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Editorial for “Materials Chemistry” Sections on Molecules
No full textMaterials chemistry has been one of the most talked-about areas of materials research over the past decades [...
The “Materials Chemistry” Section of Molecules: A Multidisciplinary Environment for Materials-Based Researches
No full textThe “Materials Chemistry” Section of Molecules is an open access place for the dissemination of theoretical and experimental studies related to the chemical approaches to materials-based problems [...
Editorial for “Materials Chemistry” Section, in Journal Molecules
Full text linkDear colleagues and friends, it is a great pleasure to summarize the most significant successes achieved during 2019 in the “Materials Chemistry” Section (https://www [...
Materials Chemistry
No full textThe 2nd edition of Materials Chemistry builds on the strengths that were recognized by a 2008 Textbook Excellence Award from the Text and Academic Authors Association (TAA). Materials Chemistry addresses inorganic-, organic-, and nano-based materials from a structure vs. property treatment, providing a suitable breadth and depth coverage of the rapidly evolving materials field. The 2nd edition continues to offer innovative coverage and practical perspective throughout. After briefly defining materials chemistry and its history, seven chapters discuss solid-state chemistry, metals, semiconducting materials, organic "soft" materials, nanomaterials, and materials characterization. All chapters have been thoroughly updated and expanded with, for example, new sections on ‘soft lithographic’ patterning, ‘click chemistry’ polymerization, nanotoxicity, graphene, as well as many biomaterials applications. The polymer and ‘soft’ materials chapter represents the largest expansion for the 2nd edition. Each chapter concludes with a section that describes important materials applications, and an updated list of thought-provoking questions. The appendices have also been updated with additional laboratory modules for materials synthesis and a comprehensive timeline of major materials developments. Appropriate for junior/senior undergraduate students, as well as first-year graduate students in chemistry, physics, or engineering. Materials Chemistry may also serve as a reference to industrial researchers. The author chose depth over breadth, resulting in deep, detailed prose. The strenghts of this book are its illustrations and color graphics, as well as up-to-date references and examples. 'Choice Reviews Online', 2008 on Materials Chemistry 1st edition
Room-Temperature Solid-State Lithium-Ion Battery Using a LiBH4-MgO Composite Electrolyte
Full text linkLiBH4 has been widely studied as a solid-state electrolyte in Li-ion batteries working at 120 °C due to the low ionic conductivity at room temperature. In this work, by mixing with MgO, the Li-ion conductivity of LiBH4 has been improved. The optimum composition of the mixture is 53 v/v % of MgO, showing a Li-ion conductivity of 2.86 × 10-4 S cm-1 at 20 °C. The formation of the composite does not affect the electrochemical stability window, which is similar to that of pure LiBH4 (about 2.2 V vs Li+/Li). The mixture has been incorporated as the electrolyte in a TiS2/Li all-solid-state Li-ion battery. A test at room temperature showed that only five cycles already resulted in cell failure. On the other hand, it was possible to form a stable solid electrolyte interphase by applying several charge/discharge cycles at 60 °C. Afterward, the battery worked at room temperature for up to 30 cycles with a capacity retention of about 80%
Conductor-Insulator Interfaces in Solid Electrolytes: A Design Strategy to Enhance Li-Ion Dynamics in Nanoconfined LiBH4/Al2O3
Full text linkSynthesizing Li-ion-conducting solid electrolytes with application-relevant properties for new energy storage devices is a challenging task that relies on a few design principles to tune ionic conductivity. When starting with originally poor ionic compounds, in many cases, a combination of several strategies, such as doping or substitution, is needed to achieve sufficiently high ionic conductivities. For nanostructured materials, the introduction of conductor-insulator interfacial regions represents another important design strategy. Unfortunately, for most of the two-phase nanostructured ceramics studied so far, the lower limiting conductivity values needed for applications could not be reached. Here, we show that in nanoconfined LiBH4/Al2O3 prepared by melt infiltration, a percolating network of fast conductor-insulator Li+ diffusion pathways could be realized. These heterocontacts provide regions with extremely rapid 7Li NMR spin fluctuations giving direct evidence for very fast Li+ jump processes in both nanoconfined LiBH4/Al2O3 and LiBH4-LiI/Al2O3. Compared to the nanocrystalline, Al2O3-free reference system LiBH4-LiI, nanoconfinement leads to a strongly enhanced recovery of the 7Li NMR longitudinal magnetization. The fact that almost no difference is seen between LiBH4-LiI/Al2O3 and LiBH4/Al2O3 unequivocally reveals that the overall 7Li NMR spin-lattice relaxation rates are solely controlled by the spin fluctuations near or in the conductor-insulator interfacial regions. Thus, the conductor-insulator nanoeffect, which in the ideal case relies on a percolation network of space charge regions, is independent of the choice of the bulk crystal structure of LiBH4, either being orthorhombic (LiBH4/Al2O3) or hexagonal (LiBH4-LiI/Al2O3). 7Li (and 1H) NMR shows that rapid local interfacial Li-ion dynamics is corroborated by rather small activation energies on the order of only 0.1 eV. In addition, the LiI-stabilized layer-structured form of LiBH4 guarantees fast two-dimensional (2D) bulk ion dynamics and contributes to facilitating fast long-range ion transport
