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The study of electrochemical cycle for LiCoO_(2) by dual-mode EPR

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Magnetic Resonance Letters 2023年第1期3卷 61-66,I0003页

作者： Bei hu Fushan Geng Ming Shen bingwen hu Shanghai Key Laboratory of Magnetic Resonance State Key Laboratory of Precision SpectroscopySchool of Physics and Electronic ScienceEast China Normal UniversityShanghai200241China

Dual-mode electron paramagnetic resonance(EPR)spectroscopy was employed to analyze redox mechanisms in lithium cobalt oxide LiCoO_(2)(LCO)cathode material during delithiation and lithiation.It was found that the O_(3)-II could not fully convert back to the pristine O_(3) -I phase while oxygen vacancies quickly generate and accumulate during the cycling.Our study paves the way for better understanding the doping effects of different elements on LiCoO_(2) in the future.

关键词： LiCoO_(2) EPR Redox mechanism Lithium-ion battery

Probing microstructure of solid-state synthesized LiCoO_(2)with MAS NMR spectroscopy

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Magnetic Resonance Letters 2023年第4期3卷 298-305页

作者： Suyu Gu Guozhong Lu Nianrui Guo Juncheng Xu Yu Jiang Ming Shen bingwen hu Shanghai Key Laboratory of Magnetic Resonance State Key Laboratory of Precision SpectroscopySchool of Physics and Electronic ScienceEast China Normal UniversityShanghai200241China

LiCoO_(2)is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density,good thermal stability,and stable voltage platform.Recent works on LiCoO_(2)have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity.However,an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation.Here we employ highresolution solid-state nuclear magnetic resonance(NMR)spectroscopy to study the local atomic environments in LiCoO_(2)synthesized with three common sintering methods.While one-dimensional 7Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry,both 7Li and 59Co relaxation times are highly dependent on the sintering method.We prove that the two-step sintering method favors the elimination of unreacted Co3O4,thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO_(2)/LGPS/LiIn,which is in accordance with its narrowest 7Li linewidth and the longest 7Li/59Co T1.

关键词： LiCoO_(2) Solid-state NMR T1 relaxation Local structure

One-Pot Synthesis of Co-Based Coordination Polymer Nanowire for Li-Ion Batteries with Great Capacity and Stable Cycling Stability

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Nano-Micro Letters 2018年第2期10卷 3-11页

作者： Peng Wang Xiaobing Lou Chao Li Xiaoshi hu Qi Yang bingwen hu State Key Laboratory of Precision Spectroscopy Shanghai Key Laboratory of Magnetic Resonance School of Physics and Materials Science East China Normal University

Nanowire coordination polymer cobalt–terephthalonitrile(Co-BDCN) was successfully synthesized using a simple solvothermal method and applied as anode material for lithium-ion batteries(LIBs). A reversible capacity of 1132 mAh g^(-1) was retained after 100 cycles at a rate of 100 mAg^(-1), which should be one of the best LIBs performances among metal organic frameworks and coordination polymers-based anode materials at such a rate. On the basis of the comprehensive structural and morphology characterizations including fourier transform infrared spectroscopy,~1 H NMR,^(13)C NMR, and scanning electron microscopy, we demonstrated that the great electrochemical performance of the as-synthesized Co-BDCN coordination polymer can be attributed to the synergistic effect of metal centers and organic ligands, as well as the stability of the nanowire morphology during cycling.

关键词： Nanowire Coordination polymer Lithiumion battery Anode Ultra-high capacity

低温诱导桑蚕体内腺体相行为的高分辨^(13)C固体核磁共振研究(英文)

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波谱学杂志 2009年第1期26卷 17-26页

作者：周平胡炳文聚合物分子工程教育部重点实验室复旦大学高分子科学系上海200433 UCCS CNRS-8181 Universite des Sciences et Technologies de Lille FR-59652 Villeneuve d＇Ascq France

为什么蚕在常温常压水溶液条件下即能纺出力学性能优异的蚕丝纤维,一直是科学家们感兴趣的问题.在过去的几十年,人们曾用多种表征手段,如双折射、扫描电镜、原子力显微镜和电子散射等,在界观尺度下对蚕在吐丝过程中腺体的相行为进行研究... 详细信息

