Solid State NMR Spectroscopic Study of Na2MPO4F (M = Fe,Mn) as Cathode Materials for Li/Na Ion Batteries

氟代磷酸盐正极材料Na2MPO4F(M=Fe,Mn)在锂/钠离子电池体系中有着广泛的应用前景。对其材料结构及充放电机理进行研究可以帮助我们了解其充放电过程，从而优化合成方法提高其电化学性能。固体核磁共振（SolidStateNuclearMagneticResonance,SSNMR）技术可用于探测固体材料中目标原子核周围的局部化学环境，是一种有效的研究短程结构的表征手段。本论文通过固体核磁共振技术（SSNMR）结合X射线衍射表征技术（XRD）对Na2MPO4F(M=Fe,Mn)材料及其充放电过程进行了详细的研究。 通过非原位XRD和23NaMASNMR谱研究了Na2MnPO4F材料充放电过...Polyanion-type fluorophosphates Na2MPO4F ( M= Fe, Mn ) are promising cathode materials for Lithium/Sodium ion batteries. To optimize the synthetic method and improve the electrochemical performance, studying the structure of materials and the charge-discharge mechanism is quite essential. Solid state NMR can probe the local chemical environment of the nucleus in solid materials, being a useful cha...学位：理学硕士院系专业：化学化工学院_物理化学(含化学物理)学号：2052011115156

Progress in research of hypoxia in estuaries and coastal areas in China

对长江、珠江等河口及其近海水域缺氧现象与影响因素进行研究,结果表明,主要分布于长江与珠江河口及其邻近海域的缺氧现象,夏季(6-8月)达到最盛,秋; 冬季消失;长江口的缺氧区域主要位于30.75°N~32°N,122.5°E~123.25°E附近海域,具有南北2个缺氧中心;珠江口缺氧程度相对较; 轻,缺氧区域主要在广州黄埔区河段至虎门水域和伶仃洋;辽河、钱塘江、海河等河口区域也时而出现零星的缺氧现象;水体缺氧受控于多项环境要素,物理层化作; 用是缺氧产生的最初诱因之一,陆源污染物的分解则是重要的耗氧负荷;各河口区特征各异,潮汐、洋流、营养盐、叶绿素a等要素对缺氧区的范围、程度和持续时; 间影响程度不一。In order to study hypoxia in the main estuaries and adjacent coastal; areas in China, we compared the hypoxia in the estuaries of the Yangtze; River, the Pearl River, and other rivers, and analyzed the factors. We; found that hypoxia mainly occurred in the estuaries of the Yangtze; River, the Pearl River, and the adjacent coastal areas; it had the most; significant increase in the summer (from June to August) and disappeared; in the autumn and winter. The hypoxia zone in the Yangtze River Estuary; was mainly located in the area with latitudes from 30.75°N to 32°N and; longitudes from 122.5°E to 123.25°E, and there were two hypoxia centers; in the south and north, respectively. The degree of hypoxia in the Pearl; River Estuary was relatively moderate, and hypoxia mainly occurred from; the Huangpu section to Humen waters in Guangzhou and in the Lingdingyang; Channel. In addition, hypoxia occasionally occurred in the estuaries of; the Liaohe River, Qiantang River, and Haihe River. We also found that; hypoxia was subjected to many environmental factors, of which the; stratification of water was one of the initial factors and the; decomposition of terrigenous pollutants was a major factor of oxygen; consumption. Tides, upwellings, nutrients, and chlorophyll-a had; different influences on the scale, degree, and duration of hypoxia, due; to the various characteristics of the estuaries

Chemiresistive Nanosensors with Convex/Concave structures

航空航天学院陈松月副教授和化学化工学院、物理科学与技术学院双聘教授侯旭共同在国际著名期刊Nano Today (纳米科学领域权威刊物，IF=17.476)上发表了该文章。随着纳米技术和新材料的涌现，纳米传感器自90年代末出现后，因其高比表面积带来的优越性受到了越来越多的研究上和应用上的关注。本论文综述了基于一维结构（特殊凹凸结构）的化学电阻式纳米传感器，包括纳米线、纳米管和纳米孔道结构。根据传感器的不同材料和结构，分别讨论了它们的传感原理、材料和结构设计、界面设计、在不同领域中的应用。在此基础上讨论了各种纳米传感器在应用中表现出的优缺点。并提出了未来的发展将更注重传感器的稳定性、灵敏度、特异性以及器件的可集成性。【Abstract】Nanosensors have attracted tremendous, scientific and application, interests promoted by the advances in nanotechnology and emerging new nanomaterials. There has been rapid progress in developing chemiresistive nanosensors, and these sensor technologies are being transferred among a variety of different fields, from energy, environment to life science. This review presents nanomaterials with special convex/concave structures used for chemiresistive sensors, which mainly composed of one-dimensional conductive structures, e.g. nanowires, nanotubes, nanopores and nanochannels. Furthermore, designing, operation, and applications of current chemiresistive nanosensors are discussed to give an outlook of this field, especially for ionic solution and gas as the working chemical environments. The authors hope this review could inspire the active interest in the scientific field of sensor development and application.This work was supported by the National Natural Science Foundation of China (grant numbers 61601387, 21673197, U1505243), the Natural Science Foundation of Fujian Province of China (grant number 2017J05107), Young Overseas High-level Talents Introduction Plan, the 111 Project (grant number B16029), the Open Funding of State Key Laboratory of Precision Measuring Technology and Instruments (grant number pilab1709), and the Fundamental Research Funds for the Central Universities of China (grant number 20720170050). 该工作得到了国家自然科学基金（项目批准号: 61601387, 21673197, U1505243），福建省自然科学基金（项目批准号: 2017J05107），高等学校学科创新引智计划（项目批准号: B16029），精密测试技术及仪器国家重点实验室开放基金（项目批准号: pilab1709）和厦门大学校长基金（项目批准号: 20720170050）等资助与支持

