Electrostatic Self-assembly Process Research Articles

Multifunctional composite phase change material with electrostatic self-assembly structure based on carboxylated multi-walled carbon nanotubes

The need for improved thermal regulation in electronic devices and solar thermal energy storage, prompted by the energy crisis, has expedited the advancement of phase change materials (PCMs). Carboxylated multi-walled carbon nanotubes (MWCNT-COOH) were produced by introducing carboxyl functional groups onto MWCNTs utilizing a concentrated acid treatment. The novel composite was engineered through an electrostatic self-assembly process between the negatively charged MWCNT-COOH and the positively charged Poly dimethyl diallyl ammonium chloride (PDDA) solution, filling the structure with the PCM polyethylene glycol (PEG) and incorporating the (magnesium hydrate) Mg(OH)2 to enhance the material's flame resistance at high temperatures. The thermal conductivity of the obtained composites improved significantly from 0.25 W/m·K to 1.183 W/m·K, while maintaining an enthalpy of phase transition of phase change of 135.1 J/g. Owing to the capillary effect of the closely packed MWCNT-COOH tubular structure, the composite material exhibited excellent high-temperature shape retention ability. Additionally, the composite demonstrated high absorption with an absorbance reaching 1.18 L/(g·cm) and composite materials can convert up to 86.8 % of light energy into heat energy.

Low-Contact Impedance Textile Electrode for Real-Time Detection of ECG Signals.

The quality of the electrocardiography (ECG) signals depends on the effectiveness of the electrode-skin connection. However, current electrocardiogram electrodes (ECGE) often face challenges such as high contact impedance and unstable conductive networks, which hinder accurate measurement during movement and long-term wearability. Herein, in this work, a bionic 3D pile textile as an ECGE with high electrical conductivity and flexibility is prepared by a facile, continuous, and high-efficiency electrostatic self-assembly process. Integrating pile textiles with conductive materials creates a full textile electrode for bioelectrical signal detection that can retain both the inherent characteristics of textiles and high conductivity. Moreover, the dense piles on the textile surface make full contact with the skin, mitigating motion artifacts caused by the sliding between the textile and the skin. The continuous conductive network formed by the interconnected piles allows the pile textile ECGE (PT-ECGE) to function effectively under both static and dynamic conditions. Leveraging the unique pile structure, the PT-ECGE achieves superior flexibility, improved conductivity, low contact impedance, and high adaptivity, washability, and durability. The textile electrode, as a promising candidate for wearable devices, offers enormous application possibilities for the unconscious and comfortable detection of physiological signals.

Superelastic, ultralight aramid fibre/tannic acid/graphene nanohybrid aerogel constructed using a cross–scale strengthening strategy for rapid and high–flux oil–water separation

Graphene-based aerogels are efficient oil–water separation materials with enormous potential, but their poor mechanical strength and cycling stability limit their applications. A cross-scale strengthening strategy was used to construct aramid fibre (A)/tannic acid (T)/graphene (G) (ATG) aerogel using an in situ electrostatic self-assembly and freeze-drying process. At 95 % of the ultimate compressive strain, the ATG aerogel could withstand a stress of up to 147 kPa and can rebound quickly. The mechanism for the high mechanical strength of the ATG aerogel was explored by structure characterisation and density functional theory (DFT) calculation. A superhydrophobic aerogel (named H-ATG) was prepared by a hydrophobic modification of ATG using a vapor deposition reaction method. The H-ATG aerogel exhibited excellent superoleophilicity/superhydrophobicity with the oil and water contact angles of 0° and 152.48°, respectively. The hydrophobicity of the H-ATG aerogel was stable over the pH range of 1–13 and the temperature range of -80–600 °C. In addition, the aerogel had an ultra-fast absorption speed and excellent absorption capability, rapidly absorbing various oil-based organic solvents up to 101 times its own weight within 5 s. After the absorption of oil or solvents, it could be easily recovered by combustion, distillation or extrusion, and the performance remained relatively unchanged after 10 cycles. When H-ATG was used as a filter to achieve fast and efficient oil–water separation with a high flux of 20,371.83 L·h−1·g−1. Therefore, the H-ATG aerogel has excellent potential for applications in the oil–water separation and the purification of oily wastewater.

