Hollow Stair-Stepping Spherical High-Entropy Prussian Blue Analogue for High-Rate Sodium Ion Batteries.

Prussian blue analogues (PBAs) are considered to be one of the most suitable sodium storage materials, especially with the introduction of the high-entropy (HE) concept into their structure to further improve their various abilities. However, severe agglomeration of the HEPBA particles still limits the fast charging capabilities. Here, an HEPBA (Nax(FeMnCoNiCu)[Fe(CN)6]y□1-y·nH2O) with a hollow stair-stepping spherical structure has been prepared through the chemical etching process of the traditional cubic structure of HEPBA. Electrochemical characterization (sodium ion battery), kinetic analysis, and COMSOL Multiphysics simulations reveal that the nature of the high-entropy and the hollow stair-stepping spherical structure can greatly improve the diffusion behavior of Na+ ions. Moreover, the hollow structure effectively mitigates the volume change of HEPBA during SIBs operation, ultimately extending the lifespan. Consequently, the as-prepared HEPBA cathode exhibits excellent rate performance (126.5 and 76.4 mAh g-1 at 0.1 and 4.0 A g-1, respectively) and stable long-term capability (maintaining its 75.6% capacity after 1000 cycles) due to its unique structure. Furthermore, the waste of the etching process can easily be recycled to prepare more HEPBA product. This processing method holds great promise for designing nanostructures of advanced high-entropy Prussian blue analogues for sodium ion batteries.

Electronic Skin for Health Monitoring Systems: Properties, Functions and Applications.

Electronic skin (e-skin), a skin-like wearable electronic device, holds great promise in the fields of telemedicine and personalized healthcare because of its good flexibility, biocompatibility, skin conformability, and sensing performance. E-skin can monitor various health indicators of the human body in real time and over the long term, including physical indicators (exercise, respiration, blood pressure, etc.) and chemical indicators (saliva, sweat, urine, etc.). In recent years, the development of various materials, analysis, and manufacturing technologies has promoted significant development of e-skin, laying the foundation for the application of next-generation wearable medical technologies and devices. Herein, we discuss the properties required for e-skin health monitoring devices to achieve long-term and precise monitoring and summarize several detectable indicators in the health monitoring field. Subsequently, the applications of integrated e-skin health monitoring systems are reviewed. Finally, current challenges and future development directions in this field are discussed. This review is expected to generate great interest and inspiration for the development and improvement of e-skin and health monitoring systems. This article is protected by copyright. All rights reserved.

Noble-Metal-Free High-Entropy Alloy Nanoparticles for Efficient Solar-Driven Photocatalytic CO2 Reduction.

Metal nanoparticle (NP) cocatalysts are widely investigated for their ability to enhance the performance of photocatalytic materials; however, their practical application is often limited by the inherent instability under light irradiation. This challenge has catalyzed interest in exploring high-entropy alloys (HEAs), which, with their increased entropy and lower Gibbs free energy, provide superior stability. In this study, 3.5 nm-sized noble-metal-free NPs composed of a FeCoNiCuMn HEA are successfully synthesized. With theoretic calculation and experiments, the electronic structure of HEA in augmenting the catalytic CO2 reduction has been uncovered, including the individual roles of each element and the collective synergistic effects. Then, their photocatalytic CO2 reduction capabilities are investigated when immobilized on TiO2. HEA NPs significantly enhance the CO2 photoreduction, achieving a 23-fold increase over pristine TiO2, with CO and CH4 production rates of 235.2 and 19.9 µmol g-1 h-1, respectively. Meanwhile, HEA NPs show excellent stability under simulated solar irradiation, as well high-energy X-ray irradiation. This research emphasizes the promising role of HEA NPs, composed of earth-abundant elements, in revolutionizing the field of photocatalysis.

Crystal-Phase-Engineered High-Entropy Alloy Aerogels for Enhanced Ethylamine Electrosynthesis from Acetonitrile.

