Hybrid solid electrolyte interphases formed in conventional carbonate electrolyte enable high-voltage and ultra-stable magnesium metal batteries

Magnesium metal batteries are considered as viable alternatives of lithium-ion batteries for their low cost and high capacity of magnesium.Nevertheless,the practical application of magnesium metal batteries is extremely challenging due to a lack of suitable electrolyte that can stabilize magnesium metal anode and high-voltage cathode simultaneously.Herein,we found that in-situ formed lithium/magnesium hybrid electrolyte interphases in conventional LiPF6-containing carbonate-based electrolyte can not only prevent the production of passivation layer on the magnesium metal anode,but also inhibit the oxidation of the electrolyte under high voltage.The symmetric magnesium‖magnesium battery can achieve reversible stripping/plating for 1600 and 600 h at 0.02 and 0.1 mA cm^(-2),respectively.In addition,when coupled with a carbon fiber cathode,the magnesium metal battery exhibited a capacity retention rate of 96.3% for 1000 cycles at a current density of 500 mA g^(-1)and presented a working voltage of ~3.1 V.This research paves a new and promising path to the commercialization process of rechargeable magnesium metal batteries.

Balanced Fracturing and Cold-welding of Magnesium during Ball Milling Assisted by Carbon Coating:Experimental and Molecular Dynamic Simulation

The lignite-derived carbon from self-protection pyrolysis was employed to balance the fracturing and cold-welding of magnesium during ball milling.Particle size analysis indicates that the introduction of lignite-derived carbon can effectively reduce the particle size of Mg while the introduction of graphite does no help.Besides,the effect of lignite-derived carbon on crystallite size reduction of Mg is also better than graphite.A moderate cold-welding phenomenon was observed after ball-milling Mg with the lignite-derived carbon,suggesting less Mg is wasted on the milling vials and balls.Molecular dynamic simulations reveal that the balanced fracturing and cold-welding of magnesium during ball milling is mainly attributed to the special structure of the lignite-derived carbon:graphitized short-range ordered stacking function as dry lubricant and irregular shape/sharp edge function as milling aid.The preliminary findings in current study are expected to offer implications for designing efficient Mg-based hydrogen storage materials.

Separation of manganese from calcium and magnesium in sulfate solutions via carbonate precipitation

The separation of manganese from sulfate solutions containing 14.59 g/L Mn2+, 1.89 g/L Mg2+ and 1.54 g/L Ca2+ was preformed successfully by carbonate precipitation. The results of thermodynamic analysis and tests indicate that carbonate precipitation holds better selectivity for manganese over magnesium than hydroxide precipitation and the feeding method is the most critical factor for minimizing the co-precipitation of calcium and magnesium. Furthermore, with adding MnSO4 solution to NH4HCO3 solution, the effects of the initial NH4HCO3 concentration, NH4HCO3 amount, solution pH value, reaction temperature and time on carbonate precipitation were evaluated and the optimum precipitation conditions were obtained. Under the optimum conditions, the precipitation rates of Mn2+, Ca2+ and Mg2+ are 99.75%, 5.62% and 1.43%, respectively. Moreover, the prepared manganese carbonate was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX). The results demonstrate that the product can be indexed to the rhombohedral structure of MnCO3.

Synthesis of cyclic carbonates from epoxides and CO_2 in acetonitrile via the synergistic action of BMIMBr and electrogenerated magnesium

Using 1-butyl-3-methyl-imidazolium bromide （BM1MBr） as the supporting electrolyte and magne- sium as the sacrificial anode, a new and highly efficient electrochemically catalytic route was devel- oped for the synthesis of cyclic carbonates from epoxides and CO2. Based on the cooperative action of BMIMBr and an electrogenerated magnesium salt obtained under a N2 atmosphere, CO2 reacted with a wide range of epoxides to readily generate cyclic carbonates in moderate to excellent yields under mild conditions.

