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Modification strategies for non-aqueous, highly proton-conductive benzimidazole-based high-temperature proton exchange membranes

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Chinese Chemical Letters 2024年第4期35卷 43-51页

作者： yunfa dong Shijie Zhong Yuhui He Zhezhi Liu Shengyu Zhou Qun Li Yashuai Pang Haodong Xie Yuanpeng Ji Yuanpeng Liu Jiecai Han Weidong He National Key Laboratory of Science and Technology on Advanced Composites in Special Environments and Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080China School of Petroleum Engineering Chongqing University of Science and TechnologyChongqing 401331China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China Chongqing Research Institute Harbin Institute of TechnologyChongqing 401151China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

High-temperature proton exchange membranes(HT-PEMs) possess excellent thermal and outstanding electrochemical stability, providing an avenue to realize high-temperature proton exchange membranes fuel cells(HT-PEMFCs) with both superior power density and long-term durability. Unfortunately, polybenzimidazole(PBI), a typical material for conventional HT-PEMs, fails to compromise the high nonaqueous proton conductivity and high mechanical properties, thus hindering their practical applications.Achieving efficient nonaqueous proton conduction is crucial for HT-PEMFC, and many insightful research works have been done in this area. However, there still lacks a report that integrates the host-guest interactions of phosphoric acid doping and the structural stability of polymers to systematically illustrate modification strategies. Here, we summarize recent advancements in enhancing the nonaqueous proton conduction of HT-PEMs. Various polymer structure modification strategies, including main chain and side group modification, cross-linking, blocking, and branching, are reviewed. Composite approaches of polymer, including compounding with organic porous polymers, filling the inorganic components and modifying with ionic liquids, etc., are also covered in this work. These strategies endow the HT-PEMs with more free volume, nanophase-separated structure, and multi-stage proton transfer channels, which can facilitate the proton transportation and improve their performance. Finally, current challenges and future directions for further enhancements are also outlined.

关键词： Benzimidazole Nonaqueous proton conduction Free volume Nanophase-separated structure Structure modification

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Talcum-doped composite separator with superior wettability and heatproof properties for high-rate lithium metal batteries

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Chinese Chemical Letters 2023年第1期34卷 139-144页

作者： Mengqiu Yang Yuanpeng Ji yunfa dong Botao Yuan Liwei dong Yuanpeng Liu Sue Hao Chunhui Yang Xiaoqiang Wu Qingquan Kong Jiecai Han Weidong He MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150080China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments and Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080China State Key Laboratory of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150080China School of Mechanical Engineering Chengdu UniversityChengdu 610106China Chongqing Research Institute Harbin Institute of TechnologyChongqing 401151China

Separator is supposed to own outstanding thermal stability,superior wettability and electrolyte uptake,which is essential for developing high-rate and safe lithium metal batteries(LMBs).However,commercial polyolefin separators possess poor wettability and limited electrolyte uptake.For addressing this issue,we put forward a composite separator to implement above functions by doping layered-silicate(talcum)into polyvinylidene fluoride(PVDF).With significant improvement of electrolyte absorption benefiting from the strong adsorption energy values(-1.64-1.70 eV)between talcum and the electrolyte in lithium metal batteries,PVDF/Talcum(PVDF/TM)composite separator owns a small contact angle and superior electrolyte uptake.PVDF/TM composite separator with 10 wt%talcum(T-10)owns a tiny contact angle of 8°,while those of polypropylene(PP)and PVDF are 48°and 20°with commercial electrolyte.Moreover,the addition of thermotolerant talcum endows the T-10 composite separator with great thermostability,whose thermal shrinkage is only 5.39%at 150°C for 0.5 h.The cell with LiFeO4cathode and the T-10 composite separator reaches 91.7 m Ah/g in discharge capacity at 4.8 m A/cm^(2)(10 C),far superior to that with pure PVDF separator(56.3 m Ah/g)and PP(51.4 m Ah/g).

关键词： Lithium metal batteries Composite separator PVDF Talcum Wettability Thermal stability

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Unified throughout-pore microstructure enables ultrahigh separator porosity for robust high-flux lithium batteries

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Electron 2023年第1期1卷 37-49页

作者： dongjiang Chen Yuanpeng Liu Chao Feng Yuhui He Shengyu Zhou Botao Yuan yunfa dong Haodong Xie Guangfeng Zeng Jiecai Han Weidong He National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbinChina Center for Composite Materials and Structures Harbin Institute of TechnologyHarbinChina State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of ChinaChengduChina Chongqing Research Institute Harbin Institute of TechnologyChongqingChina Interdisciplinary Graduate Program in Materials Science Vanderbilt UniversityNashvilleTennesseeUSA

