Chemistry of Materials最新文献

{"title":"Onset Reaction Mechanism of Cr and S Poisoning on Perovskite Oxide Surfaces","authors":"Mengren Bill Liu,&nbsp; and ,&nbsp;Bilge Yildiz*,&nbsp;","doi":"10.1021/acs.chemmater.4c0193610.1021/acs.chemmater.4c01936","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c01936https://doi.org/10.1021/acs.chemmater.4c01936","url":null,"abstract":"<p >Perovskite oxides serve as oxygen electrode materials in solid oxide fuel and electrolysis cells. These compounds are susceptible to poisoning by volatile chromium and sulfur species in the gas environment. The reaction mechanism of chromium and sulfur poisoning on perovskite oxide surfaces as a function of surface chemistry has not been resolved to date. Understanding the role of different surface chemistries in this degradation mechanism can help to guide the engineering of more stable surfaces. In this study, we take a state-of-the-art perovskite oxide (ABO₃), La_0.6Sr_0.4Co_0.2Fe_0.8O₃ (LSCF), as a model oxygen electrode material. We investigate the onset of poisoning reactions by CrO₃ and SO₂, and their activity on different surface terminations of LSCF by density functional theory (DFT) calculations and <i>ab initio</i> molecular dynamics (AIMD) simulations. We find that both CrO₃ and SO₂ molecules bind more strongly onto the AO-terminated surfaces than do the BO₂ surfaces. AO-terminated LSCF surfaces, especially the Sr sites, result in more strongly adsorbed species with reduced mobility at the surface. The adsorption of CrO₃ and SO₂ on Sr sites of an AO-terminated LSCF surface forms atomic coordinations similar to SrCrO₄ and SrSO₄, thereby serving as nucleation sites for the formation of these secondary phases. We find two physical traits, surface oxygen Bader charge and subsurface oxygen 2p-band center, that correlate with the distinctly different adsorption energies of these species on the AO- and BO₂-terminated surfaces. This indicates that the electrostatic interaction and charge transfer between the adsorbate and the surface play a major role in the onset of these poisoning reactions on perovskite oxides. The results reveal the role of surface chemistry in affecting the thermodynamics and the kinetics of CrO₃ and SO₂ reactions at perovskite oxide surfaces and inform effective strategies for mitigation.</p>","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142608801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigating Calendar Aging in Si-NMC Batteries with Advanced Dual-Salt Glyme Electrolytes","authors":"Guang Yang, Katie Browning, Harry M Meyer, III, Yuanshun Li, Nathan R. Neale, Gabriel M. Veith, Jagjit Nanda","doi":"10.1021/acs.chemmater.4c00971","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c00971","url":null,"abstract":"In addressing the critical challenge of calendar aging in silicon (Si)-based lithium-ion batteries, this study introduces a groundbreaking strategy utilizing glyme-type dual-salt electrolytes (lithium bis(trifluoromethanesulfonyl)imide [LiTFSI] and lithium difluoro(oxalato)borate [LiDFOB]). These electrolytes are demonstrated to significantly mitigate parasitic reactions and capacity loss in Si-NMC (lithium nickel manganese cobalt oxide) full cells, especially when compared with traditional carbonate-based electrolytes. Our exhaustive mechanistic analysis reveals that such electrolytes not only preserve the integrity of the Si anode but also improve the cathode/electrolyte interphases (CEI) through the formation of a conformal coating on the high-voltage cathode surface. This dual-salt approach, enhanced by the addition of a phosphate additive, effectively decelerates calendar aging, marking a substantial advance in the quest for durable and reliable Si-based energy storage technologies. The findings underscore the vital role of electrolyte composition in extending the calendar life of Si batteries, offering an alternative avenue toward maximizing the performance and longevity of next-generation Li–Si batteries.