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Rational Self-Supported Electrode Design with Optimized Ion Migration and Gas Diffusion for Efficient Anion Exchange Membrane Water Electrolyzer

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SSRN

SSRN 2024年

作者： Ning, Minghui Wang, Yu Wu, Libo Zhang, Fanghao Yuan, Chuqing Song, Shaowei Yu, Luo Wang, Dezhi Chen, Shuo Ren, Zhifeng University of Houston HoustonTX77204 United States Materials Science and Engineering Program and TcSUH University of Houston HoustonTX77204 United States Department of Chemistry and TcSUH University of Houston HoustonTX77204 United States

The ion migration and gas diffusion are two of the most critical topics in water electrolysis. Many self-supported electrodes (SSEs) exhibit efficient performance in fundamental research studies due to their excellent gas diffusion. However, such performance is not guaranteed in large-scale electrolyzers due to the extremely large ion migration resistance of these SSEs. Here we find that a commercial SSE (Ni foam) exhibits efficient performance in fundamental research but performs poorly in an anion exchange membrane water electrolyzer (AEMWE). Further investigations reveal that the poor performance of the AEMWE originates from the large ion migration resistance caused by the long OH− migration distance within the SSE. After its design is optimized to minimize the ion migration resistance and enhance gas diffusion efficiency, the AEMWE is found to deliver a current density of 1 A/cm2 at 1.778 V in 1 M KOH at 65 °C. A triple-cell stack is further assembled and found to reach 1 A/cm2 at 5.464 V and to exhibit excellent stability over 216 h in 1 M KOH. © 2024, The Authors. All rights reserved.

关键词： Potassium hydroxide

An ultrahigh fatigue resistant liquid crystal elastomer-based material enabled by liquid metal

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science China materials 2022年第6期65卷 1679-1686页

作者： Hai-Feng Lu Zhen-Zhou Nie Hari Krishna Bisoyi Meng Wang Shuai Huang Xu-Man Chen Zhi-Yang Liu Hong Yang Institute of Advanced Materials School of Chemistry and Chemical EngineeringState Key Laboratory of BioelectronicsSoutheast UniversityNanjing 211189China Institute for Science and Applications of Molecular Ferroelectrics Key Laboratory of the Ministry of Education for Advanced Catalysis MaterialsZhejiang Normal UniversityJinhua 321004China Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program Kent State UniversityKentOH 44242USA

The low crosslink density characteristic of liquid crystal elastomer(LCE)materials causes poor fatigue resistance performance,which has seriously plagued their prospects in industrial *** we report that the introduction of 5 wt%liquid metal nanodroplets(average diameter:ca.195 nm)into the LCE network can dramatically reinforce the corresponding composite’s mechanical properties,in particular ultrahigh fatigue resistance,capable of bearing unprecedented 10,000 tensile cycles within a large range of strain amplitude up to 70%and 2000 times of continuous actuating ***,this liquid metal-incorporated LCE composite material exhibits large actuation stroke(maximum actuation strain:55%),high actuation stress(blocking stress:1.13 MPa),fully reversible thermal/photo-actuation functions,and self-healing ability at moderate temperatures,which qualifies the composite material for high-load actuators.

关键词： liquid crystal elastomer liquid metal fatigue resistance actuation

Shark Skin Denticles: From Morphological Diversity to Multi-functional Adaptations and Applications

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Advanced Functional materials 2024年第35期34卷

作者： Ghimire, Ashish Dahl, Rikke Beckmann Shen, Sheng-Feng Chen, Po-Yu Dept. of Materials Science and Engineering National Tsing Hua University Hsinchu300044 Taiwan Biodiversity Research Center Academia Sinica Taipei115201 Taiwan Dept. of Life Science National Taiwan Normal University Taipei116059 Taiwan Biodiversity Program Taiwan International Graduate Program Academia Sinica and National Taiwan Normal University Taiwan

The energy crisis of the 1970s sparked growing concern over minimizing fuel consumption in water, land, and air transportation. Researchers fascinated by sharks' effortless swimming abilities investigated shark skin denticles and uncovered functions beyond drag reduction, such as antifouling, protection, and bioluminescence. Over the past five decades, significant progress has been made in comprehending drag reduction and antifouling functions of denticle structures;however, the investigation of other functions remains limited. Recent discoveries of diverse denticle morphologies have ignited a keen interest in obtaining morphogroups that can aid other functional studies. This work integrates advances in antifouling, hydrodynamics, aerodynamics, bioluminescence, and protective functions to provide a holistic understanding of their diverse roles. Additionally, this work also dictates multi-functional adaptations of denticles and contributes to the relatively less-explored but essential aspects, such as protective functions and denticle morphogroups. By examining these functions together, this work aims to uncover potential synergies and interactions, facilitating the development of multifunctional materials inspired by shark skin denticles. © 2024 Wiley-VCH GmbH.

