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Sodium‐based layered oxide cathodes are competitive candidates for commercial sodium‐ion batteries owing to their high theoretical capacities, low costs, and simple synthesis. P3‐type layered oxides with large open channels enable fast Na+ transport and hence good rate performance. However, the lower crystal symmetry of P3‐type oxides and variation of Na+ contents in the Na layer during desodiation/sodiation lead to large electrostatic repulsion changes between TMO2 slabs (TM=Transition Metal), resulting in irreversible phase transitions, and fast performance degradation. Herein, a potential Na+ conductor Na2SeO4 is first found that it can be easily in situ grown on P3‐Na0.45Ni0.2Mn0.8O2 to form a novel heterostructure P3‐Na0.45Ni0.2Mn0.8O2/Na2SeO4. The synergy between P3‐Na0.45Ni0.2Mn0.8O2 and Na2SeO4 functions in promoting Na+ diffusion and suppressing P3‐O3 phase transitions upon deep sodiation, which results in recorded high‐rate capability (68.2% capacity retention with retained 83.9 mAh g−1 capacity at 6400 mA g−1) and superior cycling stability (capacity retention 75% after 1000 cycles) among all reported P3‐type cathodes. Thus, it is believed that this novel heterostructure design opens a new pathway to promote practical applications for layered oxide cathodes in sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Converting and patterning high‐quality perovskite quantum dots (PQDs) into flexible thin films is of great significance for high‐performance solid‐state optical applications. However, the poor stability and low quantum efficiency of PQDs after film formation is a big challenge hindering their usability. Here, an in situ synthesis strategy to prepare ligand‐free long‐term stable CsPb(Br0.3I0.7)3@poly(methylmethacrylate) (PMMA) PQDs fibers with thermal responsive fluorescence performance is demonstrated. The luminescence of the CsPb(Br0.3I0.7)3@PMMA PQDs fibers can rapidly and reversibly quench and recover between heating and cooling cycles. It reveals that the thermally induced phase transition of CsPb(Br0.3I0.7)3 results in this thermally reversible luminescence phenomenon. This temperature‐reversible luminescence characteristic not only deepens the comprehension of the temperature‐dependent phase transition behavior of perovskite materials but also broadens their applications in the fields of information encryption storage, anti‐counterfeiting, temperature warning, and other temperature‐responsive fields. [ABSTRACT FROM AUTHOR]

Phase change memory (PCM) based on chalcogenide compounds is considered to be an excellent candidate for next-generation memory because of its high speed, low energy consumption, high-density information storage, and durable stability. This has become a topic of general interest during the last two decades. Various systems have been proposed to explore more suitable compositions for PCM applications such as Ge-Te and Sb-Te binary alloys, GeTe-Sb2Te3 pseudo-binary alloys, and novel Te-free Sb-based alloys. In spite of this, the comprehensive performance of these pure systems still cannot fully satisfy the need for commercialization. Modification of alloys is an effective approach to enhance performance; this has been investigated significantly. Nevertheless, there are relatively few reports that directly provide integrated data on the effect of various alloying modifiers on the properties of PCM materials to obtain the relevant information conveniently, understand the role of chemical tailors on the properties of PCM materials deeply, and select modifiers matching the matrix systems efficiently. To achieve these goals and facilitate studies on PCM materials, this overview begins by summarizing and analyzing the role of alloying tailors on the performance of representative GeTe, Sb2Te3, Ge2Sb2Te5, and Sb-based systems containing Te (Sb2Te, Sb3Te, Sb4Te) and without Te (Sb-M), followed by comparing the comprehensive performance of optimized systems. [ABSTRACT FROM AUTHOR]