Room temperature NH3 gas sensor based on In(OH)3/Ti3C2Tx nanocomposites.

Industrialization and agricultural demand have both improved human life and led to environmental contamination. Especially thedischarge of a lot of poisonous and harmful gases, including ammonia, ammonia pollution has become a pressing problem. High concentrations of ammonia can pose significant threats to both the environment and human health. Therefore, accurate monitoring and detection of ammonia gas are crucial. To address this challenge, we have developed an ammonia gas sensor using In(OH)3/Ti3C2Tx nanocomposites through an in-situ electrostatic self-assembly process. This sensor was thoroughly characterized using advanced techniques like XRD, XPS, BET, and TEM. In our tests, the I/M-2 sensor exhibited remarkable performance, achieving a 16.8% response to 100ppm NH3 at room temperature, which is a 3.5-fold improvement over the pure Ti3C2Tx MXene sensor. Moreover, it providesswift response time (20s), high response to low NH3concentrations (≤ 10ppm), and excellent long-term stability (30days). These exceptional characteristics indicate the immense potential of our In(OH)3/Ti3C2Tx gas sensor in ammonia detection.

Electrostatic Self-Assembly Synthesis of Pd/In2O3 Nanocatalysts with Improved Performance Toward CO2 Hydrogenation to Methanol.

CO2 hydrogenation to methanol has emerged as a promising strategy for achieving carbon neutrality and mitigating global warming, in which the supported Pd/In2O3 catalysts are attracting great attention due to their high selectivity. Nonetheless, conventional impregnation methods induce strong metal-support interaction (SMSI) between Pd and In2O3, which leads to the excessive reduction of In2O3 and the formation of undesirable PdIn alloy in hydrogen-rich atmospheres. Herein, we innovatively synthesized Pd/In2O3 nanocatalysts by the electrostatic self-assembly process between surface-modified composite precursors with opposite charges. And the organic ligands concurrently serve as Pd nanoparticle protective agents. The resultant Pd/In2O3 nanocatalyst demonstrates the homogeneous distribution of Pd nanoparticles with controllable sizes on In2O3 supports and the limited formation of PdIn alloy. As a result, it exhibits superior selectivity and stability compared to the counterparts synthesized by the conventional impregnation procedure. Typically, it attains a maximum methanol space-time yield of 0.54 gMeOH h-1gcat -1 (300 °C, 3.5 MPa, 21,000 mL gcat -1 h-1). Notably, the correlation characterization results reveal the significant effect of small-size, highly dispersed Pd nanoparticles in mitigating MSI. These results provide an alternative strategy for synthesizing highly efficient Pd/In2O3 catalysts and offer a new insight into the strong metal-support interaction.

Engineering a Z-Scheme Heterostructure on ZnIn2S4@NH2-MIL-125 Composites for Boosting the Photocatalytic Performance.

Constructing a Z-scheme heterostructure on a metal-organic framework (MOF) composite with an explicit charge transfer mechanism at the interface is considered to be an effective strategy for improving the photocatalytic performance of MOFs. Herein, an internal electric field (IEF)-induced Z-scheme heterostructure on the ZnIn2S4@NH2-MIL-125 composite is designed and fabricated by a facile electrostatic self-assembly process. Systematic investigations reveal that close interfacial contact and difference in work function between NH2-MIL-125 and ZnIn2S4 enable the formation of the IEF, which drives the Z-scheme charge transfer as revealed by the in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS), photoirradiated Kelvin probe force microscope (KPFM) measurement, electron paramagnetic resonance (EPR) radical trapping experiment, as well as density functional theory (DFT) calculation; meanwhile, directions of the interfacial IEFs are determined. Benefiting from the unique merit of IEF-induced Z-scheme charge transfer, the optimized ZnIn2S4@NH2-MIL-125 composite exhibits significantly enhanced photocatalytic activity for the photoreduction of 4-nitroaniline (4-NA) to p-phenylenediamine (PPD) under visible light irradiation. This work not only provides in-depth insights for charge transfer in the IEF-induced Z scheme heterostructure but also affords useful inspirations on designing the Z-scheme MOF composite to boost the photocatalytic performance.

