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Chemical adsorption on 2D dielectric nanosheets for matrix free nanocomposites with ultrahigh electrical energy storage

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Science Bulletin 2022年第6期67卷 609-618,M0004页

作者： Jie Chen Zhonghui Shen Qi Kang Xiaoshi Qian Shengtao Li Pingkai Jiang Xingyi Huang Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing Department of Polymer Science and EngineeringThe State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center of Smart Materials and DevicesWuhan University of TechnologyWuhan 430070China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'an 710054China

Relaxor ferroelectric polymers display great potential in capacitor dielectric applications because of their excellent flexibility,light weight,and high dielectric ***,their electrical energy storage capacity is limited by their high conduction losses and low dielectric strength,which primarily originates from the impact-ionization-induced electron multiplication,low mechanical modulus,and low thermal conductivity of the dielectric *** a matrix free strategy is developed to effectively suppress electron multiplication effects and to enhance mechanical modulus and thermal conductivity of a dielectric polymer,which involves the chemical adsorption of an electron barrier layer on boron nitride nanosheet surfaces by chemically adsorbing an amino-containing polymer.A dramatic decrease of leakage current(from 2.4×10^(-6)to 1.1×10^(-7)A cm^(-2)at 100 MV m^(-1))and a substantial increase of breakdown strength(from 340 to 742 MV m^(-1))were achieved in the nanocompostes,which result in a remarkable increase of discharge energy density(from 5.2 to 31.8 J cm^(-3)).Moreover,the dielectric strength of the nanocomposites suffering an electrical breakdown could be restored to 88%of the original *** study demonstrates a rational design for fabricating dielectric polymer nanocomposites with greatly enhanced electric energy storage capacity.

关键词： Boron nitride nanosheets Electron barrier layer Relaxor ferroelectric polymers Nanocomposites Electrical energy storage

Low Temperature Method-Based Evaporation/Spray-Coating technology for Wide Bandgap Perovskite Solar Cells

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SSRN 2024年

作者： Liang, Cheng Du, Hong-Qiang Geng, Cong Yu, Xinxin Jiang, Xiongzhuang Huang, Shangwei Long, Fei Han, Liyuan Li, Wangnan Liang, Guijie Li, Bin Cheng, Yi-Bing Peng, Yong State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China College of Materials Science and Engineering Guilin University of Technology Guangxi Guilin541004 China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai200240 China Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science Xiangyang441053 China Hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration Zone Xiangyang441000 China

Years of working on perovskite solar cells (PSCs) based tandem devices and single-junction devices have approved that low annealing temperature can be beneficial of improving devices performances. In this paper, a pseudo-halogen ion engineering works well in the evaporation/spray-coating method. According to our research, it is proved that the addition of formamidine acetate (FAAc) can effectively reduce annealing temperature from 170 ℃ to 150 ℃, accelerate the maturation process of the perovskite films, and broaden the annealing window. As a result, a perovskite film with homogeneous crystallization and low residual stress is achieved, leading to extended charge carrier lifetimes, elevated photoluminescence quantum yields (PLQY), reduced Urbach energies. The corresponding PSCs prepared through evaporation/spray-coating method achieve an impressive power conversion efficiency (PCE) of 19.46%, which is the highest efficiency among wide-bandgap (WBG) PSCs fabricated by this method. And the unencapsulated devices exhibit satisfactory stability, retaining 80% of the initial PCE after 600 h of thermal aging at 60 ℃ and retaining 90% of the initial PCE after 1500 h of 50% humidity aging at 25 °C, respectively. © 2024, The Authors. All rights reserved.

关键词： Evaporation

Wetting Tunning of Al/B4c Interface Through Constructing Periodic Surface Structures Via Femtosecond Laser

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SSRN 2023年

作者： Chen, Beidi Chai, Nianyao Zhang, Jinyong Ren, Lin Wang, Weimin Zhang, Fan Wang, Xuewen Fu, Zhengyi Hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration Zone Hubei Xiangyang441000 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China School of Science Wuhan University of Technology Wuhan430070 China

Nowadays, femtosecond laser processing can realize the specialized surface of materials to be applied to different functional fields. However, there are few reports on the application of laser processing super-hard ceramics. In this study, a study on the phase change and surface morphology of boron carbide ceramic samples after femtosecond laser processing was explored. After femtosecond laser processing with certain parameters, ordered periodic micro nano structures can be realized on the surface of boron carbide. According to XRD, femtosecond laser can promote the formation of boron rich structure. Raman showed that carbon can be knocked out by femtosecond laser to form boron rich boron carbide and a little tensile stress occurs on the material surface without affecting the mechanical properties. Moreover, the contact angle of boron carbide after processing and aluminum melt is 24 ° smaller than that of untreated one, which means that femtosecond laser processing can improve the wetting between boron carbide and aluminum. © 2023, The Authors. All rights reserved.

