Modulating the Electrolyte Inner Solvation Structure via Low Polarity Co-solvent for Low-Temperature Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries are regarded as the promising candidates for large-scale energy storage systems owing to low cost and high safety;however,their applications are restricted by their poor low-temperature performance.Herein,a low-temperature electrolyte for low-temperature aqueous zinc-ion batteries is designed by introducing low-polarity diglyme into an aqueous solution of Zn(ClO_(4))_(2).The diglyme disrupts the hydrogenbonding network of water and lowers the freezing point of the electrolyte to-105℃.The designed electrolyte achieves ionic conductivity up to16.18 mS cm^(-1)at-45℃.The diglyme and ClO_(4)^(-)reconfigure the solvated structure of Zn^(2+),which is more favorable for the desolvation of Zn^(2+)at low temperatures.In addition,the diglyme effectively suppresses the dendrites,hydrogen evolution reaction,and by-products of the zinc anode,improving the cycle stability of the battery.At-20℃,a Zn‖Zn symmetrical cell is cycled for 5200 h at 1 mA cm^(-2)and 1 mA h cm^(-2),and a Zn‖polyaniline battery achieves an ultra-long cycle life of 10000 times.This study sheds light on the future design of electrolytes with high ionic conductivity and easy desolvation at low temperatures for rechargeable batteries.

Effect of Co-solvent and Pressure on the Thermal Decomposition of 2,2′Azobis-(isobutyronitrile) in Supercritical CO_2

The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and 14.0 MPa. Both of the cosolvents can accelerate the decomposition rate, and the effect of methanol is more significant than that of the cyclohexane.

Dispersion of ZnO Nanocrytals in Co-solvent and Its Application in Photovoltaic Material

To overcome the aggregation of nanocrystals in a blend of inorganic material with conjugated polymers to prepare photovoltaic material, we used a co-solvent blend of CHCl3 with MeOH at a certain volume fraction to disperse inorganic nanocrystals. The results show that when the volume fraction of MeOH is 50%, ZnO nanocrystals with an average diameter of 30 nm disperse well in the co-solvent solution. Its application in photovoltaic material was investigated in this work, and the photoluminescence（PL） spectra show that when ZnO was 50%（volume fraction） in solution and 25%（volume fraction） in film, the fluorescence quenching reached the maximum values 83.34% and 64.4%, respectively, indicating that electron could transfer from conjugated polymer to electron-acceptor ZnO effectively.

Influence of Co-Solvent on the Extraction Behaviour of Uranium and Thorium Nitrates with Organophosphorous Compounds

Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metal ions. In the present study, the extraction of nitrates of uranium and thorium was carried out using supercritical carbon dioxide (Sc-CO2) modified with various organophosphorous compounds such as dialkylalkyl phosphonates, trialkyl phosphates and trialkyl phosphine oxides in the presence of co-solvents such as methanol, dichlormethane and n-hexane. The influence of ligand and co-solvent on the extraction of the metal nitrates was studied in detail. These studies have established that co-solvent plays an important role in the extraction as well as fractionation of uranium and thorium nitrates. Polar co-solvent, methanol provided faster extraction without fractionation whereas the non-polar solvent, e.g. n-hexane provided some fractionation of metal nitrates though the extraction kinetics was slower.

Supercritical Synthesis of Ethyl Esters via Transesterification from Waste Cooking Oil Using a Co-Solvent

Biofuels became more promising alternative to the fossil fuels because of the depletion of fossil resources, renewability, environmental benefits, and energy security. Ethanolysis of waste cooking oil with hexane as co-solvent was carried out for the production of fatty acid ethyl ester (FAEE). This process reduced the severity of process parameters with high purity biodiesel yield. Process variables such as co-solvent ratio, ethanol to oil molar ratio, reaction temperature and reaction time were optimized. The maximum biodiesel yield of 88% was obtained at ethanol/oil molar ratio of 40:1, co-solvent (hexane) to oil ratio of 0.2% (v/v), reaction temperature of 300°C in 20 min of reaction time. Fatty acid ethyl ester (biodiesel) samples produced from this process were measured and evaluated using GC-MS analytical instrument. Thermo gravimetric analysis (TGA) was also performed to examine the thermal stability of waste cooking oil, ethyl esters and fuel blends. Fuel properties of ethyl esters were determined and compared with the ASTM standards for biodiesel, regular diesel and ethyl esters from different feedstock.

