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Lithium–sulfur batteries (LSBs) have drawn significant attention owing to their high theoretical discharge capacity and energy density. However, the dissolution of long‐chain polysulfides into the electrolyte during the charge and discharge process ("shuttle effect") results in fast capacity fading and inferior electrochemical performance. In this study, Mn2O3 with an ordered mesoporous structure (OM‐Mn2O3) was designed as a cathode host for LSBs via KIT‐6 hard templating, to effectively inhibit the polysulfide shuttle effect. OM‐Mn2O3 offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar–polar interactions, polysulfides, and sulfur chain catenation. The OM‐Mn2O3/S composite electrode delivered a discharge capacity of 561 mA h g−1 after 250 cycles at 0.5 C owing to the excellent performance of OM‐Mn2O3. Furthermore, it retained a discharge capacity of 628 mA h g−1 even at a rate of 2 C, which was significantly higher than that of a pristine sulfur electrode (206 mA h g−1). These findings provide a prospective strategy for designing cathode materials for high‐performance LSBs. [ABSTRACT FROM AUTHOR]

Abstract Lithium–sulfur batteries (LSBs) have drawn significant attention owing to their high theoretical discharge capacity and energy density. However, the dissolution of long‐chain polysulfides into the electrolyte during the charge and discharge process (“shuttle effect”) results in fast capacity fading and inferior electrochemical performance. In this study, Mn2O3 with an ordered mesoporous structure (OM‐Mn2O3) was designed as a cathode host for LSBs via KIT‐6 hard templating, to effectively inhibit the polysulfide shuttle effect. OM‐Mn2O3 offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar–polar interactions, polysulfides, and sulfur chain catenation. The OM‐Mn2O3/S composite electrode delivered a discharge capacity of 561 mA h g−1 after 250 cycles at 0.5 C owing to the excellent performance of OM‐Mn2O3. Furthermore, it retained a discharge capacity of 628 mA h g−1 even at a rate of 2 C, which was significantly higher than that of a pristine sulfur electrode (206 mA h g−1). These findings provide a prospective strategy for designing cathode materials for high‐performance LSBs.

Complex transition‐metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition‐metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6, using Zr, yields LaSrCoRuO5. This reduced phase contains an ordered array of apex‐linked square‐based pyramidal Ru3+O5, square‐planar Co1+O4 and octahedral Co3+O6 units, consistent with the coordination‐geometry driven disproportionation of Co2+. Coordination‐geometry driven disproportionation of d7 transition‐metal cations (e.g. Rh2+, Pd3+, Pt3+) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition‐metal such as cobalt leads to the expectation that d7+ Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+O4 and Co3+O6 units in LaSrCoRuO5 is surprising. Low‐temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=1/2 Ru3+ and S=1 Co1+. [ABSTRACT FROM AUTHOR]

Complex transition‐metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition‐metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6, using Zr, yields LaSrCoRuO5. This reduced phase contains an ordered array of apex‐linked square‐based pyramidal Ru3+O5, square‐planar Co1+O4 and octahedral Co3+O6 units, consistent with the coordination‐geometry driven disproportionation of Co2+. Coordination‐geometry driven disproportionation of d7 transition‐metal cations (e.g. Rh2+, Pd3+, Pt3+) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition‐metal such as cobalt leads to the expectation that d7+ Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+O4 and Co3+O6 units in LaSrCoRuO5 is surprising. Low‐temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=1/2 Ru3+ and S=1 Co1+. [ABSTRACT FROM AUTHOR]

Complex transition‐metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition‐metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6, using Zr, yields LaSrCoRuO5. This reduced phase contains an ordered array of apex‐linked square‐based pyramidal Ru3+O5, square‐planar Co1+O4 and octahedral Co3+O6 units, consistent with the coordination‐geometry driven disproportionation of Co2+. Coordination‐geometry driven disproportionation of d7 transition‐metal cations (e.g. Rh2+, Pd3+, Pt3+) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition‐metal such as cobalt leads to the expectation that d7+ Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+O4 and Co3+O6 units in LaSrCoRuO5 is surprising. Low‐temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=1/2 Ru3+ and S=1 Co1+. [ABSTRACT FROM AUTHOR]

Complex transition‐metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition‐metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6, using Zr, yields LaSrCoRuO5. This reduced phase contains an ordered array of apex‐linked square‐based pyramidal Ru3+O5, square‐planar Co1+O4 and octahedral Co3+O6 units, consistent with the coordination‐geometry driven disproportionation of Co2+. Coordination‐geometry driven disproportionation of d7 transition‐metal cations (e.g. Rh2+, Pd3+, Pt3+) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition‐metal such as cobalt leads to the expectation that d7+ Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+O4 and Co3+O6 units in LaSrCoRuO5 is surprising. Low‐temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=1/2 Ru3+ and S=1 Co1+. [ABSTRACT FROM AUTHOR]