为什么蚕在常温常压水溶液条件下即能纺出力学性能优异的蚕丝纤维,一直是科学家们感兴趣的问题.在过去的几十年,人们曾用多种表征手段,如双折射、扫描电镜、原子力显微镜和电子散射等,在界观尺度下对蚕在吐丝过程中腺体的相行为进行研究.发现腺体在靠近吐丝口时呈液晶态,并认为这是导致蚕丝力学性能的重要因素.本文则在分子水平尺度下利用核磁共振方法,对五龄蚕活体在常温和6℃下存储数天后解剖的腺体进行研究.经对化学位移及其线型的各向异性分析发现,当将体内腺体沿吐丝方向分为3部,即后部、中部及靠近吐丝口的前部时,常温下,腺体后部和中后部分子呈无规线团,而腺体中中部、中前部和前部分子呈液晶态.6℃时,中后部分子亦呈液晶态,前部分子排列则各向异性更大,说明更为有序.这种液晶态呈分形结构,在小于纳米尺度下为无规线团,大于纳米尺度呈有序排列.这表明,降温过程可使呈无规线团的丝素蛋白分子转变为液晶态,其效果如同蚕在吐丝过程中对其腺体施加的剪切应力.该结果对于人们探索人工合成高性能类丝素纤维的纺丝工艺和条件将有启发和指导作用.

关键词：固体核磁共振丝素蛋白相变温度影响

Three-dimensional clogging structures of granular spheres near hopper orifice

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Chinese Physics B 2022年第1期31卷 388-394页

作者：杨敬宫殿锦丰汪晓雪王志超李建奇胡炳文夏成杰 Shanghai Key Laboratory of Magnetic Resonance School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China

The characteristic clogging structures of granular spheres blocking three-dimensional granular flow through hopper outlet are analyzed based on packing structures reconstructed using magnetic resonance imaging techniques.Spheres in clogging structures are arranged in a way with typical features of load-bearing,such as more contacting bonds close to the horizontal plane and more mutually-stabilized contact configurations than packing structures away from the orifice.The requirement of load-bearing inevitably leads to the cooperativity of clogging structures with a correlation length of several particle diameters.This correlation length being comparable with the orifice diameter suggests that a clogging structure is composed of several mutually-stabilized structural motifs to span the orifice perimeter,instead of a collection of independent individual spheres to cover the whole orifice area.Accordingly,we propose a simple geometric model to explain the unexpected linear dependence of the average size of three-dimensional clogging structures on orifice diameter.

关键词： granular materials clogging magnetic resonance imaging

锂离子电池中重要正极材料体系的磁共振研究进展

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储能科学与技术 2019年第6期8卷 1017-1023页

作者：耿福山胡炳文华东师范大学物理与电子科学学院&上海市磁共振重点实验室

锂离子电池得到了快速发展,并改变了我们的生活。锂离子电池正极材料的研究是提高电池性能的关键;而理解正极材料的性能与结构之间的关系、阐释正极材料的电化学反应机理(尤其是性能衰减与失效机理)有助于提高材料的能量密度和功率密度... 详细信息

锂离子电池得到了快速发展,并改变了我们的生活。锂离子电池正极材料的研究是提高电池性能的关键;而理解正极材料的性能与结构之间的关系、阐释正极材料的电化学反应机理(尤其是性能衰减与失效机理)有助于提高材料的能量密度和功率密度。磁共振技术(含核磁共振和顺磁共振)在过去三十多年的研究中不断进步,逐渐成为研究正极材料构效关系的关键技术之一。本文总结了几个重要的已经商业化的正极材料(LiCoO2、NCA、NMC和LiFePO4)的磁共振研究进展,展示了核磁共振、顺磁共振在正极材料构效关系研究中的重要作用;尤其值得一提的是原位技术的发展在电化学反应机理中逐渐显示出其重要性。本文有助于了解磁共振技术在电池材料研究中的重要价值,并进一步推动磁共振技术的发展。

关键词：正极材料核磁共振顺磁共振

基于氮原子氧化还原的双金属沸石咪唑框架用于高性能锂离子电池负极(英文)

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Science China Materials 2018年第8期61卷 1040-1048页

作者：娄霄冰宁艳群李超胡小诗沈明胡炳文 State Key Laboratory of Precision Spectroscopy Shanghai Key Laboratory of Magnetic Resonance Institute of Functional Materials School of Physics and Materials Science East China Normal University Shanghai 200062 China

本文首次水热合成了一种双金属沸石咪唑有机框架(CoZn-ZIF)并将其用于锂离子电池负极.该材料在以100 mAg^(-1)电流充放电时,具有605.8 mAhg^(-1)的可逆容量,远远大于同类单金属材料(Co-ZIF-67和Zn-ZIF-8).为了探知该高容量来源,我们进... 详细信息

