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Mg/Fe site-specific dual-doping to boost the performance of cobalt-free nickle-rich layered oxide cathode for high-energy lithium-ion batteries

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Journal of Energy Chemistry 2024年第4期91卷 670-679页

作者： Yunting Wang gaohui du Di Han Wenhao Shi Jiahao Deng Huayu Li Wenqi Zhao Shukai Ding Qingmei Su Bingshe Xu Materials Institute of Atomic and Molecular Science Shaanxi University of Science and TechnologyXi'an 710021ShanxiChina Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024ShanxiChina Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

Layer-type LiNi0.9Mn0.1O2is promising to be the primary cathode material for lithium-ion batteries(LIBs)due to its excellent electrochemical performance.Unfortunately,the cathode with high nickel content suffers from severely detrimental structural transformation that causes rapid capacity attenuation.Herein,site-specific dual-doping with Fe and Mg ions is proposed to enhance the structural stability of LiNi0.9Mn0.1O2.The Fe3+dopants are inserted into transition metal sites(3b)and can favorably provide additional redox potential to compensate for charge and enhance the reversibility of anionic redox.The Mg ions are doped into the Li sites(3a)and serve as O_(2)^(-)-Mg^(2+)-O_(2)^(-)pillar to reinforce the electrostatic cohesion between the two adjacent transition-metal layers,which further suppress the cracking and the generation of harmful phase transitions,ultimately improving the cyclability.The theoretical calculations,including Bader charge and crystal orbital Hamilton populations(COHP)analyses,confirm that the doped Fe and Mg can form stable bonds with oxygen and the electrostatic repulsion of O_(2)^(-)-O_(2)^(-)can be effectively suppressed,which effectively mitigates oxygen anion loss at the high delithiation state.This dual-site doping strategy offers new avenues for understanding and regulating the crystalline oxygen redox and demonstrates significant potential for designing high-performance cobalt-free nickel-rich cathodes.

关键词： Cobalt-free Layered oxide Cathode dual dopants Density functional theory calculation

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Sulfur-deficient CoNi_(2)S_(4)nanoparticles-anchored porous carbon nanofibers as bifunctional electrocatalyst for overall water splitting

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Frontiers of Chemical Science and Engineering 2023年第11期17卷 1707-1717页

作者： gaohui du Yi Fan Lina Jia Yunting Wang Yawen Hao Wenqi Zhao Qingmei Su Bingshe Xu Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030000China Materials Institute of Atomic and Molecular Science Shaanxi University of Science and TechnologyXi’an 710021China

Water electrolysis technology is considered to be one of the most promising means to produce hydrogen.Herein,aiming at the problems of high overpotential and slow kinetics in water splitting,N-doped porous carbon nanofibers-coupled CoNi_(2)S_(4)nanoparticles are prepared as bifunctional electrocatalyst.In the strategy,NaCl is used as the template to prepare porous carbon nanofibers with a large surface area,and sulfur vacancies are created to modulate the electronic structure of CoNi_(2)S_(4).Electron spin resonance confirms the formation of abundant sulfur vacancies,which largely reduce the bandgap of CoNi_(2)S_(4)from 1.68 to 0.52 eV.The narrowed bandgap is conducive to the migration of valence electrons and decreases the charge transfer resistance for electrocatalytic reaction.Moreover,the uniform distribution of CoNi_(2)S_(4)nanoparticles on carbon nanofibers can prevent the aggregation and facilitate the exposure of electrochemical active sites.Therefore,the composite catalyst exhibits low overpotentials of 340 mV@100 mA·cm^(-2)for oxygen evolution reaction and 380 mV@100 mA·cm^(-2)for hydrogen evolution reaction.The assembled electrolyzer requires 1.64 V to achieve 10 mA·cm^(-2)for overall water-splitting with good long-term stability.The excellent performance results from the synergistic effect of porous structures,sulfur deficiency,nitrogen doping,and the well-dispersed active component.