The flake-like nature of materials possessing continuous porous skeletons makes them naturally suited for energy storage and other applications. Nickel oxide (NiO) stands out as a highly attractive anode material for lithium-ion batteries due to its relatively high theoretical specific capacity. Nevertheless, the sluggish kinetics of its reactions and significant volume variations during cycling curtail its rate capability and electrochemical stability. In this work, we successfully fabricate nanoporous oxygen-deficient NiO@Al 2 O 3 flakes by a multi-step process involving magnetron sputtering deposition, subsequent thermal oxidation treatment, and a particle atomic layer deposition surface coating technique. The resultant nanoporous oxygen-deficient NiO@Al 2 O 3 flakes demonstrate the potential to establish an intricate network that facilitates efficient charge transfer, rapid ion diffusion, and mechanical robustness throughout electrochemical processes. Particularly noteworthy is the role of the ultrathin Al 2 O 3 coating, which greatly bolsters the cycle life. When employed as lithium storage materials, the nanoporous NiO@Al 2 O 3 flakes exhibit remarkable attributes, including high specific capacity (720 mAh g−1 at 25 mA g−1), superior rate capability (300 mAh g−1 at 5000 mA g−1) and sustained cycling ability, showcasing a reversible capacity of 413 mAh g−1 after 500 cycles at 150 mA g−1 (equivalent to a duration exceeding 4 months). Moreover, the distinctive morphologies and compositions observed after extended cycles definitively corroborate the efficacy of the nanoporous flake architecture. Finally, we present a full-cell configuration comprising a NiO@Al 2 O 3 flakes anode paired with a LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode, which notably exhibits remarkable cycle stability, retaining 84.2 % of its capacity after 100 cycles at 200 mA g−1. This effective and versatile strategy might hold promise for extension to alternative anode and cathode materials, potentially enabling enhanced specific capacity and rendering them suitable for energy storage applications. [ABSTRACT FROM AUTHOR]

Transition-metal oxides show lots of interesting and useful properties. The wide variety of their crystal structures gives rise to various electronic structures, which lead to various chemical and physical properties. The author has been interested in such transition-metal oxides and is seeking new materials with novel functional properties. In this review article new functional properties found in A-site-ordered quadruple perovskite structure oxides with the unusually high-valence cations are highlighted. Negative thermal expansion was found in NdCu3Fe4O12 at the intersite-charge-transfer transition temperature near room temperature. The property is useful for developing materials to compensate the normal positive thermal expansion. Significant latent heat was also found to be provided by the intersite-charge-transfer transition in NdCu3Fe4O12. The large latent heat is considered to be related with unusual first-order magnetic entropy change induced by the charge transition. The large entropy change can be utilized for thermal control through a caloric effect, which can make effective energy systems for thermal energy storage and refrigeration. [ABSTRACT FROM AUTHOR]

Organic solar cell (OSC) has drawn considerable interest in recent decades owing to their advantages of light weight, flexible, large area and potentially low-cost. Employing an appropriate hole-transporting layer (HTL) into an OSC device has been proved as an efficient method to obtain high efficiency OSC due to the enhancement of the hole transporting and extraction of the device. In this work, aqueous solution-processed MoO3 (s-MoO3) thin films were employed as HTLs to construct non-fullerene PM6:Y6 OSCs. The s-MoO3 thin film was prepared by using an aqueous solution process from an isopolymolybdate [NH4]6Mo7O24.4H2O precursor followed by thermal annealing treatment to convert the precursor to MoO3. The s-MoO3 HTL based PM6:Y6 device demonstrates a power conversion efficiency of 15.75%, which is 38% improved than that of the device with thermally evaporated-MoO3 as HTL and 8% improved than that of the device with PEDOT:PSS as HTL. The enhancement of the device performance could be attributed to the enhanced hole mobility and better band matching of the s-MoO3 HTL. Moreover, the s-MoO3 HTL based PM6:Y6 device exhibited higher device stability than those of the reference devices. Our finding indicates that this s-MoO3 film has great potential as efficient HTL for high performance non fullerene OSCs. [ABSTRACT FROM AUTHOR]