Effects of Temperature on the Preparation of Magnesium Carbonate Hydrates by Reaction of MgCI2 with Na2CO3

Homogeneous(unseeded)precipitation of magnesium carbonate hydrates by the reaction of MgCl2 with Na2CO3 in supersaturated solutions between 273 and 363K was investigated.The compositions,morphologies and filtration characteristics of the precipitates were studied in detail.The magnesium carbonate hydrates obtained at 313K and in the range of 343-363K showed good morphologies and filtration characteristics.Magnesium oxides(MgO)with high purity(97.6%-99.4%)were obtained by calcining magnesium carbonate hydrates at 1073K.

Efficient Solvent-free Synthesis of Chloropropene Carbonate from the Coupling Reaction of CO_2 and Epichlorohydrin Catalyzed by Magnesium Porphyrins as Chlorophyll-like Catalysts

Highly efficient solvent-free coupling reaction of carbon dioxide(CO2)and epichlorohydrin catalyzed by meso-tetraphenyl porphyrin magnesium(MgTPP)in the presence of triethylamine as co-catalysts is reported.As a chlorophyll-like catalyst,MgTPP showed excellent activity for the coupling reaction of CO2 and epichlorohydrin to chloropropene carbonate,in which the turnover number could reach up to 9200.Moreover,different factors including the amount of catalyst,reaction temperature,pressure and time were systematically investigated and the optimal reaction conditions were obtained(epichlorohydrin 50 mmol,MgTPP 5.0×10- 3mmol,triethylamine 6.25×10-3 mmol,140°C,1.5 MPa,8 h).A plausible two-pathway mechanism for the coupling reaction of CO 2and epichlorohydrin is proposed to propound the catalysis of MgTPP.

Preparation and growth mechanism of plate-like basic magnesium carbonate by template-mediated/homogeneous precipitation method

In order to expand the application of the basic magnesium carbonate in the field of flame retardant,the plate-like basic magnesium carbonate(Mg5(CO3)4(OH)2.4H2O)was prepared successfully by template-mediated/homogeneous precipitation method,using magnesium chloride hexahydrate(MgCl2.6H2O)and urea(CO(NH2)2)as reaction materials.Phase and morphology of the product were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and atomic force microscope(AFM),respectively.The results showed that well-crystallized plate-like Mg5(CO3)4(OH)2.4H2O can be prepared at the water bath temperature of 100°C,water bath time of 24 h,the aging time of 5 h after adding organic template agent.The investigation on organic template mediated mechanism shows that the template affects the crystal morphology by changing surface energy of different crystal plane.Through a preliminary study on the growth mechanism of the product,it is found that the generation of the plate-like Mg5(CO3)4(OH)2.4H2O could be explained by two-dimensional nucleation/step growth mechanism.

Preparation of basic magnesium carbonate and its thermal decomposition kinetics in air

The thermal decomposition process of basic magnesium carbonate was investigated. Firstly, Basic magnesium carbonate was prepared from magnesite, and the characteristics of the product were detected by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Subsequently, the thermal decomposition process of basic magnesium carbonate in air was studied by thermogravimetry-differential thermogravimetry （TG-DTG）. The results of XRD confirm that the chemical composition of basic magnesium carbonate is 4MgCO3·Mg（OH）2·4H2O. And the SEM images show that the sample is in sheet structure, with a diameter of 0.1-1 μm. The TG-DTG results demonstrate that there are two steps in the thermal decomposition process of basic magnesium carbonate. The apparent activation energies （E） were calculated by Flyrm-Wall-Ozawa method. It is obtained from Coats-Redfem＇s equation and Malek method that the mechanism functions of the two decomposition stages are D3 and A1.5, respectively. And then, the kinetic equations of the two steps were deduced as well.