关键词： Hydrodynamics

Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

Improved Band Gaps and Structural Properties from Wannier-Fermi-Löwdin Self-Interaction Corrections for Periodic Systems

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arXiv 2022年

作者： Shinde, Ravindra Yamijala, Sharma S.R.K.C. Wong, Bryan M. Department of Chemical & Environmental Engineering Materials Science & Engineering Program Department of Chemistry Department of Physics & Astronomy University of California-Riverside RiversideCA United States

The accurate prediction of band gaps and structural properties in periodic systems continues to be one of the central goals of electronic structure theory. However, band gaps obtained from popular exchange-correlation functionals (such as LDA and PBE) are severely underestimated partly due to the spurious self-interaction error (SIE) inherent to these functionals. In this work, we present a new formulation and implementation of Wannier function-derived Fermi-Löwdin (WFL) orbitals for correcting the SIE in periodic systems. Since our approach utilizes a variational minimization of the self-interaction energy with respect to the Wannier charge centers, it is computationally more efficient than the HSE hybrid functional and other self-interaction corrections that require a large number of transformation matrix elements. Calculations on several (17 in total) prototypical molecular solids, semiconductors, and wide-bandgap materials show that our WFL self-interaction correction approach gives better band gaps and bulk moduli compared to semilocal functionals, largely due to the partial removal of self-interaction errors. © 2022, CC BY.

关键词： Energy gap

Machine Learning-Enhanced Design of Lead-Free Halide Perovskite materials Using Density Functional Theory

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arXiv 2024年

作者： Kumar, Upendra Kim, Hyeon Woo Maurya, Gyanendra Kumar Raj, Bincy Babu Singh, Sobhit Kushwaha, Ajay Kumar Cho, Sung Beom Ko, Hyunseok Jinju52851 Korea Republic of Department of Materials Science and Engineering Hanyang University Seoul04763 Korea Republic of Department of Physics GLA University Mathura281406 India School of Material Science and Engineering Pusan National University 2 Busandaehak-ro 63beon-gil Geumjeong-gu Busan46241 Korea Republic of Department of Mechanical Engineering The University of Rochester New York14611 United States Materials Science Program University of Rochester RochesterNY14627 United States Department of Metallurgy Engineering and Materials Science Indian Institute of Technology Indore Khandwa Road Simrol Indore453552 India Department of Energy Systems Research Ajou University Suwon16499 Korea Republic of

The investigation of emerging non-toxic perovskite materials has been undertaken to advance the fabrication of environmentally sustainable lead-free perovskite solar cells. This study introduces a machine learning methodology aimed at predicting innovative halide perovskite materials that hold promise for use in photovoltaic applications. The seven newly predicted materials are as follows: CsMnCl4, Rb3Mn2Cl9, Rb4MnCl6, Rb3MnCl5, RbMn2Cl7, RbMn4Cl9, and CsIn2Cl7. The predicted compounds are first screened using a machine learning approach, and their validity is subsequently verified through density functional theory calculations. CsMnCl4 is notable among them, displaying a bandgap of 1.37 eV, falling within the Shockley-Queisser limit, making it suitable for photovoltaic applications. Through the integration of machine learning and density functional theory, this study presents a methodology that is more effective and thorough for the discovery and design of materials. © 2024, CC BY.

关键词： Density functional theory

Chiral, Topological, and Knotted Colloids in Liquid Crystals

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arXiv 2024年

作者： Yuan, Ye Smalyukh, Ivan I. Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan Department of Physics Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program Soft Materials Research Center University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

The geometric shape, symmetry, and topology of colloidal particles often allow for controlling colloidal phase behavior and physical properties of these soft matter systems. In liquid crystalline dispersions, colloidal particles with low symmetry and nontrivial topology of surface confinement are of particular interest, including surfaces shaped as handlebodies, spirals, knots, multi-component links, and so on. These types of colloidal surfaces induce topologically nontrivial three-dimensional director field configurations and topological defects. Director switching by electric fields, laser tweezing of defects, and local photo-thermal melting of the liquid crystal host medium promote transformations among many stable and metastable particle-induced director configurations that can be revealed by means of direct label-free three-dimensional nonlinear optical imaging. The interplay between topologies of colloidal surfaces, director fields, and defects is found to show a number of unexpected features, such as knotting and linking of line defects, often uniquely arising from the nonpolar nature of the nematic director field. This review article highlights fascinating examples of new physical behavior arising from the interplay of nematic molecular order and both chiral symmetry and topology of colloidal inclusions within the nematic host. Furthermore, the article concludes with a brief discussion of how these findings may lay the groundwork for new types of topology-dictated self-assembly in soft condensed matter leading to novel mesostructured composite materials, as well as for experimental insights into the pure-math aspects of low-dimensional topology. © 2024, CC BY.

