Magnesium Electrolytes Research Articles

Effect of Chloride Ions on the Electrochemical Performance of Magnesium Metal‐Organic‐Frameworks‐Based Semi‐Solid Electrolytes

AbstractThe majority of research on magnesium (Mg) electrolytes has focused on enhancing reversible Mg deposition, often employing chloride‐containing electrolytes. However, there is a notable gap in the literature regarding the influence of chloride ions in semi‐solid Mg electrolytes. In this study, we systematically explore the impact of chloride ions on Mg deposition/dissolution on a copper (Cu) anode using a semi‐solid electrolyte composed of Mg‐based mixed metal‐organic frameworks, MgCl2 and Mg[TFSI]2. We separate the Mg deposition/dissolution process from changes in the anode's surface morphology In this respect, the morphological and compositional transformations in the electrolyte and electrode following galvanostatic cycling are meticulously investigated. Initial potential cycling reveals the feasibility of Mg deposition/dissolution on Cu electrodes, albeit with reduced reversibility in subsequent cycles. Extending the upper potential limit to 4.0 V vs. Mg/Mg2+ enhances Mg dissolution, attributed to chloride ions facilitating Cu surface dissolution. Our findings provide insights into optimizing semi‐solid electrolytes for advanced Magnesium battery technologies.

Lithium fluoride additive helps construct stable electrode-electrolyte interfaces to boost the performance of Mg-S batteries

Most magnesium electrolytes react with the Mg anode surface to form a non-favorable passive layer that inhibits shuttling of the Mg ions and results in the short cycle life of the Mg cells. In this work, we probe LiF as an effective electrolyte additive to address the challenges of electrolyte degradation, Mg anode passivation, and polysulfide shuttle. The key to our strategy lies in modifying the halogen-free electrolytes (HFE) electrolyte-based Mg(NO3)2·6H2O salt dissolved in acetonitrile (ACN) and tetra ethylene glycol dimethyl ether (G4) with LiF additives, which play a crucial role in engineering stable electrolyte interfaces. These additives alter the chemical composition of the solid electrolyte interface (SEI) layer on the surface of the Mg anode, enabling low overpotential of Mg2+ extraction/insertion, improving the Mg2+ transference, and enhancing the electrochemical performance of the electrolyte. The Mg-S cell with modified electrolyte delivers a high discharge capacity of over 400 mAh g−1 for >10 cycles, compared with the short cycle life in the case of using a blank electrolyte. This remarkable performance underscores the potential of our findings in advancing magnesium sulfur battery technology.

Nanoconfinement of an ammine magnesium borohydride composite electrolyte in a mesoporous silica scaffold

Improvements of magnesium ionic conducting materials are important for the development of novel magnesium solid-state batteries. Here we investigate the effect of nanoconfinement of one of the most conductive magnesium electrolytes − the (Mg(BH4)2·NH3)x(Mg(BH4)2·2NH3)1−x composite. The synthesis of nanoconfined Mg(BH4)2·1.47NH3 in a mesoporous silica scaffold (SBA-15, pore size 5.8 nm) is achieved through melt infiltration. Various degrees of pore filling are investigated, ranging from 100 to 300 %. Solid-state 11B nuclear magnetic resonance analysis confirms the successful stabilization of the highly dynamic eutectic molten state of Mg(BH4)2·1.47NH3 through nanoconfinement. The confined sample exhibits notable thermal stability, maintaining integrity up to approximately 100 °C, and the eutectic molten composite does not recrystallize within five months after synthesis, upon storing at room temperature. Notably, among the confined samples, 200 % pore filling displays promising Mg2+ ionic conductivity within the range of 9.1 × 10−6 to 2.7 × 10−4 S cm−1 and a low activation energy of 0.69 eV at temperatures from 32 to 80 °C. Furthermore, the compound was found to have a low electronic conductivity of 7.93 × 10−11 S cm−1 at 70 °C resulting in an ionic transport number close to unity.