本文首次水热合成了一种双金属沸石咪唑有机框架(CoZn-ZIF)并将其用于锂离子电池负极.该材料在以100 mAg^(-1)电流充放电时,具有605.8 mAhg^(-1)的可逆容量,远远大于同类单金属材料(Co-ZIF-67和Zn-ZIF-8).为了探知该高容量来源,我们进行了一系列非原位实验,包括同步辐射软线、粉末衍射、透射电镜以及顺磁共振.研究表明该双金属高容量主要得益于配位氮原子参与锂化反应,在这一过程中还伴随了金属氮配位键的打开与重新配合.另外,少量金属氮配位键的不可逆反应会导致该材料晶体的无序化以及一些氮自由基的生成.这种高活性双金属的设计思路和反应机理可推广到包括催化、气体吸附等的其他应用中.

关键词：电池负极双金属氮原子锂离子氧化还原框架咪唑沸石

Molecular fluorescence significantly enhanced by gold nanoparticles@zeolitic imidazolate framework-8

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Chinese Physics B 2023年第5期32卷 462-470页

作者：张钰伊卞亚杰张炜刘易婷张晓磊陈梦迪胡炳文金庆原 State Key Laboratory of Precision Spectroscopy Shanghai Key Laboratory of Magnetic ResonanceSchool of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Department of Optical Science and Engineering Fudan UniversityShanghai 200433China

Noble metal nanoparticles exhibit unique surface plasmon resonance dependent optical properties.On this basis,gold nanoparticles(AuNPs)encapsulated in metal–organic frameworks(MOFs)can form AuNPs@MOFs composites to modulate the optical properties of fluorescent molecules,which is less reported.In this paper,based on the fluorescence enhancement effect of AuNPs on 2-(2-hydroxyphenyl)-1H-benzimidazole(HPBI)molecules,zeolitic imidazolate framework-8(ZIF-8)crystals with structural stability were introduced.AuNPs@ZIF-8 exhibited a significantly pronounced fluorescence enhancement of the HPBI molecules.In addition,by comparing the fluorescence characteristics of the HPBI molecules adsorbed on AuNPs@ZIF-8 and those captured in AuNPs@ZIF-8,we found that the ZIF-8 can act as a spacer layer with highly effective near-field enhancement.All our preliminary results shed light on future research on the composite structures of noble metal particles and MOFs for fluorescent probes and sensing applications.

关键词： ZIF-8 gold nanoparticles fluorescence spectra fluorescence lifetime

面向金属离子电池研究的固体核磁共振和电子顺磁共振方法

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物理化学学报 2020年第4期36卷 12-27页

作者：李超沈明胡炳文华东师范大学物理与材料科学学院上海市磁共振重点实验室上海200062

电池,尤其是锂离子电池的快速发展极大改变了我们的生活。从移动电子设备到新能源汽车再到电网储能,电池应用于多个领域且目前在能量密度和功率密度方面难以被取代。电池技术的向前发展要求我们对其电化学反应机理有完整的认识,这需要... 详细信息

电池,尤其是锂离子电池的快速发展极大改变了我们的生活。从移动电子设备到新能源汽车再到电网储能,电池应用于多个领域且目前在能量密度和功率密度方面难以被取代。电池技术的向前发展要求我们对其电化学反应机理有完整的认识,这需要来自不同领域研究人员的交叉碰撞。磁共振波谱技术包括核磁共振波谱(NMR)和电子顺磁共振波谱(EPR),前者适合于研究Li、Na、P、O等电池材料中常见的轻元素,后者适合于研究Co、Mn、Fe、V等电池材料中常见的过渡金属。加上它们具有对样品无损、对结晶度无要求、能够定量分析等优点,NMR和EPR在过去三十年的电池研究中不断进步,日益成为电池表征的重要角色。本文从磁共振方法的角度出发,首先概述了固体NMR和EPR中的主要相互作用及其哈密顿表达形式,接着概述了固体NMR和EPR常用的重要方法及其在金属离子电池研究领域的代表性应用。本文有助于让我们直观地了解磁共振技术本身在金属离子电池研究领域的重要价值,并有望为解决利用固体NMR和EPR进行电池研究的过程遇到的困难提供指导。

关键词：固体核磁共振电子顺磁共振锂离子电池钠离子电池充放电机理构效关系局域结构