Search

Abstract High‑efficiency electromagnetic interference (EMI) shielding materials are of great importance for electronic equipment reliability, information security and human health. In this work, bidirectional aligned Ti3C2Tx@Fe3O4/CNF aerogels (BTFCA) were firstly assembled by bidirectional freezing and freeze-drying technique, and the BTFCA/epoxy nanocomposites with long-range aligned lamellar structures were then prepared by vacuum-assisted impregnation of epoxy resins. Benefitting from the successful construction of bidirectional aligned three-dimensional conductive networks and electromagnetic synergistic effect, when the mass fraction of Ti3C2Tx and Fe3O4 are 2.96 and 1.48 wt%, BTFCA/epoxy nanocomposites show outstanding EMI shielding effectiveness of 79 dB, about 10 times of that of blended Ti3C2Tx@Fe3O4/epoxy (8 dB) nanocomposites with the same loadings of Ti3C2Tx and Fe3O4. Meantime, the corresponding BTFCA/epoxy nanocomposites also present excellent thermal stability (T heat-resistance index of 198.7 °C) and mechanical properties (storage modulus of 9902.1 MPa, Young's modulus of 4.51 GPa and hardness of 0.34 GPa). Our fabricated BTFCA/epoxy nanocomposites would greatly expand the applications of MXene and epoxy resins in the fields of information security, aerospace and weapon manufacturing, etc.

Highlights: Ti3C2Tx@Fe3O4/CNF aerogels (BTFCA)/epoxy electromagnetic interference (EMI) shielding nanocomposites with long-range aligned lamellar structures were prepared by bidirectional freezing, freeze-drying and vacuum-assisted impregnation of epoxy resins. Successful construction of 3D long-range aligned lamellar structures and electromagnetic synergistic effect could significantly increase the EMI shielding effectiveness and reduce the secondary contamination. BTFCA/epoxy EMI shielding nanocomposites possessed outstanding EMI shielding effectiveness of 79 dB, and also presented excellent thermal stabilities and mechanical properties. High‑efficiency electromagnetic interference (EMI) shielding materials are of great importance for electronic equipment reliability, information security and human health. In this work, bidirectional aligned Ti3C2Tx@Fe3O4/CNF aerogels (BTFCA) were firstly assembled by bidirectional freezing and freeze-drying technique, and the BTFCA/epoxy nanocomposites with long-range aligned lamellar structures were then prepared by vacuum-assisted impregnation of epoxy resins. Benefitting from the successful construction of bidirectional aligned three-dimensional conductive networks and electromagnetic synergistic effect, when the mass fraction of Ti3C2Tx and Fe3O4 are 2.96 and 1.48 wt%, BTFCA/epoxy nanocomposites show outstanding EMI shielding effectiveness of 79 dB, about 10 times of that of blended Ti3C2Tx@Fe3O4/epoxy (8 dB) nanocomposites with the same loadings of Ti3C2Tx and Fe3O4. Meantime, the corresponding BTFCA/epoxy nanocomposites also present excellent thermal stability (Theat-resistance index of 198.7 °C) and mechanical properties (storage modulus of 9902.1 MPa, Young's modulus of 4.51 GPa and hardness of 0.34 GPa). Our fabricated BTFCA/epoxy nanocomposites would greatly expand the applications of MXene and epoxy resins in the fields of information security, aerospace and weapon manufacturing, etc. [ABSTRACT FROM AUTHOR]

