吡唑基镁卤化物/四氢呋喃可充镁电池电解液

将不同配比的吡唑与格氏试剂反应制得的吡唑基镁卤化物/四氢呋喃（THF）溶液用作可充镁电池电解液,采用循环伏安和恒电流充放电测试研究了该电解液的镁沉积-溶出性能和氧化分解电位;并通过X射线衍射（XRD）和扫描电镜（SEM）对沉积物的组分和形貌进行了分析. 结果表明,吡唑上的取代基、吡唑与格氏试剂的反应配比对电解液的电化学性能都有影响. 1 mol·L^-1 1-甲基吡唑-PhMgCl（1：1摩尔比）/THF反应配制的电解液在不锈钢（SS）集流体的阳极氧化分解电位达到2.4 V（vs Mg/Mg²⁺）,并具有镁沉积-溶出电位低、循环稳定性高、配制方便的特点,有希望应用于实际的可充镁电池体系中.     

哌啶型离子液体混合电解液在Li/LiCoO2电池中的性能研究

合成并考察了N-甲基-N-乙（丙,丁）基哌啶-二( 三氟甲基磺酰) 亚胺三种离子液体( PP12（3,4）TFSI )作为电解液添加剂的影响. 使用热分析和电化学技术研究了离子液体混合电解液的热稳定性和电化学性能.实验表明,哌啶型离子液体可以提高有机电解液的热稳定性,并且侧链的长短对 LiCoO₂ 电极的电化学性能有重要的影响.当以PP13TFSI配成的混合电解液,在3.0~4.35 V之间、电流密度为150 mA•g^-1时, LiCoO₂ 电极的首次放电容量为156.6 mAh•g^-1,200周循环后容量为133.9mAh•g^-1,容量保持率为85.5%,远远优于在传统有机电解液中的循环性能.     

吡唑基镁卤化物/四氢呋喃可充镁电池电解液

将不同配比的吡唑与格氏试剂反应制得的吡唑基镁卤化物/四氢呋喃(THF)溶液用作可充镁电池电解液,采用循环伏安和恒电流充放电测试研究了该电解液的镁沉积-溶出性能和氧化分解电位;并通过X射线衍射(XRD)和扫描电镜(SEM)对沉积物的组分和形貌进行了分析.结果表明,吡唑上的取代基、吡唑与格氏试剂的反应配比对电解液的电化学性能都有影响.1 mol·L-11-甲基吡唑-PhMgCl(1:1摩尔比)/THF反应配制的电解液在不锈钢(SS)集流体的阳极氧化分解电位达到2.4 V(vs Mg/Mg2+),并具有镁沉积-溶出电位低、循环稳定性高、配制方便的特点,有希望应用于实际的可充镁电池体系中.     

五种1-烷基-2,3-二甲基咪唑型离子液体的合成及作为Li/LiFeO_4电池电解液的研究

合成了五种新的1-烷基-2,3-二甲基咪唑二(三氟甲基磺酰)亚胺离子液体(alkyl-DMimTFSI).以离子液体作为Li/LiFeO4电池电解液,分别考察不同烷基(正丁基、正戊基、正辛基、异辛基和正癸基)对电解液理化性质、界面性质和电池行为的影响.结果表明离子液体的电化学窗口都可以达到5.6V(-0.4～5.2Vvs.Li+/Li),显示它们具有较好的电化学稳定性.加入碳酸亚乙烯酯作为添加剂后,离子液体电解液在Li负极形成稳定的固体电解质相界面膜(SEI),从而提高了Li负极的稳定性,保护了Li片不受腐蚀.电化学阻抗和循环伏安分析进一步揭示LiFeO4正极与离子液体电解液也有良好的兼容性.此外,研究还表明离子液体中烷基种类严重影响它们的电池行为.采用butyl-DMimTFSI和amyl-DMimTFSI电解液体系的电池充放电容量和可逆性明显优于另外三种离子液体,它们的首次放电容量分别达到145和152.6mAh/g,并表现出良好的充放电循环性能.因粘度最大,采用isooctyl-DMimTFSI电解液的电池首次放电容量仅为8.3mAh/g,但添加碳酸丙烯酯(质量比1∶1)稀释后首次放电容量上升至132.4mAh/g.     