Accelerating carrier separation to boost the photocatalytic CO2 reduction performance of ternary heterojunction Ag-Ti3C2Tx/ZnO catalysts.

Developing low-cost and efficient photocatalyst/co-catalyst systems that promote CO2 reduction remains a challenge. In this work, Ag-Ti3C2Tx composites were made using a self-reduction technique, and unique Ag-Ti3C2Tx/ZnO ternary heterojunction structure photocatalysts were created using an electrostatic self-assembly process. The photocatalyst's close-contact heterogeneous interface increases photogenerated carrier migration efficiency. The combination of Ti3C2Tx and Ag improves the adsorption active sites and reaction centers for ZnO, making it a key site for CO2 adsorption and activation. The best photocatalysts had CO and CH4 reduction efficiencies of 11.985 and 0.768 μmol g-1 h-1, respectively. The CO2 conversion was 3.35 times better than that of pure ZnO, which demonstrated remarkable stability even after four cycle trials with no sacrificial agent. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) and valence band spectroscopy were utilized to propose the photocatalytic reaction mechanism and electron transfer channels of the Ag-Ti3C2Tx/ZnO system, confirming that CHO* and CO* are the important intermediates in the generation of CH4 and CO. This study introduces a novel method for the development of new and efficient photocatalysts and reveals that Ti3C2Tx MXene is a viable co-catalyst for applications.

Flexible, ultrathin and integrated nanopaper supercapacitor based on cationic bacterial cellulose

Cellulose composite nanopaper is extensively employed in flexible energy storage systems owing to their light weight, good flexibility and high specific surface area. Nevertheless, achieving flexible and ultrathin nanopaper supercapacitors with excellent electrochemical performance remains a challenge. Herein, surface cationization of bacterial cellulose (BC) nanofibers was conducted using 2,3-epoxypropyltrimethylammonium chloride (EPTMAC). Anion-doped polypyrrole (PPy) was incorporated onto the surface of the cationic bacterial cellulose (BCE) nanofibers by an interfacial electrostatic self-assembly process. The obtained PPy@BCE electrode exhibited excellent electrochemical performance, including an areal capacitance of 3988 mF cm−2 at 1.0 mA cm−2 and a capacitance retention of 97 % after 10,000 cycles. A laminated paper-forming strategy was adopted to design and fabricate all-in-one integrated flexible supercapacitors (IFSCs) using PPy@BCE nanopaper as electrodes and BC nanopaper as a separator. The IFSCs showed superior areal capacitance (3669 mF cm−2 at 1 mA cm−2), high energy density (193.7 μWh cm−2 at a power density of 827.3 μW cm−2), and outstanding mechanical flexibility (with no significant capacitance attenuation after repeatedly bending for 1000 times). The present strategy paves a way for the large-scale production of paper-based energy storage devices.

Bimetallic MOFs/MXene derived CoNi@C@Ti3C2Tx/TiO2 nanocomposites for high-efficiency electromagnetic wave absorption

Constructing intricately designed multiple heterogeneous interfaces offers an effective strategy for exploring lightweight and efficient microwave absorbing materials (MAMs). Herein, the CoNi@C@Ti3C2Tx/TiO2 (CNCTT) nanocomposites with multiple heterogeneous interfaces were synthesized using the straightforward solvothermal method, electrostatic self-assembly, and subsequent heat treatment process, utilizing bimetallic CoNi-MOF-74@few-layered Ti3C2Tx MXene as the precursor. The modulation of composition, microstructure, and electromagnetic wave absorption (EMWA) properties of the CNCTT nanocomposites was comprehensively investigated by simply controlling the ratio of magnetic metal sources. Hierarchical porous structure simultaneously promotes interfacial polarization by quaternary CoNi/C/MXene/TiO2 interfaces, enhances magnetic loss by the CoNi nanoparticles coupling network, enlarges conduction loss by the graphite carbon layer/MXene/TiO2 triple-network, and optimizes impedance matching with the synergistic effect of dielectric loss and magnetic loss. Significantly, it is observed that the C3N3CTT nanocomposite, with the molar ratio of Co:Ni is 3:3 and a filler loading of 30 wt%, demonstrates an impressive minimum reflection loss (RLmin) of −70.26 dB at 15.92 GHz and an effective absorbing bandwidth (EAB, RL < −10 dB) of 4.19 GHz with an absorption layer thickness of 1.7 mm. Furthermore, the RLmin remains notable −40.50 dB with an expanded EAB of 5.17 GHz at a thickness of 1.8 mm. This endeavor can provide significant insights into the potential applications of MOF-derived composites in the realm of efficient electromagnetic wave absorption.

