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Lithium Volatilization and Phase Changes during Aluminum-Doped Cubic Li6.25La3Zr2Al0.25O12 (c-LLZO) Processing 铝掺杂立方体 Li6.25La3Zr2Al0.25O12 (c-LLZO) 加工过程中的锂挥发和相变

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-09 DOI: 10.3390/cryst14090795

Steven T. Montoya, Shah A. H. Shanto, Robert A. Walker

{"title":"Lithium Volatilization and Phase Changes during Aluminum-Doped Cubic Li6.25La3Zr2Al0.25O12 (c-LLZO) Processing","authors":"Steven T. Montoya, Shah A. H. Shanto, Robert A. Walker","doi":"10.3390/cryst14090795","DOIUrl":"https://doi.org/10.3390/cryst14090795","url":null,"abstract":"Stabilized Li6.25La3Al0.25 Zr2O12 (cubic LLZO or c-LLZO) is a Li+-conducting ceramic with ionic conductivities approaching 1 mS-cm. Processing c LLZO so that it is suitable for use as a solid state electrolyte in all solid state batteries, however, is challenging due to the formation of secondary phases at elevated temperatures. The work described in this manuscript examines the formation of one such secondary phase La2Zr2O7 (LZO) formed during sintering c LLZO at 1000 °C. Specifically, spatially resolved Raman spectroscopy and X-ray Diffraction (XRD) measurements have identified gradients in Li distributions in the Li ion (Li+)-conducting ceramic Li6.25La3Al0.25 Zr2O12 (cubic LLZO or c-LLZO) created by thermal processing. Sintering c-LLZO under conditions relevant to solid state Li+ electrolyte fabrication conditions lead to Li+ loss and the formation of new phases. Specifically, sintering for 1 h at 1000 °C leads to Li+ depletion and the formation of the pyrochlore lanthanum zirconate (La2Zr2O7 or LZO), a material known to be both electronically and ionically insulating. Circular c-LLZO samples are covered on the top and bottom surfaces, exposing only the 1.6 mm-thick sample perimeter to the furnace’s ambient air. Sintered samples show a radially symmetric LZO gradient, with more LZO at the center of the pellet and considerably less LZO at the edges. This profile implies that Li+ diffusion through the material is faster than Li+ loss through volatilization, and that Li+ migration from the center of the sample to the edges is not completely reversible. These conditions lead to a net depletion of Li+ at the sample center. Findings presented in this work suggest new strategies for LLZO processing that will minimize Li+ loss during sintering, leading to a more homogeneous material with more reproducible electrochemical behavior.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Near-Infrared Spectroscopic Study of Secondary Minerals in the Oxidation Zones of Copper-Bearing Deposits 含铜矿床氧化带次生矿物的近红外光谱研究

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-07 DOI: 10.3390/cryst14090791

Shaokun Wu, Mingyue He, Mei Yang, Bijie Peng, Yujia Shi, Kaiyue Sun

{"title":"Near-Infrared Spectroscopic Study of Secondary Minerals in the Oxidation Zones of Copper-Bearing Deposits","authors":"Shaokun Wu, Mingyue He, Mei Yang, Bijie Peng, Yujia Shi, Kaiyue Sun","doi":"10.3390/cryst14090791","DOIUrl":"https://doi.org/10.3390/cryst14090791","url":null,"abstract":"This study measured the infrared spectra of secondary minerals in the oxidation zones of three types of copper ores: dioptase, malachite, and azurite, and assigned the peak positions of OH stretching vibrations and the origins of OH combination vibrations. Dioptase contains three types of water molecules with different orientations within its ring channels, which exhibit six kinds of OH stretching vibrations in the 3000–3600 cm−1 range; the bond length range is 2.652 to 2.887 Å. Among them, the 3443 cm−1 band shows strong near-infrared activity and combines with Si–O vibrations or OH bending vibrations in the structure, resulting in five combination vibration peaks in the 4000–5000 cm−1 range. Malachite contains two inequivalent hydroxyls in its structure, leading to two OH stretching vibrations in the high-frequency region located at 3314 and 3402 cm−1, respectively. Azurite contains only one type of hydroxyl, and thus only one characteristic OH stretching vibration is present at 3424 cm−1. The OH stretching vibrations of malachite and azurite mainly combine with [CO3]2− vibrations or OH bending vibrations, leading to six and five combination peaks in the OH combination vibration region, respectively. By analyzing the combination of peak positions at 4341 cm−1 in the near-infrared spectrum, the merged OH bending vibration at 921 cm−1 in azurite was discovered. Spectroscopic research on secondary minerals can better provide a basis for ore exploration and geological remote sensing.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Crystal Growth of LiNa5Mo9O30 Crystals of High Optical Quality 高光学质量 LiNa5Mo9O30 晶体的晶体生长