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":8.6,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142541662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-Coordinate Coinage Metal Complexes Featuring Imidazolium Carbenes: Realization of Efficient Blue Thermally Activated Delayed Fluorescence (TADF) for Organic-Light-Emitting Diodes (OLEDs)","authors":"Li-Ping Bai, Shu-Jia Zheng, Rui Xue, Deng-Feng Li, Ke-Die Li, Si-Qi Yu, Yuan Liu, Tian-Yi Li","doi":"10.1021/acs.chemmater.4c02517","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02517","url":null,"abstract":"As the most readily accessible <i>N</i>-heterocyclic carbenes (NHCs), imidazolium carbenes have traditionally been ruled out for the design of TADF coinage metal carbene–metal–amine (<b>CMA</b>) complexes due to their high-lying unoccupied π orbitals, which lead to a dark interligand charge transfer (ICT) state. In this work, in cooperation with strong electron-donating acridine ligands, a series of <b>CMA</b> complexes featuring imidazolium carbenes are prepared, exhibiting desired blue thermally activated delayed fluorescence (TADF) with high photoluminescent (PL) quantum yields (Φ_PL) close to unity and emission decay lifetimes as short as 1.0 μs. The small energy differences between S₁ and T₁ (Δ<i>E</i>_ST) of around 100 meV and the high radiative decay rates of S₁ on the order of 1 × 10⁷–10⁸ s^–1 contribute to the decent TADF behavior. Solution-processed blue OLEDs based on the Cu(I) emitter show an external quantum efficiency (EQE) exceeding 8.0%, demonstrating the practicality of using imidazolium carbenes in the design of TADF <b>CMA</b> luminophores.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":8.6,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142519793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction of a Lanthanide Cage with a Hollow-Walled Cavity and Large Windows to Promote Nucleophilic Additions","authors":"Jingzhe Li, Fan Dong, Manchang Kou, Shengbin Zhou, Xiaoyu Huang, Meilin Wu, Yu Tang, Xiaoliang Tang, Weisheng Liu","doi":"10.1021/acs.chemmater.4c02252","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02252","url":null,"abstract":"Metal–organic cages (MOCs) as artificial mimic enzymes can allow small organic molecules to freely move in and out of the cavity with confined space, which often can increase intermolecular collisions and accelerate those reactions that are difficult to occur. This kind of homogeneous catalyst possesses high catalytic activity and regioselectivity, attracting growing interest recently. However, the rational design of MOCs with large openings as well as rich active sites for efficient chemical conversions remains a great challenge. Herein, we report a decanuclear 3d-4f MOC, <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b>, with a hollow-walled cavity and four large windows self-assembled cooperatively by bridging ligands, Zn-based metalloligands, and lanthanide Yb³⁺ ions. The lantern-like <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b> not only exposes unblocked passageways for allowing more guest molecules to penetrate the cage smoothly but also provides rich Lewis centers within the cavity, which could promote nucleophilic additions to effectively boost Friedel–Crafts alkylation and the three-component Strecker reaction. With the <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b> catalyst, more than 13 bis(indolyl)methane derivatives could be synthesized easily in 53–98% through Friedel–Crafts alkylation, and the conversion of the Strecker reaction for aniline, benzaldehyde, and trimethylsilyl cyanide could achieve approximately 98% in 3 h. Furthermore, host–guest relationship investigations confirmed that the catalytic function of the <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b> cage could be mainly attributed to the synergy of the inherent confinement effect, multiple Lewis catalytic sites, and host–guest electrostatic interactions in the coordination cage. The construction of the discrete 3d-4f MOC with large windows and its catalytic applications in nucleophilic additions may represent a potential approach for developing enzyme-like supramolecular nanoreactors.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":8.6,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142519775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-Coordinate Coinage Metal Complexes Featuring Imidazolium Carbenes: Realization of Efficient Blue Thermally Activated Delayed Fluorescence (TADF) for Organic-Light-Emitting Diodes (OLEDs)","authors":"Li-Ping Bai,&nbsp;Shu-Jia Zheng,&nbsp;Rui Xue,&nbsp;Deng-Feng Li,&nbsp;Ke-Die Li,&nbsp;Si-Qi Yu,&nbsp;Yuan Liu* and Tian-Yi Li*,&nbsp;","doi":"10.1021/acs.chemmater.4c0251710.1021/acs.chemmater.4c02517","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02517https://doi.org/10.1021/acs.chemmater.4c02517","url":null,"abstract":"<p >As the most readily accessible <i>N</i>-heterocyclic carbenes (NHCs), imidazolium carbenes have traditionally been ruled out for the design of TADF coinage metal carbene–metal–amine (<b>CMA</b>) complexes due to their high-lying unoccupied π orbitals, which lead to a dark interligand charge transfer (ICT) state. In this work, in cooperation with strong electron-donating acridine ligands, a series of <b>CMA</b> complexes featuring imidazolium carbenes are prepared, exhibiting desired blue thermally activated delayed fluorescence (TADF) with high photoluminescent (PL) quantum yields (Φ_PL) close to unity and emission decay lifetimes as short as 1.0 μs. The small energy differences between S₁ and T₁ (Δ<i>E</i>_ST) of around 100 meV and the high radiative decay rates of S₁ on the order of 1 × 10⁷–10⁸ s^–1 contribute to the decent TADF behavior. Solution-processed blue OLEDs based on the Cu(I) emitter show an external quantum efficiency (EQE) exceeding 8.0%, demonstrating the practicality of using imidazolium carbenes in the design of TADF <b>CMA</b> luminophores.