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Electrosprayed porous Fe3O4/carbon microspheres as anode materials for high-performance lithium-ion batteries

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Nano Research 2018年第2期11卷 892-904页

作者： Wenjie Han Xianying Qin Junxiong Wu Qing Li Ming Liu Yue Xia hongda du Baohua Li Feiyu Kang Engineering Laboratory for Next Generation Power and Energy Storage Batteries and Engineering Laboratory for Functionalized Carbon Materials Graduate School at Shenzhen Tsinghua University Shenzhen China School of Materials Science and Engineering Tsinghua University Beijing China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology Hong Kong China

Porous Fe3Odcarbon microspheres （PFCMs） were successfully fabricated via a facile electrospray method and subsequent heat treatment, using ferrous acetylacetonate, carbon nanotubes （CNTs）, Ketjen black （KB）, polyvinylpyrrolidone （PVP）, and polystyrene （PS） as raw materials. The porous carbon sphere framework decorated with well-dispersed CNTs and KB exhibits excellent electronic conductivity and acts as a good host to confine the Fe304 nanoparticles. The abundant mesopores in the carbon matrix derived from polymer pyrolysis can effectively accommodate the volume changes of F%O4 during the charge/ discharge process, facilitate electrolyte penetration, and promote fast ion diffusion. Moreover, a thin amorphous carbon layer on the Fe304 nanoparticle formed during polymer carbonization can further alleviate the mechanical stress associated with volume changes, and preventing aggregation and exfoliation of F%O4 nanoparticles during cycling. Therefore, as anode materials for lithium-ion batteries, the PFCMs exhibited excellent cycling stability with high specific capacities, and outstanding rate performances. After 130 cycles at a small current density of 0.1 A-g-1, the reversible capacity of the PFCM electrode is maintained at almost 1,317 mAh-g-1. High capacities of 746 and 525 mAh-g-1 were still achieved after 300 cycles at the larger currents of I and 5 A-g-1, respectively. The optimized structure design and facile fabrication process provide a promising way for the utilization of energy storage materials, which have high capacities but whose performance is hindered by large volume changes and poor electrical conductivity in lithium or sodium ion batteries.

关键词： lithium ion batter35Fe304/carbon microsphere hierarchical pores electrospray technique electrochemicalperformance

Group VB transition metal dichalcogenides for oxygen reduction reaction and strain-enhanced activity governed by p-orbital electrons of chalcogen

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Nano Research 2019年第4期12卷 925-930页

作者： Shuyang Zhao Ke Wang Xiaolong Zou Lin Gan hongda du Chengjun Xu Feiyu Kang Wenhui duan Jia Li Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China Shenzhen Geim Graphene Center Division of Energy and Environment Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China Tsinghua-Berkeley Shenzhen Institute (TBSI) Tsinghua University Shenzhen 518055 China Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua University Beijing 100084 China

Developi ng alter native oxyge n reducti on reactio n (ORR) catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells. Owing to their various compositi ons and tun able electronic properties, transition metal dichalcogenides (TMDs) have the great potential to realize high-efficiency catalysts for ORR. Here, various 3R-phase dichalcogenides of group VB and VIB transition metals (MX2, M = Nb, Ta, Mo, W;X = S, Se, Te) are investigated for ORR catalysts by using density functional theory calculations. The computed over-potentials of group VB TMDs are much less than those of group VIB TMDs. For group VB TMDs, a volcano-type plot of ORR catalytic activity is established on the adsorption energies of *OH, and NbS2 and TaTe2 exhibit best ORR activity with an oveepotential of 0.54 V. To achieve even better activity, strain engineering is performed to tune ORR catalytic activity, and the minimum over-potential of 0.43 V can be realized. We further dem on strate that the shift of p orbital center of surface chalcoge n elements under strain is responsible for tuning the catalytic activity of TMDs.