N-甲基-N-丁基吡咯烷溴化物和N-甲基-N-乙基吡咯烷溴化物在锌溴液流电池中应用

在锌溴液流电池中,作为溴络合剂在电解液中使用的季铵盐对电池性能及安全性具有重要作用.本文利用循环伏安法及线性扫描伏安法研究了N-甲基-N-丁基吡咯烷溴化物（N-methyl-N-butyl-pyrrolidinium bromide,MBP）和N-甲基-N-乙基吡咯烷溴化物（N-methyl-N-ethyl-pyrrolidinium bromide,MEP）分别加入到电解液后对电极反应的影响,通过交流阻抗（EIS）的方式测量了不同组成及浓度下的电解液电导率变化,测试了不同电解液对电池充放电性能的影响及溴络合能力,结果表明加入MBP的电解液具有更好的溴络合能力和电池性能.     

(PhMgCl)2-AlCl3在混合醚溶剂中的电化学性能研究

制备了全苯基有机铝镁盐(PhMgCl)2-AlCl3,研究以3种不同混合醚,即dimethoxyethane(DME)+THF、Diglyme(DG)+THF和Tetraglyme(TG)+THF作溶剂对全苯基有机铝镁盐在不同金属电极上的电化学性能的影响.结果表明,和(PhMgCl)2-AlCl3/THF体系相比,(PhMgCl)2-AlCl3/DG+THF(3:2)仍具有较高的离子电导率(1.605×10-3S.cm-1)、良好的可逆沉积镁特性及阳极抗氧化性能(电化学窗口>2.8 V).且该DG+THF混合溶剂还可大幅降低电解液的饱和蒸汽压(由23.46 kPa降低到9.41 kPa),减少了电池使用过程电解液的挥发,从而提高了可充镁电池的安全性能.比较Pt、Ni、Cu和Al等不同金属基质电极,发现Pt的电化学性能最好,而Al最差.     

离子液体凝胶聚合物电解质的三元组分相互作用研究

采用Raman光谱、傅里叶转换红外光谱和X-射线衍射光谱研究N-甲基-N-丙基哌啶双三氟甲磺酸亚胺离子液体（PP13TFSI）和双三氟甲磺酸亚胺锂盐（LiTFSI）对PVDF-HFP聚合物聚合方式的影响,结果表明,PP13TFSI、LiTFSI和PVDF-HFP是共混存在的,同时加入PP13TFSI和LiTFSI会使聚合物的聚合方式由晶体结构转变为无定形结构. 通过对电解质及其各组分的线性扫描伏安曲线和热重曲线分析可知,溶剂N-甲基吡咯烷酮（NMP）容易残留在凝胶聚合物电解质（ILGPE）中,这会降低ILGPE的电化学稳定性和热稳定性. 作者对固态LiFePO₄|ILGPE|Li电池的倍率性能进行了研究,实验结果表明其具有较好的倍率性能,当电池倍率由C/10增大至2C,然后再回到C/10时,其容量可以恢复到原来的90.9%左右. 该研究结果对理解PP13TFSI和LiTFSI在ILGPE中的作用机理具有重要的意义.     

咪唑离子液体作为流动相添加剂的整体柱离子对色谱快速分析哌啶阳离子

以咪唑离子液体作为流动相添加剂,建立了哌啶离子液体阳离子的整体柱离子对色谱-间接紫外检测分析方法。系统研究了流动相、流速等因素对哌啶阳离子分离测定的影响情况。流动相中的咪唑离子液体不仅起到了背景紫外吸收剂的作用,还改善了阳离子的分离效果。用0.5mmol/L 1-乙基-3-甲基咪唑四氟硼酸盐-0.1mmol/L庚烷磺酸盐水溶液(pH=4.5)/甲醇(90/10,V/V)作为流动相,流速3.0mL/min,检测波长210nm,N-甲基-N-乙基、N-甲基-N-丙基和N-甲基-N-丁基哌啶阳离子在3.0min之内实现基线分离。3种哌啶阳离子的检出限分别为0.13、0.34和0.42mg/L。该方法测定实验室合成的哌啶离子液体样品的加标回收率范围为94%~98%。     

疏水性咪唑类混合离子液体的物理化学性质

本文选取疏水性和疏水性离子液体混合物作为研究对象, 将疏水性离子液体1-甲基-3-n-丁基咪唑三氟甲基磺酰胺盐[BMImN(CF3SO2)2]与BMImPF6以不同的比例进行混合, 对混合离子液体及其相应单组分离子液体进行了相关物理化学性质的测试和对比, 讨论由于混合导致的物理化学效应.     