Enhancement of Lipase-catalyzed Synthesis of Caffeic Acid Phenethyl Ester in Ionic Liquid with DMSO Co-solvent

Caffeic acid phenethyl ester(CAPE) is a natural and rare ingredient with several biological activities, but its industrial production using lipase-catalyzed esterification of caffeic acid(CA) and 2-phenylethanol(PE) in ionic liquids(ILs) is hindered by low substrate concentrations and long reaction time. To set up a high-efficiency bioprocess for production of CAPE, a novel dimethyl sulfoxide(DMSO)–IL co-solvent system was established in this study.The 2%(by volume) DMSO–[Bmim][Tf2N] system was found to be the best medium with higher substrate solubility and conversion of CA. Under the optimum conditions, the substrate concentration of CA was raised 8-fold,the reaction time was reduced by half, and the conversion reached 96.23%. The kinetics follows a ping-pong bi-bi mechanism with inhibition by PE, with kinetic parameters as follows: Vmax= 0.89 mmol · min-1· g-1, Km,CA=42.9 mmol · L-1, Km,PE= 165.7 mmol · L-1, and Ki,PE= 146.2 mmol · L-1. The results suggest that the DMSO cosolvent effect has great potential to enhance the enzymatic synthesis efficiency of CAPE in ILs.

Effects of Water-Soluble Co-Solvent on Properties of W/O Pickering Emulsions

Effects of water-soluble co-solvents （WSCs）on the properties of water/oil Picketing emulsions were investigated. Picketing emulsions were prepared in the system of 1,2,4-trimethylbenzene （TMB）/hydrophobic sil- ica/water with varied concentrations of WSCs （ethanol, acetic acid and glycerin）. Mean droplet diameter distribu- tions of the obtained emulsions were studied to investigate the effects of WSCs types and concentrations. The results demonstrated that mean droplet diameter distributions decreased at first and then increased with the increase of WSC concentration. Moreover, the effect of WSC concentration on the phase inversion locus was further investi- gated. At the same time, infrared radiation （IR）spectrometer was used to investigate the mechanism. The results showed that the WSC attaching on hydrophobic silica changed the wettability of the particles, which facilitated the formation and phase inversion of the emulsion. The hydrogen bonds between the co-solvent groups attaching on the solid particles made a great effect on the droplet size of the emulsion and strengthened the interaction among emulsifiers. Overall, proper WSC was in favor of the stability of Picketing emulsion.

Optimization of Biodiesel Production from Waste Vegetable Oil Assisted by Co-Solvent and Microwave Using a Two-Step Process

The two-step catalyzing process for biodiesel production from waste vegetable oil was assisted by both co-solvent and microwave irradiation. Central composite design (CCD) was employed to optimize the reaction conditions. Optimal reaction conditions of the first step were alcohol to oil molar ratio of 9:1, catalyst (H2SO4) amount 1 wt%, reaction temperature 333 K, and reaction time 7.5 minutes;while for the second step, optimal reaction conditions were alcohol to oil molar ratio 12:1, catalyst (NaOH) amount 1 wt%, reaction temperature 333 K, and reaction time 2.0 minutes. The total reaction time was 9.5 min and the conversion rate of fatty acid methyl esters (FAMEs) achieved was 97.4%. The total reaction time was shorter than previous studies. Therefore, the co-solvent and microwave assisted two-step catalyzing process has a potential application in producing biodiesel from waste vegetable oil.