关键词： Boron carbide

Effect of pH, milling time, and Isobam content on porous silicon nitride ceramics prepared by gel casting

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Advanced Powder Materials

advanced Powder materials 2023年第1期2卷 100-107页

作者： Hailing Yang Zhi Wang Mengyong Sun Fei Chen Jun Ji Sique Chen Yingying Chen Deli Ma Zhenyu Zhang Baocai Pan Yulin Wei Qinggang Li Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials University of JinanJinan 250022China School of Material Science and Engineering University of JinanJinan 250022China No.52 Institute of China North Industry Group Yantai 264003China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

As a non-toxic copolymer of isobutylene and maleic anhydride,Isobam is successfully used as a dispersant and a gelling agent for fabricating porous Si_(3)N_(4) ceramics by gel *** dispersity and rheological properties of the Si_(3)N_(4) slurry are influenced by the pH,milling time,and Isobam content which varies from 0.1 wt.%to 0.6 wt.%,and these factors are *** slurry with 40 vol.%solid content and milled for 4 h has a high zeta potential at pH 12(adjusted by Tetramethyl ammonium hydroxide(TMAH)),which means that the particles are well *** mechanisms of TMAH are electrostatic repulsion and steric *** viscosity of the slurry increases with the increase of Isobam *** pressureless sintering at 1700℃ for 2 h,a uniform unique interlocking microstructure of rod-like β-Si_(3)N_(4) grains is observed,which may improve the flexural strength of the ceramics by intergranular fracture and particle pullout of β-Si_(3)N_(4) *** density and porosity of the samples fluctuate negligibly with the increase of Isobam content,and the Si_(3)N_(4) ceramic with 0.1 wt.% Isobam exhibits the highest bending strength of 251.6 MPa among all samples.

关键词： Si_(3)N_(4)ceramics Viscosity Zeta potential Gel casting Isobam

Phase Boundary Mapping for High Thermoelectric Performance Β-Zn4sb3 in Zn-in-Sb Ternary System

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SSRN 2023年

作者： Zhong, Shenlong Liu, Keke Duan, Yusong Zhang, Qingjie Wu, Jinsong Su, Xianli Tang, Xinfeng Hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration Zone Xiangyang441000 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Nanostructure Research Center Wuhan University of Technology Wuhan430070 China

Zn4Sb3 with complex structure shows excellent thermoelectric performance in the low temperature region. Herein, three batches of In doped Zn4Sb3 were synthesized and the influence of In dopant and Zn content on the thermoelectric properties of Zn4Sb3 was systematically investigated by using a phase boundary method. The isothermal ternary phase diagram of Zn-In-Sb is explored at 623 K. The solubility limit of In in the single phase region with β-Zn4Sb3 structure is strongly related to the ratio between Zn+In and Sb. In atoms preferentially occupy C interstitial of 48f site in the crystallographic Wyckoff position and Zn deficiency increases the concentration of Zn vacancies on this site, enhancing the solubility limit of In in the system. The modification of structure via doping with In hinders the movement and diffusion of Zn interstitial in Zn4Sb3, accompanying with the disappearance of the low temperature phase transitions from α' to α phase and from α to β phase. The regulation of Zn and In contents in single phase region with β-Zn4Sb3 structure effectively optimizes the thermoelectric performance. A maximum ZT value of 1.43 is attained at 673 K for (Zn0.96In0.04)4.15Sb3 compound, which demonstrate a 47 % improvement in comparison with that of Zn4.15Sb3 compound. This work provides a new avenue to further improve thermoelectric properties of Zn4Sb3 compounds. © 2023, The Authors. All rights reserved.

关键词： Solubility

Modulating the Valence of in on the Thermoelectric Properties of Pb0.99in0.01te1-Xsx Compounds

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SSRN 2023年

作者： Hu, Qin Liu, Keke Wu, Jinsong Su, Xianli Zhang, Qingjie Tang, Xinfeng Hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration Zone Xiangyang441000 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Nanostructure Research Center Wuhan University of Technology Wuhan430070 China

In dopant demonstrates a distinct role in PbTe and PbS compounds though they possess the same crystal structure. Therefore, to unravel how the thermoelectric performance evolves in the In-doped PbTe1-xSx solid solution is crucial. Herein, a series of Pb0.99In0.01Te1-xSx samples were synthesized by conventional melting methods. It is found that doping In in PbTe introduces a shallow level impurity state In3+ and a deep level associated with the In+ state simultaneously. Alloying PbS in Pb0.99In0.01Te1-xSx compounds modulates the valence of In dopant, increasing the relative ratio of In3+ content due to the stronger oxidation capacity of S in comparison with that of Te. This augments the room temperature carrier concentration from 3.03×1018 cm-3 for Pb0.99In0.01Te compound to 6.51×1018 cm-3 for Pb0.99In0.01Te0.88S0.12 compound. Therefore, an improved power factor of 17.4 μW cm−1 K−2 for Pb0.99In0.01Te0.91S0.09 sample is obtained at room temperature. Additionally, alloying PbS in Pb0.99In0.01Te1-xSx compounds enhances the point defect phonon scattering and lowers the lattice thermal conductivity from 1.99 W m-1 K-1 for Pb0.99In0.01Te compound to 1.09 W m-1 K-1 for Pb0.99In0.01Te0.88S0.12 compound at room temperature. As a consequence, a maximum ZT value of 1.12 at 723 K is attained for Pb0.99In0.01Te0.95S0.05 compound, which is improved by 19% in comparison with that of Pb0.99In0.01Te compound. This work provides a new path for modulating the doping behavior of cation site dopant via alloying on anion site to further improve the ZT value in thermoelectric materials. © 2023, The Authors. All rights reserved.