关键词： transition metal dichalcogenides fuel cells oxygen reduction reaction strain density functional theory (DFT) calculations

Advances in Understanding Materials for Rechargeable Lithium Batteries by Atomic Force Microscopy

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Energy & Environmental Materials 2018年第1期1卷 28-40页

作者： Shuwei Wang Qi Liu Chenglong Zhao Fengzheng Lv Xianying Qin hongda du Feiyu Kang Baohua Li Engineering Laboratory for the Next Generation Power and Energy Storage Batteries Graduate School at ShenzhenTsinghua UniversityShenzhen 518055China Laboratory of Advanced Materials School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Key Laboratory for Renewable Energy Beijing Key Laboratory for New Energy Materials and DevicesBeijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese AcademyBeijing China

The development of advanced lithium batteries represents a major technological challenge for the new *** the fundamental electrode degradation mechanisms is important for battery performance *** complex electrochemical processes inside a working battery are being explored to a limited *** advanced material characterization techniques have been used to monitor dynamic conditions for optimizing battery ***-of-the-art atomic force microscopy methods have been applied to energy storage systems,specifically lithium-ion *** force microscopy is an ideal tool to provide localized morphological,chemical,and physical information at nanoscale for the in-depth understanding of the electrochemical processes,reaction mechanisms,and degradation of battery ***,we review recent progress in the development and application of atomic force microscopy for high-performance lithium-ion *** discuss atomic force microscopy as an analytical tool to help researchers understand graphite,silicon,layered metal oxides,and other representative electrode *** summarize the importance of atomic force microscopy technique in studying the next-generation Li–S and Li–O 2 *** also highlight some of the remaining challenges and possible solutions for future development.

关键词： battery lithium electrode

Environment-friendly preparation of exfoliated graphite and functional graphite sheets

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Journal of Materiomics 2021年第1期7卷 136-145页

作者： Shiyu Hou Shuaijie He Tianle Zhu Jihui Li Liqiang Ma hongda du Wanci Shen Feiyu Kang Zheng-Hong Huang State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China School of Space and Environment Beihang UniversityBeijing100191China School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing100083China Guangdong Province Key Lab of Thermal Management Engineering and Materials Graduate School at ShenzhenTsinghua UniversityShenzhen518055China

Exfoliated graphite(EG)is promising oil sorbent as well as an intermediate product for the preparation of flexible graphite films(FGFs).It has been a critical challenge to energy conservation and pollution abatement for the traditional EG production ***,we propose a simple and effective preparation method to acquire EG in which flake graphite is intercalated and exfoliated at room temperature,not involving any pollutant *** influence factors in the preparation process were explored,such as the amount of H_(2)SO_(4)and H_(2)O_(2),the temperature for the preparation of room temperature exfoliated graphite(RTEG).In contrast to the EG by high temperature exfoliation(HTEG),RTEG exhibits a homogeneous structure and a significantly increased volume and surface ***,EG blocks with high oil sorption capacity and excellent reuse performance can be obtained by RTEG ***,FGFs fabricated by RTEG has high flexibility,thermal conductivity and electrical *** suggests that this environment-friendly technology is suitable for large-scale industrial implementation of graphite-based oil sorbents and flexible materials.

关键词： Exfoliated graphite Room temperature Oil sorption Flexible graphite films Thermal conductivity

A simplified dispersion-compensation microstructure fiber with seven cores

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Optoelectronics Letters 2024年第4期20卷 216-221页

作者： LI Wenchao WANG Chao YANG hongda HANG Ying WANG Wei Intelligence and Information Engineering College Tangshan UniversityTangshan 063000China School of Information Science and Engineering Yanshan UniversityQinhuangdao 066004China

In order to compensate the dispersion accumulated in a single mode fiber(SMF)for higher communication capacity,a simplified dispersion-compensation microstructure fiber(DC-MSF)with seven cores is proposed in this *** fiber’s cladding is made of pure silica without air holes,and its outer cores are composed of six germanium up-doped cylinders,which has the advantage of simple *** finite element method(FEM)and beam propagation method(BPM)are used to study the properties of the fiber,and the relationship between the structural parameters of the fiber and the dispersion,as well as the phase matching wavelength,is *** optimizing the structural parameters of the fiber,the dispersion of the fiber can reach-5291.47 ps·nm^(-1)·km^(-1) at 1550 nm,and the coupling loss to the conventional single-mode fiber is only 0.137 d *** with the conventional dispersion-compensation fiber,the fiber has lots of advantages,such as single mode transmission,easy to fabricate and low coupling loss with traditional SMF,etc.