</p>","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction of a Lanthanide Cage with a Hollow-Walled Cavity and Large Windows to Promote Nucleophilic Additions","authors":"Jingzhe Li,&nbsp;Fan Dong,&nbsp;Manchang Kou,&nbsp;Shengbin Zhou,&nbsp;Xiaoyu Huang,&nbsp;Meilin Wu,&nbsp;Yu Tang,&nbsp;Xiaoliang Tang* and Weisheng Liu,&nbsp;","doi":"10.1021/acs.chemmater.4c0225210.1021/acs.chemmater.4c02252","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02252https://doi.org/10.1021/acs.chemmater.4c02252","url":null,"abstract":"<p >Metal–organic cages (MOCs) as artificial mimic enzymes can allow small organic molecules to freely move in and out of the cavity with confined space, which often can increase intermolecular collisions and accelerate those reactions that are difficult to occur. This kind of homogeneous catalyst possesses high catalytic activity and regioselectivity, attracting growing interest recently. However, the rational design of MOCs with large openings as well as rich active sites for efficient chemical conversions remains a great challenge. Herein, we report a decanuclear 3d-4f MOC, <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b>, with a hollow-walled cavity and four large windows self-assembled cooperatively by bridging ligands, Zn-based metalloligands, and lanthanide Yb³⁺ ions. The lantern-like <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b> not only exposes unblocked passageways for allowing more guest molecules to penetrate the cage smoothly but also provides rich Lewis centers within the cavity, which could promote nucleophilic additions to effectively boost Friedel–Crafts alkylation and the three-component Strecker reaction. With the <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b> catalyst, more than 13 bis(indolyl)methane derivatives could be synthesized easily in 53–98% through Friedel–Crafts alkylation, and the conversion of the Strecker reaction for aniline, benzaldehyde, and trimethylsilyl cyanide could achieve approximately 98% in 3 h. Furthermore, host–guest relationship investigations confirmed that the catalytic function of the <b>Zn</b>_<b>2</b><b>Yb</b>_<b>8</b> cage could be mainly attributed to the synergy of the inherent confinement effect, multiple Lewis catalytic sites, and host–guest electrostatic interactions in the coordination cage. The construction of the discrete 3d-4f MOC with large windows and its catalytic applications in nucleophilic additions may represent a potential approach for developing enzyme-like supramolecular nanoreactors.</p>","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-Dimensional Covalent Organic Framework Serving as Host and Electrocatalyst in the Cathode of Li–S Battery","authors":"Jun Jiang, Miaomiao Wu, Jian Li, Ting Zhou, Bingqing Xu, Zhen Shan, Yuan Zhong, Zhiyi Ling, Yongsheng Fu, Boliang Wang, Junwu Zhu, Gen Zhang","doi":"10.1021/acs.chemmater.4c02120","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02120","url":null,"abstract":"Lithium–sulfur batteries (LSBs), as very promising lithium-ion batteries, have received widespread attention from researchers. However, the low conductivity of sulfur in lithium sulfur batteries and the significant volume expansion during charging and discharging seriously affect the high rate performance of the battery, hindering its practical application. In this study, we designed bifunctional 3D covalent organic frameworks (COFs) with interconnected nanostructures and significant catalytic activity by connecting flexible cycloocta thiophene blocks with porphyrin units. 