Herein, perovskite La0.64(Ba1−xCax)0.36FeO3−δ (0≤x≤0.4$0 \leq x \leq 0.4$) samples are synthesized and investigated by X‐ray diffraction and mechanical spectroscopy. The room‐temperature structure of La0.64Ba0.36FeO3−δ is a mixture of orthorhombic and cubic phases. The structures of calcium‐doped La0.64(Ba1−xCax)0.36FeO3−δ are orthorhombic at room temperature. A modulus dip is observed above room temperature in La0.64(Ba1−xCax)0.36FeO3−δ (0≤x≤0.4$0 \leq x \leq 0.4$) samples. This corresponds to a phase transition from orthorhombic to rhombohedral structure with increasing temperature. The effect of oxygen nonstoichiometry on the room‐temperature structure and phase transition is observed by mechanical spectroscopy. [ABSTRACT FROM AUTHOR]

Phosphate tungsten and molybenum bronzes represent an outstanding class of materials displaying textbook examples of charge‐density‐wave (CDW) physics among other fundamental properties. Here we report on the existence of a novel structural branch with the general formula [Ba(PO4)2][WmO3m−3] (m=3, 4 and 5) denominated ′layered monophosphate tungsten bronzes′ (L‐MPTB). It results from thick [Ba(PO4)2]4− spacer layers disrupting the cationic metal‐oxide 2D units and enforcing an overall trigonal structure. Their symmetries are preserved down to 1.8 K and the compounds show metallic behaviour with no clear anomaly as a function of temperature. However, their electronic structure displays the characteristic Fermi surface of previous bronzes derived from 5d W states with hidden nesting properties. By analogy with previous bronzes, such a Fermi surface should result into CDW order. Evidence of CDW order was only indirectly observed in the low‐temperature specific heat, giving an exotic context at the crossover between stable 2D metals and CDW order. [ABSTRACT FROM AUTHOR]

Li2O2, as the cathodic discharge product of aprotic Li-O2 batteries, is difficult to electrochemically decompose. Transition-metal oxides (TMOs) have been proven to play a critical role in promoting the formation and decomposition of Li2O2. Herein, a NiO/CNT catalyst was prepared by anchoring a NiO nanosheet on the surface of CNT. When using the NiO/CNT as a cathode catalyst, the Li-O2 battery had a lower overpotential of 1.2 V and could operate 81 cycles with a limited specific capacity of 1000 mA h g−1 at a current density of 100 mA g−1. In comparison, with CNT as a cathodic catalyst, the battery could achieve an overpotential of 1.64 V and a cycling stability of 66 cycles. The introduction of NiO effectively accelerated the generation and decomposition rate of Li2O2, further improving the battery performance. SEM and XRD characterizations confirmed that a Li2O2 film formed during the discharge process and could be fully electrochemical decomposed in the charge process. The internal network and nanoporous structure of the NiO/CNT catalyst could provide more oxygen diffusion channels and accelerate the decomposition rate of Li2O2. These merits led to the Li-O2 battery's better performance. [ABSTRACT FROM AUTHOR]

This article is a short introduction to the modern computational techniques used to tackle the many-body problem in materials. The aim is to present the basic ideas, using simple examples to illustrate strengths and weaknesses of each method. We will start from density-functional theory (DFT) and the Kohn–Sham construction—the standard computational tools for performing electronic structure calculations. Leaving the realm of rigorous density-functional theory, we will discuss the established practice of adopting the Kohn–Sham Hamiltonian as approximate model. After recalling the triumphs of the Kohn–Sham description, we will stress the fundamental reasons of its failure for strongly-correlated compounds, and discuss the strategies adopted to overcome the problem. The article will then focus on the most effective method so far, the DFT+DMFT technique and its extensions. Achievements, open issues and possible future developments will be reviewed. The key differences between dynamical (DFT+DMFT) and static (DFT+U) mean-field methods will be elucidated. In the conclusion, we will assess the apparent dichotomy between first-principles and model-based techniques, emphasizing the common ground that in fact they share. [ABSTRACT FROM AUTHOR]