Fabricating low-temperature-tolerant and durable Zn-ion capacitors via modulation of co-solvent molecular interaction and cation solvation

Aqueous Zn-based energy-storage devices have aroused much interest in recent years.However,uncontrollable dendrite growth in the Zn anode significantly limits their cycle life.Moreover,the poor low-temperature performance arising from the freezing of aqueous electrolytes at sub-zero temperatures restricts their practical applications in cold regions.Here,we fabricated low-temperature-tolerant and durable Zn-ion hybrid supercapacitors(ZHSCs)via modulating a co-solvent water/ethylene glycol electrolyte.The interaction of intermolecular hydrogen bonds between water and ethylene glycol as well as cation solvation was systematically investigated by tuning the co-solvent composition.The results illustrate that the ZnSO_(4)/water/ethylene glycol(65%)electrolyte possesses high ionic conductivity at low temperatures and effectively prevents the dendrite formation of the Zn anode.The as-fabricated ZHSCs exhibit long-term cyclability and are capable of working at sub-zero temperatures as low as -40℃.The present ZHSCs are anti-freezing and cost-effective,which may find new applications in the fields of next-generation electrochemical energy storage devices.

Influence of co-solvent hydroxyl group number on properties of water-based conductive carbon pastes

A series of water-based conductive carbon pastes were prepared by wet ball milling, followed by vacuum defoaming using isopropyl alcohol, propylene glycol or glycerin as co-solvents. Screen printing was then used to prepare conductive patterns. To determine the influence of co-solvent hydroxyl group number on the properties of water-based conductive carbon pastes, the rheological properties of the pastes and the surface morphologies and conductivities of the printed patterns were characterized. The results show that paste viscosity increased with the number of hydroxyl groups and the latter also affected thixotropy. In addition, the boiling points and surface tensions of the co-solvents increased consistently with hydroxyl group number, affecting the hydrodynamic flow. The conductive carbon paste created using propylene glycol as a co-solvent was the best for screen printing because of its weak coffee-ring effect and appro- priate rheological properties, resulting in a smooth coating surface and uniform deposition of the fillers. The resistivity of the pattern printed using paste PG, containing the closest packing of conductive carbon black particles, was 0.44 Ω cm.

An effective'salt in dimethyl sulfoxide/water'electrolyte enables high-voltage supercapacitor operated at-50℃

Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,challenges remain for low-salt aqueous electrolytes operating at high voltage and low temperature.Herein,we report a low-salt(0.87 m,m means mol kg^(-1))'salt in dimethyl sulfoxide/water'hybrid electrolyte with non-flammability via hybridizing aqueous electrolyte with an organic co-solvent of dimethyl sulfoxide(hydrogen bond acceptor).As a result,the 0.87 m hybrid electrolyte exhibits enhanced electrochemical stability,a freezing temperature below-50℃,and an outstanding ionic conductivity of 0.52mS cm~(-1)at-50℃.Dimethyl sulfoxide can anchor water molecules through intermolecular hydrogen bond interaction,effectively reinforcing the stability of water in the hybrid electrolyte.Furthermore,the interaction between dimethyl sulfoxide and water molecules diminishes the involvement of water in the generation of ordered ice crystals,finally facilitating the low-temperature performance of the hybrid electrolyte.When paired with the 0.87 m'salt in dimethyl sulfoxide/water'hybrid electrolyte,the symmetric supercapacitor presents a 2.0 V high operating voltage at 25℃,and can operate stably at-50℃.Importantly,the suppressed electrochemical reaction of water at-50℃further leads to the symmetric supercapacitor operated at a higher voltage of 2.6 V.This modification strategy opens an effective avenue to develop low-salt electrolytes for high-voltage and low-temperature aqueous supercapacitors.