纳米孔道动电效应能量转换系统的前沿研究进展

可再生清洁能源的开发和利用对人类社会的可持续发展具有重要意义。基于动电效应的纳米孔道能量转换系统将流体机械能转化为电能,有望应用于微型电源部件、自驱动纳米机器、微机电体系等领域,为清洁能源发电系统的开发提供了全新的选择。纳米孔道中的机械能-电能转换过程涉及固体孔道与流体界面间的相互作用,合理设计孔道界面的微观结构,对其进行化学修饰及探讨界面间的相互作用,是提高能量转换效率和输出功率的关键。近年来,随着纳米技术的迅猛发展及人们对界面物理化学的深入研究,纳米孔道结构和纳流体发电体系能被更精准地设计和集成。本文主要介绍了基于动电效应的纳米孔道能量转换系统的基本概念,重点关注了纳米孔道中动电效应的最新研究进展,并对该领域进行了展望,为纳米孔道动电效应能量转换系统、纳米发电机、自驱动纳米机器、可穿戴器件等领域的进一步发展和应用提供参考。国家自然科学基金(21673197,11405143);;福建省自然科学基金计划资助项目(2018J06003);;高等学校学科创新引智计划(B16029)的支持;;中央高校基本科研专项资金(20720170050)资助~

Solid-state NMR study of electrode/electrolyte materials for lithium-ion batteries

固体核磁共振(nMr)技术可探测固态材料中目标原子核周围的化学环境,是一种研究短程结构信息灵敏的表征手段.通过高转速魔角旋转6,7lI nMr谱,2d6,7lI EXSy谱以及弛豫时间T1,T2的测定,可获得锂离子电池电极/电解质材料的微观结构和离子扩散动力学信息,并可用于研究锂离子电池正负极材料在充放电过程中的结构变化,为锂离子电池电极/电解质材料的设计与发展提供理论支持.本文综述了近年来固体nMr技术在锂离子电池正负极材料、固体电解质及固体电解质界面膜(SEI)研究中的应用和发展.Solid state NMR can probe the surrounding chemical environment of nucleus in the solid materials,which is a useful characterization tool for studying the local structure informations.Through high magic angle spinning(MAS)6,7Li NMR,2D6,7Li EXSY spectra and the testing of T1,T2,we can analyze the microstructures of batteries electrode/electrolyte materials and the dynamics of lithium ions,therefor understand the structure evolution of cathode/anode materials over charge/discharge process,which provides a theoretical support for the design and development of electrode/electrolyte materials for lithium-ion batteries.In this paper,we review the recent development and application of solid state NMR techniques in the study of cathode/anode,solid electrolyte materials and solid electrolyte interface film.国家重点基础发展研究计划(2011CB935903); 国家自然科学基金重点项目(21233004)资

Preparation and Characterization of “Water-in-Salt” Polymer Electrolyte for Lithium-Ion Batteries