Precious-metal-free mixed aliovalent-substituted CeCuO x binary oxide and NiO-modified yNi/CeCuO x ternary mixed metal oxide catalysts were successfully synthesized. The 3Ni/CeCuO x sample exhibits the best performance and excellent catalytic selectivity by microstructures optimization and grafting octadecyltrichlorosilane (OTS). the unique catalysts have great potential in practical applications for low concentration VOCs removal of painting industries. [Display omitted] • Ternary mixed catalysts metal oxide provides abundance catalytic active sites. • 3Ni/CeCuO x exhibits excellent performance towards low concentrations toluene. • Surface modified materials exhibited excellent catalytic selectivity. • The competitive adsorption of toluene and water molecules was calculated by DFT. • The materials' good catalytic stability favor to practical applications. With the widespread application of waterborne painting process, effective removal technologies for low concentration volatile organic compounds (VOCs) is a major concern of the painting industries due to the low mass transfer efficiency. This work presents a unique approach for the molecular-level preparation of precious-metal-free mixed aliovalent-substituted, CeCuO x binary oxide and NiO-modified yNi/CeCuO x ternary mixed metal oxide catalysts. In addition, the excellent catalytic selectivity (no catalytic activity decreases under 5.0 vol% water vapor) of the catalysts was successfully achieved by microstructures optimization and grafting octadecyltrichlorosilane (OTS). Its catalytic activity in the oxidation of toluene at low concentrations (50 ppm) was studied. The 3Ni/CeCuO x sample exhibits the best performance, which achieve 90 % catalytic oxidation of toluene at 197 °C without using noble metals. This results from that the ternary doping and the growth of NiO increases the specific surface area, active lattice oxygen species, activates molecular oxygen species, and provides more catalytic sites, which improve the adsorption and catalysis of toluene. Furthermore, the catalytic stability of the catalysts is also significantly improved by the addition of the hydrophobic coating. Therefore, the unique catalysts have great potential in practical applications for low concentration VOCs removal of painting industries. [ABSTRACT FROM AUTHOR]

Li2O2, as the cathodic discharge product of aprotic Li-O2 batteries, is difficult to electrochemically decompose. Transition-metal oxides (TMOs) have been proven to play a critical role in promoting the formation and decomposition of Li2O2. Herein, a NiO/CNT catalyst was prepared by anchoring a NiO nanosheet on the surface of CNT. When using the NiO/CNT as a cathode catalyst, the Li-O2 battery had a lower overpotential of 1.2 V and could operate 81 cycles with a limited specific capacity of 1000 mA h g−1 at a current density of 100 mA g−1. In comparison, with CNT as a cathodic catalyst, the battery could achieve an overpotential of 1.64 V and a cycling stability of 66 cycles. The introduction of NiO effectively accelerated the generation and decomposition rate of Li2O2, further improving the battery performance. SEM and XRD characterizations confirmed that a Li2O2 film formed during the discharge process and could be fully electrochemical decomposed in the charge process. The internal network and nanoporous structure of the NiO/CNT catalyst could provide more oxygen diffusion channels and accelerate the decomposition rate of Li2O2. These merits led to the Li-O2 battery’s better performance.

The development of efficient and low‐cost oxygen evolution reaction (OER) catalysts is essential for the generation of clean hydrogen energy from water splitting. Herein, a novel hierarchical urchin‐like cobalt‐copper (hydr)oxide in situ grown on copper foam (CoCuOxHy(S)/CF) was synthesized through the electrochemical transformation of cobalt‐copper sulfides (Co9S8‐Cu1.81S) via anodization process. This CoCuOxHy(S)/CF anode exhibited a low overpotential (η) of 274 mV at a current density of 100 mA cm−2 with a robust durability over a period of 40 h when operated at 10 mA cm−2. Further investigations imply that the unique nanowires aggregated urchin‐like structure of CoCuOxHy(S) derived from the in situ anion exchange process could facilitate the exposure of active sites and accelerate electron transfer. More importantly, the incorporation of copper resulted in an electronic delocalization around the cobalt species, which contributed to reach a high‐valent catalytically active cobalt species and further improved the OER performance. [ABSTRACT FROM AUTHOR]

The lack of precise control of particle sizes is the critical challenge in the assembly of 3D interconnected transition‐metal oxide (TMO) for newly‐emerging energy conversion devices. A self‐embedded templating strategy for preparing the TMO@carbon quasiaerogels (TMO@C‐QAs) is proposed. By mimicking an aerogel structure at a microscale, the TMO@C‐QA successfully assembles size‐controllable TMO nanoparticles into 3D interconnected structure with surface‐enriched carbon species. The morphological evolutions of intermediates verify that the self‐embedded Ostwald ripening templating approach is responsible for the dual‐channel TMO@C‐QA formation. The general self‐embedded templating strategy is easily extended to prepare various TMO@C‐QAs, including the Co3O4@C‐QA, Mn3O4@C‐QA, Fe2O3@C‐QA, and NiO@C‐QA. Benefiting from the unparalleled 3D interconnected network of aerogels, the Co3O4@C‐QA displays superior bifunctional catalytic activities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as well as high specific capacity and excellent long‐term stability for lithium‐ion battery (LIB) anode. A proof‐of‐concept battery‐powered electrolyzer with Co3O4@C‐QA cathode and anode powered by a full LIB with Co3O4@C‐QA anode is presented. The battery‐powered electrolyzer made of the state‐of‐the‐art TMOs can exhibit great competitive advantages due to its supreme multifunctional energy conversion performance for future water electrolysis. [ABSTRACT FROM AUTHOR]