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-07 DOI: 10.3390/cryst14090792

Nikolai Khokhlov, Ivan Grishchenko, Ekaterina Shevelkina, Denis Bindyug, Ekaterina Barkanova, Dmitry Denisov, Dmitry Demushkin, Ivan Telegin, Ekaterina Yezhikova, Igor Avetissov, Roman Avetisov, Alexey Konyashkin, Oleg Ryabushkin

引用次数: 0

In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin 使用商用高岭土原位合成氮化石墨碳/偏高岭土复合光催化剂并确定其特性

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-07 DOI: 10.3390/cryst14090793

Balázs Zsirka, Orsolya Fónagy, Veronika Vágvölgyi, Tatjána Juzsakova, Lajos Fodor, Csilla Őze

{"title":"In Situ Synthesis and Characterization of Graphitic Carbon Nitride/Metakaolin Composite Photocatalysts Using a Commercial Kaolin","authors":"Balázs Zsirka, Orsolya Fónagy, Veronika Vágvölgyi, Tatjána Juzsakova, Lajos Fodor, Csilla Őze","doi":"10.3390/cryst14090793","DOIUrl":"https://doi.org/10.3390/cryst14090793","url":null,"abstract":"Kaolin-based graphitic carbon nitride (g-CNx) composite photocatalysts were synthesized from a urea precursor using a commercial kaolin. Structural characterization by X-ray diffraction and infrared spectroscopy (FTIR) verified the successful thermal polycondensation of g-CNx along the thermal dehydroxylation of kaolinite to metakaolin at 550 °C. The g-CNx content of the composites were estimated by thermogravimetry and CHN analysis, ranging from ca. 87 m/m% to ca. 2 m/m% of dry mass. The addition of kaolin during the composite synthesis was found to have a significant effect: the yield of in situ formed g-CNx drastically decreased (from ca. 4.9 m/m% to 3.8–0.1 m/m%) with increasing kaolin content. CHN and FTIR indicated the presence of nitrogen-rich g-CNx, having a specific surface area of 50 m2/g, which synergistically increased after composite synthesis to 67–82 m2/g. Estimated optical band gaps indicated the affinity to absorb in the visible light spectrum (λ < 413 nm). Photocatalytic activity upon both UV and artificial sunlight irradiation was observed by hydroxyl radical evolution, however, without the synergistic effect expected from the favorable porosity.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fabrication and Characterization of Fe-Doped SnSe Flakes Using Chemical Vapor Deposition 利用化学气相沉积法制造掺铁硒化物薄片并确定其特性

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-06 DOI: 10.3390/cryst14090790

Florinel Sava, Claudia Mihai, Angel-Theodor Buruiana, Amelia Elena Bocirnea, Alin Velea