关键词： Alloying

Al-Doped Nb2o5/Carbon Micro-Particles Anodes for High Rate Lithium-Ion Batteries

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SSRN 2022年

作者： Zhu, Zhu Liu, Fang Wang, Hong Yu, Ruohan Wu, Jinsong State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and Engineering Wuhan University of Technology Hubei Wuhan430070 China Wuhan University of Technology Wuhan430070 China

Orthorhombic niobium pentoxide (T-Nb2O5 ) has attracted extensive attention in the field of ultra-fast lithium ion batteries (LIBs) due to its high rate performance. However, its instability at a low potential and inherent low conductivity limits its fast charging capability. Here, microspheres of aluminum-doped T-Nb2O5 embedded in N-doped carbon network (Al-Nb2O5@NC) are prepared. The effects of Al-doping on the crystal structure and electrochemical properties are systematically studied. It is found that Al-doping has led to increase of the density of O2- vacancies and then low-oxidized state Nb4+ ions, improving ionic and electrical conductivity. The substitution of Al3+ ions for Nb5+ ions improves the lattice stability, reduces the undesirable migration of Nb in cycling, and stabilizes the capacity during fast charging. The LIBs using Al-Nb2O5@NC as anode have high rate performance and cycling stability ( i.e. , ~82 mAh g-1 at 20 A g-1 after 9900 cycles). Meanwhile, the intercalation-type electrochemical reaction is verified by in-situ transmission electron microscope (TEM), by which it is found that Al-Nb2O5@NC has better crystalline integrity. By integrating Al doping and carbon network, the micron-size Al-Nb2O5@NC particles developed in this work are promising anodes to build fast charge/discharge LIBs with high specific capacity, stability and excellent rate performance. © 2022, The Authors. All rights reserved.

关键词： Lithium-ion batteries

A Highly Efficient High-Entropy Metal Hydroxymethylate Electrocatalyst for Oxygen Evolution Reaction

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SSRN 2022年

作者： Jiang, Qi Gu, Junfeng Zhang, Long Liu, Kailong Huang, Mengyan Liu, Peng Zuo, Shiyu Wang, Yilong Ma, Peiyan Fu, Zhengyi College of Chemistry Wuhan University of Technology Wuhan430000 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430000 China

Much attention has been paid to high entropy materials in the field of electrochemical water splitting. In this research, we present a synthesis of a high-entropy metal hydroxymethylate FeCoNiMgCr(OH)(OCH 3 ) (labeled as FeCoNiMgCr-HM) material via a one-step solvothermal method. Due to the synergistic effect of five metal cations and complete surface reconstruction induced by methoxyl group, FeCoNiMgCr-HM after electrochemical activation exhibits an outstanding performance for catalyzing lattice-oxygen-participated OER with a low overpotential of 291 mV to reach a current density of 20 mA cm -2 and a small Tafel slope of 49.1 mV dec -1 . In addition, we summarize a universal ionic potential rule for guiding the synthesis of metal hydroxymethylate materials. © 2022, The Authors. All rights reserved.

关键词： Entropy

Experimental Probing of the Effect of Nafion Poisoning at Different Pt Loadings in a Pemfc

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SSRN 2022年

作者： Zhou, Fen Zhang, Hui Guan, Shumeng Li, Guangfu Xia, Lei Pan, Mu Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen Valley Foshan528200 China State Key Laboratory of Advanced Technology for Materials Synthesis Processing Wuhan University of Technology Wuhan430070 China

The charge-transfer resistance ( R ct ) in electrochemical impedance spectroscopy (EIS) was applied as an activity indicator to study the suppression of a rotating disk electrode (RDE) and membrane electrode assembly (MEA) by Nafion with different Pt loadings. Use of the R ct avoids uncertainty in activity characterization;such uncertainty is caused by mass transfer in highly loaded catalyst agglomerates. It was found that Nafion had a stronger poisoning effect at lower Pt loadings. The simultaneous reduction in the working voltage further aggravates the poisoning, especially under low-Pt conditions. After poisoning, the normalized R ct at 20 µg/cm 2 increased from 8 times at 0.9 V to 21 times at 0.82 V. When the Nafion adsorption coverage on the surface of Pt remained constant, the suppressed activity increased as the Pt loading decreased. Therefore, it is critical to consider Nafion poisoning when constructing MEAs with low platinum and take appropriate strategies to alleviate poisoning and achieve high-performance output. © 2022, The Authors. All rights reserved.

关键词： Proton exchange membrane fuel cells (PEMFC)