Transition-metal oxides have attracted much attention due to its abundant crystalline phases and intriguing physical properties. However, some of these compounds are difficult to be fabricated directly in film form due to the ease of valence variation of transition-metal elements. In this work, we reveal the reversible structural transition between SrVO3 and Sr2V2O7 films via thermal treatment in oxygen atmosphere or in vacuum. Based on this, Sr2V2O7 epitaxial films are successfully synthesized and studied. Property characterizations show that the semitransparent and metallic SrVO3 could reversibly switch into transparent and insulating Sr2V2O7, implying potential applications in controllable electronic and optical devices. [ABSTRACT FROM AUTHOR]

Complex transition-metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition-metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO 6 , using Zr, yields LaSrCoRuO 5 . This reduced phase contains an ordered array of apex-linked square-based pyramidal Ru 3+ O 5 , square-planar Co 1+ O 4 and octahedral Co 3+ O 6 units, consistent with the coordination-geometry driven disproportionation of Co 2+ . Coordination-geometry driven disproportionation of d 7 transition-metal cations (e.g. Rh 2+ , Pd 3+ , Pt 3+ ) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition-metal such as cobalt leads to the expectation that d 7+ Co 2+ should be stable to disproportionation in oxide environments, so the presence of Co 1+ O 4 and Co 3+ O 6 units in LaSrCoRuO 5 is surprising. Low-temperature measurements indicate LaSrCoRuO 5 adopts a ferromagnetically ordered state below 120 K due to couplings between S= 1 / 2 Ru 3+ and S=1 Co 1+ ., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

In recent years, many researchers have begun to shift their focus onto the synthesis of nanomaterials as this field possesses an immense potential that may provide incredible technological advances in the near future. The downside of conventional synthesis techniques, such as co-precipitation, sol-gel and hydrothermal methods, is that they necessitate toxic chemicals, produce harmful by-products and require a considerable amount of energy; therefore, more sustainable fabrication routes are sought-after. Biological molecules have been previously utilized as precursors for nanoparticle synthesis, thus eliminating the negative factors involved in traditional methods. In addition, transition-metal nanoparticles possess a broad scope of applications due to their multiple oxidation states and large surface areas, thereby allowing for a higher reactivity when compared to their bulk counterpart and rendering them an interesting research topic. However, this field is still relatively unknown and unpredictable as the biosynthesis of these nanostructures from fungi, bacteria and plants yield undesired diameters and morphologies, rendering them redundant compared to their chemically synthesized counterparts. Therefore, this review aims to obtain a better understanding on the plant-mediated synthesis process of the major transition-metal and transition-metal oxide nanoparticles, and how process parameters—concentration, temperature, contact time, pH level, and calcination temperature affect their unique properties such as particle size, morphologies, and crystallinity.

Flower‐like MnCo2O4 was prepared in a self‐assembly process and used in the formation of MnCo2O4@polyaniline (MnCo2O4@PANi) that proceeds by a simple in situ polymerization. The MnCo2O4@PANi‐reduced graphite oxide (MnCo2O4@PANi‐rGO) composite was then synthesized by introducing rGO into MnCo2O4@PANi. This modification improves the overall electronic conductivity of the MnCo2O4@PANi‐rGO because of the dual conductive functions of rGO and PANi; it also provides a buffer for the changes in electrode volume during cycling, thus improving the lithium‐storage performance of MnCo2O4@PANi‐rGO. The electrochemical performance of the samples was evaluated by charge/discharge cycling testing, cyclic voltammetry, and electrochemical impedance spectroscopy. MnCo2O4@PANi‐rGO delivers a discharge capacity of 745 mAh g−1 and a Coulombic efficiency of 100 % after 1050 cycles at a current density of 500 mA g−1, and is a promising anode material for lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Pseudocapacitive behavior is usually observed in transition‐metal oxide anodes for lithium‐ion batteries, such as Co3O4. It is necessary to develop electrochemical technologies for clarifying the properties of the pseudocapacitance in the electrode reactions, as the understanding and controllable application of pseudocapacitance benefits the development of electrode materials with multi‐storage mechanisms for lithium‐ion batteries. To this end, in this work, electrode processes are divided into four component parts with corresponding equivalent circuit diagrams used to emphasize the pseudocapacitive behavior of Co3O4. After analyzing the properties of Bode plots in the whole frequency range (10−2–105 Hz), phase‐angle Bode plots are demonstrated to be suitable for revealing the pseudocapacitance for Co3O4 at a certain state. In addition, C=1/ωZIm is utilized to determine the magnitude of the pseudocapacitance and double‐layer capacitance. For Co3O4 in the fully charged state (3 V vs. Li+/Li), the pseudocapacitance and double‐layer capacitance are approximately 180.28 and 1.32 μF cm−2, respectively. Therefore, the goal of monitoring pseudocapacitive behavior for a transition‐metal oxide anode such as Co3O4 in a certain state without the influence of double‐layer capacitance and faradaic processes controlled by solid‐phase diffusion is realized by using Bode plots, greatly promoting the understanding and controllable application of pseudocapacitance. [ABSTRACT FROM AUTHOR]