Abstract High-performance electromagnetic wave absorption and electromagnetic interference (EMI) shielding materials with multifunctional characters have attracted extensive scientific and technological interest, but they remain a huge challenge. Here, we reported an electrostatic assembly approach for fabricating 2D/1D/0D construction of Ti3C2Tx/carbon nanotubes/Co nanoparticles (Ti3C2Tx/CNTs/Co) nanocomposites with an excellent electromagnetic wave absorption, EMI shielding efficiency, flexibility, hydrophobicity, and photothermal conversion performance. As expected, a strong reflection loss of -85.8 dB and an ultrathin thickness of 1.4 mm were achieved. Meanwhile, the high EMI shielding efficiency reached 110.1 dB. The excellent electromagnetic wave absorption and shielding performances were originated from the charge carriers, electric/magnetic dipole polarization, interfacial polarization, natural resonance, and multiple internal reflections. Moreover, a thin layer of polydimethylsiloxane rendered the hydrophilic hierarchical Ti3C2Tx/CNTs/Co hydrophobic, which can prevent the degradation/oxidation of the MXene in high humidity condition. Interestingly, the Ti3C2Tx/CNTs/Co film exhibited a remarkable photothermal conversion performance with high thermal cycle stability and tenability. Thus, the multifunctional Ti3C2Tx/CNTs/Co nanocomposites possessing a unique blend of outstanding electromagnetic wave absorption and EMI shielding, light-driven heating performance, and flexible water-resistant features were highly promising for the next-generation intelligent electromagnetic attenuation system. Highlights The 2D/1D/0D Ti3C2Tx/carbon nanotubes/Co nanocomposite is successfully synthesized via an electrostatic assembly. Nanocomposites exhibit an excellent electromagnetic wave absorption and a remarkable electromagnetic interference shielding efficiency. The flexible, waterproof, and photothermal conversion performances are achieved.

Highlights: Ti3C2Tx MXene-based coaxial zinc-ion hybrid fiber supercapacitors (FSCs) were fabricated with braided structure, which can be prepared continuously and present excellent flexibility and ultrastability. A sports watch driven by the watch belts which weaved uses the obtained zinc-ion hybrid FSC and LED arrays lighted by the FSCs under embedding into textiles, demonstrating the great potential application in smart wearable textiles. Zinc-ion hybrid fiber supercapacitors (FSCs) are promising energy storages for wearable electronics owing to their high energy density, good flexibility, and weavability. However, it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs. Herein, we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti3C2Tx MXene cathode as core electrodes, and shell zinc fiber anode was braided on the surface of the Ti3C2Tx MXene fibers across the solid electrolytes. According to the simulated results using ANSYS Maxwell software, the braided structures revealed a higher capacitance compared to the spring-like structures. The resulting FSCs exhibited a high areal capacitance of 214 mF cm–2, the energy density of 42.8 μWh cm−2 at 5 mV s−1, and excellent cycling stability with 83.58% capacity retention after 5000 cycles. The coaxial FSC was tied several kinds of knots, proving a shape-controllable fiber energy storage. Furthermore, the knitted FSC showed superior stability and weavability, which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days. [ABSTRACT FROM AUTHOR]

Highlights: Flexible Zn-ion hybrid micro-supercapacitors (MSCs) array was fabricated with Ti3C2Tx as the cathode via laser direct writing method, which present ultrastability up to 50,000 cycles after in-situ annealed treatment. A digital timer driven by the obtained single MSC under bending state, together with a flexible LED displayer of the “TiC” logo lighted by the MSC arrays under twisting, crimping and winding conditions demonstrate the great potential application of the MSCs in integrated wearable electronics.Zn-ion hybrid supercapacitors (SCs) are considered as promising energy storage owing to their high energy density compared to traditional SCs. How to realize the miniaturization, patterning, and flexibility of the Zn-ion SCs without affecting the electrochemical performances has special meanings for expanding their applications in wearable integrated electronics. Ti3C2Tx cathode with outstanding conductivity, unique lamellar structure and good mechanical flexibility has been demonstrated tremendous potential in the design of Zn-ion SCs, but achieving long cycling stability and high rate stability is still big challenges. Here, we proposed a facile laser writing approach to fabricate patterned Ti3C2Tx-based Zn-ion micro-supercapacitors (MSCs), followed by the in-situ anneal treatment of the assembled MSCs to improve the long-term stability, which exhibits 80% of the capacitance retention even after 50,000 charge/discharge cycles and superior rate stability. The influence of the cathode thickness on the electrochemical performance of the MSCs is also studied. When the thickness reaches 0.851 µm the maximum areal capacitance of 72.02 mF cm−2 at scan rate of 10 mV s−1, which is 1.77 times higher than that with a thickness of 0.329 µm (35.6 mF cm−2). Moreover, the fabricated Ti3C2Tx based Zn-ion MSCs have excellent flexibility, a digital timer can be driven by the single device even under bending state, a flexible LED displayer of “TiC” logo also can be easily lighted by the MSC arrays under twisting, crimping, and winding conditions, demonstrating the scalable fabrication and application of the fabricated MSCs in portable electronics. [ABSTRACT FROM AUTHOR]

