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A foldable battery with high flexibility provides great potential in various wearable electronic devices for health and fitness tracking, chronic disease management, performance monitoring, navigation tracking, and portable gears for soldiers. We report a highly flexible, self‐healing Zn‐ion battery with a free‐standing cathode that is composed of a 3D gear‐like NH4V4O10@C composite on carbon paper. The battery retained a capacity of up to 102.4 mAh g−1 even after being folded 60 times with a high angle of 180°. An aqueous hydrogel consisting polyvinyl alcohol, glycerin and Zn(CF3SO3)2 was used as electrolyte, which showed as high as 580 % tensile strain under a loading weight of 78 N. The battery exhibited a better capacity retention of over 100 mAh g−1 and Coulombic efficiency of over 99.8 % after cutting and twisting to 90°, thereby indicating a great self‐healing performance. The gear‐like geometry greatly improved the volume accommodation due to the increased interval space between the blades and the outward configuration. Meanwhile the Zn2+ ionic conductivity was improved by rapid re‐binding of many existing hydroxy groups from the electrolyte and the enhanced contact surface area and diffusion route from the cathode material. The highly flexible, safe aqueous Zn‐ion battery opens a practical way to power various carry‐on electronics under mechanical agitation. [ABSTRACT FROM AUTHOR]

The shuttling behavior and slow conversion kinetics of the intermediate lithium polysulfides are the severe obstacles for the application of lithium‐sulfur (Li‐S) batteries over a wide temperature range. Here, an engineered lamellar yolk–shell structure of In2O3@void@carbon for the Li‐S battery cathode is developed for the first time to construct a powerful barrier that effectively inhibits the shuttling of polysulfides. On the basis of the unique nanochannel‐containing morphology, the continuous kinetic transformation of sulfur and polysulfides is confined in a stable framework, which is demonstrated by using X‐ray nanotomography. The constructed Li‐S battery exhibits a high cycling capability over 1000 cycles at 1.0 C with a capacity decay rate as low as 0.038% per cycle, good rate performance, and temperature tolerance at −10, 25, and 50 °C. A nondestructive in situ monitoring method of the interfacial reaction resistance in different cycling stages is proposed, which provides a new analysis perspective for the development of emerging electrochemical energy‐storage systems. [ABSTRACT FROM AUTHOR]

Self‐healing and flexibility are significant for many emerging applications of secondary batteries, which have attracted broad attention. Herein, a self‐healing flexible quasi‐solid Zn‐ion battery composing of flexible all‐in‐one cathode (VS2 nanosheets growing on carbon cloth) and anode (electrochemically deposited Zn nanowires), and a self‐healing hydrogel electrolyte, is presented. The free‐standing all‐in‐one electrodes enable a high capacity and robust structure during flexible transformation of the battery, and the hydrogel electrolyte possesses a good self‐healing performance. The presented battery remains as a high retention potential even after healing from being cut into six pieces. When bending at 60°, 90°, and 180°, the battery capacities remain 124, 125, and 114 mAh g−1, respectively, cycling at a current density of 50 mA g−1. Moreover, after cutting and healing twice, the battery still delivers a stable capacity, indicating a potential use of self‐healing and wearable electronics. [ABSTRACT FROM AUTHOR]

Magnesium batteries have been considered promising candidates for next‐generation energy storage systems owing to their high energy density, good safety without dendrite formation, and low cost of magnesium resources. However, high‐performance cathodes with stable capacity, good conductivity, and fast ions transport are needed, since many conventional cathodes possess a low performance and poor preparation controllability. Herein, a liquid‐driven coaxial flow focusing (LDCFF) approach for preparing a novel microcapsule system with controllable size, high loading, and stable magnesium‐storage performance is presented. Taking the MoS2‐infilled microcapsule as a case study, the magnesium battery cathode based on the microcapsules displays a capacity of 100 mAh g−1 after 100 cycles. High capacity retention is achieved at both low and high temperatures of −10, ‒5, and 45 °C, and a stable rate‐performance is also obtained. The influences of the liquid flow rates on the size and shell thickness of the microcapsules are investigated; and electron and ion diffusion properties are also studied by first‐principle calculations. The presented LDCFF method is quite general, and the high performance of the microcapsules enables them to find broad applications for making emerging energy‐storage materials and secondary battery systems. [ABSTRACT FROM AUTHOR]