Making graphene oxide (GO)-cladded SiO2 spheres (SiO2 @GO) as inorganic fillers for dental restorative resin composites

ObjectiveGraphene oxide (GO) is of great interest in dentistry as the functional filler, mainly owing to its ability to inhibit the formation of cariogenic bacteria and possess low cytotoxicity to different cells, such as human dental pulp cells, HeLa cells, etc. However, its typical brown color limits the practical application. MethodsHere, the refractive-index-matched monodisperse SiO2 were used as the supporting substrates to synthesize GO-cladded SiO2 spheres (xSiO2 @ yGO) through a mild electrostatic self-assembly process, where x and y represent the amount of SiO2 and GO in the reaction mixture, respectively. The morphology and the optical performance of the obtained xSiO2 @ yGO particles were modulated by varying the mass ratio of SiO2 and GO (5:1, 10:1, 50:1, and 100:1). All developed hybrid particles were silanized and formulated with dimethacrylate-based resins. These were tested for curing depth, polymerization conversion, mechanical performance, in vitro cell viability, and antibacterial activity. ResultsOf all xSiO2 @ yGO materials, increasing the mass ratio to 100:1 made the 100SiO2 @GO particles appear light brown and possess the lowest light absorbance from 300 to 800 nm. The results of CIEL*a*b* system showed that all these hybrid particles exhibited obvious discoloration compared with SiO2 and GO, where 100SiO2 @GO possessed the smallest color difference. Furthermore, following the results of curing depth, polymerization conversion, and mechanical performance of dental composites, the optimal filler composition was 100SiO2 @GO at 5 wt% filler loading. The resultant 100SiO2 @GO-filled composite produced the highest flexural strength (115 ± 12 MPa) and the lowest bacterial concentration (6.7 × 108 CFU/mL) than those of the resin matrix (78 ± 11 MPa; 9.2 × 108 CFU/mL) and 5 wt% SiO2-filled composite (106 ± 9 MPa; 9.1 × 108 CFU/mL), respectively, without affecting in vitro cell viability. SignificanceThe facile and mild synthesis of xSiO2 @ yGO hybrid particles provided a convenient way to tune their optical property. The optimal 100SiO2 @GO particles could be considered as the promising antibacterial filler to be applied in dental care and therapy.

An emerging class of 3D GNPs&MWCNTs structure of Mg matrix composites with improved thermal conductivity

Graphene nanoplates (GNPs) and carbon nanotubes (CNTs) can construct efficient thermal flux channels in composites, which is becoming one of the effective methods to improve thermal conductivity (TC) of composites. In this paper, an emerging class of GNPs&MWCNTs preform with 3D orientated structures were prepared by using electrostatic self-assembly and directional freeze-drying methods, and then fabricated the GNPs&MWCNTs reinforced AZ91D magnesium (GNPs&MWCNTs/AZ91D) composites by squeeze casting process. To ensure the well preparation of the composites, the GNPs&MWCNTs preforms need to possess enough compression strength to withstand squeezing pressure. Therefore, the effects of the electrostatic self-assembly process, directional freeze drying process and thermal reduction process on the compression strength of 3D structure GNPs&MWCNTs preforms were studied. The compression strength of GNPs&MWCNTs preforms were well improved to 98KPa, which were used for the fabrication of AZ91D matrix composites. The TC of 0.5 wt.% (1:1) GNPs&MWCNTs/AZ91D composites reached 71.7 W/(m·K) in the freezing direction, which was 41.8% higher than that (50.6 W/(m·K)) of the AZ91D alloy. This work provides a novel method for preparing GNPs&MWCNTs/AZ91D composites with improved TCs.