High-performance electromagnetic wave absorption and electromagnetic interference (EMI) shielding materials with multifunctional characters have attracted extensive scientific and technological interest, but they remain a huge challenge. Here, we reported an electrostatic assembly approach for fabricating 2D/1D/0D construction of Ti3C2Tx/carbon nanotubes/Co nanoparticles (Ti3C2Tx/CNTs/Co) nanocomposites with an excellent electromagnetic wave absorption, EMI shielding efficiency, flexibility, hydrophobicity, and photothermal conversion performance. As expected, a strong reflection loss of -85.8 dB and an ultrathin thickness of 1.4 mm were achieved. Meanwhile, the high EMI shielding efficiency reached 110.1 dB. The excellent electromagnetic wave absorption and shielding performances were originated from the charge carriers, electric/magnetic dipole polarization, interfacial polarization, natural resonance, and multiple internal reflections. Moreover, a thin layer of polydimethylsiloxane rendered the hydrophilic hierarchical Ti3C2Tx/CNTs/Co hydrophobic, which can prevent the degradation/oxidation of the MXene in high humidity condition. Interestingly, the Ti3C2Tx/CNTs/Co film exhibited a remarkable photothermal conversion performance with high thermal cycle stability and tenability. Thus, the multifunctional Ti3C2Tx/CNTs/Co nanocomposites possessing a unique blend of outstanding electromagnetic wave absorption and EMI shielding, light-driven heating performance, and flexible water-resistant features were highly promising for the next-generation intelligent electromagnetic attenuation system. Highlights: The 2D/1D/0D Ti3C2Tx/carbon nanotubes/Co nanocomposite is successfully synthesized via an electrostatic assembly. Nanocomposites exhibit an excellent electromagnetic wave absorption and a remarkable electromagnetic interference shielding efficiency. The flexible, waterproof, and photothermal conversion performances are achieved. [ABSTRACT FROM AUTHOR]

Highlights: The traditional and novel etching methods are summarized and compared, especially fluorine-free method. The methods for accelerating exfoliation of Ti3C2Tx are classified. The energy storage mechanisms of Ti3C2Tx in different electrolytes are compared. Based on energy storage mechanisms, the influencing factors of morphology and surface functional groups are discussed. In response to the problems of the Ti3C2Tx, strategies for improving capacitance from structure modulation to composite structure construction are summarized and compared.Ti3C2Tx, a novel two-dimensional layer material, is widely used as electrode materials of supercapacitor due to its good metal conductivity, redox reaction active surface, and so on. However, there are many challenges to be addressed which impede Ti3C2Tx obtaining the ideal specific capacitance, such as restacking, re-crushing, and oxidation of titanium. Recently, many advances have been proposed to enhance capacitance performance of Ti3C2Tx. In this review, recent strategies for improving specific capacitance are summarized and compared, for example, film formation, surface modification, and composite method. Furthermore, in order to comprehend the mechanism of those efforts, this review analyzes the energy storage performance in different electrolytes and influencing factors. This review is expected to predict redouble research direction of Ti3C2Tx materials in supercapacitors. [ABSTRACT FROM AUTHOR]