Abstract A tetragonal distorted spinel of CuMn 2 O 4 was prepared by single step method followed by resistivity, heat capacity and magnetization measurement with respect to temperature and magnetic field. Here, resistivity data above 127 K provides the information about hopping conduction of Mott's type. Whereas, the magnetization data of χ(T) gives the ferri-magnetic order below 76 K with μ e f f = 4.37 μ B which is very close to the value obtained from the primary phase of { C u 0.62 1 + M n 0.26 2 + (C u 0.34 2 + M n 0.46 3 + M n 1.0 4 + ) O 3.6 2 − } associated with spin-canting. Due to the presence of spin-canting, the M(H) graph shows hysteresis loop indicating transition from metamagnetic to weak ferromagnetic state. Finally the spin canting below 78 K of the phase is confirmed from the magnetic field dependent heat capacity. Highlights • We have given emphasis to find out the chemical composition of the materials structure by room temperature neutron diffraction. • Subsequently, the electrical conductivity was measured which shows hopping conduction with an anomaly at 218 K. • However, the effective magnetic moment obtained from Curie-Weiss law of M(T) was found very close to theoretical value with hysteresis loop in the first and third quadrant of M(H) graph. • Finally, the effect of magnon was obtained from the heat capacity measurement. [ABSTRACT FROM AUTHOR]

We report a facile and generic method for the synthesis of hollow mesoporous silica nanoreactors (HMSNs) with small‐sized metal oxide nanoparticles (NPs) inside their cavities. They were made by deposition of silica onto metal‐containing charge‐driven polymer micelles and subsequent calcination. The micelles consist of 1) negatively charged supramolecular polyelectrolyte chains of bis‐ligand‐bound metal ions, and 2) water‐soluble, neutral/positive diblock copolymers. Owing to the facile coordination between transition‐metal ion and the employed bidentate ligand, a series of HMSNs with <2 nm MxOy NPs inside cavities (M=Mn, Co, Ni, Cu, or Zn) were obtained by simply varying the metal ions inside the micelles. The developed method circumvents the pre‐ and post‐synthesis of metal oxide NPs; after calcination, hollow mesoporous nanostructures containing small‐sized metal oxide NPs inside their cavities are directly obtained. The CoxOy‐functionalized HMSNs catalyze the degradation of various dyes with H2O2. Nanoparticles in nanoreactors: Hollow mesoporous silica nanoreactors with small metal oxide nanoparticles inside their cavities were obtained by deposition of silica onto metal‐containing polymer micelles and subsequent calcination. The CoxOy‐containing mesoporous silica nanoreactors were used as catalysts for the degradation of methylene blue and new coccine with hydrogen peroxide. [ABSTRACT FROM AUTHOR]

Ion injection controlled by an electric field is a powerful method to manipulate the diverse physical and chemical properties of metal oxides. However, the dynamic control of ion concentrations and their correlations with lattices in perovskite systems have not been fully understood. In this study, we systematically demonstrate the electric-field-controlled protonation of La 2/3 Sr 1/3 MnO 3 (LSMO) films. The rapid and room-temperature protonation induces a colossal lattice expansion of 9.35% in tensile-strained LSMO, which is crucial for tailoring material properties and enabling a wide range of applications in advanced electronics, energy storage, and sensing technologies. This large expansion in the lattice is attributed to the higher degree of proton diffusion, resulting in a significant elongation in the Mn-O bond and octahedral tilting, which is supported by results from density functional theory calculations. Interestingly, such a colossal expansion is not observed in LSMO under compressive strain, indicating the close dependence of ion-electron-lattice coupling on strain states. These efficient modulations of the lattice and magnetoelectric functionalities of LSMO via proton diffusion offer a promising avenue for developing multifunctional iontronic devices.

