MXene@c-MWCNT Adhesive Silica Nanofiber Membranes Enhancing Electromagnetic Interference Shielding and Thermal Insulation Performance in Extreme Environments.

A lightweight flexible thermally stable composite is fabricated by combining silica nanofiber membranes (SNM) with MXene@c-MWCNT hybrid film. The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination; the MXene@c-MWCNTx:y films are prepared by vacuum filtration technology. In particular, the SNM and MXene@c-MWCNT6:4 as one unit layer (SMC1) are bonded together with 5 wt% polyvinyl alcohol (PVA) solution, which exhibits low thermal conductivity (0.066 W m-1 K-1) and good electromagnetic interference (EMI) shielding performance (average EMI SET, 37.8 dB). With the increase in functional unit layer, the overall thermal insulation performance of the whole composite film (SMCx) remains stable, and EMI shielding performance is greatly improved, especially for SMC3 with three unit layers, the average EMI SET is as high as 55.4 dB. In addition, the organic combination of rigid SNM and tough MXene@c-MWCNT6:4 makes SMCx exhibit good mechanical tensile strength. Importantly, SMCx exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment. Therefore, this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.

Boron-doped three-dimensional porous carbon framework/carbon shell encapsulated silicon composites for high-performance lithium-ion battery anodes.

Deleterious volumetric expansion and poor electrical conductivity seriously hinder the application of Si-based anode materials in lithium-ion batteries (LIBs). Herein, boron-doped three-dimensional (3D) porous carbon framework/carbon shell encapsulated silicon (B-3DCF/Si@C) hybrid composites are successfully prepared by two coating and thermal treatment processes. The presence of 3D porous carbon skeleton and carbon shell effectively improves the mechanical properties of the B-3DCF/Si@C electrode during the cycling process, ensures the stability of the electrical contacts of the silicon particles and stabilizes the solid electrolyte interface (SEI) layer, thus enhancing the electronic conductivity and ion migration efficiency of the anode. The developed B-3DCF/Si@C anode has a high reversible capacity, excellent cycling stability and outstanding rate performance. A reversible capacity of 1288.5 mAh/g is maintained after 600 cycles at a current density of 400 mA g-1. The improved electrochemical performance is demonstrated in a full cell using a LiFePO4-based cathode. This study presents a novel approach that not only mitigates the large volume expansion effects in LIB anode materials, but also provides a reference model for the preparation of porous composites with various functionalities.

Modified acid polysaccharide derived from Salvia przewalskii with excellent wound healing and enhanced bioactivity.

Acid polysaccharide was extracted from Salvia przewalskii root powders (PSP), purified by diethylaminoethyl cellulose column (DEAE-52) and molecular sieve (PSP2). PSPm1 was obtained by modifying PSP2 with nitrite and phosphoric acid. The chemical structure of PSP2 and PSPm1 exhibited notable distinctions, primarily due to the absence of arabinose and promotion of glucuronic acid (GlcA). The structure of PSPm1 was deduced through the utilization of 1H, 13C, and 2-D NMR. The main chain was linked by α-D-Galp(1 â†’ 3)-α-Glcp-(1 â†’ fragments and →6)-ß-D-Galp fragments, with the presence of →4)-α-D-GlcpA-(1 â†’ 6)-ß-D-Galp-(1 â†’ ï¼Œ â†’ 4)-α-D-GalAp-(1 â†’ 2,4)-α-D-Rhap-(1 â†’ fragments and →6)-α-Glcp-(1 â†’ 2,4)-ß-D-Manp-(1 â†’ fragments. PSPm1 exhibited different immunoregulatory bioactivity in vitro, including haemostatic effects indicated by activated clotting time of 55.5 % reduction by the activated clotting time (ACT) test and wound healing function in vivo. PSPm1 also displayed better anti-tumor biological effects than unmodified. The structure-activity dissimilarity between PSP2 and PSPm1 primarily stems from variations in molecular weight (Mw), monosaccharide composition, and branching patterns. The modification of polysaccharides from the extract residues of Chinese medicinal materials may be a new form of drug supplements.