可充镁电池正极材料PTMA/石墨烯

本文制备了聚4-甲基丙烯酸-2,2,6,6-四甲基哌啶-1-氮氧自由基酯(PTMA)/石墨烯纳米复合材料,并报道了其作为可充镁电池正极材料的电化学性能.通过傅里叶变换红外(FTIR)光谱、扫描电镜(SEM)、透射电镜(TEM)表征复合材料的结构和形貌;循环伏安和恒电流充放电测试其电化学性能.粒径10 nm左右的PTMA颗粒分散在具有导电作用的石墨烯表面;在"一代"电解液Mg(AlCl2BuEt)2/四氢呋喃(THF)(0.25 mol L-1)中,22.8mA g-1充放电电流密度下,PTMA/石墨烯复合材料的起始放电容量可达到81.2 mAh g-1.研究结果表明,含有自由基的有机化合物可以作为可充镁电池的一类新型正极材料,可以进一步通过使用具有高氧化分解电压的电解液来提高其放电容量.     

Structural analysis of electrolyte solutions for rechargeable Mg batteries by stereoscopic means and DFT calculations

We present a rigorous analysis of unique, wide electrochemical window solutions for rechargeable magnesium batteries, based on aromatic ligands containing organometallic complexes. These solutions are comprised of the transmetalation reaction products of Ph(x)MgCl(2-x) and Ph(y)AlCl(3-y) in different proportions, in THF. In principle, these reactions involve the exchange of ligands between the magnesium and the aluminum based compounds, forming ionic species and neutral molecules, such as Mg(2)Cl(3)(+)·6THF, MgCl(2)·4THF, and Ph(y)AlCl(4-y)(-) (y = 0-4). The identification of the equilibrium species in the solutions is carried out by a combination of Raman spectroscopy, multinuclear NMR, and single-crystal XRD analyses. The association of the spectroscopic results with explicit identifiable species is supported by spectral analyses of specially synthesized reference compounds and DFT quantum-mechanical calculations. The correlation between the identified solution equilibrium species and the electrochemical anodic stability window is investigated. This study advances both development of new nonaqueous solution chemistry and possible development of high-energy density rechargeable Mg batteries.     

集流体对可充镁电池电解液电化学性能的影响

系统研究了铂、镍、不锈钢(SS)、铜、铝五种金属集流体和碳纤维、石墨箔、碳布三种碳纸集流体对“一代” (Mg(AlCl₂BuEt)₂/THF)、“二代” ((PhMgCl)₂-AlCl₃/THF)可充镁电池电解液阳极氧化分解电位和镁沉积-溶出性能的影响。金属镍、不锈钢、铜、铝作为可充镁电池正极的集流体时, 充电至一定电压时自身均会发生腐蚀。其中, 镍和不锈钢可用作充电电压在2.1V(vs Mg/Mg²⁺)以下正极材料的集流体; 铜可用作充电电压在1.8V(vs Mg/Mg²⁺)以下正极材料的集流体。碳集流体比金属集流体具有更高的稳定性, 其中, 碳布作为集流体, 适用于充电电压在2.25V(vs. Mg)(对“一代”电解液)和2.95V(vs Mg/Mg²⁺)(对“二代”电解液)以下的正极材料。     

Amide-Based Ionic Liquid Electrolytes for Alkali-Metal-Ion Rechargeable Batteries

Ionic liquids (ILs) have a wide variety of applications in energy storage and material production. ILs are composed of only cations and anions, without any molecular solvents, and are generally known as “designer liquids (solvents)” because their physicochemical properties can be tuned by the combination of ionic species. In recent several decades, research and development activities of rechargeable batteries have garnered considerable attention because certain groups of ILs exhibit high electrochemical stability and moderate ionic conductivity, rendering them suitable for application in high-voltage batteries. ILs with amide anions are representative electrolytes and are extensively researched by many research groups, including our group. This paper focuses on amide-based ILs as electrolytes for alkali-metal-ion rechargeable batteries, introducing their history, characteristics, and existing challenges to be addressed.     

苯硫酚盐基溶液的可充镁电池电解液

将4-甲基苯硫酚、4-异丙基苯硫酚和4-甲氧基苯硫酚(RSH)分别与格氏试剂C₂H₅MgCl/THF(四氢呋喃)反应制得的苯硫酚氯化镁(RSMgCl)(分别标记为MBMC、IPBMC和MOBMC)/THF和进一步与Lewis 酸AlCl₃反应制得的(RSMgCl)_n-AlCl₃/THF(n=1,1.5,2)苯硫酚盐基溶液用作可充镁电池电解液,采用循环伏安和恒电流充放电测试研究了电解液的镁沉积-溶出性能和氧化分解电位. 结果表明,苯硫酚上的基团种类和RSMgCl与AlCl₃的比例对其电化学性能有影响. 其中,0.5 mol·L^-1(IPBMC)_1.5-AlCl₃/THF 溶液具有最佳的电化学性能,其氧化分解电位适宜(2.4 V(vs Mg/Mg²⁺)),镁沉积-溶出循环效率稳定,过电位低,电导率较高(2.48 mS·cm^-1),与正极材料Mo₆S₈兼容性良好,且具有一定的空气稳定性,配制方便,有希望应用于实际的可充镁电池体系中.     

