NH4Cl Solution Research Articles

Pitting corrosion resistance of tempered N08825 alloy in the inner layer of bimetallic composite pipe

Pitting corrosion resistance of N08825 alloy in the inner layer of bimetallic composite pipe SA210A/N08825 tempered at 570∼720 ℃ was investigated in NH4Cl solution by scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical measurement techniques. The M23C6 precipitates, observed at the grain boundaries of inner layer alloy 825, exhibit a temperature-dependent behavior during tempering at 570∼720 ℃. The quantity of M23C6 precipitates and the pitting corrosion resistance change with the tempering temperature. When the tempering temperature increases from 570 to 660 ℃, the quantity of M23C6 precipitates increases, with the pitting potential (Ep) decreasing from about 499 ± 8.6 to 354 ± 6.7 mVSCE, the passive current density (ip) increases from about 1.9 ± 0.2 to 2.45 ± 0.3 μA cm-2, and the average number of pits on the specimen surface rises from 3 to 7. Conversely, when the tempering temperature increases from 660 to 720 ℃, the quantity of M23C6 precipitates decreases, leading to the Ep increases from about 354 ± 6.7 to 394 ± 14.6 mVSCE, the ip decreases from about 2.45 ± 0.3 to 2.34 ± 0.4 μA cm-2, and the average number of pits on the specimen surface decreases from 7 to 6. There is a strong relationship between the M23C6 precipitates and the pitting corrosion resistance. As the quantity of M23C6 precipitates increases, it results in the expansion of Cr-depleted zones on the specimen surface, the rise of passive film defects, and a subsequent reduction in the pitting corrosion resistance of inner layer alloy 825.

Effect of Chloride Solution on Liquid Limit, and Plasticity Index of Soil in Selected Sites in Erbil /North Iraq

This study is an attempt to investigate the effect of NaCl, CaCl2, KCl, and NH4Cl solutions with different concentrations (2.5%, 5%, 7.5%) on the liquid limit, plastic limit, and plasticity index of Sarbasty and Mamwastayan soil samples /Erbil Governorate. The soil samples' liquid and plastic limits were found by using the cone penetrometer method. The Results showed that the soil's liquid, plastic limits, and Plasticity index decreased with increasing salt solution concentration. Maximum reduction of liquid limit and plastic limit in Sarbasty was from 53.6 to 34.3 and in Mamwastayan from 35.9 to 27.2, both accomplished by adding a concentration of 7.5% of KCl and CaCl2 respectively. According to the Unified Soil Classification System, the Sarbasty soils were classified as high plasticity clay (CH), and Mamwastayan low plasticity clay (CL). After adding different concentrations of salt solution to the soil, the Sarbasty soil classification changed from CH to CL. Mineralogically these soils are composed of non-clay minerals of calcite and quartz and clay minerals consisting of Montmorillonite, Chlorite, swelling Chlorite, Kaolinite, Illite, Palygorskite, and Illite- Chlorite. Sarbasty soil was the most effective salt chloride solution than the Mamwastayan soil sample swelling.

A Comprehensive Comparison Analysis between Ammonium-Based and Phosphonium-Based Bifunctional Ionic Liquids for Metal Extraction and Separation Processes.

A phosphonium-based bifunctional ionic liquid (IL) Cyp-IL was synthesized to recover molybdenum and vanadium from industrial waste resources, such as the spent hydrodesulfurization catalysts. In comparison with the reported versatile Aliquat 336-based ionic liquid, the developed ionic liquid Cyp-IL was investigated for its potential application recovery of vanadium and molybdenum from industrial wastes. To assess the efficiency of the comparative extraction process, a comprehensive comparison analysis was conducted between the ammonium-based bifunctional ionic liquid Aliquat 336 and the developed phosphonium-based bifunctional ionic liquid Cyp-IL. Vanadium and molybdenum in the ionic liquid-loaded phases were selectively precipitated using NH4Cl and BaCl2 solutions in a basic medium. Compared to Aliquat 336-based Ali-IL, Cyp-IL exhibited superior performance in the extraction and separation processes of molybdenum and vanadium such as a recovery rate of Mo 91% and V 82.5% vs Mo 85% and V 72% by the ammonium-based bifunctional ionic liquid Ali-IL. The recovered components, such as molybdenum and vanadium, were characterized by energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). This method capacitates the sustainable recovery of pure vanadium and molybdenum compounds while minimizing the environmental impact.