Self-Activated Catalytic Sites on Nanoporous Dilute Alloy for High-Efficiency Electrochemical Hydrogen Evolution
Full text linkDesign and synthesis of effective electrocatalysts for hydrogen evolution reaction (HER) in wide pH environments are critical to reduce energy losses in water electrolyzers. Here, by using a self-activation strategy, we construct an atomic nickel (Ni) decorated nanoporous iridium (Ir) catalyst, which can create the reaction-favorable chemical environment and maximize the electrochemical active surface area (ECSA), enabling efficient HER over a wide pH range. By using operando X-ray absorption spectroscopy and theoretical calculations, the atomic Ni sites are identified as the synergistic sites, which not only accelerate the water dissociation under operation conditions but also activate the surface Ir sites thus leading to the efficient H2 generation. This work highlights the significance of atomic-level decorating strategy which can optimize the activity of surface Ir atoms with negligible sacrifice of the ECSA
A New Chapter for Swiss Materials Chemistry: Materials Chemistry Highlights
No full textThe division dedicated to materials chemistry at the Swiss Chemical Society (SCS) has been recently restructured by merging the Division for Polymers, Colloids, and Interfaces (DCPI) with the Materials Chemistry Network (MatChem). This column provides more insights into the process while outlining the vision and activities of the newly established SCS Division of Materials Chemistry (DMC)
Electronic structure of Tb0.5 Sr0.5 MnO3
Full text linkWe study the electronic structure of single-crystal Tb0.5Sr0.5MnO3, a non-charge-ordered mixed-valent semiconductor which exhibits a glassy magnetic ground state. We use the techniques of soft x-ray photoemission, hard x-ray photoemission, x-ray absorption, and resonant photoemission spectroscopy to investigate the occupied and unoccupied electronic states of Tb0.5Sr0.5MnO3. Core level photoemission and x-ray absorption spectroscopy allow us to determine the valence states of Tb, Sr, and Mn ions in Tb0.5Sr0.5MnO3. Model charge transfer multiplet calculations of core level photoemission and x-ray absorption spectra are employed to separate out the Mn3+ and Mn4+ states and confirm their relative concentrations. Resonant photoemission spectroscopy across the Mn 2p-3d threshold shows clear resonant enhancement of the Mn 3d partial density of states and two-hole correlation satellites. A Cini-Sawatzky analysis gives on-site Coulomb energy Udd∼5.5±0.2 eV for the Mn 3dn states and Upd = 0.7 eV±0.2 eV for the Mn 3dn+1L̲1 states. The O 1s-2p resonant photoemission is used to identify the O 2p two-hole correlation satellite which provides Upp∼3.4±0.2 eV for the O 2p states. Valence band photoemission indicates a small-gap semiconductor (<100 meV) consistent with electrical transport measurements. The estimated electronic structure parameters of the on-site Coulomb energies, in combination with the charge transfer energy and the hybridization strength obtained from the model calculations, indicate that Tb0.5Sr0.5MnO3 is a strongly correlated charge transfer type semiconductor
Rational strain engineering of single-atom ruthenium on nanoporous MoS2 for highly efficient hydrogen evolution
Full text linkMaximizing the catalytic activity of single-atom catalysts is vital for the application of single-atom catalysts in industrial water-alkali electrolyzers, yet the modulation of the catalytic properties of single-atom catalysts remains challenging. Here, we construct strain-tunable sulphur vacancies around single-atom Ru sites for accelerating the alkaline hydrogen evolution reaction of single-atom Ru sites based on a nanoporous MoS2-based Ru single-atom catalyst. By altering the strain of this system, the synergistic effect between sulphur vacancies and Ru sites is amplified, thus changing the catalytic behavior of active sites, namely, the increased reactant density in strained sulphur vacancies and the accelerated hydrogen evolution reaction process on Ru sites. The resulting catalyst delivers an overpotential of 30 mV at a current density of 10 mA cm−2, a Tafel slope of 31 mV dec−1, and a long catalytic lifetime. This work provides an effective strategy to improve the activities of single-atom modified transition metal dichalcogenides catalysts by precise strain engineering
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