First Isolation of Solvated MgCl+ species as the Sole Cations in Electrolyte Solutions for Rechargeable Mg Batteries

Synthesis of complex magnesium cations in ethereal solutions, is receiving a lot of attention due to their potential utilization in rechargeable magnesium batteries (RMB). The simplest complex cation, namely, solvated MgCl+, was hypothesized and reported as the most important cation in nonaqueous magnesium electrolyte solutions chemistry. However, such ions have never isolated as the only cationic species in ethereal solutions developed for RMB. In this study, we report on a successful isolation of the pure electrolyte MgCl(THF)5 + - PhAlCl3 - , and on the electrochemical behaviour of its ethereal solutions. The structure of this compound was proved by single-crystal X-ray diffraction, Raman, and, NMR spectroscopies. The novel MgCl(THF)5PhAlCl3/THF electrolyte solutions exhibit reversible Mg deposition/dissolution processes with anodic stability up to 2.7 V. The application of electrochemical cleaning pre-treatment for these solutions enabled to profoundly increase the coulombic efficiency of their Mg deposition/dissolution processes. Examining Mg prototype batteries with Mg foil anodes, composite MgxMo6S8Chevrel phase (CP) cathodes containing these solutions exhibited a viable battery performance, indicating that upon a further optimization, electrolyte solutions based on the complex MgCl(THF)5 + - PhAlCl3 - electrolyte may be suitable for practical RMB. Figure 1

Fluorine-based localization effect for stabilized high-voltage magnesium phenolic electrolyte

The design of electrolytes with excellent compatibility and high oxidation stability has long been the prerequisite for realizing high-voltage rechargeable magnesium batteries (RMBs). Compared with other chlorine-containing electrolytes, phenol-based magnesium electrolytes possess better water-oxygen resistance, simpler synthesis steps, and lower ingredient costs making it very promising for applications. However, lower oxidation stability renders it difficult to be applied in high-voltage RMBs. Herein, for the first time, we propose to utilize the fluorine-based localization effect (fluorine substitution from 2,4 o-para site on phenol enhances electrolyte oxidation stability) to design M24AT electrolyte (2,4-F2PhOMgCl + AlCl3 / THF). As-prepared M24AT electrolyte exhibits superior oxidation stability (3.9 V vs. Mg/Mg2+) than any other phenol-based electrolyte. Additionally, it in-situ generates a fluorinated solid electrolyte interface (SEI) that stabilizes the Mg anode during cycling. Consequently, the Mg||Mo6S8 cells with M24AT electrolyte demonstrate ∼100 % capacity retention after 500 cycles at 1C. Besides, the high-voltage stability of the M24AT electrolyte is displayed by electrochemical testing with Mg||PAQI full cells, which operate at voltages up to 3.0 V and exhibit greater than 300 stable cycles at 200 mA g−1, with average coulombic efficiency (CE) of ∼98 %. The proposed design strategy of fluorine-based localization facilitates the application of phenol-based electrolytes in high-voltage RMBs.

Ligand substitution as a strategy to tailor cationic conductivity in all-solid-state batteries

An increased electrification of society calls for a revolution of battery technologies to further improve energy densities, safety and reduce dependencies on critical raw materials. Here we present a new type of fast magnesium electrolytes for all solid-state batteries created as solid solutions of two other fast Mg2+ ionic conductors, Mg(BH4)2 ∙ NH3 and Mg(BH4)2 ∙ CH3NH2. However, the different ligands introduce stacking faults in the structures of the solid solutions, which are eliminated upon heating to T > 40 °C. The stacking faults appear to influence ionic conductivity, as the samples are less conductive after heating. Interestingly, the ionic conductivity does not correlate directly with the relative ligand content, as the highest conductivity is observed for the 1:1 molar composition (σ(Mg2+) = 7.3 ∙ 10−6 S cm−1 at 40 °C), which also has the lowest melting point of 60 °C. Thus, this work demonstrates a new approach to increase cationic conductivity using mixed ligand systems to alter conduction pathways and introduce microstructural strain.