Crystal-phase engineering that promotes the rearrangement of active atoms to form new structural frameworks achieves excellent result in the field of electrocatalysis and optimizes the performance of various electrochemical reactions. Herein, for the first time, it is found that the different components in metallic aerogels will affect the crystal-phase transformation, especially in high-entropy alloy aerogels (HEAAs), whose crystal-phase transformation during annealing is more difficult than medium-entropy alloy aerogels (MEAAs), but they still show better electrochemical performance. Specifically, PdPtCuCoNi HEAAs with the parent phase of face-centered cubic (FCC) PdCu possess excellent 89.24% of selectivity, 746.82 mmol h-1 g-1 cat. of yield rate, and 90.75% of Faraday efficiency for ethylamine during acetonitrile reduction reaction (ARR); while, maintaining stability under 50 h of long-term testing and ten consecutive electrolysis cycles. The structure-activity relationship indicates that crystal-phase regulation from amorphous state to FCC phase promotes the atomic rearrangement in HEAAs, thereby optimizing the electronic structure and enhancing the adsorption strength of reaction intermediates, improving the catalytic performance. This study provides a new paradigm for developing novel ARR electrocatalysts and also expands the potential of crystal-phase engineering in other application areas.

Red Carbon Mediated Formation of Cu2O Clusters Dispersed on the Oxocarbon Framework by Fehling's Route and their Use for the Nitrate Electroreduction in Acidic Conditions.

The oligomers of carbon suboxide, known as red carbon, exhibit a highly conjugated structure and semiconducting properties. Upon mild heat treatment, it transforms into a carbonaceous framework rich in oxygen surface terminations, called oxocarbon. In this study, the abundant oxygen functionalities are harnessed as anchors to create oxocarbon-supported nanohybrid electrocatalysts. Starting with single atomic Cu (II) strongly coordinated to oxygen atoms on red carbon, the Fehling reaction leads to the formation of Cu2O clusters. Simultaneously, a covalent oxocarbon framework emerges via cross-linking, providing robust support for Cu2O clusters. Notably, the oxocarbon support effectively stabilizes Cu2O clusters of very small size, ensuring their high durability in acidic conditions and the presence of ammonia. The synthesized material exhibits a superior electrocatalytic activity for nitrate reduction under acidic electrolyte conditions, with a high yield rate of ammonium (NH4 +) at 3.31 mmol h-1 mgcat -1 and a Faradaic efficiency of 92.5% at a potential of -0.4 V (vs RHE).

Amorphous ZnSnOx Hollow Spheres Enable Highly Efficient CO2 Reduction.

Carbon dioxide (CO2) adsorption and electron transport play an important role in CO2 reduction reaction (CO2RR). Herein, we have demonstrated a new class of diverse hollow ZnSnOx (ZSO) through the amorphization of hydroxides to enhance CO2 adsorption and accelerate electron transport. The amorphization is occurred by calcination process, as indicated by Fourier transform infrared spectroscopy and Raman spectra. In particular, the ZnSnOx hollow spheres (ZSO HSs) achieve a high Faradaic efficiency (FE) of HCOOH up to 92.7 % at best, outperforming the commercial ZSO (Comm. ZSO, 85.7 %). ZSO HSs also exhibit durable stability with negligible activity decay after 10 h of successive electrolysis. In-situ attenuated total reflectance infrared absorption spectroscopy further reveals strong adsorption of CO2 and rapid intermediate configuration transformation in amorphous ZSO HSs. This work demonstrates the practical application of ZSO for CO2RR and provides a new insight to create efficient CO2RR electrocatalysts.

Inducing Directional Charge Delocalization in 3D-Printable Micro-Supercapacitors Based on Strongly Coupled Black Phosphorus and ReS2 Nanocomposites.