Reversible Magnesium Metal Anode Enabled by Cooperative Solvation/Surface Engineering in Carbonate Electrolytes

Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry enable the reversible Mg plating/stripping,while they fail to match most cathode materials toward highvoltage magnesium batteries. Herein,reversible Mg plating/stripping is achieved in conventional carbonate electrolytes enabled by the cooperative solvation/surface engineering. Strongly electronegative Cl from the MgCl_(2) additive of electrolyte impairs the Mg…O = C interaction to reduce the Mg^(2+) desolvation barrier for accelerated redox kinetics,while the Mg^(2+)-conducting polymer coating on the Mg surface ensures the facile Mg^(2+) migration and the e ective isolation of electrolytes. As a result,reversible plating and stripping of Mg is demonstrated with a low overpotential of 0.7 V up to 2000 cycles. Moreover,benefitting from the wide electrochemical window of carbonate electrolytes,high-voltage(> 2.0 V) rechargeable magnesium batteries are achieved through assembling the electrode couple of Mg metal anode and Prussian blue-based cathodes. The present work provides a cooperative engineering strategy to promote the application of magnesium anode in carbonate electrolytes toward high energy rechargeable batteries.

Carbon nanotube and graphene reinforced magnesium matrix composites:A state-of-the-art review

Magnesium(Mg)composites reinforced with carbon-based nanomaterial(CBN)often exhibit low density,enhanced strength,good conductivity,improved wear resistance,and excellent biocompatibility when compared to current industry Mg alloys.This review aims to critically evaluate recent developments in Mg-CBN composites and is divided into five sections:First,a brief introduction to Mg-CBN composites is provided,followed by a discussion of different fabrication techniques for these composites,including powder metallurgy,casting,friction stir processing,and selective laser melting.A particular focus is on the current processing challenges,including dispersion strategies to create homogeneous Mg-CBN composites.The effect of processing on the quantifying disorder in CBNs and distinguishing different sp2carbon materials is also highlighted.Then,the effect of CBN on various properties of Mg-CBN composites is thoroughly analyzed,and the strengthening efficiency of CNTs and graphene in the Mg matrix is examined.Finally,the potential applications of Mg-CBN composites in various industries are proposed,followed by a summary and suggestions for future research directions in the field of Mg-CBN composites.

Prepartion of Flake-Like Basic Magnesium Carbonate from the Ammonium Sulfte Leaching Liquid of Asbestos Tailing

The flake-like basic magnesium carbonate was prepared from the ammonium sulfate leaching liquid of asbestos tailings. The method of X-ray diffraction, Fourier transform infrared spectra, TA-DTG and SEM analysis had been used to research the influence of the reaction temperature on the phase, structure and morphology of the product during the preparation of the basic magnesium carbonate. The results indicates that the product was needle-like magnesium carbonate hydrate at the lower reaction temperature (from 35 ℃ to 65℃), with the increase of the reaction temperature (75 ℃ to 95 ℃ ), the needle-like magnesium carbonate hydrate (MgCO3·xH2O) transformed to flake-like basic magnesium carbonate [Mg5(CO3)4(OH)2·4H2O], the reaction temperature plays an important role in the preparation of flake-like basic magnesium carbonate, the preparation of flake-like basic magnesium carbonate was a nucleation-dissolution-recrystallization growth mechanism process.

Cytotoxicity,in Vivo Skin Irritation and Acute Systemic Toxicity of the Mesoporous Magnesium Carbonate Upsalite^(█)

Upsalite®is a mesoporous magnesium carbonate synthesized without using surfactants and therefore highly attractive from environmental and production economy points of view. The material has recently been suggested as drug delivery vehicle and as topical bacteriostatic agent. In order to continue exploring these and other bio-related applications of the material, primary biocompatibility studies are needed. Herein we present the first in vivo acute systemic toxicity and skin irritation analyses as well as in vitro cytotoxicity evaluations of Upsalite®. The material was found to be non-toxic for human dermal fibroblasts cells up to a concentration of 1000 μg/ml and 48 h exposure in contrast to the mesoporous silica material SBA-15, used as reference, which significantly affected cell viability at particle concentration of 500 and 1000 μg/ml after the same exposure time. Topical application of Upsalite®resulted in negligible cutaneous reactions in a rabbit skin irritation model and no evidence of significant systemic toxicity was found when saline extracts of Upsalite®were injected in mice. Injection of sesame oil extract, however, resulted in transient weight loss, most likely due to injection of particles, and not toxic leachables. The presented results form the basis for future development of Upsalite®and similar mesoporous materials in biomedical applications and further toxicity as well as biocompatibility studies should be directed towards specific areas of use.