Expermintal Research of Electrochemical Behaviour of Zinc in Ammonium Chloride Solutions

A present study was investigated “Experimental Research of Electrochemical Behaviour of Zinc in Ammonium Chloride Solutions.” The study was investigated by the electrochemical corrosion of sine is a problem of high significance both in the fundamental and applied fields of electrochemistry. Hence investigations were undertaken to study the corrosion of zinc in storage systems, the electrodeposition and characterisation of sine and the electrodeposition and characterisation of Siti nickel alloy. Results was shows that Potential-pH diagram for zinc in ZnClg/ NH₄Cl electrolyte, as used in Laclanche’s cell. When the surface composition of polished zinc. A freshly polished Zn surface was immersed in 0.5M NH₄Cl for 45 seconds and then analysed for energy measurements by ESCA. The composition of the modified zinc surface is summarised in table-1, When the binding energy was scanned in a narrow range of 1021 to 1010 eV, the participation of Zn 2PI electrons in the bond formation was confirmed. The investigations on the zinc- NH₄Cl system were hence carried out with the following specific objectives: IC4 find out the structure and nature of the species formed un the surface of sine when introduced in NH₄Cl solutions.

Sorption/desorption and degradation of long- and short-chain PFAS by anion exchange resin and UV/sulfite system

A combined sorption/desorption and UV/sulfite degradation process was investigated for achieving efficient elimination of PFAS from water. Two gel-type resins, Purolite A532E and A600, and one macroporous resin, Purolite A860, were firstly tested for the sorption of individual PFPrA, PFHxA, PFOA, PFOS, and GenX at different concentrations. Sorption data and density functional theory (DFT) calculations revealed that electrostatic interactions predominated for short-chain PFAS sorption and hydrophobic interactions played a more significant role for long-chain PFAS than for short-chain PFAS. A600 and A860 were selected for desorption tests with 0.025% NaOH, 5% NaCl, and 5% NH4Cl solution with or without 20% ethanol (EtOH) due to their high sorption capacity for all target PFAS. The mixture of 5% NH4Cl and 20% EtOH as the desorption solution typically showed the highest desorption efficiency. PFOS was the most resistant for desorption but its desorption could be enhanced by stronger mixing conditions (in 5% NaCl + 20% EtOH). Direct degradation of studied PFAS in the desorption solution (0.025% NaOH, 5% NaCl, and 5% NH4Cl) by UV/sulfite achieved 97.6–100% degradation and 46.6–86.1% defluorination. EtOH hindered degradation and thus should be separated from the water before UV/sulfite degradation.

Investigations of thermochemical fluids as cleanup system for polymer-based fracturing fluids

The cleanup of fracturing fluids, involving polymer degradation and well flowback, is crucial for the success of the fracturing operations and revenue generation. Breakers, such as oxidizers and enzymes, are commonly employed to break down polymers, resulting in lower viscosity, improved flowback, and facilitated well cleanup. However, these conventional breakers, which contribute solely to the cleanup process through polymer degradation, have some drawbacks, such as premature breaking and insufficient release of breakers. In this study, thermochemical fluids (TCFs) are proposed as a cleanup system. This system can improve the cleanup process by lowering viscosity through temperature increase and thermal degradation of polymers, reducing hydrostatic pressure via gas generation, and eliminating phase trapping damage in tight reservoirs through the heat produced. The TCFs investigated in this study were NH4Cl and NaNO2 solutions, where a substantial amount of heat was determined from the thermal energy study using an autoclave reactor. In this study, the thermal degradation of guar gum (GG) polymer derivatives, hydroxypropyl guar gum (HPG), and carboxymethyl hydroxypropyl guar gum (CMHPG) were assessed using Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), viscosity measurements, and coreflood experiments. Both FTIR and TGA analyses of linear gels of GG and its derivatives confirmed alterations in the chemical and thermal properties of these polymers following thermal treatments. The coreflood results showed a regained permeability of 87% for thermally treated HPG borate-crosslinked, 96% for CMHPG dual crosslinked (borate and zirconate), and 90% for slickwater fracturing fluids, respectively. The regained permeability of thermally treated slickwater was even better than that for slickwater with ammonium persulfate breaker.

Cation interception and permeability characteristics of bentonite barriers exposed to NaCl and NH4Cl solutions.

