Amorphous MnO2 Lamellae Encapsulated Covalent Triazine Polymer-Derived Multi-Heteroatoms-Doped Carbon for ORR/OER Bifunctional Electrocatalysis.

The intelligent construction of non-noble metal materials that exhibit reversible oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with bifunctional electrocatalytic performance is greatly coveted in the realm of zinc-air batteries (ZABs). Herein, a crafted structure-amorphous MnO2 lamellae encapsulated covalent triazine polymer-derived N, S, P co-doped carbon sphere (A-MnO2/NSPC) is designed using a self-doped pyrolysis coupled with an in situ encapsulation strategy. The customized A-MnO2/NSPC-2 demonstrates a superior bifunctional electrocatalytic performance, confirmed by a small ΔE index of 0.64 V for ORR/OER. Experimental investigations, along with density functional theory calculations validate that predesigned amorphous MnO2 surface defects and abundant heteroatom catalytic active sites collectively enhance the oxygen electrocatalytic performance. Impressively, the A-MnO2/NSPC-based rechargeable liquid ZABs show a large open-circuit potential of 1.54 V, an ultrahigh peak power density of 181 mW cm-2, an enormous capacity of 816 mAh g-1, and a remarkable stability for more than 1720 discharging/charging cycles. Additionally, the assembled flexible all-solid-state ZABs also demonstrate outstanding cycle stability, surpassing 140 discharging/charging cycles. Therefore, this highly operable synthetic strategy offers substantial understanding in the development of magnificent bifunctional electrocatalysts for various sustainable energy conversions and beyond.

Fibrous Conductive Metallogels with Hybrid Electron/Ion Networks for Boosted Extreme Sensitivity and High Linearity Strain Sensor.

Fibrous strain sensing materials with both high sensitivity and high linearity are of significant importance for wearable sensors, yet they still face great challenges. Herein, a photo-spun reaction encapsulation strategy is proposed for the continuous fabrication of fibrous strain sensor materials (AMGF) with a core-sheath structure. Metallogels (MOGs) formed by bacterial cellulose (BC) nanofibers and Ag nanoparticles (AgNPs), and thermoplastic elastomers (TPE) are employed as the core and sheath, respectively. The in situ ultraviolet light reduction of Ag+ ensured AgNPs to maintain the interconnections between the BC nanofibers and form electron conductive networks (0.31 S m-1 ). Under applied strain, the BC nanofibers experience separation, bringing AMGF a high sensitivity (gauge factor 4.36). The concentration of free ions in the MOGs uniformly varies with applied deformation, endowing AMGF with high linearity and a goodness-of-fit of 0.98. The sheath TPE provided AMGF sensor with stable working life (>10 000 s). Furthermore, the AMGF sensors are demonstrated to monitor complex deformations of the dummy joints in real-time as a wearable sensor. Therefore, the fibrous hybrid conductive network fibers fabricated via the photo-spun reaction encapsulation strategy provide a new route for addressing the challenge of achieving both high sensitivity and high linearity.

Bimetallic-Coordinated Covalent Triazine Framework-Derived FeNi Alloy Nanoparticle-Decorated Coral-Like Nanocarbons for Oxygen Electrocatalysis.

It is highly desirable to fabricate transition bimetallic alloy-embedded porous nanocarbons with a unique nanoarchitecture for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in rechargeable zinc-air batteries. In this work, we introduce a template-assisted in situ alloying synthesis of FeNi alloy nanoparticle-decorated coral-like nanocarbons (FeNi-CNCs) as efficient OER/ORR dual-functional electrocatalysts. The present materials are produced through polycondensation of a covalent triazine framework (CTF), the coordination of Ni and Fe ions, and sequential pyrolytic treatment. Through the pyrolysis process, the nanolamellar FeNi-CTF precursors can be facilely converted into FeNi alloy nanoparticle-decorated nanocarbons. These nanocarbons possess a distinctive three-dimensional (3D) coral-like nanostructure, which is favorable for the transport of oxygen and the diffusion of electrolyte. As a result, FeNi-CNC-800 with the highest efficiency exhibited remarkable electrocatalytic performance and great durability. Additionally, it also can be assembled into rechargeable zinc-air batteries that can be assembled in both liquid and solid forms, offering a superior peak power density, large specific capacity, and outstanding reusability during charging/discharging cycles (e.g., 5160 charging-and-discharging cycles at 10 mA cm-2 for the liquid forms). These traits make it a highly promising option in the burgeoning field of wearable energy conversion.

Magnetic field evolution in [Formula: see text] collisions at [Formula: see text].

