Ultrafast universal fabrication of configurable porous silicone-based elastomers by Joule heating chemistry.

Silicone-based elastomers (SEs) have been extensively applied in numerous cutting-edge areas, including flexible electronics, biomedicine, 5G smart devices, mechanics, optics, soft robotics, etc. However, traditional strategies for the synthesis of polymer elastomers, such as bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization, are inevitably restricted by long-time usage, organic solvent additives, high energy consumption, and environmental pollution. Here, we propose a Joule heating chemistry method for ultrafast universal fabrication of SEs with configurable porous structures and tunable components (e.g., graphene, Ag, graphene oxide, TiO2, ZnO, Fe3O4, V2O5, MoS2, BN, g-C3N4, BaCO3, CuI, BaTiO3, polyvinylidene fluoride, cellulose, styrene-butadiene rubber, montmorillonite, and EuDySrAlSiOx) within seconds by only employing H2O as the solvent. The intrinsic dynamics of the in situ polymerization and porosity creation of these SEs have been widely investigated. Notably, a flexible capacitive sensor made from as-fabricated silicone-based elastomers exhibits a wide pressure range, fast responses, long-term durability, extreme operating temperatures, and outstanding applicability in various media, and a wireless human-machine interaction system used for rescue activities in extreme conditions is established, which paves the way for more polymer-based material synthesis and wider applications.

Robust Ionics Reinforced Fiber As Implantable Sensor for Early Operando Monitoring Cell Thermal Safety of Commercial Lithium-Ion Batteries.

Commercial batteries have been largely applied in mobile electronics, electric vehicles, and scalable energy storage systems. However, thermal runaway of batteries still obstructs the reliability of electric equipment. Considering this, building upon recent investigations of energy thermal safety, commercially available organogel fiber-based implantable sensors have been developed through 3D printing technology for first operando implantable monitoring of cell temperature. The printed fibers present excellent reliability and superelasticity because of internal supramolecular cross-linking. High temperature sensitivity (-39.84% °C-1/-1.557% °C-1) within a wide range (-15 to 80 °C) is achieved, and the corresponding mechanism is clarified based on in situ temperature-dependent Raman technology. Furthermore, taking the pouch cell as an example, combined with finite element analysis, the real-time observation system of cell temperature is successfully demonstrated through an implanted sensor with wireless Bluetooth transmission. This enlightening approach paves the way for achieving safety monitoring and smart warnings for various electric equipment.

Constructing Carbon Nanotube Hybrid Fiber Electrodes with Unique Hierarchical Microcrack Structure for High-Voltage, Ultrahigh-Rate, and Ultralong-Life Flexible Aqueous Zinc Batteries.

Flexible aqueous zinc batteries are promising candidates as safe power sources for fast-growing portable and wearable electronics. However, the low working voltage, poor rate capability, and cycling stability have greatly restricted their development and applications. Here, a new family of flexible bimetallic phosphide/carbon nanotube hybrid fiber electrodes with unique macroscopic microcrack structure and microscopic porous nanoflower structure is reported. The hierarchical microcrack structure not only facilitates the penetration of electrolyte for effective exposure of active sites, but also can serve as buffers to relieve the stress concentrations of the fiber electrode under deformations, enabling impressive electrochemical performance and mechanical flexibility. Particularly, the fabricated flexible aqueous zinc batteries demonstrate high working voltage plateau and specific capacity (≈1.7 V, 258.9 mAh g-1 at 2 A g-1 ), ultrahigh rate capability (135.8 mAh g-1 at 50 A g-1 , fully charged in only 9.8 s) and impressive power density of 79 000 W kg-1 . Moreover, the flexible batteries show ultralong cycling life with 74.6% capacity retention after 20 000 cycles. The fiber batteries are also highly flexible and can be easily knitted into soft electronic textiles to power a smartphone, which are particularly promising for the next-generation of flexible and wearable electronics.

Electrolyte Dynamics Engineering for Flexible Fiber-Shaped Aqueous Zinc-Ion Battery with Ultralong Stability.