High concentrations of Na+ and NH4+ in landfill leachate lead to deterioration of bentonite barrier and pose a threat to the environment. This study focused on the pollution interception and permeability characteristics of the bentonite barrier exposed to NaCl and NH4Cl solutions. Based on previous findings, salt solution concentrations were established at 74.80, 37.40, 18.70, and 9.4 mmol/L. The bentonite contents in the mixture were set at 0, 5, 10, and 15%. The results indicate that the samples exhibit better interception of NH4+ compared to Na+. This difference arises from the cation exchange sequence, the size of the hydration radius, and the hydrogen bonding of the two cations. Additionally, the difference in hydration enthalpy between the two cations leads to variations in the swelling of bentonite, resulting in a higher hydraulic conductivity coefficient in NH4Cl solution. This study shows that although bentonite barriers have better interception for NH4+, they exhibit greater hydraulic conductivity in NH4Cl solution, increasing the risk of leachate carrying other contaminants.

Study on Corrosion Behavior of Sour Water Stripper in Ammonium Chloride by Electrochemical Techniques

The corrosion features of 20# carbon steel, the base material of sour water stripper, in NH4Cl solution were examined in this research. The anatomical samples of the corroded parts were characterized by an X-ray diffractometer and other analytical tools. It was found to be a localized perforation caused by pitting, and the corrosion product was FeCl2. 20# steel was subjected to electrochemical testing using Tafel polarization and Electrochemical impedance spectroscopy. The studies showed that the 20# steel’s cathodic depolarization reaction rate speeds as density rises, and that the concentration polarization gets more marked as temperature rises. The corrosion rate of 20# steel is the fastest when temperature hits its highest point of 80°C, measuring 4.7142 mm/a. When density rose from 5 to 20%, corrosion rate grew from 1.6378 to 7.2430 mm/a.

High-performance aqueous organic redox flow battery enabled by sulfonated anthrone-containing poly(aryl ether ketone) membranes

Aqueous organic redox flow batteries (AORFBs) have become a promising electrochemical energy storage technology due to their low cost, high safety, and sustainability. As key components of emerging AORFBs, membranes face challenges such as scarcity of available membranes and high prices. Moreover, currently available membranes have low battery performance because these membranes are not optimized for specific AORFBs. In this work, a new cation exchange membrane sulfonated anthrone-containing poly(aryl ether ketone) (SAnPEK) membrane was prepared for the first time and achieved significantly improved performance in (SPr)2V/K4[Fe(CN)6] AORFBs. SAnPEK membrane has excellent selectivity and high mechanical strength (>50 MPa). SAnPEK membranes exhibit high conductivity in 1 M NH4Cl solution. For example, SAnPEK-4 membranes exhibit low surface resistance (0.176 Ωcm2) in 1 M NH4Cl solution, which is significantly better than Nafion117 (1.02 Ωcm2) and Nafion212 membranes (0.276 Ωcm2). SAnPEK membrane exhibtis impressive performance in (SPr)2V/K4[Fe(CN)6] AORFB. The SAnPEK-4 membrane exhibits high coulombic efficiency (CE) and excellent energy efficiency (EE) (CE = 99.1 %, EE = 83.4 % at 100 mAcm−2), and the EE for SAnPEK-4 membrane is significantly better than that for the Nafion117 membrane (CE = 99.3 %, EE = 62.4 %) and Nafion212 membrane (CE = 99.1 %, EE = 80.8 %, 100 mAcm−2). In addition, the SAnPEK-4 membrane exhibits excellent cycle stability over 3000 cycles in AORFB. As a high-performance, easy-to-prepare, low-cost cation exchange membrane, SAnPEK membranes have good application potential in AORFBs.

Studies on the inhibitory effect of different surfactants on ammonium chloride corrosion

Corrosion of heat exchangers by ammonium chloride (NH4Cl) is a common occurrence in the refineries. A variety of methods have been adopted to prolong the service life of equipment in such circumstances, such as the use of various additives such as surfactants or by washing with water. In this paper, a series of experiments are performed to investigate the effects of different surfactants (cationic, anionic, amphoteric, and nonionic) on NH4Cl corrosion using the sessile drop technique and electrochemical measurements. The results show that the presence of a surfactant can increase the wettability of an NH4Cl solution, decreasing the contact angle between the solution and a test material. The surface tension of an NH4Cl solution containing an anionic surfactant is the lowest, but the self-corrosion potential of such a solution is the greatest. The addition of a cationic surfactant has no inhibitory effect on corrosion, and indeed increases the corrosion rate. However, with a nonionic surfactant, it is possible to significantly decrease the corrosion rate of an NH4Cl solution, although the inhibitory effect decreases with increasing temperature.

