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Preventing the distortion of CoO6 Octahedra of LiCoO2 at High-Voltage Operation of Lithium-Ion Battery: An Organic Surface reinforcement

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Polymers 2023年第9期15卷

作者： Wang, Fu-Ming Graduate Institute of Applied Science and Technology National Taiwan University of Science and Technology Taipei106335 Taiwan Sustainable Energy Center National Taiwan University of Science and Technology Taipei106335 Taiwan Department of Chemical Engineering Chung Yuan Christian University Taoyuan320314 Taiwan R&D Center for Membrane Technology Chung Yuan Christian University Taoyuan320314 Taiwan

Lithium cobalt oxide (LiCoO2, LCO) has been widely used in electronic markets due to its high energy density and wide voltage range applications. recently, high-voltage (HV, >4.5 V) operation has been required to obey the requirements of high energy density and cycle life in several applications such as electric vehicles and energy storage. However, the HV operation causes structure instability due to the over de-lithiation of LCO, as well as decomposing common carbonate solvents, thereby incurring the decay of battery performance. Moreover, a distortion of the CoO6 octahedra of LCO during de-lithiation induces a rehybridization of the Co 3d and O 2p orbitals. According to above reasons, decreasing the Co-O covalent bond promptly triggers high risks that significantly limit further use of LCO. In this research, an organic surface reinforcement by using bismaleimide–uracil (BU) that electrochemically forms a cathode electrolyte interphase (CEI) on LCO was explored. The results of electrochemical impedance spectroscopy and battery performance, such as the c-rate and cyclability tests, demonstrated that the modified CEI formed from BU significantly prevents the distortion of CoO6 octahedra. X-ray photoelectronic spectroscopy and in situ XAS indicated less LiF formation and higher bond energy of Co-O improved. Finally, the differential scanning calorimetry showed the onset temperature of decomposition of LCO was extended from 245 to 270 °C at 100% state of charge, which is about a 25 °C extension. The exothermic heat of LCO decreased by approximately 30% for high-safety use. This research confirms that the BU is eligible for high voltage (>4.5 V) LCO and presents outstanding electrochemical properties and safety performances. © 2023 by the author.

关键词： Cobalt compounds

Multiple Confinement-Limited Activation and defect Effect Co-Triggered the Ultra-Long Lifetime of Carbon dots

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SSrN 2024年

作者： Luo, Yimeng Jiang, Qin Liu, Jinkun Huang, Feiyan Liao, Xuelin Zhuang, Jianle Hu, Chaofan Zheng, Mingtao Lei, Bingfu He, Jiangling Liu, Yingliang Key Laboratory for Biobased Materials and Energy Ministry of Education Guangdong Provincial Engineering Technology Research Center for Optical Agriculture College of Materials and Energy South China Agricultural University Guangzhou510642 China National R&D Center for Se-rich Agricultural Products Processing Hubei Engineering Research Center for Deep Processing of Green Se-rich Agricultural Products School of Modern Industry for Selenium Science and Engineering Wuhan Polytechnic University Wuhan430023 China

The luminescence process of carbon dots (Cds) is typically influenced by spin-forbidden transition, triplet exciton quenching, and non-radiative transition. Thus, it faces great challenges to achieve efficient and ultra-long lifetime afterglow for Cds. The commonly employed strategy to obtain efficient afterglow performance of Cds is to encapsulate Cds into a rigid matrix to protect the afterglow signal from quenching. Generally, the ultra-long lifetime and excellent luminescent properties of inorganic rTP (room temperature phosphorescence) nanomaterials attribute to the slow release of electrons trapped in defect states of the surfaces. This capture-release mechanism has advanced afterglow lifetime of Cds towards longer levels via the design of defect states. Anchoring Cds onto a rigid matrix can preserve the rigid structure for the restrictive effect, and also can create structural defects. Herein, as-prepared rHCds@SiO2 composite can exhibit an ultra-long afterglow lifetime of 7.76 s, which is the highest value achieved for Cds in silica matrix to date. This composite is also successfully applied in anti-counterfeiting and cell imaging fields. The synergistic multiple confinement effect and defect effect from the composite provides a universal strategy to design and achieve the ultra-long afterglow lifetime of Cds. © 2024, The Authors. All rights reserved.

关键词： Chemical activation

Electrical Tree Propagation in Epoxy resin under Superimposed Sinusoidal and repetitive Pulse Waveforms for Converter-fed Motor Insulation

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Electrical Tree Propagation in Epoxy Resin under Superimpose...