Experimental and theoretical studies on thermodynamic activities of binaries ferric and magnesium chlorides in aqueous solutions at various temperatures

The investigation of the thermodynamic properties of binary systems of ferric and magnesium chlorides in aqueous solutions was reported at various temperatures using both the hygrometric method and thermodynamic modeling. Water activities were measured over a molality range of 0.100 up to mmax(FeCl3)= 2.500 mol·kg−1 and to mmax(MgCl2)=(5.798, 6.090, 6.394, and 6.839) mol·kg−1at temperatures from 298.15 K to 353.15 K, respectively. From the new measurements, the osmotic coefficients of water were evaluated and compared with the existing literature data at ambient temperature. These coefficients were treated at various temperatures using established thermodynamic models of the Pitzer, Filippov–Charykov–Rumyantsev, extended ion interaction, and Clegg–Pitzer–Brimblecombe. The relevant properties of ferric and magnesium electrolyte solutions were determined in the temperature range. Indeed, the parameterizations of FeCl3(aq) and MgCl2(aq) were evaluated and employed for the computation of solute activity and osmotic coefficients. Based on literature emf data for MgCl2(aq) at a temperature of 298.15 K, the consistency of the activity coefficients was evaluated using an adequate model, and an excellent description of the prediction activity coefficients is obtained by the extended ion interaction model. Then, the recommended activity coefficients were given at various temperatures by extending this procedure. An experimental investigation was also carried out to evaluate the solubility equilibrium of MgCl2 in aqueous solutions at different temperatures. The solubility product and standard Gibbs energies of dissolution and formation were also calculated at different temperatures and compared with those existing in the literature.

From Bulk to Interface: Solvent Exchange Dynamics and Their Role in Ion Transport and the Interfacial Model of Rechargeable Magnesium Batteries.

Multivalent battery chemistries have been explored in response to the increasing demand for high-energy rechargeable batteries utilizing sustainable resources. Solvation structures of working cations have been recognized as a key component in the design of electrolytes; however, most structure-property correlations of metal ions in organic electrolytes usually build upon favorable static solvation structures, often overlooking solvent exchange dynamics. We here report the ion solvation structures and solvent exchange rates of magnesium electrolytes in various solvents by using multimodal nuclear magnetic resonance (NMR) analysis and molecular dynamics/density functional theory (MD/DFT) calculations. These magnesium solvation structures and solvent exchange dynamics are correlated to the combined effects of several physicochemical properties of the solvents. Moreover, Mg2+ transport and interfacial charge transfer efficiency are found to be closely correlated to the solvent exchange rate in the binary electrolytes where the solvent exchange is tunable by the fraction of diluent solvents. Our primary findings are (1) most battery-related solvents undergo ultraslow solvent exchange coordinating to Mg2+ (with time scales ranging from 0.5 μs to 5 ms), (2) the cation transport mechanism is a mixture of vehicular and structural diffusion even at the ultraslow exchange limit (with faster solvent exchange leading to faster cation transport), and (3) an interfacial model wherein organic-rich regions facilitate desolvation and inorganic regions promote Mg2+ transport is consistent with our NMR, electrochemistry, and cryogenic X-ray photoelectron spectroscopy (cryo-XPS) results. This observed ultraslow solvent exchange and its importance for ion transport and interfacial properties necessitate the judicious selection of solvents and informed design of electrolyte blends for multivalent electrolytes.

