低共熔溶剂在电池和电催化中的应用

绿色且高效的电池和电催化反应是可持续发展的基本要求,其关键因素之一在于选择能提高效率的绿色电解质和合成高效电极材料的绿色溶剂。低共熔溶剂(DESs)是一种新型环境友好的电解质和溶剂。与传统的溶剂和电解质(如离子液体、水、超临界二氧化碳)相比,DESs具有合成简便、价格低廉、可设计等优点,在电池和电催化领域有着广阔的应用前景。这方面的研究还处于起步阶段,未见有综述系统介绍。本综述内容包括以下几个部分。(1) DESs作为电池和电催化反应的电解质,其中电池包括太阳能电池、锂离子电池、钠电池、锌电池、铝电池、液流电池、超级电容器,电催化反应包括析氧反应、析氢反应、氧还原反应、全解水反应、氮气电催化反应、二氧化碳电还原反应;(2) DESs作为制备电池和电催化反应电极材料的溶剂;(3) DESs作为回收电极材料的溶剂;(4)结论和展望。     

ChCl-urea-ZnO低共熔溶剂体系的电化学行为

研究了ChCl-urea-ZnO低共熔溶剂（DES）体系的电化学行为与ZnO浓度的相互关系。电导率测定结果表明,ChCl-urea-ZnO体系的电导率随ZnO浓度的增加而增大,但当ZnO浓度超过0.24 mol·L^-1,体系电导率趋于稳定。随着温度的升高,ChCl-urea-ZnO的电导率增大,电导率与温度的关系符合Kohlraush经验公式。循环伏安测试结果表明,在ChCl-urea-ZnO低共熔体系中,Zn（Ⅱ）还原为金属锌是受扩散控制的准可逆过程,Zn（Ⅱ）的扩散系数约为1.2×10^-7 cm²·s^-1。而且金属锌的析出电位随ZnO浓度的增加而正移,峰值电流明显增大,说明增大ZnO浓度有利于锌的沉积。此外,ZnO浓度对锌沉积层的形貌有明显影响,不同ZnO浓度下得到锌沉积物的形貌各不相同,有短棒状、方形等。     

低共熔溶剂在废旧锂离子电池正极材料回收中的研究进展

大规模储能与电动汽车市场的发展壮大对锂离子电池的需求水涨船高,由此产生的废旧锂离子电池数量也即将迎来爆发式增长。废旧锂离子电池正极材料蕴含丰富的锂、钴、镍、锰等有价金属元素,回收经济价值高,环境效益显著。低共熔溶剂（DESs）作为一种绿色溶剂,在废旧锂离子电池有价金属元素回收方面显示出巨大的潜力。本文在简要介绍DESs性质及应用的基础上,系统综述了DESs在废旧锂离子电池正极材料回收链中的研究现状,主要包括正极材料的分离、活性物质的浸出以及有价金属的提取,着重介绍了现阶段回收的方法及工艺流程,比较了不同DESs浸出正极活性物质的优缺点,探讨了当前DESs在废旧锂离子电池回收中的共性问题,并展望了未来DESs回收锂离子电池的发展方向。     

低共熔溶剂中温度对钒离子氧化还原特性的影响

相比于传统水系电解质,低共熔溶剂（DES）因其所具有的独特优势,越来越多地被作为液流电池的电解液进行研究。DES的物理属性和电化学特性对温度较为敏感,但迄今为止对其研究较少。报道了温度对VCl₃在DES中的物理化学特性的影响。在100 mV·s^-1的扫速时,循环伏安（CV）曲线说明在25℃时,钒离子呈现准可逆的状态;随着温度从室温升高至55℃,氧化峰与还原峰之差从0.271 V降低至0.249 V。随着温度的增加,电导率也明显增加,从室温时的2.2 mS·cm^-1升高至55℃时的11.16 mS·cm^-1,而且黏度出现较大的下降。结果表明温度对DES特性的影响巨大,有必要更加深入研究温度对非水系电解液液流电池性能的影响。     