A Cellulose/Chitosan Dual Cross-Linked Multifunctional and Resilient Hydrogel for Emergent Open Wound Management.

Adhesive hydrogel holds huge potential in biomedical applications, such as hemostasis and emergent wound management during outpatient treatment or surgery. However, most adhesive hydrogels underperform to offer robust adhesions on the wet tissue, increasing the risk of hemorrhage and reducing the fault tolerance of surgery. To address this issue, this work develops a polysaccharide-based bioadhesive hydrogel tape (ACAN) consisting of dual cross-linking of allyl cellulose (AC) and carboxymethyl chitosan (CMCS). The hygroscopicity of AC and CMCS networks enables ACAN to remove interfacial water from the tissue surface and initializes a physical cross-link instantly. Subsequently, covalent cross-links are developed with amine moieties to sustain long-term and robust adhesion. The dual cross-linked ACAN also has good cytocompatibility with controllable mechanical properties matching to the tissue, where the addition of CMCS provides remarkable antibacterial properties and hemostatic capability. Moreover, compared with commercially available 3 M film, ACAN provides an ultrafast wound healing on tissue. The ACAN hybrid hydrogels have advantages such as biocompatibility and antibacterial, hemostatic, and wound healing properties, shedding new light on first-aid tape design and advancing the cellulose-based materials technology for high-performance biomedical applications.

Phyllostachys nigra (Lodd. ex Lindl.) derived polysaccharide with enhanced glycolipid metabolism regulation and mice gut microbiome.

This study focuses on the characterization and regulation of glycolipid metabolism of polysaccharides derived from biomass of Phyllostachys nigra (Lodd. ex Lindl.) root (PNr). The extracts from dilute hydrochloric acid, hot water, and 2 % sodium hydroxide solution were characterized through molecular weight, gel permeation chromatography, monosaccharides, Fourier transform infrared, and nuclear magnetic resonance spectroscopy analyses. Polysaccharide from alkali extraction and molecular sieve purification (named as: PNS2A) exhibited optimal inhibitory of 3T3-L1 cellular differentiation and lowered insulin resistance. The PNS2A is made of a hemicellulose-like main chain of →4)-ß-D-Xylp-(1→ that was connected by branches of 4-O-Me-α-GlcAp-(1→, T-α-D-Galp-(1→, T-α-L-Araf-(1→, →2)-α-L-Araf-(1→, as well as ß-D-Glcp-(1→4-ß-D-Glcp-(1→ fragments. Oral delivery of PNS2A in diabetes mice brought down blood glucose and cholesterol levels and regulated glucose and lipid metabolism. PNS2A alleviated diabetes symptoms and body weight and protected liver and kidney function in model animals by altering the gut microbiome. Polysaccharides can be a new approach to develop bamboo resources.

An overview of green synthesized silver nanoparticles towards bioactive antibacterial, antimicrobial and antifungal applications.

Present review emphatically introduces the synthesis, biocompatibility, and applications of silver nanoparticles (AgNPs), including their antibacterial, antimicrobial, and antifungal properties. A comprehensive discussion of various synthesis methods for AgNPs, with a particular focus on green chemistry mediated by plant extracts has been made. Recent research has revealed that the optical properties of AgNPs, including surface plasmon resonance (SPR), depend on the particle size, as well as the synthesis methods, preparation synthesis parameters, and used reducing agents. The significant emphasis on the use of synthesized AgNPs as antibacterial, antimicrobial, and antifungal agents in various applications has been reviewed. Furthermore, the application areas have been thoroughly examined, providing a detailed discussion of the underlying mechanisms, which aids in determining the optimal control parameters during the synthesis process of AgNPs. Furthermore, the challenges encountered while utilizing AgNPs and the corresponding advancements to overcome them have also been addressed. This review not only summarizes the achievements and current status of plant-mediated green synthesis of AgNPs but also explores the future prospects of these materials and technology in diverse areas, including bioactive applications.

An Overview of Metal-Organic Framework Based Electrocatalysts: Design and Synthesis for Electrochemical Hydrogen Evolution, Oxygen Evolution, and Carbon Dioxide Reduction Reactions.