With small thickness,commercial polyolefin separators own low porosity to ensure sufficient thermomechanical properties,resulting in tortuous and enlarged Li+diffusion pathways that induce large overpotentials and detrimental dendrite growth.As a dilemma,the exploration of highly porous separators has been challenged by their large thickness,impairing the applicability of such pursuits.Herein,an ultraporous architecture is designed to shorten Li+transfer pathways by impregnating electrolyteaffinitive poly(vinylidene fluoride-co-hexafluoropropylene)into ultralight~3μm 3D-polytetrafluoroethylene scaffold(abbreviated as UP3D).The UP3D separator with a porosity of 74%gives rise to 70%enhancement in Li+transference and 77%reduction in Li+transfer resistance(2.67 mΩmm^(−1))and thus enables an ultrahigh Li+flux of 22.7 mA cm^(−2),effectively alleviating Li+concentration gradient across the separator.With the separator,the LiFePO4 half cell delivers a capacity of 118 mAh g^(−1) with an unparalleled capacity retention of 90%after 1000 cycles at 2 C,and a graphite||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)pouch full cell delivers an areal energy density of 6.8 mWh cm^(−2)at 8.848 mA(1.4 mA cm^(−2))with a high cathode loading of 134.9 mg.Such results,together with the scalable production of the separator,reflect its promising potential in high-flux battery applications of separators that require both ultrahigh porosity and reliability.

关键词： Li deposition Li-ion batteries polytetrafluoroethylene separator ultrahigh porosity

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Relationships between modern pollen and vegetation and climate on the eastern Tibetan Plateau

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Research in Cold and Arid Regions 2023年第2期15卷 92-104页

作者： Lin Lin yunfa Miao YongTao Zhao dong Yang Gen Wang College of Geography and Environmental Science Northwest Normal UniversityLanzhouGansu 730070China Key Laboratory of Oasis Resources Environment and Sustainable DevelopmentNorthwest Normal UniversityLanzhouGansu 730070China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources ResearchInstitute of Geology and GeophysicsChinese Academy of SciencesLanzhouGansu 73000China

The Tibetan Plateau ecosystem is fragile and sensitive to climate change. Understanding the relationships between modern pollen and the vegetation and climate of the region is critical for the evaluation of ecological processes.Here, we explore modern pollen assemblages of typical land-cover types at a large spatial scale by analyzing 36surface samples from the southeastern Tibetan Plateau, supplemented by typical desert, desert-steppe, and steppe meadow transition data selected from the Chinese Surface Pollen Database, giving a total of 75 samples. We used redundancy analysis(RDA) to explore the responses of vegetation in the assemblages to regional climate. Our results show that pollen assemblages generally reflect the vegetation composition: assemblages from alpine meadow samples are dominated by Cyperaceae, Asteraceae, Rosaceae, and Polygonaceae;alpine shrublands mainly comprise Fabaceae, Rosaceae, Ericaceae, and Quercus(Q. spinosa);and coniferous forest surface samples mainly comprise Picea, Abies, Pinus, and Betulaceae. Our RDA shows that mean annual precipitation(MAP) is the main meteorological factor affecting the pollen assemblage and vegetation type;MAP positively correlates with percentages of Cyperaceae, Poaceae, Rosaceae, and Asteraceae, and negatively correlates with percentages of Chenopodiaceae, Ephedraceae, Nitraria, and Tamaricaceae. The ratio of Artemisia to Chenopodiaceae is a useful indicator to distinguish temperate desert from other land-cover types on the Tibetan Plateau, while the ratio of Cyperaceae + Asteraceae to Artemisia + Chenopodiaceae can be used to distinguish arid desert from other landcover types, and may provide a useful altitude index for the eastern Tibetan Plateau.

关键词： Surface pollen Tibetan Plateau Climate change Vegetation

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化工冶金跨行业耦合二氧化碳循环利用技术

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洁净煤技术 2024年第4期30卷 171-178页

作者：李双德李振荣董笑陈为刘一凡李少鹏程景才李会泉陈运法中国科学院过程工程研究所北京100190 中国科学院大学北京100049 中国科学院山西煤炭化学研究所山西太原030001 中国科学院上海高等研究院上海201210

双碳战略是国家重大战略,也是推动国家经济高质量可持续发展的必由之路。我国碳达峰到碳中和时间短、任务重。我国化工冶金每年碳排放约36亿t,约占全国工业碳排放量的36%,此外化工冶金废气、固废、废热产生量大、堆存量多、难利用、循... 详细信息

