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Design and fabrication of Nd-Fe-B magnet with excellent thermal stability

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Journal of Rare Earths 2024年第5期42卷 980-986,I0006页

作者： Rui Han Shengzhi Dong Dong Li Dongmin Zhang Hongsheng Chen Jiyuan Xu George CHadjipanayis Zhuolin Li Ying Zhang Wei Li Division of Functional Materials Research Central Iron and Steel Research InstituteBeijing100081China Department of Physics and Astronomy Sharp Lab University of DelawareNewarkDE19716USA Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing100190China

A novel Nd-Fe-B type permanent magnet with excellent thermal stability was designed by Co replacing Fe in the main phase and the grain boundary phase.The remanence and coercivity temperature coefficient reach 0.058%/℃and 0.465%/℃in the te mperature range from 25 to 100℃,which are much lower than those of commercial Nd-Fe-B magnet.An enhanced Curie temperature is obtained for the novel magnet due to the Co substitution,which significantly improves the operating temperature.The microstructure result reveals that an amorphous phase exists in the intergranular grains which is probably responsible for the deterioration of intrinsic coercivity.This work can provide a reference for the design and optimization of components of sintered Nd-Fe-B magnets with excellent thermal stability.

关键词： Thermal stability Remanence temperature coefficient operating temperature Atomic substitution Rare earths

Simulation of three-stage operating temperature for supersaturation water-based condensational growth tube

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Journal of Environmental Sciences 2020年第4期32卷 275-285页

作者： Jiejie Bian Huaqiao Gui Zhibo Xie Tongzhu Yu Xiuli Wei Wenyu Wang Jianguo Liu Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China CAS Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

In order to realize accurate dynamic control of supersaturation and to study condensation growth characteristics of nanoparticles through different levels of super saturation,a series of parametric analyses and systematic comparisons between two-stage and three-stage operating temperature designs were simulated with COMSOL Multiphysics.The simulation results showed that the three-stage operating temperature did not change peak supersaturation compared with two operating temperatures,and the three-stage operating temperature was superior in decreasing the amount of water vapor and the temperature,thus lowering particle loss and variation in detection and collection.The peak supersaturation level increased by 0.3 as the flow rate increased from 0.6 to 2.0 L/min,but the supersaturation peak moved from 0.0027 z0 to 0.08 z0(i.e.,the growth time and the final size decreased by 40%).Peak supersaturation increased as the temperature difference increased or the temperature difference window was shifting left,and minimum activation size decreased.Shifting the 70℃temperature difference window from 9℃,79℃-1℃,71℃for the condenser and initiator temperatures resulted in peak supersaturation in the centerline being above 5.8,and the activation size changed as low as 1 nm.Experiments with flow rates varying by a factor of 2.5(from 0.6 to 1.5 L/min)resulted in a final size decrease of 43%(from 3.2 to 1.8μm),and experimental results of outlet particle size distributions were equivalent with theoretical analysis as the operating temperature was changed.

关键词： operating temperature Supersaturation profile Flow rate Minimum activation size temperature difference

Revealing performance of 78Li_(2)S-22P_(2)S_(5) glass ceramic based solid-state batteries at different operating temperatures

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Chinese Chemical Letters 2023年第7期34卷 418-422页

作者： Chaochao Wei Xinrong Liu Chuang Yu Shaoqing Chen Shuai Chen Shijie Cheng Jia Xie State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

78Li_(2)S-22P_(2)S_(5) are sulfide electrolytes with high lithium-ion conductivity and wide electrochemical windows in the Li_(2)S-P_(2)S_(5) system,making them attractive solid electrolytes for ASSLBs.However,the role and potential of 78Li_(2)S-22P_(2)S_(5) solid electrolytes over a wide temperature range are still not fully understood.Therefore,we constructed solid-state batteries with NCM622 as the positive electrode and 78Li_(2)S-22P_(2)S_(5) glass-ceramics as the electrolyte to investigate in depth the differences in battery performance over a wide temperature range and their intrinsic mechanisms.The in-situ impedance and relaxation time distribution (DRT) demonstrated the electrochemical stability of the electrolyte over a wide temperature range,while the in-situ stacking pressure observed a large volume change during cycling at 60℃,leading to local solid-solid contact failure and poor cycling stability.This study provides insight into the advantages and problems of 78Li_(2)S-22P_(2)S_(5) in the wide temperature range as well as a basis for the construction of ASSLBs with high energy density and long cycle life.