• Ultrahigh through-plane thermal conductivity achieved by continuous carbon fibers. • Thermal-induced and slant slicing-induced flexibility. • Leakage proof capacity from polymer skeleton and carbon fiber arrays. • Novel thermal management capacity from high through-plane thermal conductivity and heat absorbed during phase change. With the rapid development of micro-nano electronics, thermally conductive materials with remarkable through-plane thermal conductivity (κ ⊥) and great flexibility are greatly urgent to effective thermal management. The fillers with high thermal conductivity (TC) are commonly assembled to achieve this target. However, the imperfect contact between the joint fillers will lead to high thermal resistance (R), hindering thermal transport. Herein, we fabricated thermal interface materials (TIMs) with ultra-high κ ⊥ (up to 168.4 W m−1 K−1) and adjustable flexibility by the combination of highly thermally conductive carbon fiber bundles (CF) and polymer encapsulated phase change materials (PCMs). The alignment of consecutive CF guarantees the continuity of thermal paths, greatly facilitating thermal transport. While the slantly slicing technique and softening effect of PCMs beyond phase transition temperature lead to an attenuated compression stress (1.6 MPa@10% strain with a CF loading of 50 wt%). What's more, the latent heat absorbed by PCMs is also conducive to thermal management. Thus, during a CPU temperature-control experiment, the application of as-prepared TIMs manifests a temperature decline of 33.9 °C of CPU. This work opens a new perspective to fabricating TIMs with ultrahigh κ ⊥ and low compression stress (σ) by the combination of thermally induced flexible matrix and the slantly slicing technique of aligned CFs. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) are potential candidates in passive thermal regulation and energy storage fields due to their high latent heat capacity around phase transition temperature. However, the leakage problem and low thermal conductivity are two obstructive factors for the extended application of PCMs. Herein, a series of paraffin@silicon dioxide microcapsules (Pa@SiO 2)/graphene sheets (GS)/silicone rubber (SR) phase change composites (PCCs) were prepared. It is found that the inorganic SiO 2 shell is conducive to enhancing the thermal conductivity of PCCs and the double encapsulation by the SiO 2 shell and SR skeleton can restrict the leakage of liquid Pa during phase transition. With a Pa@SiO 2 content of 70 wt%, the PCCs have a high latent heat of 126.1 J/g and enhanced thermal conductivity of 0.37 W m−1 K−1, which is 131.25% higher compared to that of pure SR. In addition, the introduction of graphene sheets further boosts the thermal conductivity of PCCs to 2.69 W m−1 K−1. The obtained PCCs lead to a surprising temperature decline of nearly 35 °C of a commercial lithium-ion battery during a high discharge rate (7.4 C). This work provides an efficient route to fabricate microcapsules-based PCCs for passive thermal regulation. [Display omitted] [ABSTRACT FROM AUTHOR]

A new 0D iron-based magnetic chalcohalide, Ba3FeS4Br, has been prepared by the spontaneous crystallization method. It crystallizes in the orthorhombic space group Pnma. Interestingly, the structure contains a Ba-Br reticulate structure in which isolated FeS4 tetrahedra are located. Its band gap was experimentally determined to be 1.65 eV. Despite the large separation between the Fe atoms, with the shortest distance being more than 6.33(2) Å, temperature-dependent magnetic susceptibility and field-dependent magnetization measurements on Ba3FeS4Br unexpectedly showed an antiferromagnetic phase transition at 85 K, which may be due to the antiferromagnetic super exchange of Fe3+ spins. [ABSTRACT FROM AUTHOR]

As a symbolic ceramic oxide, the reaction of SiO 2 as an insulating layer with the Fe–Si–Al/SiO 2 soft magnetic composites (SMCs), substrate during heat treatment, as well as the resulting microscopic phase transition of the core–shell structure and its influence on the magnetic properties, are worth investigating. In this study, based on the successful synthesis of Fe–Si–Al based SMCs using fluidised chemical vapour deposition combined with an electric hot–press sintering method, the evolution of the insulating layers was investigated under different heat–treatment temperatures and closely linked to the magnetic performance of the composites. During heat treatment at high temperatures, the formation of high–resistivity oxides (Al 2 O 3) after heat treatment results in a low inter–particle eddy current loss, while excessive temperature causes disintegration of the core–shell heterostructure. This leads to a discernible increase in eddy current and hysteresis losses and a decrease in permeability and resistivity. The SMCs had an Ms of 115.8 emu/g, a resistivity of 6.86 mΩ cm, and a hysteresis loss of 56.3 kW/m3 at 10 mT and 100 kHz when heat-treated at 1373 K for 120 min, which was the best among all samples. This research provides a novel approach to building SMCs with inorganic ceramic insulating layers and a comprehensive understanding of the relationship between the heat–treatment process parameters, microstructure, and magnetic properties which is highly significant for industrial production. [Display omitted] [ABSTRACT FROM AUTHOR]