Carbon dioxide has attracted considerable attention owing to its physics and abundant polymorphs. Despite decades of extensive experiments and theoretical simulations, the structure and properties of carbon dioxide under extreme pressures and temperatures are yet to be properly understood. Particularly, the intermediate phase IV of solid carbon dioxide, which separates the molecular phases at low pressures from the non‐molecular phases at high pressures, has not been fully investigated, and its structure remains controversial. Here, based on the second‐order Møller‐Plesset perturbation (MP2) theory and the embedded fragment method, we study the crystal structure, equation of state, and Raman spectra of solid carbon dioxide phase IV at high pressures and temperatures. We demonstrate that the solid carbon dioxide phase IV is a molecular structure that remains in a molecular state rather than the bent state shown in other literature works, which is consistent with the experimental work by Datchi et al and denies the observed results by Park et al. The proposed work is of great significance in determining the structure of the high‐pressure phases of carbon dioxide and further exploring the new phase of molecular crystals. [ABSTRACT FROM AUTHOR]

Microencapsulated materials are receiving broad attention for applications as diverse as energy storage and conversion, biomedicine, self‐healing materials, and electronics. Here, a general microfluidic approach is presented to prepare phase‐change material‐infilled microcapsules with unique thermal and mechanical properties. Aqueous sodium acetate solutions are encapsulated by an acrylate‐based shell via a microfluidic method. To understand and optimize microcapsule formation, flow behavior during the encapsulation is numerically simulated. When the microcapsules are embedded in an acrylate matrix (same composition as the shell wall material), the microcapsules exhibit a significant 46.6 ºC difference between the crystallization and melting temperatures as determined by differential scanning calorimetry at a rate of 10 ºC per min. Variable temperature dynamic mechanical analysis over the range of 50 to ‐90 ºC reveals up to a 50% change in the composite's elastic modulus at a given temperature, depending on if the sample is being cooled or heated, due to significant undercooling of the core material crystallization as shown by X‐ray diffraction. [ABSTRACT FROM AUTHOR]

FeF2 is considered a promising conversion compound for the positive electrode in lithium-ion batteries due to its high thermodynamic reduction potential (2.66 V vs Li/Li+) and high theoretical specific capacity (571 mA h g−1). However, the sluggish reaction kinetics and rapid capacity decay caused by side reactions during cycling limit its practical application. Here, the fabrication of Ni-supported 3D Al2O3-coated FeF2 electrodes is presented, and it is shown that these structured electrodes significantly overcome these limitations. The electrodes are prepared by iron electrodeposition on a Ni support, followed by a facile fluorination process and Al2O3 coating by atomic layer deposition. The 3D FeF2 electrode delivers an initial discharge capacity of 380 mA h g−1 at a current density of 200 mA g−1 at room temperature. The 3D scaffold improves the reaction kinetics and enables a high specific capacity by providing an efficient electron pathway to the insulating FeF2 and short Li diffusion lengths. The Al2O3 coating significantly improves the cycle life, probably by preventing side reactions through limiting direct electrode-electrolyte contact. The fabrication method presented here can also be applied for synthesis of other metal fluoride materials on different 3D conductive templates. [ABSTRACT FROM AUTHOR]

We model histories between two cohorts of urban Chinese couples (N = 1,191) of a rarely studied living arrangement—coresidence with the wife's parents—using a dynamic life history analysis in contrast to previous cross-sectional studies of coresidence. We examine patterns of entry into and exit from coresidence with the wife's parents, comparing the predictive power of modernization theory to the effect of demographic change and the resources and needs of each generation. Given China's well-known patrilineal family system, we find a surprisingly high number of couples ever residing nonnormatively, and significant differences between cohorts in what determines the pattern of coresidence. Resources and needs that reflect conscious choices to coreside most strongly influence nonnormative coresidence. Its importance may increase as the children of the One-Child Family Policy grow up and marry. [ABSTRACT FROM AUTHOR]

Safe and high‐performance secondary batteries using for all‐climate conditions with different temperatures are highly required. Here, we develop a three‐dimensional ball cactus‐like MgV2O4 as cathode material for magnesium‐ion (Mg‐ion) batteries. After cycling 300 times, the capacity maintains 111.7 mAh g−1, while Coulombic efficiency stabilizes at about 100 %. Under temperatures of 45 °C and −5 °C, the capacities remain stable after 200 cycles. After three rounds of rate‐performance tests, the capacity keeps quite stable. It is ascribed to the ball cactus‐like morphology buffers the volumetric change during Mg2+ insertion/extraction, and provides sufficient pathways for ion diffusion, which has been verified by constant‐current intermittent titration technology. It is believed that the good performance enables the Mg‐ion batteries to have a all‐climate capability. [ABSTRACT FROM AUTHOR]