水相循环对乙醇-水体系液化蜈蚣草产油特性和砷富集影响

砷富集植物的生态友好处置是实现植物修复产业化发展的关键环节,对土壤重金属污染治理高质量发展起到了制约作用。该研究以蜈蚣草为原料,采用乙醇-水作为反应共溶剂体系,考察了乙醇占比和水相循环次数对蜈蚣草水热产油及重金属砷分布的影响。研究结果显示:在乙醇浓度60%、水相循环3次的条件下,蜈蚣草液化生物油产率最高可达51.08%,其热值为29.15 MJ/kg。生物油主要由酯(>80%)、酚、醇、酮、烃等组成。随水相循环次数的增加,生物油中的酯类和酚类物质增加,高沸点化合物会减少,生物油产率和能量回收率分别提高了58%和32.23%;经过水相循环液化后,超过80%的重金属砷主要分布在水相,且砷的浓度增加至215.05 mg/kg,该结果可为砷富集植物无害化后处置提供参考。因此,水相循环利用是砷富集植物液化处置制取高产率生物油与砷富集的有效途径,为富集植物生态友好处置提供了新的思路。

柔性压电复合材料的研究进展

柔性压电复合材料常被应用于医学和航空航天等多个领域,具有广阔的工程应用前景和巨大的商业价值。因此,综述了柔性压电复合材料,介绍了以聚二甲基硅氧烷(PDMS)为代表的柔性基体和纳米填料。随后分析了制备工艺以及在制备中出现的团聚问题。同时,总结了物理与化学分散法以及双亲助溶剂促进分散的机理。最后归纳了机器学习(ML)、分子模拟和宏观试验3种研究方法。

聚丁二酸-共-对苯二甲酸丁二醇酯/氧化镁复合薄膜的制备及性能

以聚丁二酸-共-对苯二甲酸丁二醇酯(PBST)为基体,纳米氧化镁(MgO NPs)为抗菌剂,通过溶剂挥发法制备了PBST/MgO纳米复合薄膜,并探讨了复合薄膜在食品包装中的应用。研究了MgO NPs对纳米复合薄膜的机械性能、水蒸汽透过率(WVP)、氧气透过率(OTR)和紫外阻隔性能的影响。结果表明:MgO NPs的加入改善了PBST基体的力学性能和阻隔性能。与PBST薄膜相比,复合膜的拉伸强度和断裂伸长率分别提高了43.7%和32.2%,水蒸汽透过率和氧气透过率分别降低了28.1%和23.6%,并具有良好的紫外阻隔性能。当MgO NPs质量含量为5%时,复合膜的性能最佳。

锂离子电池低温电解液的挑战及研究进展

近年来,锂离子电池(LIB)已广泛应用于便携式电子设备、电动汽车、储能领域,是目前最有前景的新能源应用技术之一。然而低温条件下,LIB仍面临循环寿命和能量/功率密度衰减过大等诸多挑战,严重限制了其在极端工况下的实际应用。其主要原因包括:Li+在电极材料中的扩散及其界面处的电荷传递和去溶剂化过程较为缓慢;电解液粘度增大,对材料和隔膜的润湿性变差;石墨负极嵌锂时容易形成锂枝晶等。基于多年来低温锂离子电池的开发经验和相关文献报道,从电解液的角度综述了提高低温锂离子电池的策略,重点介绍了低粘度、宽液程的共溶剂,高电导率、低去溶剂化能的新型锂盐以及形成薄且致密固体电解质中间相(solid electrolyte interphase,SEI)的成膜添加剂对低温性能的影响及其挑战,并对未来低温电解液的发展方向进行了展望。

