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Utilizing a metal-forging inspired chain combing strategy to enhance properties and expand applications of Nylon 66 plastic via heat inducing

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Nano Research 2024年第3期17卷 2164-2171页

作者： Junyu Yang Jiangwei Zhang Nan Wang Guangyuan Zhou Division of Energy Materials Daglian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Innovation Center of Energy Material and Chemistry College of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot 010021China

The mechanical properties of engineering plastics can be enhanced through effective surface mechanical treatment(SMT),which can be applied to various types of engineering plastics,eliminating the limitations of conventional polymer processing and could potentially extend their applications and improve their performance and reliability as structural-functional materials.Inspired by metal forging,this work proposes a simple and effective SMT strategy to enhance the mechanical properties of polyamide 66(PA66).Tensile tests have shown that SMTed PA66 samples exhibit significant improvements in both Young’s modulus and ultimate tensile strength(UTS),with a 2104 MPa Young’s modulus,almost double that of the pristine samples,and a 35.56%increase in UTS,reaching 183 MPa.Additionally,the modulus within the localized SMTed surface layer could reach up to 14 GPa,which is approximately 14 times higher than that of the pristine sample.The Vickers hardness within the localized SMTed surface layer can be doubled,reaching 10.72 Hv,and the crystallinity can increase by approximately 20%compared to the untreated region.Furthermore,force field molecular dynamics(FFMD)simulations were conducted to investigate the ternary relationship between the SMT method,PA66’s molecular structure,and its properties.The combination of MD simulations and versatile structural characterizations provides evidence that the SMT method’s mechanism,under heat induction,results in a chain-combing procedure that changes the polymer’s molecular morphology microscopically and enhances its mechanical properties macroscopically.

关键词： Nylon 66 mechanical properties hardness crystallinity structural characterizations molecular dynamics simulation

Theory-driven designed TiO_(2)@MoO_(2)heterojunction:Balanced crystallinity and nanostructure toward desirable kinetics and highrate sodium-ion storage

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Nano Research 2023年第4期16卷 4941-4949页

作者： Junyi Yin Pengqi Hai Yuan Gao Zihan Gan Chao Wu Yonghong Cheng Xin Xu State Key Laboratory of Electrical Insulation and Power Equipment Center of Nanomaterials for Renewable EnergySchool of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China Frontier Institute of Science and Technology Xi’an Jiaotong UniversityXi’an 710049China

Sodium-ion batteries(SIBs)are promising candidates for large-scale energy storage due to their cost effectiveness and the unlimited availability of sodium.However,there remains a need for the rational design of better anodic materials than are currently available,as these materials are critical for the sodium-ion storage process.In this work,theoretical calculations were performed to design a conceptually novel TiO_(2)@MoO_(2)heterojunction(TMH)anode that was expected to exhibit better electrochemical performance than current anodes.The TMH anode was fabricated via a facile and cost-effective method,and the results of in-depth sodium-ion-storage performance and reaction kinetics analyses indicate that it exhibited an excellent rate capability and enhanced pseudocapacitive response,due to its high crystallinity.This electrochemical performance was superior to that of previously reported anodic materials,confirming the accuracy of the theoretical calculations.Destruction of TMH’s nanostructure at high temperatures resulted in a decrease in its electrochemical performance,indicating the key role played by the nanostructure in TMH’s ability to store sodium ions.This study demonstrates that integration of theoretical predictions with experimental investigations offers insights into how materials’crystallinity and nanostructure affect their pseudocapacitive sodiumion storage capabilities,which will help to guide the rational design of effective anodic materials for SIBs.

关键词： theory-driven electrode development heterojunction crystallinity nanostructure enhanced pseudocapacitive response

Influence of charge transport layer on the crystallinity and charge extraction of pure tin-based halide perovskite film

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Journal of Energy Chemistry 2022年第6期31卷 612-615,I0017页

作者： Yaohong Zhang Muhammad Akmal Kamarudin Qiao Li Chao Ding Yong Zhou Yingfang Yao Zhigang Zou Satoshi Iikubo Takashi Minemoto Kenji Yoshino Shuzi Hayase Qing Shen School of Physics Northwest UniversityXi'an 710127China Faculty of Informatics and Engineering The University of Electro-CommunicationsTokyo 182-8585Japan Eco-materials and Renewable Energy Research Center Jiangsu Key Laboratory for Nano TechnologyNanjing UniversityNanjing 210093China Department of Advanced Materials Science and Engineering Faculty of Engineering SciencesKyushu UniversityFukuoka 819-0395Japan Department of Electrical and Electronic Engineering Faculty of Science and EngineeringRitsumeikan UniversityShiga 525-8577Japan Department of Electrical and Electronic Engineering Miyazaki UniversityMiyazaki 889-2192Japan

As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].