Due to the increasing global energy demands, scarce fossil fuel supplies, and environmental issues, the pursued goals of energy technologies are being sustainable, more efficient, accessible, and produce near zero greenhouse gas emissions. Electrochemical water splitting is considered as a highly viable and eco-friendly energy technology. Further, electrochemical carbon dioxide (CO2 ) reduction reaction (CO2 RR) is a cleaner strategy for CO2 utilization and conversion to stable energy (fuels). One of the critical issues in these cleaner technologies is the development of efficient and economical electrocatalyst. Among various materials, metal-organic frameworks (MOFs) are becoming increasingly popular because of their structural tunability, such as pre- and post- synthetic modifications, flexibility in ligand design and its functional groups, and incorporation of different metal nodes, that allows for the design of suitable MOFs with desired quality required for each process. In this review, the design of MOF was discussed for specific process together with different synthetic methods and their effects on the MOF properties. The MOFs as electrocatalysts were highlighted with their performances from the aspects of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical CO2 RR. Finally, the challenges and opportunities in this field are discussed.

MXene Enhanced 3D Needled Waste Denim Felt for High-Performance Flexible Supercapacitors.

MXene, a transition metal carbide/nitride, has been prominent as an ideal electrochemical active material for supercapacitors. However, the low MXene load limits its practical applications. As environmental concerns and sustainable development become more widely recognized, it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton. The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization. The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles, resulting in more efficient ion exchange between the electrolyte and electrodes. Furthermore, the carbonization process removed the specific adverse groups in MXenes, further improving the specific capacitance, energy density, power density and electrical conductivity of supercapacitors. The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94% after 15,000 galvanostatic charge/discharge cycles. Besides, the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm-2, energy density of 80.2 µWh cm-2 and power density of 3 mW cm-2, respectively. The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches, laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.

Initiating Binary Metal Oxides Microcubes Electrsomagnetic Wave Absorber Toward Ultrabroad Absorption Bandwidth Through Interfacial and Defects Modulation.

Cobalt nickel bimetallic oxides (NiCo2O4) have received numerous attentions in terms of their controllable morphology, high temperature, corrosion resistance and strong electromagnetic wave (EMW) absorption capability. However, broadening the absorption bandwidth is still a huge challenge for NiCo2O4-based absorbers. Herein, the unique NiCo2O4@C core-shell microcubes with hollow structures were fabricated via a facile sacrificial template strategy. The concentration of oxygen vacancies and morphologies of the three-dimensional (3D) cubic hollow core-shell NiCo2O4@C framework were effectively optimized by adjusting the calcination temperature. The specially designed 3D framework structure facilitated the multiple reflections of incident electromagnetic waves and provided rich interfaces between multiple components, generating significant interfacial polarization losses. Dipole polarizations induced by oxygen vacancies could further enhance the attenuation ability for the incident EM waves. The optimized NiCo2O4@C hollow microcubes exhibit superior EMW absorption capability with minimum RL (RLmin) of -84.45 dB at 8.4 GHz for the thickness of 3.0 mm. Moreover, ultrabroad effective absorption bandwidth (EAB) as large as 12.48 GHz (5.52-18 GHz) is obtained. This work is believed to illuminate the path to synthesis of high-performance cobalt nickel bimetallic oxides for EMW absorbers with excellent EMW absorption capability, especially in broadening effective absorption bandwidth.

Facile Design of Flexible, Strong, and Highly Conductive MXene-Based Composite Films for Multifunctional Applications.