7-羟乙基白杨素聚乳酸-羟基乙酸共聚物纳米粒的制备及体外释放评价

目的:制备和评价7-羟乙基白杨素(7-HEC)聚乳酸-羟基乙酸共聚物(PLGA)纳米粒。方法:采用乳化溶剂挥发法制备7-HEC/PLGA纳米粒,以粒径、多分散系数(PDI)、包封率、载药量及Zeta电位为评价指标,通过单因素考察结合Box-Behnken响应面法优化处方。采用甘露醇作为冻干保护剂制备冻干粉,对最优处方制备的7-HEC/PLGA纳米粒进行表征及体外释放研究。结果:经Box-Behnken响应面法优化后的最优处方为:药载比2.12∶20,油水体积比1∶14.7,乳化剂为2.72%大豆磷脂。最优处方条件制备的7-HEC/PLGA纳米粒的平均粒径为(240.28±0.96)nm、PDI为0.25±0.69、包封率为(75.74±0.80)%、载药量为(6.98±0.83)%、电位为(-18.17±0.17)mV。体外释放48 h内累积释放度达到50%以上。结论:优化所得处方工艺稳定、操作简便。所得7-HEC/PLGA纳米粒粒度均匀,包封率较高。相对于7-HEC原料药,7-HEC/PLGA纳米粒的溶出度显著提高。

低渗透油田用CO_2气溶性泡沫体系研发及性能评价

利用可视化高温高压泡沫仪筛选出具有良好CO_2泡沫性能的表面活性剂,在醇类等共溶剂的辅助下,评价其在超临界CO_2中的溶解性能;利用高温高压岩心驱替实验装置,评价CO_2气溶性泡沫体系提高采收率的能力。结果表明,所筛选的非离子型表面活性剂N-P-12在125℃高温条件下可以产生具有一定稳定性的CO_2泡沫,醇类等共溶剂的加入可以明显提高其在超临界CO_2中的溶解度。CO_2气溶性泡沫体系驱油过程中阻力因子呈先增大后减小的趋势,生成的泡沫对体系流动起到流度控制的作用,且较常规CO_2泡沫能够显著提高原油采收率,最终采收率高达92.50%。

相分离法制备相变材料微胶囊

相分离法是一种较为简便的微结构聚合物制备方法,通过改变表面活性剂的种类、浓度和聚合物的种类等,可以方便地控制所制备聚合物微球的形貌。研究采用聚甲基丙烯酸甲酯(PMMA)与聚苯乙烯(PS),油相使用的是相变材料十六烷(HD),共溶剂使用的是二氯甲烷(DCM)或三氯甲烷(TCM),将聚合物溶于油相中,通过溶剂挥发导致的相分离作用,以及在界面张力的调控作用下,可以制得多种形貌的微胶囊。

乙醇/柴油混合燃料的相溶性及对发动机性能影响的研究

利用助溶剂解决乙醇/柴油的相溶性问题,讨论了混合燃料中乙醇和助溶剂添加量对相溶性的影响,并使用助溶剂体积分数为1.5%、乙醇体积分数分别为5%、10%、15%的混合燃料及-20号纯柴油(分别表示为E5、E10、E15和E0)在发动机台架上进行了性能和排放试验。研究结果表明,柴油的烃组成是决定相分离温度的决定性因素;对全部测试油品,乙醇体积分数在10%、助溶剂添加体积分数为1.5%时,混合燃料相溶性较好。台架试验显示,随着混合燃料中乙醇掺烧比例的增加,发动机的燃油消耗率逐渐增加,而发动机的额定功率和最大扭矩逐渐降低,但最大扭矩降低的幅度较小;此外,随着乙醇掺烧比例的增加,CO比排放量减少,HC、NOx和PM的比排放量逐渐增加,但NOx和PM的比排放量增加幅度不大。10%体积分数的乙醇添加量是乙醇/柴油的最佳掺烧比。

叔丁醇共溶剂用于制备生物柴油的研究

利用叔丁醇作为共溶剂可使棕榈油、甲醇和催化剂形成均相体系,用于酯交换反应制备生物柴油,可以缩短反应时间。实验以棕榈油为原料,氢氧化钠为催化剂,在带夹套的玻璃反应器内进行反应。考察了共溶剂质量分数、催化剂质量分数、反应温度、醇油摩尔比等因素对生物柴油产率的影响,获得了最佳反应条件。实验结果表明,当叔丁醇质量为棕榈油质量的11.6%,催化剂质量为油质量的1.0%,反应温度为60℃,醇油摩尔比为6∶1时,反应2 m in后生物柴油产率达到了90%。