Flexible aqueous zinc-ion batteries (ZIBs) are considered as promising energy storage devices for wearable electronics due to their cost-effectiveness, environmental friendliness, and high theoretical energy density. Herein, a flexible fiber-shaped aqueous ZIB is demonstrated by using a self-assembled Co3O4 nanosheet array on a carbon nanotube fiber as the cathode and Zn nanosheets deposited on a carbon nanotube fiber as the anode. The cycle life span of the fiber-shaped battery is largely enhanced by a simple electrolyte dynamics engineering strategy of preadding a trace amount of Co2+ cations in the mild aqueous electrolyte. The assembled fiber-shaped ZIB shows a high specific capacity (158.70 mAh g-1 at 1 A g-1), superior rate capacity, and excellent cycling life span (97.27% capacity retention after 10,000 cycles). Additionally, the fiber-shaped ZIB also shows superior flexibility, which can charge a smart watch under deformed states. This work provides new opportunities for the development of flexible, safe, and high-performance energy storage devices for wearable electronics.

Metallic Sandwiched-Aerogel Hybrids Enabling Flexible and Stretchable Intelligent Sensor.

Flexible strain sensors have been widely investigated with their rapid development in human-machine interfaces, soft robots, and medical care monitoring. Here, we report a new in situ catalytic strategy toward the fabrication of metallic aerogel hybrids, which are composed of vanadium nitride (VN) nanosheets decorated with well-defined vertically aligned carbon nanotube arrays (VN/CNTs) for the first time. In this architecture, the two-dimensional VN nanosheets as the main bone structure are favorable for the flexible devices due to their excellent structural compatibility during the repetitive deforming process. In addition, the sandwiched aerogel hybrids form highly conductive 3D network, affording outstanding sensitivity for the strain-responsive behaviors. Further, the VN/CNTs-based flexible strain sensors are successfully fabricated, showing a high gauge factor of 386 within a small strain of 10%, fast response, and extraordinary durability. The monitoring of physical signals and an actual real-time human-machine controlling system based on the sensors are also presented.

Robust Fiber-Shaped Flexible Temperature Sensors for Safety Monitoring with Ultrahigh Sensitivity.

Flexible temperature sensors capable of detecting and transmitting temperature data from the human body, environment, and electronic devices hold significant potential for applications in electronic skins, human-machine interactions, and disaster prevention systems. Nonetheless, fabricating flexible temperature sensors with exceptional sensing performance remains a formidable task, primarily due to the intricate process of constructing an intrinsically flexible sensing element with high sensitivity. In this study, a facile in situ two-step synthetic method is introduced for fabricating flexible fiber-shaped NiO/carbon nanotube fiber (CNTF) composites. The resulting NiO/CNTF flexible temperature sensors demonstrate outstanding deformability and temperature sensing characteristics, encompassing a broad working range (-15 to 60 °C) and high sensitivity (maximum TCR of -20.2% °C-1 and B value of 3332 K). Importantly, the mechanical and thermal behaviors of the sensor in various application conditions are thoroughly examined using finite element analysis simulations. Moreover, the temperature sensors can effectively capture diverse thermal signals in wearable applications. Notably, a temperature monitoring and warning system is developed to prevent fire accidents resulting from abnormal thermal runaway in electronic devices.

Oxr1a prevents the premature ovarian failure by regulating oxidative stress and mitochondrial function in zebrafish.

Premature ovarian failure (POF) is characterized as the ovarian dysfunction and defective oocyte development. In POF patients, ROS level is reported to be significantly higher than normal individuals. However, the involvement of oxidative stress in POF and the regulatory mechanisms underlying the antioxidative process in oocyte development remain largely unknown. Here, we discover that oxidation resistance 1a (Oxr1a), the ortholog of mammalian Oxr1, protects the oocytes of female zebrafish against oxidative stress and thus represses the POF phenotype. Oxr1a was widely expressed in oocytes at different developmental stages, of which the mRNA expression levels were significantly upregulated upon follicle activation and oocyte maturation. Oxr1a knockout exacerbated the POF phenotype, as evidenced by the decreased number and quality of oocytes. Moreover, the oocytes of oxr1a knockout zebrafish exhibited excessive ROS, increased mitochondrial DNA damage, reduced mitochondria, and abnormal morphology. Mechanistically, instead of decomposing ROS directly, Oxr1a participated in the process of oxidative stress through regulating the mRNA expression levels of the key antioxidant enzymes Cat and Sod1. Moreover, treatment with antioxidant N-Acetyl-l-cysteine attenuated the mitochondrial oxidative damage and improved the fertility of mutant females, indicating that Oxr1a may mediates the Sod1/Cat pathway to metabolize the intracellular ROS and avoid the mitochondrial oxidative damage, thus ensuring the normal development and maturation of oocytes. Taken together, these findings are useful for the elucidation of molecular mechanisms underlying the oxidative damage in oocytes and beneficial to the clinical therapeutics of POF.