Strong, conductive, and flexible materials with improving ion accessibility have attracted significant attention in electromagnetic interference (EMI) and foldable wearable electronics. However, it still remains a great challenge to realize high performance at the same time for both properties. Herein, a microscale structural design combined with nanostructures strategy to fabricate TOCNF(F)/Ti3 C2 Tx (M)@AgNW(A) composite films via a facile vacuum filtration process followed by hot pressing (TOCNF = TEMPO-oxidized cellulose nanofibrils, NW = nanowires) is described. The comparison reveals that different microscale structures can significantly influence the properties of thin films, especially their electrochemical properties. Impressively, the ultrathin MA/F/MA film with enhanced layer in the middle exhibits an excellent tensile strength of 107.9 MPa, an outstanding electrical conductivity of 8.4 × 106 S m-1 , and a high SSE/t of 26 014.52 dB cm2 g-1 . The assembled asymmetric MA/F/MA//TOCNF@CNT (carbon nanotubes) supercapacitor leads to a significantly high areal energy density of 49.08 µWh cm-2 at a power density of 777.26 µW cm-2 . This study proposes an effective strategy to circumvent the trade-off between EMI performance and electrochemical properties, providing an inspiration for the fabrication of multifunctional films for a wide variety of applications in aerospace, national defense, precision instruments, and next-generation electronics.

Impact mechanisms of aggregation state regulation strategies on the microwave absorption properties of flexible polyaniline.

In the field of electromagnetic (EM) wave absorption, intrinsic conductive polymers with conjugated long-chain structures, such as polyaniline (PANI) and polypyrrole (PPy), have gained widespread use due to their remarkable electrical conductivity and loss ability. However, current research in this area is limited to macroscopic descriptions of the absorption properties of these materials and the contribution of various components to the absorption effect. There has been insufficient exploration of the impact mechanisms of polymer aggregation states on the material's absorption performance and mechanism. To address this, a series of flexible PANI sponge absorbers with different molecular weights and aggregation states were prepared. By carefully controlling the crystallinity and other aggregation characteristics of PANI through the adjustment of its preparation conditions, we were able to influence its electrical conductivity and electromagnetic parameters, thereby achieving control over the material's absorption properties. The resulting PANI sponge absorbers exhibited an effective absorption bandwidth (EAB) that covered the entire X-band at a thickness of 3.2 mm. This study comprehensively explores the absorption mechanisms of conductive polymer absorbers, starting from the microstructure of PANI, and providing a more complete theoretical support for the research and promotion of polymer absorbers.

Bamboo fiber strengthened poly(lactic acid) composites with enhanced interfacial compatibility through a multi-layered coating of synergistic treatment strategy.

In this study, a mild and eco-friendly synergistic treatment strategy was investigated to improve the interfacial compatibility of bamboo fibers with poly(lactic acid). The characterization results in terms of the chemical structure, surface morphology, thermal properties, and water resistance properties demonstrated a homogeneous dispersion and excellent interfacial compatibility of the treated composites. The excellent interfacial compatibility is due to multi-layered coating of bamboo fibers using synergistic treatment involving dilute alkali pretreatment, polydopamine coating and silane coupling agent modification. The composites obtained using the proposed synergistic treatment strategy exhibited excellent mechanical properties. Optimal mechanical properties were observed for composites with synergistically treated bamboo fiber mass proportion of 20 %. The tensile strength, elongation at break and tensile modulus of the treated composites were increased by 63.06 %, 183.04 % and 259.04 %, respectively, compared to the untreated composites. This synergistic treatment strategy and the remarkable performance of the treated composites have a wide range of applicability in bio-composites (such as industrial packaging, automotive lightweight interiors, and consumer goods).

A Multifunctional Asymmetric Fabric for Sustained Electricity Generation from Multiple Sources and Simultaneous Solar Steam Generation.

Harvesting electrical energy from water and moisture has emerged as a novel ecofriendly energy conversion technology. Herein, a multifunctional asymmetric polyaniline/carbon nanotubes/poly(vinyl alcohol) (APCP) that can produce electric energy from both saline water and moisture and generate fresh water simultaneously is developed. The constructed APCP possesses a negatively charged porous structure that allows continuous generation of protons and ion diffusion through the material, and a hydrophilicity-hydrophobic interface which results in a constant potential difference and sustainable output. A single APCP can maintain stable output for over 130 h and preserve a high voltage of 0.61 V, current of 81 µA, and power density of 82.4 µW cm-3 with 0.15 cm3 unit size in the water-induced electricity generation process. When harvesting moisture energy, the APCP creates dry-wet asymmetries and triggers the spontaneous development of electrical double layer with a current density of 1.25 mA cm-3 , sufficient to power small electronics. A device consisting of four APCP can generate stable electricity of 3.35 V and produce clean water with an evaporation rate of 2.06 kg m-2  h-1 simultaneously. This work provides insights into the fabrication of multifunctional fabrics for multisource energy harvesting and simultaneous solar steam generation.