关键词： Crystal symmetry

Enhancing dye degradation in darkness: The role of SnO2 nanorod clusters in flexocatalysis

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Chemical engineering Journal 2024年 494卷

作者： Chang, Nai-Jen Chen, Yu-Ching Lai, Sz-Nian Ming Wu, Jyh Department of Materials Science and Engineering National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan Program in Prospective Functional Materials Industry National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan High Entropy Materials Center National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan

Flexoelectricity is present in all dielectric materials and exhibits spontaneous electrical polarization when subjected to a strain gradient. In the present study, low-dimensional, pinecone-like tin oxide (SnO2) nanorod clusters demonstrated favorable flexocatalytic properties during a dye degradation experiment in which light irradiation was excluded;the catalytic activity was driven solely by mechanical force. Notably, the SnO2 lattice did not have a non-centrosymmetrical structure, indicating the absence of a piezoelectric effect. However, the nanoscale structure exhibited notable flexocatalysis under ultrasonic vibration. During the aforementioned dye degradation experiment, the concentration of dye molecules underwent nearly complete degradation under ultrasonic treatment. The corresponding rate constant was 0.484 hr-1, indicating a 28-fold improvement compared with commercially available SnO2 nanoparticles. Further characterization revealed that the as-synthesized SnO2 exhibited abundant oxygen vacancies. Through heat treatment at multiple temperatures, the concentration of oxygen vacancies was systematically reduced, and this reduction demonstrated a negative correlation with dye degradation efficiency. Within this system, oxygen vacancies played a pivotal role in modifying the band structure, thereby hindering the recombination rate of electron-hole pairs. This behavior indicates a notable enhancement in flexocatalysis efficiency with the elevation of defect concentration through thermal treatment. The present study demonstrated the viability of flexocatalysis for SnO2 with a wide band gap and highlighted the synergistic effect of defects, even in the absence of light, to present a promising strategy for polluted water treatment applications. © 2024 Elsevier B.V.

关键词： Oxygen vacancies

Magnetochiral Tunneling in Paramagnetic Co1/3NbS2

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arXiv 2024年

作者： Lim, Seongjoon Singh, Sobhit Huang, Fei-Ting Pan, Shangke Wang, Kefeng Kim, Jaewook Kim, Jinwoong Vanderbilt, David Cheong, Sang-Wook Rutgers Center for Emergent Materials Department of Physics and Astronomy PiscatawayNJ08854 United States Department of Mechanical Engineering University of Rochester RochesterNY14627 United States Materials Science Program University of Rochester RochesterNY14627 United States State Key Laboratory Base of Novel Function Materials and Preparation Science School of Material Sciences and Chemical Engineering Ningbo University Zhejiang Ningbo315211 China Department of Physics and Astronomy Rutgers University PiscatawayNJ08854 United States

Electric currents have the intriguing ability to induce magnetization in nonmagnetic crystals with sufficiently low crystallographic symmetry. Some associated phenomena include the non-linear anomalous Hall effect in polar crystals and the nonreciprocal directional dichroism in chiral crystals when magnetic fields are applied. In this work, we demonstrate that the same underlying physics is also manifested in the electronic tunneling process between the surface of a nonmagnetic chiral material and a magnetized scanning probe. In the paramagnetic but chiral metallic compound Co1/3NbS2, the magnetization induced by the tunneling current is shown to become detectable by its coupling to the magnetization of the tip itself. This results in a contrast across different chiral domains, achieving atomic-scale spatial resolution of structural chirality. To support the proposed mechanism, we used first-principles theory to compute the chirality-dependent current-induced magnetization and Berry curvature in the bulk of the material. Our demonstration of this magnetochiral tunneling effect opens up a new avenue for investigating atomic-scale variations in the local crystallographic symmetry and electronic structure across the structural domain boundaries of low-symmetry nonmagnetic crystals. © 2024, CC BY.

关键词： Magnetization