Single Carbon Fibers with a Macroscopic-Thickness, 3D Highly Porous Carbon Nanotube Coating

Porous Conductive Textiles for Wearable Electronics

Over the years, researchers have made significant strides in the development of novel flexible/stretchable and conductive materials, enabling the creation of cutting-edge electronic devices for wearable applications. Among these, porous conductive textiles (PCTs) have emerged as an ideal material platform for wearable electronics, owing to their light weight, flexibility, permeability, and wearing comfort. This Review aims to present a comprehensive overview of the progress and state of the art of utilizing PCTs for the design and fabrication of a wide variety of wearable electronic devices and their integrated wearable systems. To begin with, we elucidate how PCTs revolutionize the form factors of wearable electronics. We then discuss the preparation strategies of PCTs, in terms of the raw materials, fabrication processes, and key properties. Afterward, we provide detailed illustrations of how PCTs are used as basic building blocks to design and fabricate a wide variety of intrinsically flexible or stretchable devices, including sensors, actuators, therapeutic devices, energy-harvesting and storage devices, and displays. We further describe the techniques and strategies for wearable electronic systems either by hybridizing conventional off-the-shelf rigid electronic components with PCTs or by integrating multiple fibrous devices made of PCTs. Subsequently, we highlight some important wearable application scenarios in healthcare, sports and training, converging technologies, and professional specialists. At the end of the Review, we discuss the challenges and perspectives on future research directions and give overall conclusions. As the demand for more personalized and interconnected devices continues to grow, PCT-based wearables hold immense potential to redefine the landscape of wearable technology and reshape the way we live, work, and play.

Pore-Matched Sponge for Microorganisms Pushes Electron Extraction Limit in Microbial Fuel Cells

Microbial fuel cells (MFCs) are of great potential for wastewater remediation and chemical energy recovery. Nevertheless, limited by inefficient electron transfer between microorganisms and electrode, the remediation capacity and output power density of MFCs are still far away from the demand of practical application. Herein, a pore-matching strategy is reported to develop uniform electroactive biofilms by inoculating microorganisms inside a pore-matched sponge, which is assembled of core-shell polyaniline@carbon nanotube (PANI@CNT). The maximum power density achieved by the PANI@CNT bioanode is 7549.4 ± 27.6 mW m-2 , which is higher than the excellent MFCs with proton exchange membrane reported to date, while the coulombic efficiency also attains a considerable 91.7 ± 1.2%. The PANI@CNT sponge enriches the exoelectrogen Geobacter significantly, and is proved to play the role of conductive pili in direct electron transfer as it down-regulates the gene encoding pilA. This work exemplifies a practicable strategy to develop excellent bioanode to boost electron extraction in MFCs and provides in-depth insights into the enhancement mechanism.

Interfacial engineering of transition metal dichalcogenide/carbon heterostructures for electrochemical energy applications

To support the global goal of carbon neutrality, numerous efforts have been devoted to the advancement of electrochemical energy conversion (EEC) and electrochemical energy storage (EES) technologies. For these technologies, transition metal dichalcogenide/carbon (TMDC/C) heterostructures have emerged as promising candidates for both electrode materials and electrocatalysts over the past decade, due to their complementary advantages. It is worth noting that interfacial properties play a crucial role in establishing the overall electrochemical characteristics of TMDC/C heterostructures. However, despite the significant scientific contribution in this area, a systematic understanding of TMDC/C heterostructures' interfacial engineering is currently lacking. This literature review aims to focus on three types of interfacial engineering, namely interfacial orientation engineering, interfacial stacking engineering, and interfacial doping engineering, of TMDC/C heterostructures for their potential applications in EES and EEC devices. To accomplish this goal, a combination of experimental and theoretical approaches was used to allow the analysis and summary of the fundamental electrochemical properties and preparation strategies of TMDC/C heterostructures. Moreover, this review highlights the design and utilization of the interfacial engineering of TMDC/C heterostructures for specific EES and EEC devices. Finally, the challenges and opportunities of using interfacial engineering of TMDC/C heterostructures in practical EES and EEC devices are outlined. We expect that this review will effectively guide readers in their understanding, design, and application of interfacial engineering of TMDC/C heterostructures.