We prepared Na x TO 2 (T = Mn, Co) nanostructures to use as cathode material in Na-ion batteries. The Rietveld refinement of X-ray diffraction data confirms the hexagonal symmetry. Scanning and transmission electron microscopy measurements show hexagonal and rod-shape morphology for T = Co and Mn, respectively. The magnetic measurements indicate the presence of variable oxidation states of Mn/Co ions, but no long range ordering till 5 K. We find that the Na 0.6 MnO 2 is highly insulating whereas Na 0.7 CoO 2 is semiconducting in nature. The conduction in Na 0.7 CoO 2 takes place through both variable range hopping (VRH) as well as activation mechanisms in different temperature ranges. However, for Na 0.6 MnO 2 the VRH prevails at elevated temperatures. Furthermore, the coin cells have been fabricated and tested the electrochemical behavior using cyclic voltammetry, which confirms the reversibility of Na-ions during intercalation/de-intercalation. [ABSTRACT FROM AUTHOR]

Pre‐edge peaks in 3d transition‐metal element (Sc, Ti, V, Cr and Mn) K‐edge XANES (X‐ray absorption near‐edge structure) spectra in AO2 (A = Ti and V), A2O3 (A = Sc, Cr and Mn) and AO (A = Mn) are measured at various temperatures. Quantitative comparisons for the XANES spectra were investigated by using absorption intensity invariant point normalization. The energy position of the difference peak (D peak) is obtained from the difference between the low‐ and high‐temperature XANES spectra. There are two kinds of temperature dependence for pre‐edge peak intensity: rutile‐ and anatase‐type. The true temperature dependence of a transition to each orbital is obtained from the difference spectrum. In both anatase and rutile, the pre‐edge peak positions of A2 and A3 are clearly different from the D1‐ and D2‐peak positions. The A1 peak‐top energies in both phases of VO2 differ from the D1 peak‐top energies. The D‐peak energy position determined by the difference spectrum should represent one of the true energies for the transition to an independent orbital. The peak‐top positions for pre‐edge peaks in XANES do not always represent the true energy for independent transitions to orbitals because several orbital transitions overlap with similar energies. This work suggests that deformation vibration (bending mode) is effective in determining the temperature dependence for the D‐peak intensity. [ABSTRACT FROM AUTHOR]

Spinel Co 3 O 4 -MnCo 2 O 4 was synthesized by a two-step method, with a post annealing step after loading MnO 2 on the surface of Co-MOF (ZIF-67). For the first step, the methyl (-CH 3 ) groups of ZIF-67 were oxidized to carboxyl (-COOH) groups, with MnO 2 uniformly loaded on ZIF-67. Benefiting from this step, the uniform distribution of spinel Co 3 O 4 -MnCo 2 O 4 was achieved after calcination. Based on the stable framework of Co-MOF, a nanoparticle spinel Co 3 O 4 -MnCo 2 O 4 was obtained with an average diameter of 20–50 nm. This nano-sized characteristic not only shortens the diffusion lengths of lithium ion, but also alleviates the volume expansion of material during the Li + insertion/extraction process. The as-synthesized spinel Co 3 O 4 -MnCo 2 O 4 exhibited superior rate stability and cycle stability with high energy density and power density. Even at 5000 mA g −1 , a specific capacity of 614 mA h g −1 can be maintained. In view of the remarkable performance of spinel Co 3 O 4 -MnCo 2 O 4 , it can be concluded that spinel Co 3 O 4 -MnCo 2 O 4 has a potential to be an anode material in LIBs. Further, this two-step method can be used to prepare other mixed transition-metal oxides in various fields. [ABSTRACT FROM AUTHOR]

In this work, we present a simple, general, effective yet mass-production strategy to prepare transition-metal oxides (TMOs) nanoparticles using the metal-phthalocyanine as both the precursor and the starting self-sacrificial template. As the central metals of metal-phthalocyanine are easily tunable, various TMOs nanoparticles including Co 3 O 4 , Fe 2 O 3 , and CuO have been successfully prepared by deriving from the corresponding metal-phthalocyanine. As a proof-of-concept demonstration of the application of such nanostructured TMOs, Co 3 O 4 nanoparticles were evaluated as anode materials for LIBs, which show high initial capacity (1132.9 mAh g −1 at 0.05 A g −1 ), improved cycling stability (585.6 mAh g −1 after 200 cycles at 0.05 A g −1 ), and good rate capability (238.1 mAh g −1 at 2 A g −1 ) due to the unique properties of the ultrafine Co 3 O 4 nanoparticles. This present strategy might open new avenues for the design of a series of transition metal oxides using organometallic compounds for a range of applications. [ABSTRACT FROM AUTHOR]

