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A universal performance-enhancing method for Li-S batteries:the cathode material of Li_(2)S@Li_(2)S_(2)@Li_(2)S_(6) double-shell structure

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Science China Chemistry 2024年第4期67卷 1229-1241页

作者： Shunjin Yang Yujiang Sun Qiaran Zhang Xiaohu Hu Xing Chen Guoran Li Xiao Sun Yuzhe Zhang Shijie Xu Xinyu Wang Yongan Yang Institute of Molecular Plus School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China College of Materials Science and Engineering Nankai UniversityTianjin 300350China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China tianjin Key Laboratory of Advanced Carbon and Electrochemical Energy Storage Tianjin 300072China

Lithium sulfide(Li_(2)S)as a cathode material for lithium-sulfur(Li-S)batteries,one of the most promising advanced batteries in the future,has received tremendous attention in the past ***,developing the practical Li_(2)S cathode confronts challenges of low conductivity for Li-ions and electrons,high sensitivity to environmental moisture,big overpotential barrier to electrochemical activation,and poor cyclability due to the shuttle effect of intermediate *** article herein reports a simple and effective strategy for making Li_(2)S@Li_(2)S_(2)@Li_(2)S_(6) double-shelled microparticles,which can significantly mitigate these *** are synthesized by dissolving Li2S together with S in dimethoxyethane,then drying off the solvent,and finally calcining the collected *** with pure Li_(2)S,such a double-shell material presents a 26.7% improvement in cycling capacity,0.5 V lower in activation overpotential,and prolonged tolerance in the ambient *** density functional theory calculation shows that the performance enhancement lies in the higher stability of Li2S6in contact with moisture and some autocatalytic effect of Li_(2)S_(2)@Li_(2)S_(6).Such a double-shell structure becomes a universal performanceenhancing approach when being combined with other means,such as cathodes composited with catalytic MoS_(2),separators modified with selenium-doped sulfurized-polyacrylonitrile/montmorillonite,electrolytes containing fluorenone additive,and Li anodes coated with a layer of Li_(3)*** corresponding capacity retention shows up to 80%improvement compared with pure Li_(2)S.

关键词： lithium-sulfur batteries lithium sulfide lithium polysulfides cathode performance double shell structure

Effect of cis/trans molecular structures on pyrolysis performance and heat sink of decalin isomers

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Frontiers of Chemical Science and Engineering 2024年第1期18卷 51-60页

作者： Qing Liu Kang Xue Tinghao Jia Zhouyang Shen Zehao Han Lun Pan Ji-Jun Zou Xiangwen Zhang Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovative Center of Chemical Science and Engineering(tianjin) Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of tianjin University Ningbo 315201China

Decalin is considered as an important compound of high-energy-density endothermic fuel,which is an ideal on-board coolant for thermal management of advanced ***,decalin contains two isomers with a tunable composition,and their effects on the pyrolysis performance,such as the heat sink and coking tendency have not been ***,we investigated the pyrolysis of decalin isomers,i.e.,cis-decalin,trans-decalin and their mixtures(denoted as mix-decalin),in order to clarify the effects of the cis-/trans-structures on the pyrolysis performance of decalin *** pyrolysis results confirmed that conversion of the tested fuels(600–725℃,4 MPa)decreased in the order cis-decalin>mix-decalin>*** analyses of the pyrolysis products were used to compare the product distributions from cis-decalin,mix-decalin and trans-decalin,and the yields of some typical components(such as cyclohexene,1-methylcyclohexene,benzene and toluene)showed significant differences,which could be ascribed to deeper cracking of ***,the heat sinks and coking tendencies of the decalins decreased in the order cis-decalin>mix-decalin>*** work demonstrates the relationship between the cis/trans structures and the pyrolysis performance of decalin,which provides a better understanding of the structure-activity relationships of endothermic hydrocarbon fuels.