The growing interest in so-called interface coupling strategies arises from their potential to enhance the performance of active electrode materials. Nevertheless, designing a robust coupled interface in nanocomposites for stable electrochemical processes remains a challenge. In this study, an epitaxial growth strategy is proposed by synthesizing sulfide rhenium (ReS2 ) on exfoliated black phosphorus (E-BP) nanosheets, creating an abundance of robust interfacial linkages. Through spectroscopic analysis using X-ray photoelectron spectroscopy and X-ray absorption spectroscopy, the authors investigate the interfacial environment. The well-developed coupled interface and structural stability contribute to the impressive performance of the 3D-printed E-BP@ReS2 -based micro-supercapacitor, achieving a specific capacitance of 47.3 mF cm-2 at 0.1 mA cm-2 and demonstrating excellent long-term cyclability (89.2% over 2000 cycles). Furthermore, density functional theory calculations unveil the positive impact of the strongly coupled interface in the E-BP@ReS2 nanocomposite on the adsorption of H+ ions, showcasing a significantly reduced adsorption energy of -2.17 eV. The strong coupling effect facilitates directional charge delocalization at the interface, enhancing the electrochemical performance of electrodes and resulting in the successful construction of advanced micro-supercapacitors.

Langmuir-Blodgett Film Formed by Amphiphilic Molecules for Facile and Rapid Construction of Zinc-Iodine Cell.

Zinc-iodine batteries (ZIBs) are promising candidates for ecofriendly, safe, and low-cost energy storage systems, but polyiodide shuttling and the complex cathode fabrication procedures have severely hindered their broader commercial usage. Herein, a protocol is developed using phospholipid-like oleylamine molecules for scalable production of Langmuir-Blodgett films, which allows the facile preparation of ZIB cathodes in less than 1 min. The resulting inhomogeneous cathode allows for the continuous conversion of iodine. Moreover, the amine group of the oleylamine molecule at the cathode is capable of producing [OA*I+]I3- charge-transfer complexes with iodine, which facilitates the rapid migration of iodine and results in a highly reversible iodine conversion process. Consequently, the as-prepared ZIBs can deliver over 2000 cycles at 0.5 mA cm-2 with a capacity retention of 75.3%. This work presents a novel, straightforward, and efficient method for the rapid construction of ZIBs.

Anti-Freezing Electrolytes in Aqueous Multivalent Metal-Ion Batteries: Progress, Challenges, and Optimization Strategies.

Aqueous rechargeable multivalent metal-ion batteries (ARMMBs) have attracted considerable attention due to their high capacity, high energy density, and low cost. However, their performance is often limited by low temperature operation, which requires the development of anti-freezing electrolytes. In this review, we summarize the anti-freezing mechanisms and optimization strategies of anti-freezing electrolytes for aqueous batteries (especially for Zn-ion batteries). Besides, we investigate the possible interactions and side reactions between electrolytes and electrodes. We also analyze the problems between electrolytes and electrodes at low temperature, and propose possible solutions. The research progress in the field of low temperature energy storage for aqueous Mg-ion, Ca-ion, and Al-ion batteries, and the challenges faced in their anti-freezing electrolytes are investigated in detail. Last but not least, the outlook on the energy storage applications of ARMMBs is provided to guide the future research.

Lattice-Strained Metallic Aerogels as Efficient and Anti-Poisoning Electrocatalysts for Oxygen Reduction Reaction.

Lattice strain engineering optimizes the interaction between the catalytic surface and adsorbed molecules. This is done by adjusting the electron and geometric structure of the metal site to achieve high electrochemical performance, but, to date, it has been rarely reported on anti-poisoned oxygen reduction reaction (ORR). Herein, lattice-strained Pd@PdBiCo quasi core-shell metallic aerogels (MAs) were designed by "one-pot and two-step" method for anti-poisoned ORR. Pd@PdBiCo MAs/C maintain their original activity (1.034 A mgPd -1 ) in electrolytes with CH3 OH and CO at 0.85 V vs. reversible hydrogen electrode (RHE), outperforming the commercial Pd/C (0.156 A mgPd -1 ), Pd MAs/C (0.351 A mgPd -1 ), and PdBiCo MAs/C (0.227 A mgPd -1 ). Moreover, Pd@PdBiCo MAs/C also show high stability and anti-poisoning with negligible activity decay after 8000 cycles in 0.1 m KOH+0.3 m CH3 OH. These results of X-ray photoelectron spectroscopy, CO stripping, and diffuses reflectance FTIR spectroscopy reveal that the tensile strain and strong interaction between different elements of Pd@PdBiCo MAs/C effectively optimize the electronic structure to promote O2 adsorption and activation, while suppressing CH3 OH oxidation and CO adsorption, leading to high ORR activity and anti-poisoning property. This work inspires the rational design of MAs in fuel cells and beyond.