Reversible S0/MgSx Redox Chemistry in a MgTFSI2/MgCl2/DME Electrolyte for Rechargeable Mg/S Batteries

The redox chemistry of magnesium and its application in rechargeable Mg batteries has received increasing attention owing to the unique benefits of Mg metal electrodes, namely high reversibility without dendrite formation, low reduction potentials, and high specific capacities. The Mg/S couple is of particular interest owing to its high energy density and low cost. Previous reports have confirmed the feasibility of a rechargeable Mg/S battery; however, only limited cycling stability was achieved, and the complicated procedure for the preparation of the electrolytes has significantly compromised the benefits of Mg/S chemistry and hindered the development of Mg/S batteries. Herein, we report the development of the first rechargeable Mg/S battery with a MgTFSI₂/MgCl₂/DME electrolyte (DME=1,2‐dimethoxyethane, TFSI=bis(trifluoromethanesulfonyl)imide) and realize the best cycling stability among all reported Mg/S batteries by suppressing polysulfide dissolution. Mechanistic studies show that the battery works via S⁰/MgS_x redox processes and that the large voltage hysteresis is mainly due to the Mg anode overpotential.     

Alkali and alkaline-earth metal ion–solvent co-intercalation reactions in nonaqueous rechargeable batteries

Alkali and alkaline-earth metal ion–solvent co-intercalation reactions have attracted extensive attention in recent years owing to the advantage of the absence of a desolvation process, which generally results in fast kinetics and good rate performance for batteries. However, less attention has been paid to summarizing the mechanism, performance and other related aspects about ion–solvent co-intercalation reaction in batteries. A summary of alkali and alkaline-earth metal ion–solvent co-intercalation reactions in nonaqueous rechargeable batteries is presented in this review, which mainly focuses on the electrochemical performance, ion–solvent co-intercalation mechanism, conditions for reversible ion–solvent co-intercalation and potential for practical application. It is suggested that future research should focus on reducing the redox potential of the ion–solvent co-intercalation reaction to achieve high energy-density and power-density full cells. This review provides an understanding of alkali and alkaline-earth metal ion–solvent co-intercalation reactions in nonaqueous rechargeable batteries and will serve as significant guidance for researchers to further develop ion–solvent co-intercalation reactions for fast-charging batteries.

This review summarizes the recent progress of alkali and alkaline-earth metal ion–solvent co-intercalation reactions in nonaqueous rechargeable batteries.     

Polyether-functionalized disiloxanes as new film-forming electrolyte additive for Li-ion cells with graphitic anodes

New type of film-forming electrolyte additive (functional co-solvent) for rechargeable lithium batteries has been demonstrated. The additive prevents solvent co-intercalation and graphite exfoliation in propylene carbonate based electrolytes. The additive performs best at 15% w/w ratio and is a mixture of homologous disiloxanes functionalized with polyether side chains of variable length. Galvanostatic and potentiodynamic charge/discharge characteristics are presented. SEM/EDX analysis has been carried out to evidence the suppression of PC co-intercalation.     

Fluorine and Lithium: Ideal Partners for High‐Performance Rechargeable Battery Electrolytes

Further enhancement in the energy densities of rechargeable lithium batteries calls for novel cell chemistry with advanced electrode materials that are compatible with suitable electrolytes without compromising the overall performance and safety, especially when considering high‐voltage applications. Significant advancements in cell chemistry based on traditional organic carbonate‐based electrolytes may be successfully achieved by introducing fluorine into the salt, solvent/cosolvent, or functional additive structure. The combination of the benefits from different constituents enables optimization of the electrolyte and battery chemistry toward specific, targeted applications. This Review aims to highlight key research activities and technical developments of fluorine‐based materials for aprotic non‐aqueous solvent‐based electrolytes and their components along with the related ongoing scientific challenges and limitations. Ionic liquid‐based electrolytes containing fluorine will not be considered in this Review.