable batteries remain as one of the potential candidates offering similar chemistry, which might provide an affordable solution. Nevertheless, there are quite a few challenges that restrict their adaptation. One of the major issues is the choice of solvent-based electrolytes that hampers the thermal and electrochemical stability apart from the safety limitations imposed by the volatile and flammable solvents. Herein, we report an unexplored class of electrolytes composed of 1-ethyl-3-methylimidazolium chloride (EMIC) with Mg(ClO4)2 or Mg(CF3SO3)2 based on the class of deep eutectic solvents (DESs) for application in rechargeable magnesium batteries. The optimized molar ratio 1:0.16 and 1:0.14 identified for EMIC-Mg(ClO4)2 and EMIC-Mg(CF3SO3)2 offers appreciably high conductivity, σ25°C of 2.8 and 2.4 mS cm–1, respectively. The anodic stability recorded with graphite as a working electrode was ∼3.0 V vs Mg/Mg2+, and the Graphite|DES|Mg cells were found to deliver ∼40 mAh g–1 over 50 cycles with remarkable stability. Albeit preliminary, the study opens up prospects for designing an alternate class of safe and stable eutectic electrolytes for rechargeable magnesium battery application.

A Nonaqueous Eutectic Electrolyte for Rechargeable Iron Batteries

“…Vibrational spectroscopic techniques such as Fourier Transform Infrared (FTIR) and Raman spectroscopies were employed to understand the following characteristic features that cause the eutectic formation: (i) hydrogen bonding interactions, (ii) key ionic complexes, (iii) free ions, and (iv) ion clusters present in the binary eutectic compositions. Typical FTIR spectra of pure (Et 3 NH)­Cl, as shown in Figure (d)-(i), denote all the characteristic peaks corresponding to ν C–H and ν C–N stretches in the frequency range of 3050–2850 cm –1 and 1200–1000 cm –1 , respectively. , FeCl 3 shows characteristic Fe–Cl stretching vibrations at ∼400–300 cm –1 , typically identified as far-IR radiation range . The FTIR spectra of all the eutectic compositions have shown considerable changes from pure (Et 3 NH)Cl or FeCl 3 .…”

“…Typical FTIR spectra of pure (Et 3 NH)Cl, as shown in Figure 1(d)-(i), denote all the characteristic peaks corresponding to ν C−H and ν C−N stretches in the frequency range of 3050−2850 cm −1 and 1200−1000 cm −1 , respectively. 18,19 FeCl 3 shows characteristic Fe−Cl stretching vibrations at ∼400−300 cm −1 , typically identified as far-IR radiation range. 20 The FTIR spectra of all the eutectic compositions have shown considerable changes from pure (Et 3 NH)Cl or FeCl 3 .…”

The fabrication of bifunctional supramolecular glycolipid-based nanocomposite gel: insights into electrocatalytic performance with effective selectivity towards gold

“…Conductivity measurements on the gels were performed with the help of temperature-step electrochemical impedance spectroscopy (EIS) on an electrochemical workstation (Model: Zahner®Zennium) employing Thales operational software and coupled with a PID-controlled oven. 34,35 The EIS data were collected within the temperature window of 25–75 °C with a frequency sweep of 1 MHz and 500 MHz and applying an amplitude of ±10 mV across the open circuit voltage of cell. Temperature was modulated and monitored using two K-type thermocouples, one to provide oven temperature feedback to the PID controller while the other was kept close to the sample.…”

“…Electrochemical performance of the gel and gel nanocomposites was evaluated by employing cyclic voltammetry. 34,35 Typical three-electrode setup was arranged using Ag/AgCl (sat. KCl) as the reference electrode (RE), glassy carbon as the working electrode (WE), and platinum wire as the counter electrode (CE) for cyclic voltammetry (CV) studies.…”

The Metamorphosis of Mg(SO3CF3)2‐based Electrolytes for Rechargeable Magnesium Batteries

“…The as-prepared DES electrolyte exhibited a high conductivity of 2.4×10 À 3 S • cm À 1 at 25 °C and anodic stability of ~3.0 V. Moreover, the assembled full cell of Mg j graphite offered ~40 mAh • g À 1 over 50 cycles with high stability (Figure 10c, d). [98]…”