低共熔溶剂及其应用的研究进展

简述了低共熔溶剂的分类、性质,综述了低共熔溶剂在化学反应、电化学和分离领域的应用,并对低共熔溶剂的发展趋势进行了展望。     

COSMO-RS模型在离子液体/低共熔溶剂筛选中的应用研究进展

离子液体(ILs)和低共熔溶剂(DESs)作为一类新型的绿色溶剂,由于其独特的物理化学性质,在混合物分离方面已经受到了研究者的广泛关注,因此逐渐成为绿色化学领域的研究重点。针对特定的分离过程,选择合适的溶剂是非常重要的,然而,由于ILs和DESs种类较多,结构复杂,通过实验的方法逐一进行筛选费时费力、成本高,且几乎不可能找到最优选择,因此应用理论计算模型对ILs和DESs进行筛选是非常有必要的。真实溶剂类导体屏蔽模型(COSMO-RS模型)是一种由量子化学计算与统计热力学方法相结合的预测模型,它可以在不需要实验数据的情况下预测液体混合物的热力学性质,已经被研究者广泛用作各种分离问题的快速筛选工具。整理了应用COSMO-RS模型筛选ILs/DESs用于各种油中酚类、含氮化合物、含硫化合物、萜类化合物、天然维生素E的萃取分离,以及CO₂捕获和共沸混合物等的分离过程,表明COSMO-RS模型用于特定混合物萃取溶剂的筛选是快速有效的,可为难分离混合物分离过程中ILs/DESs的预筛选提供有价值的参考。     

ChCl-Urea低共熔溶剂中电沉积锌的工艺研究

在摩尔比为1:2的氯化胆碱-尿素低共熔溶剂(ChCl-Urea DES)中于纯铜基体表面制备了锌镀层.通过调整沉积电位、沉积温度和锌盐配比等参数,采用正交实验优化了电沉积工艺,并通过动电位极化曲线对比研究了ChCl-Urea DES和传统水溶液中锌镀层的耐蚀性能.采用扫描电子显微镜(SEM)和X-射线衍射技术(XRD)对ChCl-Urea DES中锌镀层的微观形貌和物相组成进行了表征.结果表明,在摩尔比为1:2的ChCl-Urea DES中锌电沉积的最佳方案为沉积电位1.0 V、锌盐配比2ZnCl2:1ZnO(摩尔比)、沉积温度70℃.在此方案下可获得均匀平整,颗粒致密的锌镀层,且其耐蚀性与传统水溶液相当.SEM表明,锌镀层是由排列紧密的六方形立体结构的灰白色颗粒物质构成.XRD表明,锌镀层主要由六方结构的多晶锌组成.     

离子液体基低共熔溶剂在转化CO2中的应用

CO₂作为一种温室气体,是一种宝贵的C₁资源,为实现“碳达峰、碳中和”战略目标,大力发展二氧化碳利用与封存技术是当务之急。离子液体是由有机阳离子和有机或无机阴离子组成的绿色溶剂,而低共熔溶剂是由氢键受体和氢键供体通过氢键形成的一种新型的溶剂。离子液体基低共熔溶剂不仅拥有离子液体相似的性质,如低饱和蒸气压、宽液温范围、高热化学稳定性、结构性能可调控等,还具备了低共熔溶剂的氢键特性。本文综述了离子液体基低共熔溶剂在CO₂热催化、电催化、生物催化领域的应用,并分析了各种催化方式中的CO₂转化机理和影响因素,展望了低共熔溶剂应用于转化CO₂的前景,对目前该领域的发展所面临的主要问题和进一步的研究工作提出了建议。     

低共熔溶剂预处理提高甘草渣酶解效果优化

近年来,低共熔溶剂（deep eutectic solvent,DES）以易制备、成本低、易回收等优势,在生物质预处理方面受到广泛关注。本研究以氯化胆碱为氢键受体,乙醇胺为氢键供体,合成DES,研究了不同温度、时间和固液比预处理条件对中药渣组分和酶解效果的影响。结果表明：固液比1∶20、120℃、预处理4h后原料中木质素去除率达到78.42%,纤维素回收率为83.89%。随后对不同条件下所得底物进行酶水解,反应96h后发现,较优条件下所得底物酶解效率为78.57%,较未处理中药渣（30.40%）提高了1.58倍。类分形动力学分析表明,预处理温度对酶解效果影响最大。SEM、XRD和FTIR检测发现,预处理后底物形貌、结晶指数和官能团变化有利于酶解效果的提高。     

全钒液流电池电解液流场结构优化设计

全钒液流电池电解液流场结构合理可使电流密度、钒电解液分布均匀,降低极化,提高电池性能。设计3种不同的电解液流场,研究流场结构对电池极化、充放电电流电压、功率密度和能量效率的影响。结果表明蛇形流场结构简单且易于加工,可使钒电解液均匀分布,增强电解液对流传质能力,能较充分利用钒电解液储能容量,电池的输出功率密度最高可达31.6 mW/cm2,与传统平行流场相比,电池电流效率提高13.9%,电压效率提高6.3%,能量效率提高14.8%,放电容量提高了35.3%。     