Magnesium-based electrolytes with ionic liquids chloride additives: Quantum chemical stationary point analysis

The application of magnesium in electrolytes may decrease rechargeable battery production and utilization costs and improve some aspects of their performance. Yet, the development of robust electrolyte technologies remains a technological challenge. The search for optimal chemical compositions to avoid the formation of passivation layers on the electrode and increase the electrochemical stabilities of the electrolytes are underway. We hereby report the computational investigation on the magnesium-based electrolyte magnesium triflate supplemented by two chloride-containing additives tetrabutylammonium chloride and 1-ethyl-3-methylimidazolium chloride. Dimethoxy ethane (DME) is used as a molecular cosolvent. By revealing all possible ion-ionic and ion-molecular coordination patterns, we characterize the structural properties of these many-component systems and link them to the recently reported experimental results. Furthermore, the computed binding and cohesion energies were correlated to the transport properties of the electrolytes. We unveiled that the performances of both 1-ethyl-3-methylimidazolium chloride and tetrabutylammonium chloride additives were similar in all respects. However, 1-ethyl-3-methylimidazolium may be preferred because of its smaller size favoring lower shear viscosity. DME extensively participates in the coordination of Mg2+ by competing with chloride and triflate. The nucleophilic oxygen atoms of the anions and solvent molecules dominate the low-energy magnesium solvation patterns. The presence of the chloride anion in the first solvation shell of magnesium routinely corresponds to the highest thermodynamic stabilities of all investigated electrolyte solutions. The reported results foster the understanding of the magnesium-based ion-molecular systems. They are addressed to the researchers of electrolyte solutions and electrostatic coupling.

Protective Al2O3 Thin Film Coating by ALD to Enhance the Anodic Stability of Metallic Current Collectors in Ethereal Mg Electrolyte Solutions

Rechargeable magnesium batteries (RMBs) have the potential to contribute towards alternative energy storage due to their low cost, high abundance, dendrites free deposition of Mg and high volumetric energy density. Organometallic complex-based electrolytes in ethereal solutions have been extensively studied in the context of RMBs due to their ability to facilitate highly reversible magnesium deposition in rechargeable magnesium batteries, while demonstrating wide enough electrochemical stability windows. However, these solutions containing unique mixture of organo-halo aluminate complexes have detrimental effect on the anodic stability of metallic current collectors for cathodes, like Ni and Al foils. In this work, we were able to synthesize and isolate Mg2Cl3(THF)6Ph2AlCl2/THF electrolyte as the sole electroactive species using simple precursors: Ph2AlCl and MgCl2 in THF, via atom efficient mono-chloro abstraction Schlenk technique. We characterized the anodic stability of Ni, Ni@C, Al, and Al@C current collectors by monitoring their electrochemical behavior. In addition, we investigated the anodic stability enhancement of various current collectors by Al2O3 thin films coating using Atomic Layer Deposition (ALD). Linear sweep voltametric studies showed that coating current collectors enhanced the oxidative stability of Al and Ni foils by 0.1–0.3 V vs Mg/Mg2+ compared to the uncoated foils. In particular, Al2O3 coated Al@C showed an improved oxidative stability of 2.8 V vs Mg/Mg2+. Our findings show that current collectors protection by ALD coating can help in long-term stability and improving RMBs’ energy density by using high voltage cathode materials, a crucial step in developing practical rechargeable Mg batteries.

Electrokinetic study of pyrochlore in the presence of calcium and magnesium electrolytes in the context of water reuse

This paper aims to present an adequate methodology for pyrochlore from flotation process sample to be used in fundamentals surface properties studies based on zeta potential measurements under Ca and Mg electrolytes in chlorides and sulfate media. A niobium ore concentrate with small amount of fine particles (−38 µm < 2.5%), composed by 61.8% (Nb2O5), 16.5% (CaO), 7.19% (TiO2), and 6.30% (Na2O), being pyrochlore (92.8%) the Nb-bearing mineral was used. The association of acid leaching (HCl 0.1 mol/L, 70 °C, 120 min, 20 g/L and 300 rpm) and heat treatment (300 °C, 120 min and 5 g/crucible) reduced the sample's flotability by 94% which was suitable for fundamental studies. Ca and Mg ions modified the zeta potential curve of the pyrochlore without causing any changes in the pHPIE, which occurs at pH 3.1. Ca(OH)2 precipitation was not evidenced in the system containing calcium ions. Thermodynamic simulation predicted its precipitation above pH 12.3 which is outside of the range of pH studied (2.0 to 12.0). However, Mg(OH)2 precipitation associated to the formation of metal hydroxy complexes predicted by PHREEQC (version 3.7.3, llnl.dat database) contributed to the reversal in the zeta potential of the sample. The anion supporting the metallic cations also contributed to the zeta potential alteration mainly due to the ionic strength modification associated to sulfate and chloride anion charges. The alternation of chloride and sulfate sources for [Ca + Mg] system did not affect the zeta potential curves.