Electrical Insulation Conference and Electrical Manufacturing & Coil Winding Conference

作者： Takahiro Umemoto Masahiro Sato Ayato Yoshida Kunihiko Hidaka Yuta Yamanaka Takuro Yamada Tetsushi Okamoto Akiko Kumada Dept. of Electrical Engineering and Information Systems The University of Tokyo Tokyo Japan Dept. of Electrical and Electronic Engineering Tokyo Denki University Tokyo Japan Advanced Technology R&D Center Mitsubishi Electric Corporation Amagasaki Japan Rotating Machinery Systems Division Toshiba Mitsubishi-Electric Industrial Systems Corporation Nagasaki Japan

ISBN: (数字)9798350360431

ISBN: (纸本)9798350360448

The ground-wall insulation (epoxy/mica insulation) of form-wound converter-fed rotating machines is subjected to pulse width modulation (PWM) waveforms during operation. In this study, the behavior of electrical trees in epoxy resin, a major cause of the insulation degradation, is experimentally investigated under simulated operating waveforms, i.e. superimposed sinusoidal and repetitive pulse waveforms. Tree length, propagation speed, and morphology are evaluated through microscope observations. The results show that the tree propagation speed becomes significantly faster with an increase in pulse voltage ratio, compared to the case of the AC waveform alone. Considering the observation of the tree morphology, it is inferred that the tree channel density under the superimposed waveforms becomes sparser than that under the sinusoidal alone, resulting in the electric field enhancement at the tip of the tree channels and the faster propagation.

关键词： degradation Insulation rotating machines Microscopy Morphology Epoxy resins Voltage

Multiple Confinement-Limited Activation and defect Effect Co-Triggered the Ultra-Long Lifetime of Carbon dots

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SSrN 2024年

关键词： Chemical activation

CoIn2S4/rGO Composite as Anode Materials for Li-Ion Batteries

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SSrN 2022年

作者： Lee, Ting-Yu Liu, Wei-ren Department of Chemical Engineering Chung Yuan Christian University R&D Center for Membrane Technology Center for Circular Economy 200 Chung Pei Road Chungli District Taoyuan City32023 Taiwan

In this study, we proposed a novel CoIn2S4/reduced graphene oxide composite anode (CoIn2S4/rGO) by a hydrothermal method. Via introducing electronic-conductive reduced graphene oxide (rGO) to buffer the dramatically volume expansion of CoIn2S4 and avoid its polysulfide dissolution during charge and discharge processes. The pristine CoIn2S4 electrode demonstrated poor cycle performance of only 120 mAh/g at 0.1 A/g after 100 cycles. The composition-optimized CoIn2S4/rGO composite anode exhibited much better reversible capacity of 580 mAh/g after 100 cycles, which was much higher than that of commercial graphite (372 mAh/g). Moreover, the reaction mechanism and electrochemical behavior of CoIn2S4/rGO electrode was conducted by ex-situ Xrd measurements. The results indicated that CoIn2S4/rGO composite anode was a promising candidate as an anode material for lithium ion battery applications. © 2022, The Authors. All rights reserved.

关键词： Anodes

An On-Line Inductance Identification Method for Permanent Magnet Synchronous Motors Under Sensorless Control in The Full Speed domain

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An On-Line Inductance Identification Method for Permanent Ma...

International Conference on Power Electronics and Motion Control (IPEMC)

作者： Yue Liu Liguo Wang Qiang Gao Yong Li Fei E Department of Electrical Engineering Shanghai Jiao Tong University Shanghai China State Grid Suzhou Power Supply Company Substation Maintenance Center Suzhou China Department of R&D Contemporary Amperex Electric Vessel Technology Co. Limited Ningde China Department of Technology Contemporary Amperex Electric Vessel Technology Co. Limited Ningde China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

This work presents an online inductance identification method for permanent magnet synchronous motors in the full speed domain. Online inductance estimation is realized by injecting two modified high-frequency square wave voltage signals into the d-q axis simultaneously. This method can achieve high-precision identification of inductance in the full sensorless speed domain. The simulation results show that the inductance identification accuracy of this method can reach ±4% whether under constant loading, sudden addition and subtraction loading or dynamic loading.

关键词： Inductance Accuracy Simulation Loading Asia Estimation Sensorless control

Mesoporous Collapsing Encapsulated Carbon dots: direct Evidence for the Effect of Multiple-Confined Interactions of Silica on Efficient Long-Lived Phosphorescence

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SSrN 2024年

作者： Luo, Yimeng Jiang, Qin Liu, Jinkun Yang, Hongwei Liao, Xuelin Huang, Feiyan Zhuang, Jianle Hu, Chaofan Lei, Bingfu Liu, Yingliang He, Jiangling Key Laboratory for Biobased Materials and Energy of Ministry of Education Guangdong Provincial Engineering Technology Research Center for Optical Agriculture College of Materials and Energy South China Agricultural University Guangzhou510642 China National R&D Center for Se-rich Agricultural Products Processing Hubei Engineering Research Center for Deep Processing of Green Se-rich Agricultural Products School of Modern Industry for Selenium Science and Engineering Wuhan Polytechnic University Wuhan430023 China

Coupling with a matrix is the common strategy to improve the phosphorescence performance of carbon dots (Cds). However, there is a lack of clear and direct evidence about the formation mechanism of the inner relationship between Cds and matrix, and the specific effect of matrix on the phosphorescence performance. Mesoporous silica nanospheres (MSNs) were used as the research model to provide the direct evidence of the dense structure formation process and to construct a quantum chemical theoretical computational model of the effect of dense matrix on phosphorescence performance. due to the multiple domain-limiting effects of rigid Si-C covalent bonds and SiO2 dense structure, the calcined-carbonized polymer dots-mesoporous silica nanospheres (C-CPds-MSNs) can exhibit thermally activated delayed fluorescence (TAdF) by tuning the HOMO-LUMO gap and enriching the electrons in the surface region. With a long lifetime of 3.07 s, the composite can also maintain stable phosphorescence performance under harsh conditions and has been successfully applied in multilevel information encryption, fingerprint identification, and cellular imaging. This work provides the direct evidence for the process of dense SiO2 structure enhancing the phosphorescence performance of Cds and offers a general strategy and method for the design and preparation of efficient and practical Cds-based phosphorescent materials. © 2024, The Authors. All rights reserved.