Biosensing by Polymer-Coated Etched Long-Period Fiber Gratings Working near Mode Transition and Turn-around Point.

A methodology to enhance the sensitivity of long-period fiber gratings (LPFGs) based on the combination of three different enhancement approaches is presented; the methods here adopted are the working near mode transition (MT) of a cladding mode (CM), working near the turn-around point of a CM and the enhancement of the evanescent field of CMs by reducing the cladding diameter or by increasing the order number of CMs. In order to combine these enhancement methodologies, an electrostatic self-assembly (ESA) process was used to deposit a polymeric overlay, with a chosen thickness, onto the etched fiber. The add-layer sensitivity of the sensor was theoretically calculated, and the demonstration of the real applicability of the developed LPFG as a biosensor was performed by means of an IgG/anti-IgG immunoassay in human serum in a thermostated microfluidic system. The limits of detection (LODs) calculated by following different procedures (three times the standard deviation of the blank and the mean value of the residuals) were 6.9 × 10-8 µg/mL and 4.5 × 10-6 µg/mL, respectively. The calculated LODs demonstrate the effectiveness of the applied methodology for sensitivity enhancement.

Graphene oxide–MnFe2O4 nanohybrid material as an adsorbent of Congo red dye

The aim of this work is the synthesis and characterization of graphene oxide (GO)–MnFe2O4 nanohybrid material, as well as the study of its performance in the removal of Congo red (CR) dye from aqueous solutions. The GO–MnFe2O4 was prepared via a three-step method. Firstly, GO was produced via a modified Hummers' method, using graphite powder as starting material. Subsequently, GO was functionalized with ionic surfactants, cetyltrimethylammonium bromide and poly(sodium-4-styrenesulfonate). Following this, the functionalized GO was decorated with magnetic MnFe2O4 nanoparticles via an electrostatic self-assembly process using a solvothermal treatment at 200 °C for 12 h. The as-prepared GO–MnFe2O4 nanohybrid material was characterized by several techniques: X-ray diffraction analysis, Fourier-transform infrared spectroscopy, micro-Raman spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, and high-resolution transition electron microscopy with energy-dispersive spectroscopy mapping. The adsorption performance of GO–MnFe2O4 in the removal of CR dye was evaluated at different initial CR concentrations and contact times using an ultraviolet–visible spectrophotometer. In addition, its recyclability performance was investigated for 10 cycles. It is noteworthy that even after the last cycle, the removal efficiency of GO–MnFe2O4 exceeded 65%, indicating that the adsorbent had very good reusability. Finally, the Freundlich isotherm model yielded a better fit for the adsorption data, compared to Langmuir, while adsorption of CR by GO–MnFe2O4 showed pseudo-second-order kinetics.

Cooperative energy storage behaviors derived from PANI and V2CTx MXene for advanced aqueous zinc-ion batteries

Polyaniline (PANI) were anchored to the surface of O-V2CTx MXene to arrange a three-dimensional architecture of hybrid composites via an electrostatic self-assembly process. The accessible surface of O-V2CTx MXene derived from the emergence of vanadium-oxygen terminations in the opening aqueous suspension contributes to attracting positively charged PANI, followed by the transformation of C-V/V2+ to V3+ and V4+ species on the surface of O-V2CTx MXene through an in situ oxidation process. The intercalation of PANI as spacing blocks into the interlayer region between O-V2CTx nanosheets is capable to suppress the re-stacking of O-V2CTx MXene in favor of accelerating Zn2+ diffusion processes and enrich surface electrochemical active sites of O-V2CTx MXene in dependence on cooperative charge storage processes between heterogeneous constituents. The result shows that PANI/O-V2CTx composites achieve a reversible capacity of 267.7 mAh g−1 at 0.2 A g−1 in comparison with those of 135.1 mAh g−1 for PANI and 116.2 mAh g−1 for O-V2CTx MXene. After 2000 cycles, PANI/O-V2CTx composites also exhibit the excellent cycling stability with a high capacity retention of 91.8% at 5 A g−1. Moreover, ex situ structural characterizations reveal the realization of the reversible redox transformation between V4+ and V5+ species on the surface vanadium-oxygen coating of O-V2CTx MXene with the aid of electrochemical active PANI.