Corrosion Behavior of CoCrNi Medium-Entropy Alloy in NH4Cl Solution with Different pH

Corrosion Behavior of CoCrNi Medium-Entropy Alloy in NH4Cl Solution with Different pH

Investigating antimicrobial behavior of thymol/Zn encapsulated hierarchically structured zeolite and thymol release kinetics

A new bioactive material was proposed by encapsulating thymol molecules and Zn2+ cations within the post-modified intracrystalline voids of hierarchical zeolite X crystals. To enhance the accessibility of thymol molecules within zeolite X crystals, commercial zeolite samples underwent post-synthesis treatment involving consecutive aqueous KCl, NH4Cl, and Na2H2EDTA solutions. The gas adsorption method utilized the encapsulation of both Zn2+ cation and thymol molecules into the resulting hierarchical zeolite X framework, which demonstrated improved antimicrobial activity. While sole thymol-encapsulated zeolite X exhibited no antimicrobial activity against S. aureus, Zn2+ encapsulated zeolite X (ZnX), thymol encapsulated post-treated zeolite X (HX-thy), and both Zn2+ and thymol encapsulated post-treated zeolite X (ZnHX-thy) displayed zone of inhibition values of 18.7 mm, 25.0 mm, and 37.5 mm, respectively. Adding Zn2+ and creating a hierarchical pore system in the zeolite X framework altered the release profiles. The Higuchi kinetic release model has the highest R2 value to describe the process of thymol release from X-thy, whereas the Elovich release model has the best fitting profile of thymol release kinetics from ZnX-thy, HX-thy, and ZnHX-thy. Results indicate that thymol and Zn2+ containing hierarchical porous materials could be beneficial tools for obtaining enhanced antibacterial activity and stability with reduced degradation and volatility of thymol with extended protection against microbial attack due to the controlled release. These findings highlight an innovative approach to designing sustainable and green materials, utilizing modified porous networks that encapsulate natural antibacterial compounds with environmentally benign metal ions.

Electro-assisted sorption behavior and mechanism of low-concentration rare earth elements on carbon based materials

With increasing demands for rare earth elements (REEs) in high-tech and futuristic applications, developing efficient methods for recovering low-concentration REEs is necessary. Here, electro-assisted sorption of low-concentration REEs, La(III), Gd(III) and Y(III) (as symbol of light, medium, and heavy REEs) on carbon-based materials, activated carbon (AC), graphene, and graphite by a facile method was reported. Recovery of La(III), Gd(III) and Y(III) could reach ∼100 % under low-concentration condition where the maximum adsorption capacity was up to 342.38 mg/(g·dm2). Variants including applied voltage, electrodes-distance, pH, impurities, and concentration were considered to study the effects on REEs recovery. Interestingly, adsorption capacity and recovery under low voltage were respectively almost 20 and 14 folds than that without voltage, because voltage promoted REEs transfer and strengthened electrostatic interaction between electrodes and REEs. The mechanism for enhancing REEs recovery on carbon-based electrodes was resulted from high electric double layer (EDL) capacitance and low charge transfer resistance. Total desorption of REEs from electrodes could be quickly realized using NH4Cl or HCl solution. Overall, the study gave a new insight of low-concentration REEs recovery using carbon-based materials, and provided an efficient route using electric method with porous materials for REEs recovery.

Exploration of rice husk ash as a green corrosion inhibitor immersed in NH4Cl 7.5 % solution

The study reports the development of a liquid smoke solution of rice husk ash (RHA) as a green corrosion inhibitor in NH4Cl solution in approaching corrosion protection for refinery facilities. The recent utilization of RHA has a partial solution to address the possible chemical to form a filming layer to disconnect bare metal and their environment. This work prepared the RHA solution by condensing the RHA vapor before adding it to various concentrations. The corrosion test of potentiodynamic and electrochemicals intends to discover the inhibitor's corrosion resistance before examining the electronic transition corresponding to the contribution of several functional groups using Ultraviolet Visible (UV–Vis) and Fourier-Transform Infrared Spectroscopy (FTIR). Surface evaluation intends to unveil the nature of the corrosion by utilizing the Scanning Electronic and Atomic Force Microscope. The corrosion test result shows the depression of corrosion rate to 0.120 mmpy with high efficiency beyond 96 % in the addition of 7.5 ppm RHA inhibitor. The greater Nyquist semicircle diameter at high concentrations increases the adsorption of the RHA on the surface of C1018. The electronic transition of n–π* and π –π* shows an extensive contribution of CC, CO, and –OH based on the UV–Vis and FTIR test. The formation of a complex compound of Fe-(NH4Cl-RHA)n blocks the corrosion active sites to reduce the corrosion. This study paves the way for using RHA as an organic compound under NH4Cl conditions, such as in a refinery process facility.