关键词： Silica

Hydrolysis Co-deposition of Bio-Inspired Hybrid Hydrophilic Network Antifouling Loose Nanofiltration Membrane for Effective dye/Salt Separation

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SSrN 2023年

作者： Tong, Yi-Hao Wu, Yu-Zhe Xu, Zhen-Liang Luo, Li-Han Jia, rui Han, rui Xu, Sun-Jie State Key Laboratory of Chemical Engineering Membrane Science and Engineering R&D Lab Chemical Engineering Research Center School of Chemical Engineering East China University of Science and Technology Shanghai200237 China School of Materials Science and Engineering East China University of Science and Technology Shanghai200237 China Shanghai Electronic Chemicals Innovation Institute East China University of Science and Technology Shanghai200237 China

Nowadays, loose nanofiltration (LNF) membranes with effective filtration performance toward textile wastewater have drawn intensive attention. In this work, a high-performance LNF membrane was prepared via fast co-deposition of bio-inspired TA-based hydrophilic coating with in-situ hydrolysis of tetra butyl titanate (TBT) on polyethersulfone (PES) substrate. Various additives containing amino acid (L(+)-Arginine) and silane coupling agent (KH792) were mixed in the coating solution and researched their synergistic effects during membrane preparation. In-situ growth of TiO2 and co-deposition of TA-based coating endowed the LNF membrane with a uniformly rough hydrophilic surface. Therefore, the optimal LNF membrane showed a significantly high pure water permeability (92.9 L·m-2·h-1·bar-1) with high rejection (>99.0 %) in treating negatively charged dyes including Eriochrome Black T, Congo red, Chlorazol Black T, and Coomassie Brilliant Blue G. Meanwhile, low rejections for inorganic salts (Na2SO4: 7.9 %, NaCl: 2.5 %, MgCl2: 2.8%, MgSO4: 7.3%) were reached, and it kept distinguished separation performance in dealing with highly saline dye wastewater (containing 50 g·L-1 NaCl and Na2SO4, respectively). Beyond that, the membrane had excellent antifouling properties with low flux decline of multiple model pollutants and long-term stability during separation dye/salt mixture, which revealed the LNF membrane prepared promising potential in actual textile wastewater treatment. © 2023, The Authors. All rights reserved.

关键词： Coatings

Enhancement of the Magnetic Properties of Fe-Si-Cr Soft Magnetic Composite by Selective Oxidation Annealing

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SSrN 2022年

作者： Park, Jae-Young Park, Kwangsuk Fadonougbo, Julien O. Jang, Kyung rok Park, Sun dong Park, Chang-Soo Mo, Chan Bin Hwang, Nong-Moon Park, Hyung-Ki Functional Materials and Components R&D Group Korea Institute of Industrial Technology Gangneung 25440 Korea Republic of Department of Materials Science and Engineering Seoul National University Seoul08826 Korea Republic of R&D Center TODAISU Corporation Wonju26362 Korea Republic of

In this study, we examined the possibility for the surface insulation of Fe-3Si-5.5Cr powders through the selective oxidation annealing. To form an insulation oxide layer on the powder surface, the heat treatment was performed in an atmosphere in which Fe is reduced while Cr and Si are selectively oxidized. The oxidation potential was controlled by the [[EQUATION]] ratio and the powders were annealed at 600 ℃ under a [[EQUATION]] of 41.8. As the selective oxidation annealing time increased, the oxygen concentration of the powders was increased, and accordingly, the surface oxide layer thickened. To investigate the possibility of improving insulation and magnetic properties by the selective oxidation, disk and toroidal core samples were prepared. The powder without the selective oxidation treatment was subjected to wet chemical coating process for the insulation and after that it was mixed with the binder. On the other hand, the selectively oxidized powder was only mixed with the binder without an additional insulation coating. After mixing the powders with the binder, they were press molded to disk and toroidal core samples. The insulation property of the disk samples was compared in terms of withstanding voltage, which turned out to be improved by the selective oxidation. Magnetic properties were assessed by measuring the inductance, permeability, and quality factor of the toroidal core samples. The magnetic properties of the cores prepared using the selectively oxidized powders were superior to those prepared by wet chemical coating process. These results confirmed that a uniform insulating oxide layer could be formed on the Fe-Si-Cr powder surface by the selective oxidation, and this leads to the improvement of the magnetic properties of the cores. © 2022, The Authors. All rights reserved.

关键词： Powders