Fast and scalable production of crosslinked polyimide aerogel fibers for ultrathin thermoregulating clothes.

Polyimide aerogel fibers hold promise for intelligent thermal management fabrics, but their scalable production faces challenges due to the sluggish gelation kinetics and the weak backbone strength. Herein, a strategy is developed for fast and scalable fabrication of crosslinked polyimide (CPI) aerogel fibers by wet-spinning and ambient pressure drying via UV-enhanced dynamic gelation strategy. This strategy enables fast sol-gel transition of photosensitive polyimide, resulting in a strongly-crosslinked gel skeleton that effectively maintains the fiber shape and porous nanostructure. Continuous production of CPI aerogel fibers (length of hundreds of meters) with high specific modulus (390.9 kN m kg-1) can be achieved within 7 h, more efficiently than previous methods (>48 h). Moreover, the CPI aerogel fabric demonstrates almost the same thermal insulating performance as down, but is about 1/8 the thickness of down. The strategy opens a promisingly wide-space for fast and scalable fabrication of ultrathin fabrics for personal thermal management.

Highly Reversible Zn Anodes Achieved by Enhancing Ion-Transport Kinetics and Modulating Zn (002) Deposition.

Uncontrolled dendrite growth and water-related side reactions in mild electrolytes are the main causes of poor cycling stability of zinc anodes, resulting in the deterioration of aqueous zinc-based batteries. Herein, a multifunctional fluorapatite (Ca5(PO4)3F) aerogel (FAG) interface layer is proposed to realize highly stable zinc anodes via the integrated regulation of Zn2+ migration kinetics and Zn (002) orientation deposition. Owing to the well-defined aerogel nanochannels and the rich Zn2+ adsorption sites resulting from the ion exchange between Ca2+ and Zn2+, the FAG interface layer could significantly accelerate the Zn2+ migration and effectively homogenize the Zn2+ flux and nucleation sites, thus promoting rapid and uniform Zn2+ migration at the electrode/electrolyte interface. Additionally, during the cycling process, the F atoms from FAG promote the in situ generation of ZnF2, which facilitates the manipulation of the preferred Zn (002) orientation deposition, thus efficiently suppressing dendrite growth and side reactions by combining with the above synergistic effects. Consequently, the FAG-modified Zn anode displays a stable cycle life of over 4000 h at 1 mA cm-2 and exhibits highly reversible Zn plating/stripping behavior. Meanwhile, the Zn||MnO2 full cells exhibit improved cycle stability over 2000 cycles compared with that of the bare Zn, highlighting the virtues of the FAG protective layer for highly reversible Zn anodes. Our work brings the insight in to stabilize Zn anodes and power the commercial applications of aqueous zinc-based batteries.

Sequential *CO management via controlling in situ reconstruction for efficient industrial-current-density CO2-to-C2+ electroreduction.