Core-shell FeCo@carbon nanocages encapsulated in biomass-derived carbon aerogel: Architecture design and interface engineering of lightweight, anti-corrosion and superior microwave absorption

The development of multifunctional microwave absorbing materials for practical applications in complex environments is a challenging research hotspot. Herein, the core–shell structure FeCo@C nanocages were successfully anchored on the surface of biomass-derived carbon (BDC) from pleurotus eryngii (PE) via freeze-drying and electrostatic self-assembly process, achieving lightweight, anti-corrosive, and excellent absorption properties. The superior versatility benefits from the large specific surface area, high conductivity, three-dimensional cross-linked networks, and appropriate impedance matching characteristics. The as-prepared aerogel realizes a minimum reflection loss (RLmin) of −69.5 dB with a corresponding effective absorption bandwidth (EAB) of 8.6 GHz at 2.9 mm. Simultaneously, the computer simulation technique (CST) further proves that the multifunctional material can dissipate microwave energy in actual applications. More importantly, the special heterostructure of aerogel endows excellent resistance to acid, alkali, salt medium, allowing potential applications of the microwave absorbing materials under complex environmental conditions.

Z-scheme 2D/2D heterojunction of ZnIn2S4/Ti-BPDC enhancing photocatalytic hydrogen evolution under visible light irradiation

Two-dimensional (2D) lamellar materials have an appealing prospect in the field of photocatalysis due to their ultrathin thickness and exposed reactive sites. The regulation of photogenerated carrier transfer is more conducive to further enhancing catalytic performance. Herein, a direct Z-scheme 2D/2D heterojunction of ZnIn2S4/Ti-BPDC was synthesized using a simple electrostatic self-assembly process. The morphology of the ultrathin lamellar endows the catalyst with more exposed active sites and a short charge transfer distance. The large contact interface and intimate interaction between the two semiconductors ensure a smooth interphase electron transport channel. The matching of staggered band structures provides the basis for constructing an internal electric field and band bending to realize Z-scheme charge transfer. Benefiting from the combined effects of these aspects, ZnIn2S4/Ti-BPDC showed substantially enhanced interface photogenerated carrier transfer efficiency and photocatalytic hydrogen evolution performance. Moreover, the 2D/2D ZnIn2S4/Ti-BPDC heterojunction possessed excellent stability and recyclability, showing potential for applications in sustainable energy conversion.

The properties and formation mechanism of ovalbumin-fucoidan complex

The polymeric materials formed by proteins and polysaccharides through molecular interactions have attracted public attention. In this study, a novel binary complex consisting of ovalbumin (OVA) and fucoidan (FUC) was obtained by electrostatic self-assembly. The self-assembly properties and the formation mechanism of the OVA-FUC binary complex were investigated by changing the charging degree and density of complex through altering pH value and polysaccharides proportion. Structural changes during the OVA-FUC electrostatic self-assembly process were investigated by a phase diagram, ζ-potential, and particle size. The optimal conditions for preparing soluble OVA-FUC binary complex were determined by the protein retention rate and insoluble solids content. Results showed that the soluble OVA-FUC binary complex could be obtained at the pH of 3.5 to 5, and the insoluble OVA-FUC binary complex was generated at the pH of 2.5 to 3.5. The OVA-FUC binary complex (19 ± 0.29 mN/m) possessed a medium ability to reduce interfacial tension of the water-oil interface compared with OVA (15 ± 1.13 mN/m) and FUC (24 ± 0.3 mN/m), indicating that OVA-FUC binary complex has good amphiphilicity and can be applied as a potential pH-controlled emulsifier in function food systems for delivering bioactive substances.