Electrolyte Engineering with Carboranes for Next-Generation Mg Batteries.

To realize an energy storage transition beyond Li-ion competitive technologies, earth-abundant elements, such as Mg, are needed. Carborane anions are particularly well-suited to realizing magnesium-ion batteries (MIBs), as their inert and weakly coordinating properties beget excellent electrolyte performance. However, utilizing these materials in actual electrochemical cells has been hampered by the reliance on the Mg2+ salts of the commercially available [HCB11H11]- anion, which is not soluble in more weakly binding solvents apart from the higher glymes. Herein, we demonstrate it is possible to iteratively engineer the [HCB11H11]- anion surface synthetically to address previous solubility issues and yield a highly conductive (up to 7.33 mS cm-1) and electrochemically stable (up to +4.2 V vs Mg2+/0) magnesium electrolyte that surpasses the state of the art. This novel non-nucleophilic electrolyte exhibits highly dissociative behavior regardless of concentration and is tolerant of prolonged periods of cycling in symmetric cells at high current densities (up to 2.0 mA cm-2, 400 h). The hydrocarbon functionalized carborane electrolyte presented here demonstrates >96% Coulombic efficiency when paired with a Mo6S8 cathode. This approach realizes a needed candidate to discover next-generation cathode materials that can enable the design of practical and commercially viable Mg batteries.

Mixed-Anion Contact Ion-Pair Formation Enabling Improved Performance of Halide-Free Mg-Ion Electrolytes.

Discovery of stable and efficient electrolytes that are compatible with magnesium metal anodes and high-voltage cathodes is crucial to enabling energy storage technologies that can move beyond existing Li-ion systems. Many promising electrolytes for magnesium anodes have been proposed with chloride-based systems at the forefront; however, Cl-containing electrolytes lack the oxidative stability required by high-voltage cathodes. In this work, we report magnesium trifluoromethanesulfonate (triflate) as a viable coanion for Cl-free, mixed-anion magnesium electrolytes. The addition of triflate to electrolytes containing bis(trifluoromethane sulfonyl) imide (TFSI-) anions yields significantly improved Coulombic efficiency, up to a 100 mV decrease in the plating/stripping overpotential, improved tolerance to trace H2O, and improved oxidative stability (0.35 V improvement compared to that of hybrid TFSI-Cl electrolytes). Based on 19F nuclear magnetic resonance and Raman spectroscopy measurements, we propose that these improvements in performance are driven by the formation of mixed-anion contact ion pairs, where both triflate and TFSI- are coordinated to Mg2+ in the electrolyte bulk. The formation of this mixed-anion magnesium complex is further predicted by the density functional theory to be thermodynamically driven. Collectively, this work outlines the guiding principles for the improved design of next-generation electrolytes for magnesium batteries.