A Simple and Effective Physical Ball-Milling Strategy to Prepare Super-Tough and Stretchable PVA@MXene@PPy Hydrogel for Flexible Capacitive Electronics.

Biomimetic flexible electronics for E-skin have received increasing attention, due to their ability to sense various movements. However, the development of smart skin-mimic material remains a challenge. Here, a simple and effective approach is reported to fabricate super-tough, stretchable, and self-healing conductive hydrogel consisting of polyvinyl alcohol (PVA), Ti3 C2 Tx MXene nanosheets, and polypyrrole (PPy) (PMP hydrogel). The MXene nanosheets and Fe3+ serve as multifunctional cross-linkers and effective stress transfer centers, to facilitate a considerable high conductivity, super toughness, and ultra-high stretchability (elongation up to 4300%) for the PMP hydrogel with. The hydrogels also exhibit rapid self-healing and repeatable self-adhesive capacity because of the presence of dynamic borate ester bond. The flexible capacitive strain sensor made by PMP hydrogel shows a relatively broad range of strain sensing (up to 400%), with a self-healing feature. The sensor can precisely monitor various human physiological signals, including joint movements, facial expressions, and pulse waves. The PMP hydrogel-based supercapacitor is demonstrated with a high capacitance retention of ≈92.83% and a coulombic efficiency of ≈100%.

Conductive polymer based hydrogels and their application in wearable sensors: a review.

Hydrogels have been attracting increasing attention for application in wearable electronics, due to their intrinsic biomimetic features, highly tunable chemical-physical properties (mechanical, electrical, etc.), and excellent biocompatibility. Among many proposed varieties of hydrogels, conductive polymer-based hydrogels (CPHs) have emerged as a promising candidate for future wearable sensor designs, with capability of realizing desired features using different tuning strategies ranging from molecular design (with a low length scale of 10-10 m) to a micro-structural configuration (up to a length scale of 10-2 m). However, considerable challenges remain to be overcome, such as the limited strain sensing range due to the mechanical strength, the signal loss/instability caused by swelling/deswelling, the significant hysteresis of sensing signals, the de-hydration induced malfunctions, and the surface/interfacial failure during manufacturing/processing. This review aims to offer a targeted scan of recent advancements in CPH based wearable sensor technology, from the establishment of dedicated structure-property relationships in the lab to the advanced manufacturing routes for potential scale-up production. The application of CPHs in wearable sensors is also explored, with suggested new research avenues and prospects for CPHs in the future also included.

Bioengineered exosomal-membrane-camouflaged abiotic nanocarriers: neurodegenerative diseases, tissue engineering and regenerative medicine.

A bio-inspired strategy has recently been developed for camouflaging nanocarriers with biomembranes, such as natural cell membranes or subcellular structure-derived membranes. This strategy endows cloaked nanomaterials with improved interfacial properties, superior cell targeting, immune evasion potential, and prolonged duration of systemic circulation. Here, we summarize recent advances in the production and application of exosomal membrane-coated nanomaterials. The structure, properties, and manner in which exosomes communicate with cells are first reviewed. This is followed by a discussion of the types of exosomes and their fabrication methods. We then discuss the applications of biomimetic exosomes and membrane-cloaked nanocarriers in tissue engineering, regenerative medicine, imaging, and the treatment of neurodegenerative diseases. Finally, we appraise the current challenges associated with the clinical translation of biomimetic exosomal membrane-surface-engineered nanovehicles and evaluate the future of this technology.

High adsorption performance for trace lead (II) cation from sewage by Fe/Cu metal organic nanosheets modified with terephthalic acid.