In high energy heavy-ion collisions, the high speed valence charges will produce intense electromagnetic fields within the resulting quark-gluon plasma. Utilizing the AMPT model, this paper presents a comprehensive analysis of the magnetic field distribution generated from non-central collisions between [Formula: see text] nuclei at [Formula: see text]. The initial geometric parameters of the collision and the electric conductivity of the quark-gluon plasma have a dominant influence on the evolution of the magnetic field, while the plasma diffusion and the CME effect have a lesser impact and only slightly involve the original magnetic field by inducing new magnetic fields. This finding suggests that the dynamics of the quark-gluon plasma can be roughly decoupled from the effect of the electromagnetic field.

Hierarchical Response Network Boosts Solvent-Free Ionic Conductive Elastomers with Extreme Stretchability, Healability, and Recyclability for Ionic Sensors.

The construction of solvent-free ionic conductive elastomers with high mechanical stretchability and large dynamic reversibility of chain segments is highly desired yet challenging. Here, a hierarchical response network strategy is presented for preparing highly stretchable yet mechanical robust ionic conductive elastomer composites (ICECs), among which poly(ethylene oxide) (PEO) microcrystalline serves as a physical cross-linking site providing high mechanical strength and elasticity, while dense hydrogen bonds endow superior mechanical toughness and dynamic reversibility. Due to the formation of the hierarchical response network, the resultant ICECs exhibit intrinsically high stretchability (>1500%), large tensile strength (∼2.1 MPa), and high fracture toughness (∼28 MJ m-3). Intriguingly, due to the high reversibility of hydrogen-bonded networks, the ICECs after being crushed are capable of healing and recycling by simple hot-pressing for multiple cycles. Moreover, the ICECs are dissolvable under an alkaline condition and easily regenerated in an acid solution for manifold cycles. Importantly, the healed, recycled, and regenerated ICECs are capable of maintaining their initial mechanical elasticity and ionic conducting performance. Due to the integration of high stretchability, fatigue resistance, and ionic conductivity, the ICECs can readily work as a stretchable ionic conductor for skin-inspired ionic sensors for real-time and accurately sensing complex human motions. This study thus provides a promising strategy for the development of healable and renewable ionic sensing materials with high stretchability and mechanical robustness, demonstrating great potential in soft ionotronics.

Stretchable, Environment-Stable, and Knittable Ionic Conducting Fibers Based on Metallogels for Wearable Wide-Range and Durable Strain Sensors.

The construction of fibrous ionic conductors and sensors with large stretchability, low-temperature tolerance, and environmental stability is highly desired for practical wearable devices yet is challenging. Herein, metallogels (MOGs) with a rapidly reversible force-stimulated sol-gel transition were employed and encapsulated into a hollow thermoplastic elastomer (TPE) microfiber through a simple coaxial spinning. The resultant MOG@TPE coaxial fiber exhibited a high stretchability (>100%) in a broad temperature range (-50 to 50 °C). The MOG@TPE fibrous strain sensor demonstrated a high-yet-linear working curve, fast response time (<100 ms), highly stable conductivity under large deformation, and excellent cycling stability (>3000 cycles). The MOG@TPE fibrous sensors were demonstrated to be directly attached to the human skin to monitor the real-time movements of large/facet joints of the elbow, wrist, finger, and knee. It is believed that the present work for preparing the stretchable ionic conductive fibers holds great promise for applications in fibrous wearable sensors with broad temperature range, large stretchability, stable conductivity, and high wearing comfort.

Molten salt-confined pyrolysis towards carbon nanotube-backboned microporous carbon for high-energy-density and durable supercapacitor electrodes.

The development of a green and scalable construction of a three-dimensional (3D) hierarchically porous carbon as an electrode material for supercapacitors is promising but challenging. Herein, a carbon nanotube-backboned microporous carbon (CNT-MPC) was prepared by molten salt-confined pyrolysis, during which the salt eutectics simultaneously acted as a high-temperature reaction solvent and reusable template. Among the CNT-MPC, the CNT backbone provided a 3D conductive framework, whereas the MPC sheath possessed integrated mesopores and micropores as an efficient ion reservoir. As a result, the as-obtained CNT-MPC exhibited a high specific capacitance of 305.6 F g-1 at 1 A g-1, high energy density of 20.5 W h kg-1 and excellent cyclic stability with no capacitance losses after 50 000 cycles. The molten-salt confined pyrolysis strategy therefore provides a low-cost, environmentally-friendly and readily industrialized route to develop a hierarchically porous carbon that is highly required for high-energy-density and durable supercapacitors.