Fatal Impurity for Electrochemical Mg Deposition/Dissolution

Rechargeable magnesium batteries (RMBs) are promising large-scale stationary energy storage devices. A manufacturing system similar to that used for lithium-ion batteries should be adoptable to the fabrication of RMBs. However, the compatibility of RMB components with atmospheric components other than moisture has not been studied yet. This might be due to the uncertain preconception and misunderstanding of the passivation characteristics of magnesium. In this study, we investigated the effects of atmospheric conditions on the electrochemical dissolution–deposition behavior of magnesium in non-aqueous electrolytes.1 The compatibility of magnesium metal and electrolytes incorporating air-stable weakly-coordinated anions [B(HFIP)4]− or [Al(HFIP)4]− (HFIP: hexafluoro-iso-propoxyl) with dry air was investigated. The results of a simple cyclic voltammetry (CV) clearly demonstrate the far excessive care of magnesium metals against atmospheric O2, because reversible magnesium deposition/dissolution is possible using magnesium metals polished under dry air. However, cells assembled under a dry-air atmosphere show no features of electrochemical magnesium deposition/dissolution. To identify which component of a dry air has a significant detrimental effect on the electrochemical characteristics, systematic CV and open-circuit potential (OCP) measurements were conducted under certain atmospheric conditions with Ar, N2, and O2 and an air-tight voltammetry cell equipped with gas-inlet lines. The platinum and magnesium working electrodes show characteristic responses dependent on the inlet gases, and O2 gas is found to be detrimental for the electrochemical activities of magnesium (Figure 1). The time-profile of OCP and that of O2 content in the electrolyte under steady flow of O2 gas are correlated well, suggesting passivation of magnesium metal upon uptake of O2 in the electrolyte. The electrochemical impedance spectra of symmetric magnesium metal cells using oxygenated and deoxygenated electrolytes and X-ray photoelectron spectra further corroborate inactivation of magnesium by even miniscule amount, ca., 10 ppm, of O2 impurity. Acknowledgement This work was financially supported by the Advanced Low-Carbon Technology-Specially Promoted Research for Innovative Next Generation Batteries Program (ALCA-SPRING, Grant Number JPMJAL1301), NEXT Center of Innovation Program (COI-NEXT, Grant Number JPMJPF2016) of the Japan Science and Technology Agency, and KAKENHI (Grant No. 21K05263) of the Japan Society for the Promotion of Science. Reference T. Mandai and M. Watanabe, under revision. Figure 1

Rationally Designed Spherical V2O5 Encapsulated by 2d-VS2 as High Capacity Insertion Cathode for Mg-Ion Battery

Owing to high energy density and economic viability, rechargeable Mg-ion batteries (MIB) are considered as alternative to lithium-ion batteries. However, beside chevrel phase, none of conventional inorganic cathode materials demonstrate reversible intercalation/deintercalation of Mg+2 ions in anhydrous electrolyte system. The lack of high voltage and high-capacity cathode frustrates the realization of MIB. Previous studies indicated that vanadium pentoxide (V2O5) has potential to reversibly insert\\extract Mg ions. However, many attempts to utilize V2O5 demonstrated limited electrochemical response, due to hindered Mg ion mobility in solid. Herein, we demonstrated a tailored approach to synthesize uniformly dispersed spherical V2O5 homogeneously coated with 2D VS2 through a facile in-situ chemical method and study the electrochemical activity in 0.2 M Mg(TFSI)2 + MgCl2 in DME electrolyte system and Mg metal anode. The V2O5@VS2 cathode exhibit the highest reported 1st discharge capacity of ~ 260 mA.h.g-1, excellent stability, retention and restricted capacity fading after 100 cycles which witness the prominence of VS2 coating in rationally designed V2O5 as a cathode material in non-aqueous electrolyte system for next generation high capacity MIB. Most interestingly, exact phase and morphology is completely retained even after repeated Mg+2 ion intercalation/deintercalation at different current rates, demonstrating pronounced electrochemical activity in anhydrous magnesium electrolyte and realization of a practical MIB.

Hydration MgCl2-NaCl-KCl molten salt using a novel approach for training machine learning potential