关键词： nanoparticle sulfur vacancy porous carbon nanofiber transition metal sulfides electrolysis

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Unraveling the degradation mechanism of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) at the high cut-off voltage for lithium ion batteries

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Journal of Energy Chemistry 2023年第2期77卷 428-437,I0011页

作者： Liming Wang Qingmei Su Bin Han Weihao Shi gaohui du Yunting Wang Huayv Li Lin Gu Wenqi Zhao Shukai Ding Miao Zhang Yongzhen Yang Bingshe Xu School of Materials Science&Engineering Shaanxi University of Science and TechnologyXi’an 710021ShaanxiChina Materials Institute of Atomic and Molecular Science Shaanxi University of Science and TechnologyXi’an 710021ShaanxiChina School of Materials Science&Engineering Tsinghua UniversityBeijing 100084China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030032ShanxiChina Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy densities at high operation voltage.However,the capacity fading under high operation voltage still restricts the practical application.Herein,the capacity degradation mechanism of NCM811 at atomic-scale is studied in detail under various cut-off voltages using aberration-corrected scanning transmission electron microscopy(STEM).It is observed that the crystal structure of NCM811 evolution from a layered structure to a rock-salt phase is directly accompanied by serious intergranular cracks under 4.9 V,which is distinguished from the generally accepted structure evolution of layered,disordered layered,defect rock salt and rock salt phases,also observed under 4.3 and 4.7 V.The electron energy loss spectroscopy analysis also confirms the reduction of Ni and Co from the surface to the bulk,not the previously reported only Li/Ni interlayer mixing.The degradation mechanism of NCM811 at a high cut-off voltage of4.9 V is attributed to the formation of intergranular cracks induced by defects,the direct formation of the rock salt phase,and the accompanied reduction of Ni^(2+)and Co^(2+)phases from the surface to the bulk.

关键词： Ni-rich layered cathode Electrochemical performance Degradation mechanism Crack Atomic scale

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石墨烯气凝胶复合材料在电化学储能中的应用研究进展

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复合材料学报 2024年第4期41卷 1694-1711页

作者：惠晨柯闫翎鹏杨未鹏崔晋超杨永珍苏庆梅杜高辉刘旭光许并社太原理工大学新材料界面科学与工程教育部重点实验室太原030024 陕西科技大学材料原子•分子材料研究所西安710021 太原理工大学材料科学与工程学院太原030024 山西浙大新材料与化工研究院太原030032

石墨烯气凝胶作为一种内部互连的三维框架体,在微观和宏观尺度上具有突出的维度特性,成为各种零维、一维、二维和三维材料的理想宿主。其高导电性、高比表面积及高结构稳定性等特点令石墨烯气凝胶在储能领域得到了广泛的应用,特别是在... 详细信息

石墨烯气凝胶作为一种内部互连的三维框架体,在微观和宏观尺度上具有突出的维度特性,成为各种零维、一维、二维和三维材料的理想宿主。其高导电性、高比表面积及高结构稳定性等特点令石墨烯气凝胶在储能领域得到了广泛的应用,特别是在高比容量金属离子电池负极和超级电容器电极等领域。首先,本文对石墨烯前体及气凝胶的处理策略进行整理,介绍当前不同处理方式对石墨烯前体及气凝胶成型影响。其次,根据储能机制的不同,介绍石墨烯气凝胶复合材料在主流储能器件中的改性应用及性能表现。最后,对电化学储能用石墨烯气凝胶复合材料的研究进展进行总结,指出当前存在的挑战并展望未来的研究方向。

关键词：石墨烯气凝胶储能材料复合材料储能应用电化学

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Numerical simulation of the dynamic migration mechanism and prediction of saturation of tight sandstone oil

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Science China Earth Sciences 2024年第1期67卷 179-195页

作者： gaohui CAO Mian LIN Likuan ZHANG Lili JI Wenbin JIANG Institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