Delayed First Feeding Chronically Impairs Larval Fish Growth Performance, Hepatic Lipid Metabolism, and Visceral Lipid Deposition at the Mouth-Opening Stage.

During the mouth-opening stage, fish larvae are susceptible to delayed first feeding (DFF). In this study, we explored the effects of DFF for two days on later growth and energy metabolism in larval fish. Results showed that DFF chronically impaired larval growth performance, thereby reducing the efficiency of feed utilization by larvae. In DFF larvae, the mRNA levels of growth inhibitors (i.e., igfbp1a and igfbp1b) were significantly upregulated and consistently maintained at high expression levels, which may be an important attribution of larval growth retardation. Concomitantly, DFF retarded the growth of adipose tissue and reduced lipid deposition in larval viscera, suggesting lipid metabolism is disordered in DFF larvae and generates inefficient lipid reserves. In the liver, we observed that DFF resulted in a significant accumulation of neutral lipids, and this phenotype did not disappear rapidly after DFF larvae received exogenous nutrition. As to the transcript analyses, we found that the expression of genes related to hepatic lipid synthesis (e.g., srebf1, srebf2, dgat1a, dgat1b, fasn, and scdb) in DFF larvae was consistently upregulated, while the expression of genes involved in lipid transport (e.g., apoa2, apoa4b.1, and apoa4b.3) was downregulated. Therefore, it appears that the inefficient lipid reserves in DFF larvae are associated with their hepatic lipid transport dysfunction. Taken together, our findings contribute to understanding the impairments to fish larvae caused by delayed first feeding during the mouth-opening stage and to aiding larval management in the aquaculture industry.

Ultrafast Universal Fabrication of Metal-Organic Complex Nanosheets by Joule Heating Engineering.

Two-dimensional metal-organic complex (MOC) nanosheets are of great interest in various areas. Current strategies applied to synthesize MOC nanosheets are suffering from low yield, usage of large amounts of environmentally unfriendly organic solvent, are time and energy consuming, and cumbersome steps for 2D nanostructures. In this work, a novel joule heating mechanism is proposed to fabricate MOC nanosheets about 5 nm in thickness with tunable metal compositions (i.e. M = Co, CoNi, and CoFe) within 60 s. Small amount of water is used as the only solvent. Under the intense irradiation of the microwave, fast heating via ionic conduction loss is realized, and urea is catalytically condensed into the long-chain organic ligands rich in N atoms that are capable of coordinating with metal ions to form the stubborn MOC framework, which is simultaneously puffed into an ultrathin nanosheet structure by the intensive release of gas. As a proof of concept, the as-synthesized Co-MOC nanosheet exhibits a superior lithium storage performance of 360 and 330 mA h g-1 after 1200 and 2300 cycles at a current density of 500 and 1000 mA g-1 , respectively.

Approaching intrinsic dynamics of MXenes hybrid hydrogel for 3D printed multimodal intelligent devices with ultrahigh superelasticity and temperature sensitivity.

Hydrogels are investigated broadly in flexible sensors which have been applied into wearable electronics. However, further application of hydrogels is restricted by the ambiguity of the sensing mechanisms, and the multi-functionalization of flexible sensing systems based on hydrogels in terms of cost, difficulty in integration, and device fabrication remains a challenge, obstructing the specific application scenarios. Herein, cost-effective, structure-specialized and scenario-applicable 3D printing of direct ink writing (DIW) technology fabricated two-dimensional (2D) transition metal carbides (MXenes) bonded hydrogel sensor with excellent strain and temperature sensing performance is developed. Gauge factor (GF) of 5.7 (0 - 191% strain) and high temperature sensitivity (-5.27% °C-1) within wide working range (0 - 80 °C) can be achieved. In particular, the corresponding mechanisms are clarified based on finite element analysis and the first use of in situ temperature-dependent Raman technology for hydrogels, and the printed sensor can realize precise temperature indication of shape memory solar array hinge.