关键词： Tin-based halide perovskite Charge transport layers crystallinity Charge extraction Photoexcited carrier dynamics

Alkyl-thiophene-alkyl linkers to construct double-cable conjugated polymers for single-component organic solar cells

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Chinese Chemical Letters 2024年第1期35卷 542-546页

作者： Wenbin Lai Safakath Karuthedath Chengyi Xiao Lei Meng Frédéric Laquai Weiwei Li Yongfang Li Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China Beijing Advanced Innovation Center for Soft Matter Science and Engineering&State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China King Abdullah University of Science and Technology(KAUST) KAUST Solar Center(KSC)Physical Sciences and Engineering Division(PSE)Material Science and Engineering Program(MSE)Thuwal 23955-6900Kingdom of Saudi Arabia University of Chinese Academy of Sciences Beijing 100049China Institute of Materials Research Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

In this work,semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct double-cable polymers.Three alkyl units,propyl(C3H6),hexyl(C6H12),and dodecyl(C12H24),are applied as semirigid linkers,yielding three double-cable polymers:PBC6-T,PBC12-T,and PBC24-T,respectively.PBC12-T which uses C6H12-thiophene-C6H12 linkers is found to exhibit the best device efficiency of 5.56%,while PBC6-T and PBC24-T with shorter or longer linkers yield device efficiencies of only 2.65%and 1.09%in single-component organic solar cells(SCOSCs).Further studies reveal that PBC12-T exhibits higher crystallinity and improved charge transport,resulting in better efficiencies.Our work provides an approach to construct double-cable conjugated polymers with long alkyl linkers,and it shows the importance of the linker length for the photovoltaic performance of SCOSCs.

关键词： Double-cable conjugated polymer Single-component organic solar cell crystallinity Semirigid linkers Alkyl-thiophene-alkyl

Substituent engineering of covalent organic frameworks modulates the crystallinity and electrochemical reactivity

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Journal of Energy Chemistry 2022年第2期31卷 490-496页

作者： Jing Ning Yang Gao Xingdi Cao Hongtao Wei Bin Wang Long Hao Chemistry and Pharmaceutical Sciences Qingdao Agricultural UniversityQingdao 266109ShandongChina Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China

Covalent organic frameworks(COFs)are emerging as powerful electrochemical energy storage/conversion materials benefiting from the controlled pore and chemical structures,which are usually determined by the regulation of the molecular building blocks.In contrast,the substituents are not considered significant for the electrochemical reactivity as they are usually removed during carbonization,which is necessary for improving the electrical conductivity of an electrode material.Here we show that the substituents play key roles not only in synthesizing COFs but also in controlling the COF structures during carbonization and thus the related electrochemical reactivity.Five characteristic substituents were used when synthesizing a new COF structure and it was found that electron-withdrawing strength of the substituents significantly influences the crystallinity of the COFs by tuning the reactivity of building blocks,or even determines whether the crystalline COF can be constructed.Moreover,the differences in chemical groups,sizes,and thermal stabilities of the substituents result in varied pore-collapse behaviors and the structures of the carbonized COFs,which show diverse effects on the electrochemical performances.An optimal material shows the highest surface area of 2131 m^(2)/g,rich pores around 1 nm,and the highest ratio of sp^(2) carbon among the samples,corresponding to the largest double-layer specific capacity over 125 F/g in an ionic liquid electrolyte,while another material with the lowest surface area and N-doping level exhibits a high H_(2)O_(2) production selectivity over 80%through selective oxygen reduction.This study shows guiding significance for the design of building blocks and substituents for COFs and further the carbonized carbons,and also exhibits the great potential of substituent engineering in modulating the electrochemical reactivity.