Sequentially managing the coverage and dimerization of *CO on the Cu catalysts is desirable for industrial-current-density CO2 reduction (CO2R) to C2+, which required the multiscale design of the surface atom/architecture. However, the oriented design is colossally difficult and even no longer valid due to unpredictable reconstruction. Here, we leverage the synchronous leaching of ligand molecules to manipulate the seeding-growth process during CO2R reconstruction and construct Cu arrays with favorable (100) facets. The gradient diffusion in the reconstructed array guarantees a higher *CO coverage, which can continuously supply the reactant to match its high-rate consumption for high partial current density for C2+. Sequentially, the lower energy barriers of *CO dimerization on the (100) facets contribute to the high selectivity of C2+. Profiting from this sequential *CO management, the reconstructed Cu array delivers an industrial-relevant FEC2+ of 86.1% and an FEC2H4 of 60.8% at 700 mA cm-2. Profoundly, the atomic-molecular scale delineation for the evolution of catalysts and reaction intermediates during CO2R can undoubtedly facilitate various electrocatalytic reactions.

Cation Substitution Strategy for Developing Perovskite Oxide with Rich Oxygen Vacancy-Mediated Charge Redistribution Enables Highly Efficient Nitrate Electroreduction to Ammonia.

The electrocatalytic nitrate (NO3-) reduction reaction (eNITRR) is a promising method for ammonia synthesis. However, its efficacy is currently limited due to poor selectivity, largely caused by the inherent complexity of the multiple-electron processes involved. To address these issues, oxygen-vacancy-rich LaFe0.9M0.1O3-δ (M = Co, Ni, and Cu) perovskite submicrofibers have been designed from the starting material LaFeO3-δ (LF) by a B-site substitution strategy and used as the eNITRR electrocatalyst. Consequently, the LaFe0.9Cu0.1O3-δ (LF0.9Cu0.1) submicrofibers with a stronger Fe-O hybridization, more oxygen vacancies, and more positive surface potential exhibit a higher ammonia yield rate of 349 ± 15 µg h-1 mg-1cat. and a Faradaic efficiency of 48 ± 2% than LF submicrofibers. The COMSOL Multiphysics simulations demonstrate that the more positive surface of LF0.9Cu0.1 submicrofibers can induce NO3- enrichment and suppress the competing hydrogen evolution reaction. By combining a variety of in situ characterizations and density functional theory calculations, the eNITRR mechanism is revealed, where the first proton-electron coupling step (*NO3 + H+ + e- → *HNO3) is the rate-determining step with a reduced energy barrier of 1.83 eV. This work highlights the positive effect of cation substitution in promoting eNITRR properties of perovskites and provides new insights into the studies of perovskite-type electrocatalytic ammonia synthesis catalysts.

Heteroatom-doped noble carbon-tailored mixed matrix membranes with ultrapermeability for efficient CO2 separation.

Membranes with ultrapermeability for CO2 are desired for future large-scale carbon capture projects, because of their excellent separative productivity and economic efficiency. Herein, we demonstrate that a membrane with ultrapermeability for CO2 can be constructed by combining N/O para-doped noble carbons, C2NxO1-x, with high-permeability polymer PIM-1. The optimal PIM-1/C2NxO1-x membranes exhibit superior CO2 permeability (22110 Barrer) with a CO2/N2 selectivity of 15.5, and an unprecedented CO2 permeability of 37272 Barrer can be obtained after a PEG activation treatment, far surpassing the 2008 upper bound. Both broad experiments and molecular dynamics simulations reveal that the numerous ordered polar channels of C2NxO1-x and their excellent compatibility with PIM-1 are responsible for the superior CO2 separation performance of the membrane. Although this is the first study on C2N-type gas separation membranes, the outstanding results indicate that noble carbon building blocks may pave a new avenue to advance high-performance CO2 separation membranes.

Bio-Inspired Aerobic-Hydrophobic Janus Interface on Partially Carbonized Iron Heterostructure Promotes Bifunctional Nitrogen Fixation.