关键词： 78Li_(2)S-22P_(2)S_(5)electrolytes Li-ion conductivity operating temperature Battery performance Volume changes Interfacial resistance

Tuning Solid Interfaces via Varying Electrolyte Distributions Enables High-Performance Solid-State Batteries

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Energy & Environmental Materials 2023年第2期6卷 26-33页

作者： Linfeng Peng Chuang Yu Ziqi Zhang Ruonan Xu Mengjun Sun Long Zhang Shijie Cheng Jia Xie State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430000China School of Physics Huazhong University of Science and TechnologyWuhan 430000China Clean Nano Energy Center State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430000China

Solid/solid interface is the major challenge for high-performance solid-state batteries.Solid electrolytes(SEs)play a crucial role in the fabrication of effective interfaces in solid-state batteries.Herein,the electrolyte distribution with varied particle sizes is tuned to construct solid-state batteries with excellent performance at different operating temperatures.Solid-state batteries with the configuration S/L(small-sized SE in composite cathode and large-sized SE in electrolyte layer)show the best performance at room temperature(168 mA h g^(−1) at 0.2 C,retention of 99%,100 cycles)and−20°C(89 mA h g^(−1) at 0.05 C),while the configuration S/S displays better performance at elevated temperature.The superior performance of S/L battery is associated with faster lithium-ion dynamics due to the better solid/solid interface between active materials and electrolytes.Moreover,the inferior performance at 60℃is caused by the formation of voids and cracks in the electrolyte layer during cycling.In contrast,the S/S battery delivers superior performance at elevated operating temperature because of the integrated structure.This work confirms that tailoring electrolyte size has significant effect on fabricating all-climate solid-state batteries.

关键词： electrochemical performance lithium argyrodite operating temperature size distribution solid-state batteries

Influence of bio-inspired flow channel designs on the performance of a PEM fuel cell

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Chinese Journal of Chemical Engineering 2020年第3期28卷 824-831页

作者： Srinivasa Reddy Badduri G.Naga Srinivasulu S.Srinivasa Rao Department of Mechanical Engineering NITWarangalTelangana 506004India

Performance of the proton exchange membrane fuel cell(PEMFC)is appreciably affected by the channel geometry.The branching structure of a plant leaf and human lung is an efficient network to distribute the nutrients in the respective systems.The same nutrient transport system can be mimicked in the flow channel design of a PEMFC,to aid even reactant distribution and better water management.In this work,the effect of bio-inspired flow field designs such as lung and leaf channel design bipolar plates,on the performance of a PEMFC was examined experimentally at various operating conditions.A PEMFC of 49 cm2 area,with a Nafion 212 membrane with a 40%catalyst loading of 0.4 mg·cm-2 on the anode side and also 0.6 mg·cm-2 on the cathode side is assembled by incorporating the bio-inspired channel bipolar plate,and was tested on a programmable fuel-cell test station.The impact of the working parameters like reactants’relative humidity(RH),back pressure and fuel cell temperature on the performance of the fuel cell was examined;the operating pressure remains constant at 0.1 MPa.It was observed that the best performance was attained at a back pressure of 0.3 MPa,75°C operating temperature and 100%RH.The three flow channels were also compared at different operating pressures ranging from 0.1 MPa to 0.3 MPa,and the other parameters such as operating temperature,RH and back pressure were set as 75°C,100%and 0.3 MPa.The experimental outcomes of the PEMFC with bio-inspired channels were compared with the experimental results of a conventional triple serpentine flow field.It was observed that among the different flow channel designs considered,the leaf channel design gives the best output in terms of power density.Further,the experimental results of the leaf channel design were compared with those of the interdigitated leaf channel design.The PEMFC with the interdigitated leaf channel design was found to generate 6.72%more power density than the non-interdigitated leaf channel design.The fuel cell with interdigitated leaf channel d

关键词： PEMFC Interdigitated leaf channel design Bio-inspired flow field design operating temperature Relative humidity

INTRAPARTICLE DIFFUSION EFFECTS IN FISCHER-TROPSCH SYNTHESIS Ⅱ.EFFECTS OF PARTICLE SIZE,temperature AND PORE STRUCTURE

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Journal of Energy Chemistry 1996年第2期 107-115页

作者： SHEN Wen-Jie ZHOU Jing-Lai ZHANG Bi-Jiang (Institute of Coal Chemistry, The Chinese Academy of Sciences Taiyuan, Shanxi 030001)

The effectiveness tactors for a commercialized precipitated Fe/Cu/k catalyst used for the Fischer-Tropsch synthesis were found to decrcase with temperature and particlc size. the calculated results showed a good agreement with those obtained by kinetic investigations. The effects of catalyst pore structure on effectivcness factor were investigatcd as well, and it was revealed that the catalyst pore size has no significant cffect on efftectiveness factor tor the special case of Fischer-Tropsch synthesis under industrial operating conditions.

关键词： Fiseher-Tropsch synthesis operating temperature catalyst pore structure effectiveness factor precipitated Fe/Cu/K catalyst