The structural information and thermophysical properties of high-temperature magnesium electrolytes play critical roles in controlling the energy consumption of industrial production and the quality of magnesium alloys. Large-scale molecular dynamics simulations can achieve accuracy similar to that of DFT while overcoming the limitations of high-temperature experiments by integrating machine learning (ML) strategies. However, many AIMD simulation tasks, computationally expensive due to configuration and volume optimization, are required to construct an initial dataset for the current ML potential training scheme. To bypass this issue, we developed a novel scheme using Deep Potential to generate ML potential that can be applied to multiple temperatures, improving efficiency without compromising accuracy. A short-time AIMD simulation at a certain target temperature was involved, followed by an iterative task using the DP-GEN package to generate an initial dataset based on a varying upper bound for model force deviation. This dataset was then used in a new DP-GEN task to train ML potential. Our method has been applied for the first time to the molten MgCl2-NaCl-KCl system with trace amounts of water (hydration MNK). The trained potential effectively predicted interatomic energies and forces, with errors of 0.5517 meV/atom and 3.063 meV/Å, respectively, denoting the trained potential is similar accuracy relative to DFT. DPMD simulation, the large-scale methodology, was performed to investigate the structural information and thermophysical properties of the hydration MNK system. Through analyzing the obtained structural information, Coulombic interactions are the dominant forces in the melt and a stronger affinity between Na+ and water molecules relative to other cations. H2O is unable to cross the first coordination layer of Cl-Mg. There are also differences in how the hydrogen and oxygen atoms of the water molecules interact with the cations in the melt. This work discusses the temperature-dependent evolution of several thermophysical properties, including density, self-diffusion coefficient, viscosity, and ionic conductivity. Our results show that density, viscosity, and ionic conductivity all exhibit negative relationships with temperature. In addition, the order of diffusion is as follows: DMg2+<DCl-<DNa+<DK+<DH2O.

Nonaqueous Magnesium Electrolyte Intermediates and Kinetics

Nonaqueous Magnesium Ion batteries are a promising strategy to overcome the shortcomings of Li ion batteries given magnesium’s lowered abundance, cost, environmental impact and increased energy density and charge-carrying capabilities. Multivalent systems are challenging to study and a mechanistic understanding of how these types of electrolytes function is hazy at best. Where studies have attempted to better characterize the mechanism of charge transfer, details of electron movement are not explicitly reported.Chemical steps are often reported to precede electron transfer steps as well, but the exact nature of these chemical steps have not been proven or well described yet either. The studies herein hope to bridge some of these gaps in knowledge for magnesium electrolyte systems with studies of kinetics and intermediate formation. The highly contested Mg+ intermediate was observed to form during electrodeposition of Mg for all, and during dissolution in some of the studied electrolytes which included three non-halogenated Mg(TFSI)2electrolytes in various organic solvents and a more traditional halogen-based Grignard APC electrolyte.

Magnesium Polymer Electrolytes Based on the Polycarbonate Poly(2-butyl-2-ethyltrimethylene-carbonate).

Magnesium electrolytes based on a polycarbonate with either magnesium tetrakis(hexafluoroisopropyloxy) borate (Mg(B(HFIP)4)2) or magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) for magnesium batteries were prepared and characterized. The side-chain-containing polycarbonate, poly(2-butyl-2-ethyltrimethylene carbonate) (P(BEC)), was synthesized by ring opening polymerization (ROP) of 5-ethyl-5-butylpropane oxirane ether carbonate (BEC) and mixed with Mg(B(HFIP)4)2 or Mg(TFSI)2 to form low- and high-salt-concentration polymer electrolytes (PEs). The PEs were characterized by impedance spectroscopy, differential scanning calorimetry (DSC), rheology, linear sweep voltammetry, cyclic voltammetry, and Raman spectroscopy. A transition from classical salt-in-polymer electrolytes to polymer-in-salt electrolytes was indicated by a significant change in glass transition temperature as well as storage and loss moduli. Ionic conductivity measurements indicated the formation of polymer-in-salt electrolytes for the PEs with 40 mol % Mg(B(HFIP)4)2 (HFIP40). In contrast, the 40 mol % Mg(TFSI)2 PEs showed mainly the classical behavior. HFIP40 was further found to have an oxidative stability window greater than 6 V vs Mg/Mg2+, but showed no reversible stripping-plating behavior in an Mg||SS cell.