The magnetic, mechanical and thermodynamic properties of LaMO3(M = Ti~Fe) have been systematically investigated using the first-principles calculations. The total magnetic moments of LaMO3are mainly from the M atom, and the contributions from La and O are very small. For LaTiO3, LaVO3, LaCrO3and LaMnO3the total magnetic moments agree well with experiment, while with somewhat larger disagreement for LaFeO3. Using the GGA + U (U = 5.6 eV), the calculated magnetic moment of LaFeO3is 4.98μB, which is in agreement with experiment data. The elastic constants and Vickers hardness suggest that LaMO3are mechanically stable and soft materials. TheB/Gratios indicate that all of LaMO3are ductile except LaVO3and LaCrO3.The LaCrO3has the highest Debye temperature, while LaVO3has the lowest Debye temperature. [ABSTRACT FROM AUTHOR]

This work presents the recent progress in nanostructured materials used as positive electrodes in Li-ion batteries (LIBs). Three classes of host lattices for lithium insertion are considered: transition-metal oxides V2O5, α-NaV2O5, α-MnO2, olivine-like LiFePO4, and layered compounds LiNi0.55Co0.45O2, LiNi1/3Mn1/3Co1/3O2 and Li2MnO3. First, a brief description of the preparation methods shows the advantage of a green process, i.e., environmentally friendliness wet chemistry, in which the synthesis route using single and mixed chelators is used. The impact of nanostructure and nano-morphology of cathode material on their electrochemical performance is investigated to determine the synthesis conditions to obtain the best electrochemical performance of LIBs. [ABSTRACT FROM AUTHOR]

Vanadium dioxide (VO2) thermochromic thin films with various thicknesses were grown on quartz glass substrates by radio frequency (RF)-plasma assisted oxide molecular beam epitaxy (O-MBE). The crystal structure, morphology and chemical stoichiometry were investigated systemically by X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses. An excellent reversible metal-to-insulator transition (MIT) characteristics accompanied by an abrupt change in both electrical resistivity and optical infrared (IR) transmittance was observed from the optimized sample. Remarkably, the transition temperature (TMIT) deduced from the resistivity-temperature curve was reasonably consistent with that obtained from the temperature-dependent IR transmittance. Based on Raman measurement and XPS analyses, the observations were interpreted in terms of residual stresses and chemical stoichiometry. This achievement will be of great benefit for practical application of VO2-based smart windows. [ABSTRACT FROM AUTHOR]

Phosphate tungsten and molybenum bronzes represent an outstanding class of materials displaying textbook examples of charge-density-wave (CDW) physics among other fundamental properties. Here we report on the existence of a novel structural branch with the general formula [Ba(PO 4 ) 2 ][W m O 3m-3 ] (m=3, 4 and 5) denominated 'layered monophosphate tungsten bronzes' (L-MPTB). It results from thick [Ba(PO 4 ) 2 ] 4- spacer layers disrupting the cationic metal-oxide 2D units and enforcing an overall trigonal structure. Their symmetries are preserved down to 1.8 K and the compounds show metallic behaviour with no clear anomaly as a function of temperature. However, their electronic structure displays the characteristic Fermi surface of previous bronzes derived from 5d W states with hidden nesting properties. By analogy with previous bronzes, such a Fermi surface should result into CDW order. Evidence of CDW order was only indirectly observed in the low-temperature specific heat, giving an exotic context at the crossover between stable 2D metals and CDW order., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Highlights • High-quality Pt/LaMnO 3 bilayer was grown on (0 0 1) MgO by PLD. • The bilayer shows the unexpected FM properties and the EB effect. • The FM behavior and the EB effect origin from strain-controlled orbital ordering. • This work open a route for tuning magnetic properties of LaMnO 3 -based multilayers. Abstract The structure and magnetic properties of Pt/LaMnO 3 bilayer film grown on (0 0 1) MgO substrate have been studied. Structural investigations demonstrate that the bilayer film is well epitaxial and possesses high-quality growth. Magnetic measurements suggest that besides anti-ferromagnetic (AFM) state, unexpected ferromagnetic (FM) behavior is also observed clearly in the Pt/LaMnO 3 bilayer structure. Moreover, exchange bias (EB) can also be found in the bilayer due to the formation of FM phase and the magnetic coupling between FM and AFM states. These interesting results provide a hopeful guidance for tuning the structure and magnetic properties of the strong-correlated materials. [ABSTRACT FROM AUTHOR]