Quantitative characterization of tight sandstone oil migration and accumulation is an emerging research frontier in the field of oil and gas exploration.In this study,a conceptual model containing multiple basic geological elements is developed,and a nonlinear seepage numerical model for tight sandstone oil migration and accumulation is established.The effects of the slip effect,overpressure driving force,buoyancy,and capillary force on the migration and accumulation of tight oil are examined.The results showed that(1)the differences in oil migration and accumulation between tight and conventional reservoirs are reflected in the growth mode of oil saturation,distribution characteristics of oil and water,and extent of the effect of the formation dip angle;(2)the slip effect has a significant impact when the average pore throat radius is less than 150 nm and the overpressure driving force and capillary force are the main mechanical mechanisms controlling oil migration and accumulation in tight sandstone,while the coupling effect of buoyancy,capillary force,and overpressure driving force controls the upper and lower limits of oil saturation.Finally,a dimensional and dimensionless identification chart for rapidly predicting the oil saturation of tight sandstone is proposed and verified using the measured data.This study provides a basis for analyzing the migration and accumulation mechanisms of tight sandstone oil and a new approach for predicting oil saturation.Additionally,we developed digital and visual analysis methods for the migration results,enriching the expression of the dynamics of hydrocarbon accumulation.

关键词： Tight sandstone Migration and accumulation Dynamics Oil saturation Numerical simulation

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Diphylleia Grayi-Inspired Intelligent Temperature-Responsive Transparent Nanofiber Membranes

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Nano-Micro Letters 2024年第4期16卷 67-78页

作者： Cengceng Zhao gaohui Liu Yanyan Lin Xueqin Li Na Meng Xianfeng Wang Shaoju Fu Jianyong Yu Bin Ding Shanghai Frontier Science Research Center of Advanced Textiles College of TextilesDonghua UniversityShanghai 201620People’s Republic of China

Nanofiber membranes(NFMs) have become attractive candidates for next-generation flexible transparent materials due to their exceptional flexibility and breathability. However, improving the transmittance of NFMs is a great challenge due to the enormous reflection and incredibly poor transmission generated by the nanofiber-air interface. In this research, we report a general strategy for the preparation of flexible temperature-responsive transparent(TRT) membranes,which achieves a rapid transformation of NFMs from opaque to highly transparent under a narrow temperature window. In this process, the phase change material eicosane is coated on the surface of the polyurethane nanofibers by electrospray technology. When the temperature rises to 37 ℃, eicosane rapidly completes the phase transition and establishes the light transmission path between the nanofibers, preventing light loss from reflection at the nanofiber-air interface. The resulting TRT membrane exhibits high transmittance(> 90%), and fast response(5 s). This study achieves the first TRT transition of NFMs, offering a general strategy for building highly transparent nanofiber materials, shaping the future of next-generation intelligent temperature monitoring, anti-counterfeiting measures, and other high-performance devices.

关键词： Biomimetic Transparent Nanofibrous membrane Temperature response Phase change materials

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中性粒细胞胞外诱捕网在动脉粥样硬化中的研究进展

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华中科技大学学报（医学版） 2023年第2期52卷 252-256页

作者：杜高辉张青魏宇淼华中科技大学同济医学院附属协和医院心内科武汉430022

动脉粥样硬化是由脂质驱动,多种细胞共同参与的血管慢性炎症性疾病。中性粒细胞胞外诱捕网(neutrophil extracellular trapping nets,NETs)是中性粒细胞响应炎症和病原体刺激时,释放染色质和颗粒物形成的网状细胞外结构,参与多种疾病的... 详细信息

动脉粥样硬化是由脂质驱动,多种细胞共同参与的血管慢性炎症性疾病。中性粒细胞胞外诱捕网(neutrophil extracellular trapping nets,NETs)是中性粒细胞响应炎症和病原体刺激时,释放染色质和颗粒物形成的网状细胞外结构,参与多种疾病的病理生理进程。近些年越来越多的研究表明中性粒细胞和其胞外诱捕网在动脉粥样硬化的进展中发挥重要作用。该文就NETs在动脉粥样硬化中作用的研究进展作一综述。

关键词：动脉粥样硬化中性粒细胞中性粒细胞胞外诱捕网

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Thermal Optimization of High-power Vertical Cavity Surface Emitting Laser Arrays

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Faguang Xuebao/Chinese Journal of Luminescence 2024年第6期45卷 970-977页