Kinetics of polyvinyl butyral (PVB) synthesis reaction catalyzed by deep eutectic solvent

In this work, the kinetics of the polyvinyl butyral (PVB) synthesis reaction catalyzed by the deep eutectic solvents (DESs) at the low-temperature stage was studied to control the particle size of PVB resin and optimize its synthesis process. The effects of stirring speed, the concentration of polyvinyl alcohol (PVA), catalyst dosage, and temperature on the synthesis reaction of PVB were investigated. The data obtained from kinetic experiments at 283.15–298.15 K were fitted with the shrinking core models, and the results showed that the model controlled by internal diffusion fitted well with the experimental data. The internal diffusion coefficient, D_A, of n-butanal in the product layer was further calculated by the obtained model parameters, and it was applied to predict the synthesis reaction of PVB at different concentrations of n-butanal. The results indicated that the shrinking core model controlled by internal diffusion is suitable to describe the kinetics of the PVB synthesis reaction. DES played a dual role in catalysis and dispersion in the synthesis of PVB, and it was a green catalyst with good potential for PVB industrial applications.     

Lithium storage performance of FeS@graphene anode materials prepared in a deep eutectic solvent

FeS has received widespread attention due to advantages such as high capacity, low-budget, and friendly to the environment. But side reactions during the charging and discharging process result in volume expansion of FeS, which limits its application and further development. In this work, FeS@graphene composites were prepared by a single step pyrolytic sulfidation method using PEG as the carbon source, FeCl₃·6H₂O as the iron source, metal chloride and organic alcohol as a deep eutectic solvent. The prepared composites which were characterized by SEM and TEM exhibited a strong bond between FeS and graphene, graphene had a lamellar structure, and FeS nanoparticles formed a homogeneous dispersion. Among the prepared composite material electrodes, the FeS/G-550 electrode displayed the best electrochemical properties with a high specific capacitance (initial discharge capacity: 1200 mAhg^-1; current density: 0.1 A g^-1), excellent rate capability (discharge specific capacitance of 443 mAh·g^-1 at the current density of 5 A g^-1), and good cyclic stability (capacity retention rate: 91%).     

全钒液流电池开路电压模型

建立全钒液流电池六参数开路电压计算模型,揭示开路电压由电池总电势和VO₂⁺/VO²⁺电极电势决定,并与电解液中钒离子透膜扩散行为密切相关。模型计算得到开路电压存在两个电压平台和一个转折点,与实验结果较为一致。利用该模型计算了电池开路时电解液中4种钒离子浓度随时间的变化关系,指出电池电解液不均衡性是由不同价态钒离子在膜相的Donnan平衡和透膜扩散系数不同产生的。该模型可为优化电池操作提供理论指导,并可为电池长期运行时电解液管理提供工程指导。     

Novel amphoteric ion exchange membranes by blending sulfonated poly(ether ether ketone) with ammonium polyphosphate for vanadium redox flow battery applications

A novel amphoteric ion exchange membrane for vanadium redox flow battery (VRFB) was explored by blending sulfonated poly(ether ether ketone) (SPEEK) and ammonium polyphosphate (APP). The high-stability flame retardant of cross-linked APP with a large number of NH₄⁺ groups was first introduced into SPEEK membrane. It was observed that the addition of APP with special structure could achieve a good balance between proton conductivity and vanadium ions permeability. The abundant NH₄⁺ in APP could block the penetration of vanadium ions by Donnan/Manning exclusion effect and ionic crossing networks due to the ionic bonds between cation and anion groups, and specially a small amount of APP within 5% could remarkably improve the proton conductivity of pristine SPEEK membrane might be ascribed to the unique fast proton transport channels formed by hydrogen bond networks and particular micro-phase separation as a result of interaction between SPEEK and APP. When 5% APP was blended, the SPEEK/APP-5% (S/APP-5%) amphoteric membrane showed a higher selectivity of 20.87 × 10⁴ S min/cm³ (with a good proton conductivity of 0.075 S/cm and a lower VO²⁺ permeability of 3.45 × 10⁻⁷ cm²/ min) and presented better thermal and chemical stability compared to Nafion115 and SPEEK membranes. The VRFB single cell assembled with S/APP-5% amphoteric membrane exhibited more excellent performance than that of Nafion115 and pristine SPEEK membranes, which revealed a higher coulombic efficiency of 96.3%–98.3%, comparable voltage efficiency of 88.4%–78.7% and higher energy efficiency of 85.1%–77.4% from 40 to 80 mA/cm², respectively, and showed relatively good stability of the efficiency up to 50 cycles at 60 mA/cm². The results demonstrated that the designed S/APP amphiprotic membrane of outstanding selectivity, high battery efficiency, and good durability is a prospected VRFB separator.     