During the slab sizing press (SP) process, the pressing force corresponds to the slab profile, which guides the production schedule design and the final profile control. To accomplish the prediction of pressing force for SP, an improved ensemble method based on chaotic Harris hawks optimizer (CHHO) and stacking is proposed. A mechanistic knowledge is introduced for feature selection that enhances the rationality of input features. Subsequently, 11 machine learning models are compared and 5 of them are selected as candidate learners for the stacking method. Based on the candidates learners, 8 stacking strategies are constructed, which the stacked model with extratree regressor, gradient boosted decision trees, and kernel ridge regression (KRR) as base‐learners and KRR as meta‐learner performs the best. The R2, MAE, mean square error, mean squared log error, and mean absolute percentage error for the test dataset are 0.9912, 0.0856, 0.0167, 0.0005, and 2.00%, respectively, and 95% of the prediction errors are less than 0.15 MN. Then, sensitivity analysis and predictive analysis based on Shapley Additive Explanations are performed to demonstrate the good alignment of the proposed model with physical reality. Furthermore, to cope with the complexity and uncertainty of the production process, the proposed CHHO‐stacking model and the kernel density estimation method are integrated to model the prediction interval. [ABSTRACT FROM AUTHOR]

Anhui Provincial Engineering Laboratory for Engineering appropriate cathode materials is significant for the development of high‐performance aluminum‐ion (Al‐ion) batteries. Here, a pyramidal metal–organic frameworks (MOFs)‐derived FeP@CoP composite was developed as cathode, which exhibits good stability and high capacity. FeP@CoP cathode maintains a high capacity of 168 mAh g−1 after 200 cycles, and displays a stable rate‐performance at both room and low temperatures of −10 °C. After three rounds of rate‐performance cycling, the FeP@CoP composite recovers 178.2 mAh g−1 at 0.3 A g−1. Moreover, density functional theory (DFT) calculations verify improved electron‐transfer kinetics with narrowed band gap and enhanced density of states. These findings inspire a broad set of studies on MOFs‐derived composites for high‐performance secondary batteries. [ABSTRACT FROM AUTHOR]

There have been significant recent developments in the growth of single‐crystal gallium nitride (GaN) on unconventional templates for large‐area blue or green light‐emitting diodes (LEDs) which, together with layer transfer onto foreign substrates, can enable flexible and stretchable lighting applications. Here, the heteroepitaxial growth of GaN on amorphous and single‐crystal substrates employing various interlayers and nucleation layers is reviewed, as well as the use of weak interfaces for layer‐transfer onto foreign substrates. Recent progress in low‐temperature GaN‐based red–green–blue (RGB) LEDs on glass substrates, which has exhibited a calculated efficiency of 11% compared with that from commertial LEDs, is discussed. Layer‐transfer techniques with various interlayers are also discussed. These heteroepitaxial GaN growth and layer‐transfer technologies are expected to lead to new lighting and display devices with high efficiency and full‐color tunability, which are suitable for large‐area, stretchable display and lighting applications. [ABSTRACT FROM AUTHOR]

Lithium metal anodes suffer from serious safety issues and rapid capacity fade because of nonideal plating/stripping behaviors. Lithium nucleation on undesired positions usually results from nonuniform multiphysical field distributions and the dynamically changing interface thermodynamics. In this study, a sandwich composite anode consisting of gold nanoparticles pillared reduced graphene oxide (rGO) is designed. Because gold nanoparticles preferentially induce lithium nucleation, the typically uncontrolled lithium deposition process becomes a highly nucleation‐guided process. Because the sandwich structure of the Au‐pillared rGO provides a stable anode morphology with cycling and stabilizes the solid electrolyte interface layer, the Au‐pillared rGO delivers a high Coulombic efficiency of up to 98% for at least 200 cycles for 1600 h. Using this pillared structure, an interlayer plating process is revealed in rGO‐sandwiched anodes, which differ from either conventional metallic anodes or intercalation anodes. The Au‐pillared design bridges the gap between metal and intercalation anodes, and provides a novel strategy to improve the efficiencies and cyclability of lithium anodes. An interlayer plating mechanism for metallic lithium anodes is revealed in a sandwich structure with gold nanoparticles pillared reduced graphene oxide. The layered composite anode is able to guide lithium plating and realize uniform through‐plane expansion and contraction, which stabilizes the solid electrolyte interphase and enhances the cyclability of metallic lithium anodes. [ABSTRACT FROM AUTHOR]