3D COFs act as catalytic nanotraps in the cathode of LSBs, providing confinement and chemical adsorption of lithium polysulfides, thereby improving the redox kinetics of sulfur. The acceleration of Li₂S nucleation by Ni-porphyrin active centers, as confirmed through in situ X-ray diffraction and Raman spectroscopy, enhances polysulfide conversion kinetics, further improving battery performance. The constructed battery that incorporates the 3D COF exhibits a minor fading trend of only 0.05% per cycle over 500 cycles at 1 C, outperforming commercial carbon nanotubes. Additionally, under lean electrolyte conditions and high sulfur loading, the 3D COF shows promise as a practical solution for high-energy-density LSBs, achieving an actual area capacity of 7.0 mAh cm^–2 at 0.2 C. This research sets a solid foundation for the tailored design of COFs-based bifunctional catalytic nanotraps that can serve dual roles as both host materials and electrocatalysts in Li–S batteries.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":8.6,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Key Role of Positional Disorder and Soft Structural Framework for Lowering the Thermal Conductivity of Quaternary Ag1–xCu3+xTiSe4 (0 ≤ x ≤ 0.8) System to an Ultralow Limit","authors":"Achintya Lakshan, Krishnendu Buxi, Paribesh Acharyya, Kishor Das, Biplab Koley, Kapildeb Dolui, Christophe Candolfi, Carmelo Prestipino, Emmanuel Guilmeau, Ahin Roy, Partha Pratim Jana","doi":"10.1021/acs.chemmater.4c02404","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02404","url":null,"abstract":"Low thermal conductive semiconductors have attracted huge attention for heat management and heat harvesting applications. Although the weak chemical bonding in the Cu/Ag-based chalcogenides is promising in suppressing heat transport, their quaternary analogs remain less explored. Here, we report on a comparative study of the crystal structure and thermal conductivity of various Ag-containing variants of Cu₄TiSe₄, i.e., Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄ (<i>x</i> = 0–0.8) samples. Analysis of the crystal structure, phase transition, and temperature-dependent lattice thermal conductivity (κ_L) of pristine AgCu₃TiSe₄ and Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄ have been carried out both experimentally and theoretically. The cubic crystal structure (space group <i>P</i>4̅3<i>m</i>) of these Ag variants is identical to that of Cu₄TiSe₄ or Cu₄TiTe₄, where a positionally disordered Cu sublattice is either replaced by Ag (for AgCu₃TiSe₄) or by Ag/Cu substructure (for Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄). Upon cooling, the symmetry reduction to a rhombohedral (space group <i>R</i>3<i>m</i>) structure is attributed to the partial ordering of the positionally disordered Ag. The proposed structural models at different temperatures have been further analyzed using the Maximum Entropy Method (MEM). X-ray photoelectron spectroscopy measurement suggests that the parent compound forms a charge-precise (Ag⁺)(Cu⁺)₃(Ti⁴⁺)(Se^2–)₄ chemical formula. Interestingly, the lattice thermal conductivity of the Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄ samples remains very low, with values varying in the range of ∼0.65–0.24 W m^–1 K^–1 between 293 and 623 K. Density Functional Theory (DFT) calculation shows the presence of antibonding states of Cu(3d)/Ag(4d)–Se(4p) below the Fermi level (<i>E</i>_F), providing softness to the lattice of AgCu₃TiSe₄. In addition, the positional disordered site plays a crucial role in further softening the framework and provides large lattice anharmonicity. The calculated phonon dispersions evidence the presence of several soft optical phonon modes at <i>ca.</i> 25 cm^–1, originating from the atomic vibrations of Ag, Cu, and Se. Further confirmation of these phonon modes is obtained from the low-temperature heat capacity study. The low-lying optical phonon modes in AgCu₃TiSe₄ are mainly caused by the presence of a soft lattice framework, positional disorder and associated rattling-like vibrations of Ag⁺/Cu⁺ ions. Their strong interaction with the heat-carrying acoustic phonon modes is key ingredient that explains the very low κ_L.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":8.6,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-Dimensional Covalent Organic Framework Serving as Host and Electrocatalyst in the Cathode of Li–S Battery","authors":"Jun Jiang,&nbsp;Miaomiao Wu,&nbsp;Jian Li,&nbsp;Ting Zhou,&nbsp;Bingqing Xu*,&nbsp;Zhen Shan,&nbsp;Yuan Zhong,&nbsp;Zhiyi Ling,&nbsp;Yongsheng Fu,&nbsp;Boliang Wang,&nbsp;Junwu Zhu* and Gen Zhang*,&nbsp;","doi":"10.1021/acs.chemmater.4c0212010.1021/acs.chemmater.4c02120","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02120https://doi.org/10.1021/acs.chemmater.4c02120","url":null,"abstract":"<p >Lithium–sulfur batteries (LSBs), as very promising lithium-ion batteries, have received widespread attention from researchers. However, the low conductivity of sulfur in lithium sulfur batteries and the significant volume expansion during charging and discharging seriously affect the high rate performance of the battery, hindering its practical application. In this study, we designed bifunctional 3D covalent organic frameworks (COFs) with interconnected nanostructures and significant catalytic activity by connecting flexible cycloocta thiophene blocks with porphyrin units. 