Competition from hydrogen/oxygen evolution reactions and low solubility of N2 in aqueous systems limited the selectivity and activity on nitrogen fixation reaction. Herein, we design an aerobic-hydrophobic Janus structure by introducing fluorinated modification on porous carbon nanofibers embedded with partially carbonized iron heterojunctions (Fe3 C/Fe@PCNF-F). The simulations prove that the Janus structure can keep the internal Fe3 C/Fe@PCNF-F away from water infiltration and endow a N2 molecular-concentrating effect, suppressing the competing reactions and overcoming the mass-transfer limitations to build a robust "quasi-solid-gas" state micro-domain around the catalyst surface. In this proof-of-concept system, the Fe3 C/Fe@PCNF-F exhibits excellent electrocatalytic performance for nitrogen fixation (NH3 yield rate up to 29.2 µg h-1 mg-1 cat. and Faraday efficiency (FE) up to 27.8 % in nitrogen reduction reaction; NO3 - yield rate up to 15.7 µg h-1 mg-1 cat. and FE up to 3.4 % in nitrogen oxidation reaction).

Multilayered Molybdate Microflowers Fabricated by One-Pot Reaction for Efficient Water Splitting.

The development of high-performance, low-cost and rapid-production bifunctional electrocatalysts towards overall water splitting still poses huge challenges. Herein, the authors utilize a facile hydrothermal method to synthesize a novel structure of Co-doped ammonium lanthanum molybdate on Ni foams (Co-ALMO@NF) as self-supported electrocatalysts. Owing to large active surfaces, lattice defect and conductive channel for rapid charge transport, Co-ALMO@NF exhibits good electrocatalytic performances which requires only 349/341 mV to achieve a high current density of 600 mA cm-2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Besides, a low cell voltage of 1.52 V is required to reach the current density of 10 mA cm-2 in alkaline medium along with an excellent long-term stability for two-electrode configurations. Density functional theory calculations are performed to reveal the reaction mechanism on Co-ALMO@NF, which shows that the Mo site is the most favorable ones for HER, while the introduction of Co is beneficial to reduce the adsorption intensity on the surface of Co-ALMO@NF, thus accelerating OER process. This work highlighted the importance of the structural design for self-supporting electrocatalysts.

Ultrasonic-assisted hydrothermal synthesis of RhCu alloy nanospheres for electrocatalytic urea production.

Herein, the electronic structure of RhCu nanospheres was optimized and the size of the nanoparticles was reduced by an ultrasonic-assisted hydrothermal method. The performance of electrocatalytic urea synthesis was improved with an enhanced faradaic efficiency and urea yield rate of 34.82 ± 2.47% and 26.81 ± 0.62 mmol g-1 h-1, respectively. This work opens a novel insight into synthesizing an electrocatalyst by ultrasonic treatment for urea production.

Quasi-Homogeneous and Hierarchical Electronic Textiles with Porosity-Hydrophilicity Dual-Gradient for Unidirectional Sweat Transport, Electrophysiological Monitoring, and Body-Temperature Visualization.

On-skin electronics based on impermeable elastomers and stacking structures often suffer from inferior sweat-repelling capabilities and severe mechanical mismatch between sub-layers employed, which significantly impedes their lengthy wearing comfort and functionality. Herein, inspired by the transpiration system of vascular plants and the water diode phenomenon, a hierarchical nonwoven electronic textile (E-textile) with multi-branching microfibers and robust interlayer adhesion is rationally developed. The layer-by-layer electro-airflow spinning method and selective oxygen plasma treatment are utilized to yield a porosity-hydrophilicity dual-gradient. The resulting E-textile shows unidirectional, nonreversible, and anti-gravity water transporting performance even upon large-scale stretching (250%), excellent mechanical matching between sub-layers, as well as a reversible color-switching ability to visualize body temperature. More importantly, the conducting and skin-conformal E-textile demonstrates accurate and stable detecting capability for biomechanical and bioelectrical signals when applied as an on-skin bioelectrode, including different human activities, electrocardiography, electromyogram, and electrodermal activity signals. Further, the E-textile can be efficiently implemented in human-machine interfaces to build a gesture-controlled dustbin and a smart acousto-optic alarm. Hence, this hierarchically-designed E-textile with integrated functionalities offers a practical and innovative method for designing comfortable and daily applicable on-skin electronics.