Influence of Composts on Agrochemical Properties of Soils of Zarafshan Valley, Salted with Magnesium Carbonates and Yield Capacity of Corn

Peculiar characteristics of soils of Zarafshan valley are salinity with carbonates. It is recommended to introduce large amount of manure or other organic fertilizers in these soils to improve soil reclamation. But currently there is no possibility to collect so many organic fertilizers in Uzbekistan. That is why other ways of production of organic fertilizers for improving soil fertility were searched. In the experiment, the influence of composts was studied, which prepared from tobacco wastes and manure on agrochemical properties of soils of Zarafshan valley, and production of composts from these industrial wastes, two salted with magnesium carbonates and yield-capacity of com. With the problems that exist in Uzbekistan can be solved at once. These include problems of environmental contamination through wastes and ensuring with organic fertilizers in the irrigated soils. Introduction of composts in the doze of 30 t.ha1 separately and on the background of mineral-NPK （nitrogen, phosphorus and potassium） fertilizers increased the humus content, total NPK and mobile nutritious substances in soil. It is proved that composts, prepared from tobacco wastes with their effect on the yield capacity and quality ofcoru production, can successfully substitute manure. Composts positively influence on the balance of nutritious substances in the system of soil-corn.

A green route for the preparation of layered double hydroxides from basic magnesium carbonate

Layered double hydroxides(LDHs)have received extensive attention in many fields such as catalysis,environmental management and medical applications.Typically,expensive soluble metal salts are commonly used as the starting materials for the synthesis of LDHs.Here,we report a novel synthesis route for Mg/Al-LDH by using inexpensive basic magnesium carbonate as the starting material.X-ray diffraction(XRD)and solid-state nuclear magnetic resonance(ssNMR)data show that LDHs with rich defects are formed rapidly at room temperature and good crystallinity can be obtained after further hydrothermal treatment.These results provide a simple,rapid and green preparation method for LDHs.

Influence of recycled carbon fiber addition on the microstructure and creep response of extruded AZ91 magnesium alloy

In this study,the recycled short carbon fiber(CF)-reinforced magnesium matrix composites were fabricated using a combination of stir casting and hot extrusion.The objective was to investigate the impact of CF content(2.5 and 5.0 wt.%)and fiber length(100 and 500μm)on the microstructure,mechanical properties,and creep behavior of AZ91 alloy matrix.The microstructural analysis revealed that the CFs aligned in the extrusion direction resulted in grain and intermetallic refinement within the alloy.In comparison to the unreinforced AZ91 alloy,the composites with 2.5 wt.%CF exhibited an increase in hardness by 16-20%and yield strength by 5-15%,depending on the fiber length,while experiencing a reduction in ductility.When the reinforcement content was increased from 2.5 to 5.0 wt.%,strength values exhibited fluctuations and decline,accompanied by decreased ductility.These divergent outcomes were discussed in relation to fiber length,clustering tendency due to higher reinforcement content,and the presence of interfacial products with micro-cracks at the CF-matrix interface.Tensile creep tests indicated that CFs did not enhance the creep resistance of extruded AZ91 alloy,suggesting that grain boundary sliding is likely the dominant deformation mechanism during creep.

Unveiling the Carbonation Behavior and Microstructural Changes of Magnesium Slag at 0℃

Magnesium slag(MS)is an industrial byproduct with high CO_(2)sequestration potential.This study investigates the carbonation behavior and microstructural changes of MS during wet carbonation at 0℃.XRD,TG,FTIR,SEM,and BET techniques were used to characterize the phase composition,microstructure,and porosity of MS samples carbonated for different durations.The results showed that the main carbonation products were calcite,vaterite,and highly polymerized silica gel,with particle sizes around 1μm.The low-temperature environment retarded the carbonation reaction rate and affected the morphology and crystallization of calcium carbonate.After 480 min of carbonation,the specific surface area and porosity of MS increased substantially by 740%and 144.6%,respectively,indicating improved reactivity.The microstructure of carbonated MS became denser with calcite particles surrounded by silica gel.This study demonstrates that wet carbonation of MS at 0℃significantly enhances its properties,creating an ultrafine supplementary cementitious material with considerable CO_(2)sequestration capacity.