A two-dimensional nanoflake (Fe/Cu-TPA) was prepared through a simple ultrasonic-centrifuge method. Fe/Cu-TPA has prominent performance on the removal of Pb2+ with low consistences. More than 99% lead (II) (Pb2+) was removed. The adsorption equipoise was established within 60 min for 50 mg L-1 Pb2+. Fe/Cu-TPA shows excellent regenerability with 19.04% decline of Pb2+ adsorption competence in 5 cycles. There are two models for Fe/Cu-TPA adsorption of Pb2+, pseudo-second-order dynamic model and Langmuir isotherm model, with a utmost adsorption competence of 213.56 mg g-1. This work offers a new candidate material for the industrial-grade Pb2+ adsorbents with promising application prospect.

The Status of Representative Anode Materials for Lithium-Ion Batteries.

Since the invention of lithium-ion batteries as a rechargeable energy storage system, it has uncommonly promoted the development of society. It has a wide variety of applications in electronic equipment, electric automobiles, hybrid vehicles, and aerospace. As an indispensable component of lithium-ion batteries, anode materials play an essential role in the electrochemical characteristics of lithium-ion batteries. In this review, we described the development from lithium-metal batteries to lithium-ion batteries in detail on the time axis as the first step; This was followed by an introduction to several commonly used anode materials, including graphite, silicon, and transition metal oxide with discussions the charge-discharge mechanism, challenges and corresponding strategies, and a collation of recent interesting work; Finally, three anode materials are summarized and prospected. Hopefully, this review can serve both the newcomers and the predecessors in the field.

Sodium alginate reinforced polyacrylamide/xanthan gum double network ionic hydrogels for stress sensing and self-powered wearable device applications.

Strong and ductile sodium alginate (SA) reinforced polyacrylamide (PAM)/xanthan gum (XG) double network ionic hydrogels were constructed for stress sensing and self-powered wearable device applications. In the designed network of PXS-Mn+/LiCl (short for PAM/XG/SA-Mn+/LiCl, where Mn+ stands for Fe3+, Cu2+ or Zn2+), PAM acts as a flexible hydrophilic skeleton, and XG functions as a ductile second network. The macromolecule SA interacts with metal ion Mn+ to form a unique complex structure, significantly improving the mechanical strength of the hydrogel. The addition of inorganic salt LiCl endows the hydrogel with high electrical conductivity, and meanwhile reduces the freezing point and prevents water loss of the hydrogel. PXS-Mn+/LiCl exhibits excellent mechanical properties and ultra-high ductility (a fracture tensile strength up to 0.65 MPa and a fracture strain up to 1800%), and high stress-sensing performance (a high GF up to 4.56 and pressure sensitivity of 0.122). Moreover, a self-powered device with a dual-power-supply mode, i.e., PXS-Mn+/LiCl-based primary battery and TENG, and a capacitor as the energy storage component was constructed, which shows promising prospects for self-powered wearable electronics.

Highly Stable Garnet Fe2 Mo3 O12 Cathode Boosts the Lithium-Air Battery Performance Featuring a Polyhedral Framework and Cationic Vacancy Concentrated Surface.

Lithium-air batteries (LABs), owing to their ultrahigh theoretical energy density, are recognized as one of the next-generation energy storage techniques. However, it remains a tricky problem to find highly active cathode catalyst operating within ambient air. In this contribution, a highly active Fe2 Mo3 O12 (FeMoO) garnet cathode catalyst for LABs is reported. The experimental and theoretical analysis demonstrate that the highly stable polyhedral framework, composed of FeO octahedrons and MO tetrahedrons, provides a highly effective air catalytic activity and long-term stability, and meanwhile keeps good structural stability. The FeMoO electrode delivers a cycle life of over 1800 h by applying a simple half-sealed condition in ambient air. It is found that surface-rich Fe vacancy can act as an O2 pump to accelerate the catalytic reaction. Furthermore, the FeMoO catalyst exhibits a superior catalytic capability for the decomposition of Li2 CO3 . H2 O in the air can be regarded as the main contribution to the anode corrosion and the deterioration of LAB cells could be attributed to the formation of LiOH·H2 O at the end of cycling. The present work provides in-depth insights to understand the catalytic mechanism in air and constitutes a conceptual breakthrough in catalyst design for efficient cell structure in practical LABs.