双碳战略是国家重大战略,也是推动国家经济高质量可持续发展的必由之路。我国碳达峰到碳中和时间短、任务重。我国化工冶金每年碳排放约36亿t,约占全国工业碳排放量的36%,此外化工冶金废气、固废、废热产生量大、堆存量多、难利用、循环利用率低。发展化工冶金低碳化转型和变革,是我国工业领域双碳目标实现的根本保证。我国化工冶金历时百年,已发展成熟,仅通过原料燃料替代及绿色工艺转型减碳容量有限,亟需开展化工冶金跨行业耦合与循环利用技术变革,深入推动工业领域减碳。我国化工冶金大多是孤立、非循环连续工艺过程,引起跨行业耦合难、循环利用难度大的问题。针对上述问题,首先分析了化工冶金行业碳排放治理现状及国家战略需求;其次,提出了废气与废热耦合热化学转化制高质气体、废气与废气耦合定向催化制高端化学品、废气与固废耦合制低碳材料3个减碳增效策略。结合其技术发展现状和趋势,提出了拟重点发展的化工冶金跨行业耦合二氧化碳循环利用技术,以期为工业低碳绿色发展提供支撑。

关键词：化工冶金二氧化碳碳减排跨行业耦合循环利用

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Filter paper-templated preparation of ZnO thin films and examination of their gas-sensing properties

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Particuology 2011年第3期9卷 253-259页

作者： Bao Wang Ning Han dong Meng Renliang Yue Jinghui Yan yunfa Chen School of Chemistry and Environmental Engineering Changchun University of Science and Technology Changchun 130022 China Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

ZnO thin films prepared by using quantitative filter paper as a template and Zn（CH3CO2）2.2H2O ethanol precursor solution were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The effects of sample calcination temperature, precursor concentration and filter paper types were studied, and the growth process was investigated by infra-red （IR） spectroscopy and thermogravimettic analysis/differential thermal analysis （TGA/DTA）. The results show that samples soaked in a 1.5 mol/L Zn（CH3 CO2）2.2H2O ethanol solution and calcined at 600 ℃ yield ZnO films of uniform particle size, approximately 30, 40 and 50 nm. for fast-, medium- and slow-speed filter papers, respectively. The formaldehyde gas sensing properties of the ZnO nanoparticles were tested, showing that the material prepared from fast-speed filter paper has a higher response to 120-205 ppm formaldehyde at 400 ℃ than that prepared from medium- or slow-sneed paper, which depends on the narticle size.

关键词： ZnO thin films Quantitative filter paper Template Gas sensing properties

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Environmental indicators from comparison of sporopollen in early Pleistocene lacustrine sediments from different climatic zones

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Chinese Science Bulletin 2010年第26期55卷 2981-2988页

作者： WU FuLi FANG XiaoMin MIAO yunfa dong Ming Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Key Laboratory of Western China's Environmental Systems Ministry of Education & College of Resources and Environment Lanzhou Univer- sity Lanzhou 730000 China The Tourism and Geography Department Yunnan Normal University Kunming 650092 China

Two lacustrine sporopollen records obtained from the Qaidam Basin (in the non-monsoonal region) and the Linxia Basin (in the monsoonal transition zone) indicate that during the early Pleistocene open forest-steppe/steppe vegetation developed in the Qaidam Basin, while in the Linxia Basin an open cypress forest-steppe shifted to a conifer/conifer-steppe and then to open forest-steppe vegetation. Existing sporopollen records from the Chinese Loess Plateau (CLP) (in the monsoonal region) indicate that around the Sanmen Paleolake open forest-steppe shifted to pine/conifer-broadleaved mixed forest. The conifer cover then changed to a subtropical evergreen broadleaved forest distributed around the Nihewan Paleolake. These changes suggest that wetter conditions progressed from western China to the east, and the climate became more humid than that of today indicating a stronger Asian summer monsoon during the early Pleistocene.

关键词：早更新世孢粉记录湖相沉积物环境指标气候带亚热带常绿阔叶林柴达木盆地草原植被

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河西走廊东部2019—2022年空气孢粉组合特征及影响因素

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地球科学进展 2023年第6期38卷 631-643页

作者：蓝小玉杨东苗运法赵永涛雷艳万正西北师范大学地理与环境科学学院甘肃兰州730070 甘肃省绿洲资源环境与可持续发展重点实验室甘肃兰州730070 中国科学院西北生态环境资源研究院沙漠与沙漠化重点实验室甘肃兰州730000 中国科学院大学北京100049 兰州大学资源环境学院甘肃兰州730000

对空气孢粉散播和沉积过程的研究有助于理解现代植被组成及其与气候变化的关系,但迄今为止在干旱区开展的空气孢粉研究工作仍十分有限。利用自主设计的孢粉收集装置,在河西走廊东部祁连山北侧的古浪地区进行了连续3年(2019年7月至2022年... 详细信息