盾构淤泥质废弃黏土氧化镁固化-碳化试验及碳化机制研究

盾构隧道施工产生的废弃土面临堆放、运输及处理等难题,将原材料丰富、生产耗能少、环境友好的MgO用于废弃土固化处理是一个值得探索的方法。通过改变MgO掺量a_(m)、养护龄期T、碳化时间H研究MgO固化-碳化淤泥质废弃黏土界限含水率w、无侧限抗压强度q_(u)、弹性模量E_(50),结合微观形貌及矿物成分变化规律探讨其固化-碳化机制。结果表明:MgO固化-碳化具有明显的加固土体效果,加固效果随a_(m)、T呈先上升后趋于稳定的趋势,随H呈先上升后下降的趋势;不同a_(m)、T下,碳化4h会使土体塑性指数I_(P)降低57%以上,土体可塑性显著下降;不同a_(m)和T的固化-碳化土q_(u)均在H为4h时取得峰值,最高可达1.4MPa,比碳化前强度提升了220%~350%;固化-碳化反应对土体的E_(50)提升受a_(m)影响较大,当a_(m)超过9%时,碳化4h试样的E_(50)增幅在500%左右;MgO固化-碳化过程中水化产物、碳化产物不断生成和发育,形成网状、花朵聚集状的形貌,填充土颗粒间的孔隙,增强了土颗粒间的胶结作用,土体结构更为密实。该研究为长三角地区土压盾构产生的淤泥质废弃黏土的固化-碳化处理与再利用提供了思路。

基于Giannakoopulou模型的MWCNT/GF/EP复合材料微波吸收性能研究

探究了加入不同质量分数多壁碳纳米管的多壁碳纳米管/玻璃纤维/环氧树脂复合材料在X波段的电磁波吸收性能,基于Giannakoopulou模型引入透波层,研究了吸波层和透波层两者的比例和分布状态对吸波材料整体的吸波性能影响。结果表明,加入多壁碳纳米管质量分数为2%的多壁碳纳米管/玻璃纤维/环氧树脂复合材料在厚度为3.0 mm时,最大反射损耗为-44.5 dB,有效吸收带宽为3.3 GHz(8.2~11.5 GHz);通过合理设计吸波层和透波层两者的比例和分布状态,得到具有不同有效吸收带宽和吸收损耗峰值的吸波材料,反射损耗峰值最高达到-62.1 dB,有效吸收带宽为3.1 GHz。

气候变化透明度机制的新发展及中国应对

透明度机制作为全球气候治理体系中的基础性程序机制,在全球气候行动中发挥着不可替代的作用。透明度机制经过几十年的变迁,与全球气候治理体系的联系愈发紧密,同时也暴露出不足。对发展中国家的支助力度不足、技术专家审评效率与审评任务不匹配、缺乏对于非国家行为体的关注、全球碳核算体系不统一等问题均制约着全球气候治理行动的推进。中国作为肩负减排重任的排放大国应积极应对:完善中国的碳数据核算体系并提高中国编制清单报告的能力,按时完成透明度框架所赋予的程序义务;在气候谈判中坚持共同但有区别的责任原则,提升中国在气候治理领域的话语权;积极与发展中国家和非国家行为体开展合作,提升中国应对气候变化的能力。

云南某含碳低磷中镁高硅磷矿浮选实验研究

云南某磷矿呈深灰色,矿石中含有无机碳源(石墨),w(P_(2)O_(5))为19.50%,w(MgO)为3.48%,w(SiO_(2))为30.41%,属低磷中镁高硅磷矿。采用一次脱碳浮选、一次脱硅粗选,一次脱硅扫选,一次脱镁浮选、脱硅扫选中矿返回脱硅粗选的闭路工艺,可以得到精矿w(P_(2)O_(5))为28.81%,P_(2)O_(5)回收率为57.75%的选别指标,实现了该类磷矿资源的有效回收,为同类矿产资源回收利用提供了借鉴。