为提高柔性锂离子电池安全性和循环稳定性能,本实验以自由基聚合结合冷冻干燥得到的聚丙烯酰胺膜为电解质载体,引入21 mol·kg-1 LiTFSI 高浓度电解液,得到“water-in-salt”聚合物电解质。通过聚合物膜的形貌和孔道结构表征,红外光谱分析,离子电导率及电化学稳定窗口测试等对其基本物化特性进行了研究。冷冻干燥得到的聚丙烯酰胺膜内部具有大量微孔结构,有利于电解液的载入。将该吸附了电解液的聚合物电解质膜与锰酸锂(LiMn2O4)正极和磷酸钛锂(LiTi2(PO4)3)负极组装全电池进行充放电性能测试。结果表明,制得的柔性聚合物电解质具有良好的拉伸性能,高离子电导率(20°C,4.34 mS·cm-1)和宽电化学稳定窗口(3.12 V)。以“water-in-salt”聚合物电解质为隔膜组装的LiMn2O4||LiTi2(PO4)3 全电池表现出优异的倍率性能和长循环稳定性。Since the development of wearable and flexible electronic products, the demand of flexible energy storage devices such as batteries and super capacitors is in urgent. To enhance the safety and cycling stability for flexible lithium-ion batteries, “water-in-salt” polymer electrolyte was prepared by introducing 21 mol·kg-1 LiTFSI electrolyte into cross-linked polyacrylamide (PAM) after freeze-drying. A great amount of holes with the size range of 10 ~ 20 μm can be found on the surface and in the bulk of polyacrylamide, which is benefited from the freeze-drying process and acts as a great support for the electrolyte uptake. The “water-in-salt” polymer electrolyte showed good tensile property, high ionic conductivity (4.34 mS·cm-1 at 20℃), and broadened electrochemical stability window (ESW, 3.12 V). Comparing the FTIR spectra of PAM, “water-in-salt” electrolyte (WiSE) and WiSE-PAM, the signal that can be assigned to H-O bending mode transfered from 3186 cm-1 in PAM to higher wavenumber of 3560 cm-1 in WiSE-PAM. Therefore, it can be inferred that the amide group in PAM participates in the Li+ solvation sheath in WiSE-PAM electrolyte, due to the hydrogen bond between amide group and water. On the one hand, the Li+ solvation sheath can transfer through the polymer bone and the liquid in the hole, resulting in high ionic conductivity. On the other hand, due to the hydrogen bond between amide group in PAM bone and free water, the enrichment of free water along the polymer bone can be obtained. Therefore, the free water content on the electrode surface is reduced, resulting in expanded ESW. With this polymer electrolyte, LiMn2O4||LiTi2(PO4)3 full cell showed high initial charge/discharge capacity (68.1/62.1 mAh·g-1) and coulombic efficiency (91.2%) at 1 C. The high capacity retention of 94.2% (with discharge capacity of 58.5 mAh·g-1) could be obtained after 100 cycles. To evaluate the rate capability, the cells were charged and discharged at different current densities varying from 1 C to 30 C. The remarkable capacity of 28.1 mAh·g-1 was still retained even at 30 C. After the rate test, the current was decreased back to 1 C, there was still 99.2% of the initial capacity could be recovered. In addition, when cycling at 10 C rate, 79% of the initial capacity was retained even over 5000 cycles. There results demonstrate that the full cell also showed superior rate capability and long-term cycling stability. This work offers an idea for the electrolyte design with high safety to enable the application of high-performance aqueous lithium-ion batteries in flexible electronics.通讯作者:李劼E-mail:[email protected]:JieLiE-mail:[email protected] Muenster (HI MS), IEK-12,Muenster 481492.四川大学化工学院,四川 成都 6100653.Politecnico di Milano, Department of Energy, Milano 201561. Helmholtz-Institute Muenster (HI MS), IEK-12,Muenster 48149, Germany2. School of Chemical Engineering Sichuan University,Chengdu 610065, Sichuan, China3. Politecnico di Milano,Department of Energy, Milano 20156, Ital

闽江下游及河口溶解无机氮的季节分布及组成

为研究闽江下游及河口区溶解无机氮（DIN）的季节分布及组成,采集并分析了四季的表层水样。平面分布上,NO3-N不同季节有所不同;NH4-N及NO2-N不同季节分布特征基本一致,仓山区、鼓楼区附近的站位受城市污水影响而含量偏高。季节变化上,NO3-N南北段春季最高,河口段冬季最高;NH4-N南北段秋季远高于其它三个季节,河口段季节变化不大;NO2-N南北段及河口段季节变化不大。DIN组成上,南北段不同季节占比相似,DIN组成上未达到热力学平衡;河口段DIN组成季节变化不大,三态间基本达到热力学平衡。DIN[2]转化上,北段三氮之间相关性总体较弱,且与DO的相关性变化较大,三氮关系受复杂的来源、人类活动及生物化学过程影响;南段三氮之间的相关性较显著也较复杂;河口段三氮及DO之间的关系季节差异比较明显。此外,闽江下游及河口DIN年际增高及超标现象较严重。国家自然科学基金(41376050

Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport

【Abstract】The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gasesandliquids underasteady-stateapplied pressure,nearlyeliminate fouling,and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores’ deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.This work was supported by the National Natural Science Foundation of China (grant no. 21673197), the Young Overseas High-level Talents Introduction Plan, the 111 Project (grant no. B16029). 研究工作得到国家自然科学基金委（项目批准号：21673197）和厦门大学校长基金（项目批准号：20720170050）等资助与支持

Research and development in the reactive systems of wet oxidation abroad

［中文文摘］简要介绍湿式氧化反应系统的应用历史、反应机理及动力学特征,以及该反应系统的设计及现有反应设备的特点、工业化中面临的难题等。重点介绍了国外主要的已工业化的湿式氧化反应系统,并针对不同反应系统在反应设备、操作条件、处理效果等方面的特点进行比较总结。在小结湿式氧化反应系统研究应用现状的基础上提出了今后研究开发的方向。［英文文摘］The history and the reactive mechanism and kinetic properties of wetoxidation processes were (introduced), and a general description of wet oxidation (processes) was given, including the features of reactors and the (design) of related reactive systems, practical problems, etc. By reviewing the commercial experiences of wet oxidation (processes) grouped as two types for further introduction, namely, non-catalytic wet oxidation process and catalytic wet oxidation process, several main commercial reaction systems abroad were focally introduced, in which the characteristics of reactors, operating conditions and treating efficiency of each type of reactive system were generalized and compared. The further research and development work were suggested