Investigation on the electrode process of the Mn(II)/Mn(III) couple in redox flow battery

The Mn(II)/Mn(III) couple has been recognized as a potential anode for redox flow batteries to take the place of the V(IV)/V(V) in all-vanadium redox battery (VRB) and the Br₂/Br⁻ in sodium polysulfide/bromine (PSB) because it has higher standard electrode potential. In this study, the electrochemical behavior of the Mn(II)/Mn(III) couple on carbon felt and spectral pure graphite were investigated by cyclic voltammetry, steady polarization curve, electrochemical impedance spectroscopy, transient potential-step experiment, X-ray diffraction and charge-discharge experiments. Results show that the Mn(III) disproportionation reaction phenomena is obvious on the carbon felt electrode while it is weak on the graphite electrode owing to its fewer active sites. The reaction mechanism on carbon felt was discussed in detail. The reversibility of Mn(II)/Mn(III) is best when the sulfuric acid concentration is 5 M on the graphite electrode. Performance of a RFB employing Mn(II)/Mn(III) couple as anolyte active species and V(III)/V(II) as catholyte ones was evaluated with constant-current charge-discharge tests. The average columbic efficiency is 69.4% and the voltage efficiency is 90.4% at a current density of 20 mA cm⁻². The whole energy efficiency is 62.7% close to that of the all-vanadium battery and the average discharge voltage is about 14% higher than that of an all-vanadium battery. The preliminary exploration shows that the Mn(II)/Mn(III) couple is electrochemically promising for redox flow battery.     

绿色低共熔溶剂提取野菊花中黄酮类化合物

研究氯化胆碱低共熔溶剂(DES)提取野菊花中的总黄酮、总槲皮素和槲皮苷.首先,合成了4种性能优异的DES,并对其物理性质进行表征.其次,以提取效果最好的氯化胆碱/尿素DES为溶剂,通过改变单一变量优化提取效果,在含水量30％、提取时间45 min、固液比1:50(g:mL,下同)、提取温度60℃的条件下,总黄酮、总槲皮...     

乳酸类低共熔溶剂分离油茶果壳木质素及其特性分析

以油茶果壳为原料,利用两种乳酸类低共熔溶剂（DES）[三乙基苄基氯化铵/乳酸（TEBAC/LA）和甜菜碱/乳酸（Bet/LA）]分离木质素,采用UV、FTIR、GPC、TG-FTIR对油茶果壳木质素元素组成、化学结构和抗氧化活性进行了表征和评价。结果表明,TEBAC/LA和Bet/LADES均表现出良好的木质素分离能力,在固液比（g∶m L）为1∶20,120℃反应5h,油茶果壳木质素提取率分别为77.87%和59.49%。油茶果壳木质素结构保留完整,主要由紫丁香基和愈创木酚基结构组成。与TEBAC/LA分离木质素相比,Bet/LA分离的木质素相对分子质量低、分散度低和结构均一。两种DES分离得到的木质素的失重速率、失重温度和热解产物均不同,说明不同木质素热稳定性存在差异。此外,两种木质素均表现出良好的抗氧化活性,其中Bet/LA分离的木质素对1,1-二苯基-2-苦基肼（DPPH）自由基清除率可达84.57%。     

乳酸类低共熔溶剂分离油茶壳木质素及结构特性分析

以油茶壳为原料,利用两种乳酸类低共熔溶剂（DES）分离木质素,并对其结构、热解特性和抗氧化活性进行分析和评价。结果表明:三乙基苄卡基氯化铵/乳酸（TEBAC/LA）和甜菜碱/乳酸（Bet/LA）DES均表现出良好的木质素分离能力,在固液比1∶20,120 ℃,5 h的反应条件下,木质素提取率分别为77.87%和59.49%。紫外和红外光谱分析结果表明油茶果壳木质素结构保留完整,主要由紫丁香基和愈创木酚基单元结构组成。与TEBAC/LA相比,Bet/LA分离得到的木质素具有相对分子量低和分布窄的特性。此外,从热解特性方面分析,两种木质素的失重速率、失重温度和热解产物均存在显著差异。同时,两种木质素均表现出良好的抗氧化活性,其中Bet/LA对DPPH清除率最高可达84.57%。