关键词： fiber dispersion simplified

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热处理对Pt纳米线电催化性能的影响

稀有金属材料与工程 2014年第7期43卷 1783-1786页

作者：吴喜明杜鸿达汤皎宁苏轶坤深圳大学深圳市特种功能材料重点实验室广东深圳518060 清华大学深圳研究生院新材料研究所广东深圳518055

采用阳极氧化铝(AAO)模板法电化学沉积制备了Pt纳米线催化剂,并进行了热处理。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学测试对热处理前后Pt纳米线催化剂的晶体结构、形貌和电催化性能进行了表征,并与商业碳载铂(Pt/C)做对比。... 详细信息

采用阳极氧化铝(AAO)模板法电化学沉积制备了Pt纳米线催化剂,并进行了热处理。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学测试对热处理前后Pt纳米线催化剂的晶体结构、形貌和电催化性能进行了表征,并与商业碳载铂(Pt/C)做对比。SEM照片表明制备了表面粗糙的Pt纳米线。循环伏安法(CV)和计时电流曲线表明,Pt纳米线较Pt/C催化活性高,退火后Pt纳米线更利于甲醇氧化,且稳定性更好。旋转圆盘电极(RDE)测试研究发现,未经热处理的Pt纳米线催化剂氧还原反应(ORR)极化曲线的半波电势相对Pt/C有正移,有更大的极限扩散电流,利于氧还原反应的发生。

关键词： AAO模板铂纳米线甲醇氧化氧还原反应

High temperature treatment induced production of unreduced 2n pollen in Camellia oleifera

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Horticultural Plant Journal 2024年第3期10卷 879-896页

作者： hongda Deng Xiaoyu Zhang Song Sheng Yuxun Huang Ziqi Ye Tongyue Zhang Xing Liu Zhiqiang Han The Laboratory of Forestry Genetics Central South University of Forestry and TechnologyChangshaHunan 410004China Yuelushan Laboratory ChangshaHunan 410128China Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees of Ministry of Education Central South University of Forestry and TechnologyChangshaHunan 410004China National Forest and Seedling Workstation of Hunan Province The Forestry Department of Hunan ProvinceChangshaHunan 410004China

Unreduced gametes through chromosome doubling play a major role in the process of plant *** previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature *** study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in *** found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n *** the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell *** on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were *** male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly *** inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell ***,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n *** findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of ***.

关键词： Camellia oleifera Pollen mother cells(PMCs) High temperature Meiosis 2n pollen CoPGX3

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石墨烯/聚甲醛复合材料的摩擦学性能

高分子材料科学与工程 2021年第12期37卷 61-66页

作者：张晓阳杜鸿达陈威康飞宇广东省热管理工程与材料重点实验室清华大学深圳国际研究生院广东深圳518055

以市售聚甲醛为原料,采用注塑法制备石墨烯/聚甲醛复合材料,并进行了摩擦学性能研究。差示扫描量热分析结果表明,石墨烯的加入会导致材料熔点降低;光学显微镜图片显示,石墨烯有助于细化晶粒。加入石墨烯后,复合材料的弯曲强度有所提升,... 详细信息

以市售聚甲醛为原料,采用注塑法制备石墨烯/聚甲醛复合材料,并进行了摩擦学性能研究。差示扫描量热分析结果表明,石墨烯的加入会导致材料熔点降低;光学显微镜图片显示,石墨烯有助于细化晶粒。加入石墨烯后,复合材料的弯曲强度有所提升,冲击强度、拉伸强度出现一定程度的下降,略低于原材料,但耐磨性有显著的提升。石墨烯的加入明显降低了复合材料的摩擦系数及磨损量,且当石墨烯质量分数为0.3%时,复合材料表现出最优的减摩耐磨性,摩擦系数和磨损量分别降低了53.6%和72.5%。

关键词：石墨烯聚甲醛复合材料摩擦磨损

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宝灵曼KEYSYS生化分析仪常见故障维修

中国医学装备 2009年第12期6卷 53-54页

作者：杜宏达大连市皮肤病医院器械科辽宁大连116021

通过分析宝灵曼KEYSYS全自动生化分析仪的三例典型故障,进行逐步排查,解决故障,由此总结出的经验,可以供从事维修工作的同仁借鉴参考。

关键词：宝灵曼生化分析仪故障