Green and selective recovery process of Mo, V, and Ni from spent hydrodesulfurization catalysts via novel ionic liquids and deep eutectic solvents technology

Ionic liquids (ILs) and deep eutectic solvents (DESs) are promising candidates as viable alternatives in the metal recovery process. Conventional methods predominantly concentrated on the extraction of metals employing ionic liquids or deep eutectic solvents from either acidic or alkaline media subjected to leaching by acids or bases. Therefore, in this work, a novel approach integrating ILs and DES was investigated, wherein the entire sequence from the leaching process to the precipitation step exclusively involves the utilization of DES and ILs. Firstly, the spent hydrodesulfurization (HDS) catalyst underwent leaching with an ionic liquid (IL), which selectively leached molybdenum (Mo) and vanadium (V). Subsequently, the residual material remaining after IL leaching underwent a further leaching process utilizing a deep eutectic solvent (DES) to facilitate the recovery of nickel (Ni). The effect of different parameters on the leaching percentage was studied and optimized for both IL and DES. Vanadium was recovered as NH4VO3 from the loaded IL phase, which was selectively precipitated over molybdenum using NH4Cl solution and molybdenum was precipitated as BaMoO4 by introducing an excess of BaCl2 solution to the filtrate. For the nickel recovery, the residue obtained after leaching using ionic liquid was treated with DES-1 and finally nickel was recovered from the mixture through cementation with aluminum. This study establishes a novel green approach based on IL and DES to recover Mo, V, and Ni from the spent catalysts without roasting and harsh acidic or basic conditions.

Renewable ammonium chloride-induced calcium leaching of gold and copper tailings and selective preparation of vaterite CaCO3 by CO2 mineralization

This study introduced a high-value green processing solution for copper tailings to prepare high-purity vaterite from gold-copper tailings. The active reaction components were determined through Gibbs free energy calculations. The study discusses the impact of different experimental parameters on the leaching rate of Ca2+ and the degree of mineralization in gold-copper tailings, and then considers the influence of different dispersants on improving the stability of vaterite. The results show that the optimal leaching efficiency of Ca2+ in the NH4Cl solution is 75%, and the optimal mineralization efficiency is 87%. Under appropriate mineralization conditions, vaterite CaCO3 with d50 < 12 μm, a purity of 98%, and a whiteness of 98.7% can be prepared. The precipitated vaterite is affected by the pH swing method connected with the neutralization reaction. The presence of excess NH3 and supersaturated CO2 are necessary for the formation of vaterite-type CaCO3. Morphological analysis results show that dispersants such as polyacrylamide and sodium tripolyphosphate can improve the dispersibility of vaterite, preventing agglomeration and enabling its stable existence in aqueous solutions. Nanoparticle aggregation and crystal growth are two possible mechanisms for the formation of vaterite. The leaching-mineralization cycle technology using NH4Cl as the leaching solution meets the requirements for CO2 removal and alkaline industrial waste residue treatment, while avoiding the significant consumption of chemical reagents in traditional mineralization. This method provides a pathway for producing vaterite using copper tailings and has a broad market prospect.

Sequential Catalytic Conversion of Methyl Oleate Into Short Chain Alkane and Alkene Compounds

Research on the conversion of methyl oleate (Methyl 9-octadecenoate) into shorter chain alkane compounds through the stages of methyl 9-octadecenoate into 1-octadecanol, 1-octadecanol into 1-octadecene and 1-octadecene into alkane compounds and short chain alkenes with a length of C12 &gt; have been done. The conversion process uses ZSiA and Ni/ZSiA catalysts which are placed in a fixed bed system reactor column and operated at temperatures of 400, 450 and 500 oC. ZSiA catalyst was made by washing natural zeolite with distilled water, soaking with 2 M HCl solution, adding 5% Na2SiO3 w/w, soaking with 2 M NH4Cl solution, calcining at a temperature of 500 oC while flowing nitrogen gas for two hours at a flow rate of 20 milliliters per minute; oxidation during a two-hour oxygen flow rate of 20 milliliters per minute; and impregnation of Ni metal onto the catalyst sample's surface using Ni(NO3)2 6H2O metal 2% w/w. Subsequently, reduction was done for two hours while hydrogen gas was flowing at a rate of 20 mL per minute. The resultant catalyst was subjected to various analyses, including AAS analysis for metal cation content, gravimetric analysis for acidity, NOVA 1000 surface area analyzer for specific surface area, and X-ray diffractometer (XRD, Shimadzu-6000) analysis for crystallinity