3D COFs act as catalytic nanotraps in the cathode of LSBs, providing confinement and chemical adsorption of lithium polysulfides, thereby improving the redox kinetics of sulfur. The acceleration of Li₂S nucleation by Ni-porphyrin active centers, as confirmed through in situ X-ray diffraction and Raman spectroscopy, enhances polysulfide conversion kinetics, further improving battery performance. The constructed battery that incorporates the 3D COF exhibits a minor fading trend of only 0.05% per cycle over 500 cycles at 1 C, outperforming commercial carbon nanotubes. Additionally, under lean electrolyte conditions and high sulfur loading, the 3D COF shows promise as a practical solution for high-energy-density LSBs, achieving an actual area capacity of 7.0 mAh cm^–2 at 0.2 C. This research sets a solid foundation for the tailored design of COFs-based bifunctional catalytic nanotraps that can serve dual roles as both host materials and electrocatalysts in Li–S batteries.</p>","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Key Role of Positional Disorder and Soft Structural Framework for Lowering the Thermal Conductivity of Quaternary Ag1–xCu3+xTiSe4 (0 ≤ x ≤ 0.8) System to an Ultralow Limit","authors":"Achintya Lakshan,&nbsp;Krishnendu Buxi,&nbsp;Paribesh Acharyya,&nbsp;Kishor Das,&nbsp;Biplab Koley,&nbsp;Kapildeb Dolui*,&nbsp;Christophe Candolfi,&nbsp;Carmelo Prestipino,&nbsp;Emmanuel Guilmeau,&nbsp;Ahin Roy and Partha Pratim Jana*,&nbsp;","doi":"10.1021/acs.chemmater.4c0240410.1021/acs.chemmater.4c02404","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02404https://doi.org/10.1021/acs.chemmater.4c02404","url":null,"abstract":"<p >Low thermal conductive semiconductors have attracted huge attention for heat management and heat harvesting applications. Although the weak chemical bonding in the Cu/Ag-based chalcogenides is promising in suppressing heat transport, their quaternary analogs remain less explored. Here, we report on a comparative study of the crystal structure and thermal conductivity of various Ag-containing variants of Cu₄TiSe₄, i.e., Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄ (<i>x</i> = 0–0.8) samples. Analysis of the crystal structure, phase transition, and temperature-dependent lattice thermal conductivity (κ_L) of pristine AgCu₃TiSe₄ and Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄ have been carried out both experimentally and theoretically. The cubic crystal structure (space group <i>P</i>4̅3<i>m</i>) of these Ag variants is identical to that of Cu₄TiSe₄ or Cu₄TiTe₄, where a positionally disordered Cu sublattice is either replaced by Ag (for AgCu₃TiSe₄) or by Ag/Cu substructure (for Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄). Upon cooling, the symmetry reduction to a rhombohedral (space group <i>R</i>3<i>m</i>) structure is attributed to the partial ordering of the positionally disordered Ag. The proposed structural models at different temperatures have been further analyzed using the Maximum Entropy Method (MEM). X-ray photoelectron spectroscopy measurement suggests that the parent compound forms a charge-precise (Ag⁺)(Cu⁺)₃(Ti⁴⁺)(Se^2–)₄ chemical formula. Interestingly, the lattice thermal conductivity of the Ag_1–<i>x</i>Cu_3+<i>x</i>TiSe₄ samples remains very low, with values varying in the range of ∼0.65–0.24 W m^–1 K^–1 between 293 and 623 K. Density Functional Theory (DFT) calculation shows the presence of antibonding states of Cu(3d)/Ag(4d)–Se(4p) below the Fermi level (<i>E</i>_F), providing softness to the lattice of AgCu₃TiSe₄. In addition, the positional disordered site plays a crucial role in further softening the framework and provides large lattice anharmonicity. The calculated phonon dispersions evidence the presence of several soft optical phonon modes at <i>ca.</i> 25 cm^–1, originating from the atomic vibrations of Ag, Cu, and Se. Further confirmation of these phonon modes is obtained from the low-temperature heat capacity study. The low-lying optical phonon modes in AgCu₃TiSe₄ are mainly caused by the presence of a soft lattice framework, positional disorder and associated rattling-like vibrations of Ag⁺/Cu⁺ ions. Their strong interaction with the heat-carrying acoustic phonon modes is key ingredient that explains the very low κ_L.</p>","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142608997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}