关键词： endothermic fuel decalin pyrolysis heat sink molecular structure

The flow behavior of droplet adsorption on a liquid-liquid interface accompanied by cross-linking reaction and phase separation in a microchannel

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Chinese Journal of Chemical Engineering 2024年第2期66卷 60-70页

作者： Haozhe Yi Taotao Fu Chunying Zhu Youguang Ma State Key Laboratory of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

The adsorption process of droplets on the liquid-liquid interface and phase separation process can regulate the spatial distribution of the fluid system,which are crucial for chemical ***,the cross-linking reaction,which is widely used in the field of polymers,can change the physical properties of the fluids and affect the flow behavior accordingly.A configuration of microchannels is designed to conveniently generate uniform droplets in one phase of the parallel *** flow behavior of the adsorption process of sodium alginate droplets on the liquid-liquid interface is investigated,and the subsequent process of phase separation is *** the process of droplet adsorption,the crosslinking reaction occurs synchronously,which makes the droplet viscosity and the elasticity modules of the droplet surface increase,thus affecting the dynamics of the adsorption process and the equilibrium shape of the *** variation of the adsorption length with time is divided into three stages,which all conform to power law *** exponents of the second and third stages deviate from the results of the Tanner's *** flow pattern maps of droplet adsorption and phase separation are drawn,and the operating ranges of complete adsorption and complete separation are *** study provides a theoretical basis for further studying the flow behavior of droplets with cross-linking reaction in a microchannel.

关键词： Microfluidics Droplet Dynamics Crosslink Adsorption Separation

Research Progress in the Fabrication of Covalent Organic Framework Membranes for Chemical Separations

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Chinese Journal of Polymer Science 2024年第2期42卷 141-158,I0005页

作者： Cui-Ting Ding Jin-Qiu Yuan Meng-Ying Xie Qing-Yuan Liu Zeng-Guang Yao Shi-Yu Zhang Run-Nan Zhang Hong Wu Zhong-Yi Jiang Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China Zhejiang Institute of tianjin University NingboZhejiang315201China Haihe Laboratory of Sustainable Chemical Transformations Tianjin300192China tianjin Key Laboratory of Membrane Science and Desalination Technology Tianjin UniversityTianjin300072China Joint School of National University of Singapore and tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou350207China

Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COFs) with intrinsically high porosity, controllable pore size, uniform pore size distribution and long-range ordered channel structure, have emerged as next-generation materials to fabricate advanced separation membranes. This feature article summarizes some latest studies in the development of pure COF membranes in our lab, including their fabrication and applications in chemical separations. Finally, current challenges facing high-performance COF separation membranes are discussed.

关键词： Covalent organic frameworks Covalent organic framework membranes Water treatment Organic solvent nanofiltration Gas separation

Vibration-assisted material damage mechanism:From indentation cracks to scratch cracks

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Chinese Journal of Aeronautics 2024年第8期37卷 527-546页

作者： Bingrui LV Bin LIN Tianyi SUI Chunyan LIU Jinshuo ZHANG Longfei WANG Xuhui CHEN Jingguo ZHOU Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin UniversityTianjin 300072China Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China Science and Technology of Advanced Functional Composite Laboratory Aerospace Research Institute of Materials and Processing TechnologyBeijing 100076China

Vibration-assisted grinding is one of the most promising technologies for manufacturing optical components due to its efficiency and quality ***,the damage and crack propagation mechanisms of materials in vibration-assisted grinding are not well *** order to elucidate the mechanism of abrasive scratching during vibration-assisted grinding,a kinematic model of vibration scratching was *** influence of process parameters on the evolution of vibration scratches to indentation or straight scratches is revealed by displacement metrics and velocity ***,scratch and vibration scratch experiments were performed on quartz glass,and the results showed that the vibration scratch cracks are a combination of indentation cracks and scratch *** scratch cracks change from indentation cracks to scratch cracks as the indenter moves from the entrance to the exit of the workpiece or as the vibration frequency changes from high to low.A vertical vibration scratch stress field model is established for the first time,which reveals that the maximum principal stress and tensile stress distribution is the fundamental cause for inducing the transformation of the vibration scratch cracking *** model provides a theoretical basis for understanding of the mechanism of material damage and crack propagation during vibration-assisted grinding.

关键词： Vibration assisted grinding Indentation Vibration scratch Material removal mechanism Stress field model Crack propagation mechanism

Enhanced Ethylene Production from Electrocatalytic Acetylene Semi-hydrogenation Over Porous Carbon-Supported Cu Nanoparticles

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Transactions of tianjin University 2024年第4期30卷 297-304页

作者： Li Li Fanpeng Chen Bo-Hang Zhao Yifu Yu Institute of Molecular Plus Department of ChemistrySchool of ScienceTianjin UniversityTianjin 300072China