{"title":"Fabrication and Characterization of Fe-Doped SnSe Flakes Using Chemical Vapor Deposition","authors":"Florinel Sava, Claudia Mihai, Angel-Theodor Buruiana, Amelia Elena Bocirnea, Alin Velea","doi":"10.3390/cryst14090790","DOIUrl":"https://doi.org/10.3390/cryst14090790","url":null,"abstract":"The development of two-dimensional (2D) materials has gained significant attention due to their unique properties and potential applications in advanced electronics. This study investigates the fabrication and characterization of Fe-doped SnSe semiconductors using an optimized chemical vapor deposition (CVD) method. Fe doping was achieved by dissolving FeCl3 in deionized water, applying it to SnSe powder, and conducting vacuum drying followed by high-temperature CVD at 820 °C. Structural and morphological properties were characterized using optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Results revealed differently shaped flakes, including rectangles, discs and wires, influenced by Fe content. Micro-Raman spectroscopy showed significant vibrational mode shifts, indicating structural changes. X-ray photoelectron spectroscopy (XPS) confirmed the presence of Sn-Se and Fe-Se bonds. Electrical characterization of the memristive devices showed stable switching between high- and low-resistance states, with a threshold voltage of 1.6 V. These findings suggest that Fe-doped SnSe is a promising material for non-volatile memory and neuromorphic computing applications.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Review of Deep-Red (650–700 nm)-Emitting Semiconductor Nanocrystals 深红（650-700 纳米）发射半导体纳米晶体综述

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-05 DOI: 10.3390/cryst14090788

Geyu Jin, Fangze Liu, Jing Wei, Hongbo Li

引用次数: 0

Investigations of Some Disordered Quaternary Compounds in the Systems Ag/Pb/Sb/Se and Ag/Pb/Sb/Te 对 Ag/Pb/Sb/Se 和 Ag/Pb/Sb/Te 体系中一些无序季化合物的研究

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-05 DOI: 10.3390/cryst14090789

Maxim Grauer, Christopher Benndorf, Valentin Rohr, Carsten Paulmann, Oliver Oeckler

引用次数: 0

Mössbauer Studies of Haltern 70 Amphorae from Castro do Vieito, Northwest of Portugal 葡萄牙西北部 Castro do Vieito 出土的 Haltern 70 安福拉的莫斯鲍尔研究

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-04 DOI: 10.3390/cryst14090786

Benilde F. O. Costa, Friedrich E. Wagner, Werner Häusler, Christian Stieghorst, António José Marques da Silva

引用次数: 0

All-Optical Switching Using Cavity Modes in Photonic Crystals Embedded with Hyperbolic Metamaterials 利用嵌入双曲超材料的光子晶体中的腔模来实现全光开关

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-04 DOI: 10.3390/cryst14090787

Chang Liu, Dong Wei, Xiaochun Lin, Yaoxian Zheng

{"title":"All-Optical Switching Using Cavity Modes in Photonic Crystals Embedded with Hyperbolic Metamaterials","authors":"Chang Liu, Dong Wei, Xiaochun Lin, Yaoxian Zheng","doi":"10.3390/cryst14090787","DOIUrl":"https://doi.org/10.3390/cryst14090787","url":null,"abstract":"Hyperbolic metamaterials (HMMs) are highly anisotropic materials with the unique property of generating electromagnetic modes. Understanding how these materials can be applied to control the propagation of light waves remains a major focus in photonics. In this study, we inserted a finite-size HMM rod into the point defect of two-dimensional photonic crystals (PhCs) and investigated the unique cavity modes of this hybrid system. The HMM enhances the efficiency of the cavity system in controlling light transmission. Numerical results demonstrate that the cavity modes based on HMMs can be categorized into various types, showing high Q-factors and promising potential for resonant modulation. Furthermore, the switching performance of the cavity with an HMM rod was examined, revealing that the finite-size HMM modes are highly frequency-sensitive and suitable for nonlinear controlled all-optical switching. These switches, characterized by low power consumption and high extinction ratios, are highly suitable for integration into photonic systems. Our investigation on the new type of HMM cavity illustrates that anisotropic materials can be effectively applied in cavity systems to generate highly efficient modes for filtering and switching.","PeriodicalId":10855,"journal":{"name":"Crystals","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mixed-Metal Coordination Polymers 混合金属配位聚合物

IF 2.7 4区材料科学

Crystals Pub Date : 2024-09-03 DOI: 10.3390/cryst14090785

Ulli Englert

引用次数: 0