P138 ST–SEGMENT ELEVATION, QTC PROLONGATION AND BRUGADA LIKE PATTERN IN THE EMERGENCY DEPARTMENT: A NEW ENTITY FOR US TO KNOW? CASE 1

Abstract Introduction ST elevation (STE) usually means acute transmural ischemia by epicardial coronary artery occlusion by a blood clot,so Guidelines recommend rapid reperfusion therapy, possibly within the first hour. Nevertheless,STE due to non–ischemic etiologies has been reported in up to 15% of the general population.We report a case of ‘likely STEMI’ presenting with marked STE,QTc prolongation and Brugada like pattern on ECG but no significant coronary obstruction on angiography.Case 1A 74y woman presented in the ER with syncope and chest pain.History of pulmonary emphysema and Crohn‘s disease previously operated on. On admission:apyretic,BP 80/40, HR130 bpm, SO2 98% on mask O2 12 l/min.WBC 20,000, 84% neut, high D–Dimer 36091 and HS–TnI 99. On transthoracic echo (TTE) akinesis in apical, apical lateral, anteroseptal, and anterior wall and EF 25%.On Chest CT bilateral emphysema,no pulmonary embolism.On ECG sinus tachycardia,frequent PVCs,diffuse deep negative waves and prolonged QTc.While in ER,a new she syncope occurred,and tachycardia with large complex,with spontaneous resolution,was observed.On ICU admission ECG diffuse STE with coved pattern in V1 and prolonged QTc 641 ms;treated with magnesium sulfate,calcium gluconate,metoprolol,ASA,heparin;on urgent coronary angiography subcritical stenosis of left anterior descending artery without blood clot:PCI with drug–eluting stent was performed. Nevertheless,ECG did not change while multiple ventricular fibrillations occurred later, requiring electric shock.Later on, after prolonged treatment with magnesium sulfate, Calcium gluconate, antibiotic, electrolytes correction,QTc,ECG and EF progressively normalized. Discussion The patient reported was labelled as a “TakoTsubo syndrome“ diagnosis,but in fact we think the ECGs (persistent STE, prolonged QTc and Brugada pattern), the TTEs and clinical features can be explained by different nosological entity due to the dysregulated INa, and in particular by increased late sodium current INa late : it leads to impaired cardiac energetics and contractile dysfunction as well as cardiac arrhythmias; acidosis and hypoxia can also increases IN late.As for our patient, unlike Takotsubo syndrome, she had no emotional trigger, no characteristic apical balloon on TTE, while severe physical trigger like hypoxia and acidosis stand out.Patients presenting with these ECG features should not be treated with thrombolysis but referred to a HUB center for coronary angiography.

STUDY THE IN HOSPITAL MORTALITY AND MORBIDITY IN PATIENTS OF ACUTE MYOCARDIAL INFARCTION WITH RESPECT TO SERUM MAGNESIUM LEVELS

Magnesium improves myocardial metabolism, reduces platelet aggregation, decreases systemic vascular resistance, dilates coronary arteries, guards against catecholamine induced myocardial necrosis, and stabilizes cell membranes. Ventricular tachyarrhythmia, sudden cardiac death and re-infarction are frequently results of hypomagnesaemia in the early post-acute myocardial infarction (AMI) period. In this prospective observational study, all patients presenting in the emergency with Acute onset anginal chest pain and associated symptoms were screened for AMI by obtaining an Electrocardiogram and Biochemical Markers. For those diagnosed to have ST elevation myocardial Infarction were subjected to detailed clinical history and examination. Serum Magnesium levels and Electrolyte would be obtained within 6 hours of the admission. Patients were treated as per the standard line of management on the advice of the treating physician/ cardiologist. In the present study there is Summary: signicant association seen between serum magnesium level and arrhythmia, morbidity of the study subjects, need of ventilator support, mortality, history of alcoholics, serum potassium level and serum troponin. I level in the study subjects. On the basis of present study, it is concluded that Magnesium plays a cardinal role in management and prevention of complications related to cardio-vascular event and its estimation in acute myocardial infarction serves as a tool for assessment of severity of the disease and envisage possible adverse outcomes including prevention of morbidities and mortality associated with hypomagnesemia in acute myocardial infarction patients