Adsorption Performance of Different Wetland Substrates for Ammonia Nitrogen: An Experimental Study

To investigate the adsorption performance of different substrates for ammonia nitrogen in wastewater, adsorption experiments are conducted on four substrates, namely, zeolite, quartz sand, volcanic rock, and biological ceramsite, and the experimental data are analyzed using adsorption isotherms and three kinetic models. The results show that with the increasing dosage of the substrates, the adsorption capacity gradually decreases, and the removal rate gradually increases. The removal rates all show a rapid increase in the early stage (the first 14 h) and gradually reach a stable state in the later stage (after more than 48 h). The higher the concentration of ammonia nitrogen in the NH4Cl solution, the greater the unit adsorption capacity of ammonia nitrogen by the substrate, the longer the adsorption time required to reach adsorption equilibrium, the lower the total removal rate of ammonia nitrogen, and the longer it takes for the concentration of ammonia nitrogen in the substrate and solution to reach equilibrium. The adsorption capacity of zeolite to ammonia nitrogen is much higher than that of quartz sand, biological ceramsite, and volcanic rock, so zeolite is suitable as the wetland substrate. The adsorption of ammonia nitrogen by the four substrates is principally multi-molecular layer adsorption, and the adsorption phase is heterogeneous.

Performance of Li exchange hierarchical X zeolite for CO2 adsorption and H2 separation

Li exchange hierarchical X zeolite (Li-H-X) was prepared by decationization of X zeolite by NH4Cl solution followed by Li exchange and subsequent calcination. NH4-X and Li-X were prepared to compare the results of Li-H-X. XRD, FE-SEM, EDS, N2 adsorption–desorption, and micro-/mesoporous volume were performed. The higher mesoporosity was confirmed in Li-H-X due to the framework dealumination during decationization. Static and dynamic sorption capacity of sorbents was evaluated to identify the performance of sorbent. The CO2 and H2 equilibrium adsorption capacity of Li-H-X was found to be 9.6 mmol g−1 and 0.78 mmol g−1, respectively, at 298 K and 20 bar, which was 25 % (CO2) and 30 % (H2) higher than Li-X. Static experimental data were validated using the Langmuir, Freundlich, and Sips models. The CO2 & H2 dynamic sorption capacity of Li-H-X sorbent for binary gas (CO2/H2, 25/75 %) was 4.145 mmol g−1 and 0.258 mmol g−1 at 303 K and 10 bar. The higher sorption capacity of Li-H-X was obtained due to large micro-/mesoporous volume of sorbent, which may allow to access unoccupied sites at higher pressure. This result reveals that micro-/mesoporous structure of zeolite adsorbs significantly higher CO2 from binary gas stream, which can use to separate pure H2 from gas stream.

Building Organic-Inorganic Robust Interphases from Deep Eutectic Solution for Highly Stable Mg Metal Anode in Conventional Electrolyte.

Magnesium metal batteries (MMBs) currently face challenges suffering from severe Mg metal passivation and extremely high overpotential in conventional electrolytes. Herein, a strategy of using a low-cost deep eutectic solution (DES) is proposed to modify Mg anode with the monolithic and compact coating of a MgCl2-Al-MgCl2 sandwich structure, enabling the stable and reversible Mg plating-stripping behavior. An organic/nanocrystal hybrid interphase is in-situ built through a facile Mg-Al displacement reaction between aluminum-chloro clusters and Mg in AlCl3/Et3NHCl solution, and it can effectively minimize the adverse interfacial passivation reaction and surface diffusion barrier, affording the high ion-conduction and electronic insulation. This DES-assisted method guarantees a highly reversible cycling of Mg metal anode (over 5000h at 0.1mA cm-2 and 400h at 2.0 mAh cm-2) in Mg(TFSI)2/DME electrolyte with the improved interfacial kinetics and low overpotential. Even at a much higher current density of 1mA cm-2, the overpotential only undergoes a slight increase from 0.2V (at 0.1mA cm-2) to 0.23V. The corresponding full cells with CuS and phenanthraquinone cathodes deliver satisfactory cyclic performance. The DES modification strategy provides a new solution to the design of robust and conductive solid electrolyte interphase for achieving high-voltage and durable MMBs.