对空气孢粉散播和沉积过程的研究有助于理解现代植被组成及其与气候变化的关系,但迄今为止在干旱区开展的空气孢粉研究工作仍十分有限。利用自主设计的孢粉收集装置,在河西走廊东部祁连山北侧的古浪地区进行了连续3年(2019年7月至2022年6月)以月为时间尺度的观测研究,分析了草本植物、木本植物花期和非花期的孢粉百分比组成特征,探究了主要花粉的代表性;同时,讨论了孢粉浓度变化基本特征及其与典型气象要素(温度、降水、风速和风向)之间的关系。研究结果表明:①研究点空气孢粉组合主要以草本类型为主,高值出现在7~10月(93.7%),低值出现在4~6月(62.9%),相应的木本植物花粉高值出现在4~6月(37.1%),低值出现在7~10月(6.3%)。草本植物和木本植物孢粉浓度与各自花期有很好的对应关系:草本植物花期和高浓度出现在7~10月,木本植物则主要出现在4~6月,草本植物浓度对总浓度影响最大。②孢粉组合与当地植被有很好的对应关系,杨属(Populus)和柏科(Cupressaceae)花粉能较好地反映当地植被特征,禾本科(Poaceae)花粉具低代表性,蒿属(Artemisia)、苋科(Amaranthaceae)、桦木属(Betula)以及云杉属(Picea)花粉具有超代表性。③由于木本植物主要分布在东南方,其花期(4~6月)的风向会影响木本植物花粉含量,非花期(11月至次年3月)风速在1.48~1.75 m/s时最有利于花粉的传播,风速过小时风的携带能力差,风速过大,对孢粉的飘散和收集产生负面影响;降水与孢粉产量存在正相关关系,即花期时降水越多孢粉浓度越高。上述研究结果可以为解释河西走廊东部不同时间尺度的孢粉记录与气候环境变化的关系,以及河西走廊地区生态环境保护提供重要的孢粉生态学方面的参考依据。

关键词：空气孢粉孢粉组合气象要素现代过程

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一种新型结合下肢动觉运动想象和视觉运动想象的脑机接口

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南京大学学报（自然科学版） 2022年第3期58卷 460-468页

作者：董煜阳龚安民丁鹏袁密桁王东庆伏云发昆明理工大学信息工程与自动化学院昆明650500 昆明理工大学脑认知与脑机智能融合团队昆明650500 武警工程大学信息工程学院西安710086

基于运动想象(Motor Imagery,MI)的脑-机接口(Brain-Computer Interface,BCI)是一类重要的BCI,传统的MI方式是动觉运动想象(Kinesthetic Motor Imagery,KMI),较少采用视觉运动想象(Visual Motor Imagery,VMI).提出一种KMI与VMI混合的BCI并评估其性能.共招募12名被试参加离线与在线实验EEG(Electroencephalogram)数据采集,离线实验先以KMI方式分别进行屈膝和伸膝,然后分别以KMI,VMI和VKMI三种方式行走,由离线分类精度与三种不同方式想象行走的脑激活程度确定在线实验方案.提取EEG幅值包络线特征,并采用朴素贝叶斯分类器、二次线性判别和决策树进行在线分类,验证系统性能.溯源分析表明,使用新的想象方式进行行走想象时,运动皮层的激活时长高于VMI,体感皮层的激活时长高于KMI,混合的想象方式可能更有利于促进这些脑区的可塑性. 12名被试在线测试三分类的平均准确度达到63.29%±0.09%,平均卡帕系数为0.45±0.13.该研究可望为未来研发下肢运动功能障碍康复训练BCI系统提供思路.

关键词：视觉运动想象动觉运动想象溯源分析下肢运动意图在线模型选择

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高速列车橡胶外风挡表面涂层的制备及性能

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电镀与涂饰 2022年第2期41卷 113-117页

作者：李嘉炜孙翌姜晓妍鉴冉冉黄靖曾宪奎王东姜云法青岛科技大学机电工程学院山东青岛266061 青岛澳泰交通设备有限公司山东青岛266109 青岛绿金源安全技术有限公司山东青岛266041

采用正交试验法考察了基材粗糙度、固化剂配比、固化温度、固化时间等工艺参数对高速列车橡胶外风挡涂层性能的影响。确定了最佳工艺方案为:基材打磨选择150目加240目的砂纸,主剂与固化剂的配比为6∶1,在100℃下固化60 min。按此工艺方... 详细信息

采用正交试验法考察了基材粗糙度、固化剂配比、固化温度、固化时间等工艺参数对高速列车橡胶外风挡涂层性能的影响。确定了最佳工艺方案为:基材打磨选择150目加240目的砂纸,主剂与固化剂的配比为6∶1,在100℃下固化60 min。按此工艺方案制备的涂层具有以下性能:附着强度0级,光泽21.6 Gs,出现裂纹的最大拉伸量181%,拉伸疲劳寿命4832次。

关键词：高速列车橡胶外风挡涂层正交试验固化附着强度光泽疲劳寿命

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