作者： Xia, Yuqi Mu, Jingfei Zhou, Yinli Zhang, Xing Zhang, Jianwei Chen, Chao Yuan, gaohui Zhang, Zhuo Liu, Tianjiao Bai, Haopeng Xu, Yuehui Sun, Jingjing Ning, Yongqiang Wang, Lijun State Key Laboratory of Luminescence and Applications Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China University of Chinese Academy of Sciences Beijing 100049 China

n this study，we designed a new parameter，the temperature impact factor，which considers the spacing between vertical-cavity surface-emitting laser（VCSEL）array units，size of the oxidation aperture，number of units，and the input current，and can be used to characterize the degree of thermal crosstalk in the array. Based on this，we designed an optimization layout algorithm for the VCSEL array and established a thermal-electric coupling model to verify the benefits of the optimized layout on temperature characteristics. Compared with the conventional layout，the temperature rise was reduced by 5%. In addition，under the condition of fixed current density and luminous area，reduction of the oxidation aperture and increasing the number of units can effectively improve the temperature characteristics of the VCSEL array. The average temperature of the 10 μm oxidation aperture was 30 K lower than that of the 30 μm oxidation aperture. The research results show that the impact of thermal crosstalk in the VCSEL array is effectively reduced and provide guidance for the design of the VCSEL array. © 2024 Editorial Office of Chinese Optics. All rights reserved.

关键词： Oxidation

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国内“搜索即学习”主题研究的现状、问题和展望

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情报理论与实践 2024年第3期47卷 188-198页

作者：孟高慧刘畅北京大学信息管理系北京100871

[目的/意义]国内搜索即学习(SAL)领域稳定发展,即将步入发展的“黄金阶段”。在这一关键时刻,揭示该领域的研究现状和现存问题,并提出相应的未来发展建议具有重要意义。[方法/过程]采用系统性文献综述方法,遵循PRISMA标准程序筛选出41... 详细信息

[目的/意义]国内搜索即学习(SAL)领域稳定发展,即将步入发展的“黄金阶段”。在这一关键时刻,揭示该领域的研究现状和现存问题,并提出相应的未来发展建议具有重要意义。[方法/过程]采用系统性文献综述方法,遵循PRISMA标准程序筛选出41篇相关文献,并聚焦于其中的34篇实证文献和70个研究问题,使用内容分析法抽取和整合数据资料。[结果/结论]国内SAL领域已经初步形成了自身的研究特色,同时存在着一些问题,具有巨大的发展潜能。建议在未来应持续推进SAL领域的研究范式转变,包括在本体论和认识论层面拓展至更广泛的研究情境和更均衡的研究问题,在方法论层面拓展至更多样的研究方法,在价值论层面拓展至更人文的用户赋能视角。

关键词：搜索即学习系统性文献综述内容分析法研究范式

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铁催化分解二甲硫醚制备碳纳米管的研究

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化工新型材料 2010年第7期38卷 49-51,66页

作者：苏庆梅杜高辉浙江师范大学物理化学研究所浙江省固体表面反应化学重点实验室金华321004

以二甲硫醚为碳源,Fe/MgO为催化剂,采用化学气相沉积法制备了碳纳米管。通过SEM、Raman、XRD、TEM表征方法研究了实验合成条件对碳纳米管产物的形貌和微结构的影响。结果表明,二甲硫醚的蒸汽浓度对碳纳米管的形貌和产量有重要影响。较... 详细信息

以二甲硫醚为碳源,Fe/MgO为催化剂,采用化学气相沉积法制备了碳纳米管。通过SEM、Raman、XRD、TEM表征方法研究了实验合成条件对碳纳米管产物的形貌和微结构的影响。结果表明,二甲硫醚的蒸汽浓度对碳纳米管的形貌和产量有重要影响。较高的二甲硫醚浓度会使催化剂的活性降低,制备出的碳纳米管较短且石墨化程度也较差。生长碳纳米管的最佳二甲硫醚浓度范围为2.69%～3.86%,且碳纳米管产物中有Y型碳纳米管的生成,并对其生长机理进行了初步讨论。

关键词：碳纳米管二甲硫醚化学气相沉积 Y型碳纳米管

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