Ti3C2Tx MXenes bonded MoS2 nanosheets for superior sodium-ion batteries

Sodium-ion batteries (SIBs) have evolved into the most potential alternatives to lithium-ion batteries (LIBs) especially for large-scale energy storage applications. However, the large radius of sodium ion inevitably causes large volume change and sluggish ion diffusion kinetics. Molybdenum disulfide (MoS2) as a rising star of anode for SIBs has raised concern because of its high theoretical capacity. Nevertheless, MoS2 suffers from low electronic conductivity and serious re-stacking, resulting in declined cycling stability and poor rate capability. Herein, we reported an electrostatic self-assembly process to synthesize three-dimensional (3D) crumpled MXene-bonded MoS2 nanosheets. The MoS2/MXene heterostructure not only avoids the serious self-aggregation of MoS2 nanoparticles but only maintains the chemical and mechanical stability of MoS2/MXene hybrids during sodiation and desodiation. Strong chemical interactions were validated on the interface of MXene and MoS2, favoring fast charge transfer kinetics and durable structural stability. The developed MoS2/MXene electrode exhibits a high specific capacity (509 mAh g−1 at 0.05 A g−1) and considerable cyclability (326 mAh g−1 at 1 A g−1 after 900 cycles), manifesting a promising application prospect for SIBs. Our work can provide a rational strategy for the electrode design strategy for SIBs.

In situ modification of MXene nanosheets with polyaniline nanorods for lightweight and broadband electromagnetic wave absorption

MXene exhibits excellent electromagnetic (EM) wave attenuation ability, but its high dielectric constant is prone to impedance mismatch. Usually, the introduction of other components can adjust EM parameters and improve the impedance matching of MXene. In this paper, MXene/polyaniline (PANI) composites with lots of heterogeneous interfaces were designed and prepared by electrostatic self-assembly process, and PANI was used as impedance matching modifier of MXene to adjust the impedance matching of the composites and achieve greater reflection loss. The effect of the content of PANI nanorods loaded on MXene nanosheets on the EM properties of the material was discussed in this work. The maximum reflection loss (RLmax) of −60.6 dB corresponds to an effective absorption bandwidth (EAB) of 6.0 GHz for the composite with only 10% PANI loading, while the EAB reaches 8.64 GHz when the sample thickness is 2.3 mm. Moreover, the introduction of PANI balances the impedance matching of MXene while bridging individual MXene nanosheets to form a three-dimensional structure that increases the EM wave propagation path. The rich loss mechanisms such as interfacial polarization and dipole polarization provide effective attenuation of EM waves. This work provides a simple way to develop lightweight and broadband EM wave absorption materials.

Self-Assembly TiNb2O7@MXene Anode Material for Fast and Stable Lithium Storage

TiNb2O7 (TNO) is a high-specific-capacity intercalation-type anodic material with excellent cycle performance and appropriate working potential (∼1.6 V vs Li+/Li). However, its low electronic conductivity and lithium-ion diffusion coefficient can lead to poor kinetics, which has become a bottleneck that needs to be urgently addressed for the further development of TiNb2O7. Herein, a unique MXene encapsulating TNO particles (TNO@MXene) was fabricated through a simple electrostatic self-assembly process. The MXene nanosheets act as the underlying conductive substrate, which can not only enable reversible fast electron and ion transport at the interface and enhance the electrochemical activity of TNO but also prevent TNO particles from aggregating during lithiation/delithiation. Consequently, the TNO@MXene composite exhibits significantly improved lithium storage characteristics compared with those of pristine TNO, such as high reversible capacity (346.4 mA h g–1 at 0.1C), excellent cycling stability (92.3% capacity retention after 500 cycles at 10C), and exceptional superior rate capability (166 mA h g–1 at 20C). These findings proved the efficacy of the MXene substrate in enhancing the lithium-ion storage capabilities of TNO and may encourage the fabrication of high-power lithium-ion batteries.