关键词： Covalent organic framework Substituent engineering crystallinity Electrochemical reactivity

crystallinity and stability of covalent organic frameworks

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Science China Chemistry 2020年第10期63卷 1367-1390页

作者： Xin Huang Chao Sun Xiao Feng Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Key Laboratory of Cluster ScienceMinistry of EducationSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China

Covalent organic frameworks(COFs)are a class of organic porous polymers with high crystallinity,and their structures can be precisely tailored via topology design.Owing to the characteristics of permanent pores,periodic structures and rich building blocks,COFs have triggered tremendous attention in the past fifteen years and are extensively investigated in various fields.crystallinity and stability are two crucial features for practical applications.In general,these two features are contradictory for COFs formed via dynamic covalent chemistry(DCC).High thermodynamic reversibility is usually required to attain exceptional crystallinity of COFs,often resulting in limited stability.The first two reported COFs are based on the boroxine and boronate ester linkages,which are unstable in water and even in humid conditions.Therefore,many researchers doubt the stability of COFs for real applications.Actually,in these years,various novel linkages have been developed for the construction of COFs,and numerous newly synthesized COFs are robust towards strong acid/base and even some of them can resist the attack of strong oxidizing and reducing agents.In this review,we focus on the linkage chemistry of the COFs in terms of crystallinity and stability,further extending it to the investigation in the mechanisms of the crystal growth and the overall regulation of the contradiction between stability and crystallinity.The strategies for improving the crystallinity,including selecting building units,introducing non-covalent interactions and slowing nucleation and growth rate,are described in the third section,while the methodologies for increasing the stability from the viewpoints of chemical modification and non-covalent interactions are summarized in the fourth section.Finally,the challenges and perspectives are presented.

关键词： covalent organic frameworks crystallinity stability dynamic covalent chemistry linkage chemistry

crystallinity dependence of electrochemical properties for LiFePO_4

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Rare Metals 2015年第5期34卷 334-337页

作者： Ting Zhao Xiang-Jun Zhang Xiang Li Shi-Gang Lu Research and Development Centre for Vehicle Battery and Energy Storage General Research Institute for Nonferrous Metals

LiFePOa composites were prepared by solid state reactions at different temperatures and time. The crystalline structure and morphology of the composites were analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, while X-ray absorption spectroscopy （XAS） was employed to characterize the crystallinity. Experimental results show that the electrochemical properties do not monotonously get better with the decrease of particle size and the traditional long reaction time is needless. Moreover, XAS is an effective technique to discover the change in crystallinity.

关键词： Lithium ion battery LiFePO4 crystallinity

Changes of crystallinity and spherulite morphology in isotactic polypropylene after rolling and heat treatment

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Journal of University of Science and Technology Beijing 2008年第4期15卷 514-520页

作者： Juan Jia Weimin Mao Dierk Raabe School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Max-Planck-Institut fur Eisenforschung Max-Planck-Str. 1 Düsseldorf 40237 Germany

The spherulite morphology of the rolled and subsequent heat-treated isotactic polypropylene （iPP） was observed by polarized microscopy, and the crystallinity evolution of materials was also measured by the wide angle X-ray scattering （WAXS）. Rolling led to the oblate spherulites in the deformed iPP samples. The sheared crystalline lamellae broke apart into sets of crystalline blocks during rolling. As a result, the crystallinity of the iPP samples was greatly reduced during deformation, which induced the unclear spherulites and spherulite boundaries. Subsequent heat treatment resulted in the strong reerystallization of the rolled iPP samples. But the recrystaUizatinn in this work only meant the rearrangement of the macromolecule along the unbroken crystalline lamellae and the existing small crystalline blocks in the deformed spherulites. Heat treatment did not change the shape of the spherulites formed during deformation. The recrystallization also resulted in very clear spherulites and spherulite boundaries.

关键词： isotaetic polypropylene （iPP） rolling heat treatment X-ray diffraction crystallinity spherulites

Improving the performance of polymer solar cells by adjusting the crystallinity and nanoscale phase separation

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Chinese Physics B 2012年第7期21卷 581-586页

作者：陈卫兵许宗祥李凯徐先贤 Roy V.A.L. 黎沛涛支志明 School of Computer and Communication Hunan University of Technology Department of Chemistry Institute of Molecular Functional Materials and HKU-CAS Joint Laboratory on New MaterialsThe University of Hong Kong Department of Physics and Materials Science City University of Hong Kong Department of Electrical&Electronic Engineering The University of Hong Kong

In this paper, we report a high-perfornmnce P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using an ultrasonic irradiation mixing approach for the polymer. The grazing incidence X-ray diffraction, UV/Vis spectroscopic, and atomic force microscopic measurement results for the P3HT/PCBM blend films reveal that the P3HT/PCBM film fabricated by ultrasonic irradiation mixing of the P3HT and PCBM solutions for 10 min has a higher degree of crystallinity, a higher absorption efficiency, and better phase separation, which together account for the higher charge transport properties and photovoltaic cell performance.

关键词： crystallinity polymer solar cell ultrasonic irradiation nanoscale phase separation