Electrocatalytic semi-hydrogenation of acetylene(C_(2)H_(2))over copper nanoparticles(Cu NPs)offers a promising non-petroleum alternative for the green production of ethylene(C2H4).However,server hydrogen evolution reaction(HER)competition in this process prominently decreases C2H4 selectivity,thereby hindering its practical ***,a Cu-based composite catalyst,wherein porous carbon with nanoscale pores was used as a support,is constructed to gather the C_(2)H_(2) feedstocks for suppressing the undesirable *** a result,the as-prepared catalyst exhibited C_(2)H_(2) conversion of 27.1%and C_(2)H_(4) selectivity of 88.4%at a C2H4 partial current density of 0.25 A/cm^(2) under optimal−1.0 V versus reversible hydrogen electrode(RHE)under the simulated coal-derived C_(2)H_(2) atmosphere,significantly outperforming the single Cu NPs *** addition,a series of in situ and ex situ experimental results show that not only the porous nature of the carbon support but also the stabilized Cu^(0)–Cu^(+) dual active sites through the strong metal–support interactions enhance the adsorption capacity of C_(2)H_(2),leading to high C_(2)H_(2) partial pressure,restraining the HER and thus improving the C2H4 selectivity.

关键词： Electrocatalysis Cu-based catalyst Hydrogenation Ethylene Selectivity

Electric Vehicle Charging Load Optimization Strategy Based on Dynamic Time-of-Use Tariff

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Energy Engineering 2024年第3期121卷 603-618页

作者： Shuwei Zhong Yanbo Che Shangyuan Zhang Key Laboratory of Smart Grid of Education Ministry Tianjin UniversityTianjin300072China

Electric vehicle(EV)is an ideal solution to resolve the carbon emission issue and the fossil fuels scarcity problem in the ***,a large number of EVs will be concentrated on charging during the valley hours leading to new load peaks under the guidance of static time-of-use ***,this paper proposes a dynamic time-of-use tariff mechanism,which redefines the peak and valley time periods according to the predicted loads using the fuzzy C-mean(FCM)clustering algorithm,and then dynamically adjusts the peak and valley tariffs according to the actual load of each time *** on the proposed tariff mechanism,an EV charging optimization model with the lowest cost to the users and the lowest variance of the grid-side load as the objective function is ***,a weight selection principle with an equal loss rate of the two objectives is proposed to transform the multi-objective optimization problem into a single-objective optimization ***,the EV charging load optimization model under three tariff strategies is set up and solved with the mathematical solver *** results show that the EV charging load optimization strategy based on the dynamic time-of-use tariff can better balance the benefits between charging stations and users under different numbers and proportions of EVs connected to the grid,and can effectively reduce the grid load variance and improve the grid load curve.

关键词： Dynamic time-of-use tariff peak and valley time electric vehicle multi-objective optimization

A perspective to ammonia-hydrogen energy industry in China

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Science China Chemistry 2024年第6期67卷 1765-1775页

作者： Baoshun Zhang Wangyang Ji Jiewei Zhu Baian Shen Menghao Lv Bin Zhang Tihu Wang Yifu Yu Department of Chemistry Institute of Molecular PlusSchool of ScienceTianjin UniversityTianjin300072China tianjin University-Asia Silicon Joint Research Center of Ammonia-Hydrogen New Energy Asia Silicon(Qinghai)Co.Ltd.Xining810007China Department of Catalysis Science and Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China

1 *** meet the 1.5℃ climate goal in our planet,the world is making a hard work for decarbonization[1-5].Constructing a clean energy system based on green energy is considered as the most promising way to achieve the ... 详细信息

关键词： ammonia planet energy

Flexible Organic Crystal with Two-Dimensional Elastic Bending and Recoverable Plastic Twisting for Circularly Polarized Luminescence

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CCS Chemistry 2024年第6期6卷 1439-1447页

作者： Wenjie Kuang Bo Jing Songgu Wu Junbo Gong State Key Laboratory of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072 Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072

Multidimensional mechanical flexible organic crystals with tunable optoelectronic properties hold significant promise for practical application in complicated environmental ***,based on a newly designed“flexible”Schiff base small molecule with chirality,we presented a compatibly bendable and twistable organic single crystal with circularly polarized luminescence for the first ***,the twodimensional elastic bending of the chiral crystal was realized at both room and liquid nitrogen temperatures,along with recoverable plastic twisting at room ***,circular dichroism and circularly polarized luminescence spectroscopy were employed to characterize the chiral enantiomer in solution and the solid *** design strategy provides a new perspective for the future construction of chiroptical flexible crystal materials.

关键词： organic crystal multidimensional flexibility circularly polarized luminescence low-temperature resistance