Fibril-Type Textile Electrodes Enabling Extremely High Areal Capacity through Pseudocapacitive Electroplating onto Chalcogenide Nanoparticle-Encapsulated Fibrils

Effective incorporation of conductive and energy storage materials into 3D porous textiles plays a pivotal role in developing and designing high-performance energy storage devices. Here, a fibril-type textile pseudocapacitor electrode with outstanding capacity, good rate capability, and excellent mechanical stability through controlled interfacial interaction-induced electroplating is reported. First, tetraoctylammonium bromide-stabilized copper sulfide nanoparticles (TOABr-CuS NPs) are uniformly assembled onto cotton textiles. This approach converts insulating textiles to conductive textiles preserving their intrinsically porous structure with an extremely large surface area. For the preparation of textile current collector with bulk metal-like electrical conductivity, Ni is additionally electroplated onto the CuS NP-assembled textiles (i.e., Ni-EPT). Furthermore, a pseudocapacitive NiCo-layered double hydroxide (LDH) layer is subsequently electroplated onto Ni-EPT for the cathode. The formed NiCo-LDH electroplated textiles (i.e., NiCo-EPT) exhibit a high areal capacitance of 12.2 F cm^-2 (at 10 mA cm^-2 ), good rate performance, and excellent cycling stability. Particularly, the areal capacity of NiCo-EPT can be further increased through their subsequent stacking. The 3-stack NiCo-EPT delivers an unprecedentedly high areal capacitance of 28.8 F cm^-2 (at 30 mA cm^-2 ), which outperforms those of textile-based pseudocapacitor electrodes reported to date.

Anchoring Oxidized MXene Nanosheets on Porous Carbon Nanotube Sponge for Enhancing Ion Transport and Pseudocapacitive Performance

Two-dimensional (2D) MXene nanosheets are attractive for electrochemical energy storage applications due to their superior surface-controlled charge storage capacity. However, the slow ion transport in the closely packed electrode limits their electrochemical performances. Meanwhile, the restricted surface-controlled pseudocapacitance of MXene nanosheets requires to be enhanced. Herein, a well-controlled electrophoretic deposition strategy is developed to disperse Ti₃C₂T_x nanosheets into a freestanding, porous carbon nanotube (CNT) sponge. The constructed Ti₃C₂T_x@CNT hybrid sponge can provide high-speed ion-transport pathways for the charge-discharge process. Furthermore, by tuning the deposition potential, the inserted MXene nanosheets can be partially oxidized, boosting the pseudocapacitance performance. A large gravimetric capacitance of 468 F g^-1 at 10 mV s^-1 and a retention of 79.8% at 100 mV s^-1 can be achieved in the Ti₃C₂T_x@CNT electrode. Meanwhile, the highest areal capacitance of 661 mF cm^-2 at 1 mA cm^-2 was obtained in the sample with high-loading Ti₃C₂T_x. For the assembled symmetric supercapacitor, 92.8% of the capacitance is retained after 10 000 cycles of the charge-discharge process at 10 mA cm^-2. Thus, this study develops a promising electrophoretic deposition strategy for dispersing 2D MXene nanosheets and boosting their pseudocapacitive performance, resulting in a high-capacitive electrochemical energy storage electrode.

Recent Advances in Functional Carbon Quantum Dots for Antitumour

Carbon quantum dots (CQDs) are an emerging class of quasi-zero-dimensional photoluminescent nanomaterials with particle sizes less than 10 nm. Owing to their favourable water dispersion, strong chemical inertia, stable optical performance, and good biocompatibility, CQDs have become prominent in biomedical fields. CQDs can be fabricated by “top-down” and “bottom-up” methods, both of which involve oxidation, carbonization, pyrolysis and polymerization. The functions of CQDs include biological imaging, biosensing, drug delivery, gene carrying, antimicrobial performance, photothermal ablation and so on, which enable them to be utilized in antitumour applications. The purpose of this review is to summarize the research progress of CQDs in antitumour applications from preparation and characterization to application prospects. Furthermore, the challenges and opportunities of CQDs are discussed along with future perspectives for precise individual therapy of tumours.

Decoration of amine functionalized zirconium metal organic framework/silver iodide heterojunction on carbon fiber cloth as a filter- membrane-shaped photocatalyst for degrading antibiotics

The development of recyclable photocatalyst with high adsorption and excellent photocatalytic performance has attracted considerable attention. Herein, we report a three-component photocatalyst by constructing porous amine functionalized zirconium metal organic framework (UiO-66-NH₂) and broad photo-responsive AgI on flexible carbon fiber cloth (CFC). UiO-66-NH₂ nanoparticles (200-400 nm) were in-situ grown on the surface of CFC (16.5 ± 0.5 μm, 4 × 4 cm²) by a solvothermal route, then AgI particles (50-100 nm) were synthesized on CFC/UiO-66-NH₂ via a modified chemical bath deposition method. The obtained CFC/UiO-66-NH₂/AgI can effectively adsorb 19.0% levofloxacin (LVFX) or 18.4% ciprofloxacin (CIP) in 60 min in the dark and degrade 84.5% LVFX or 79.6% CIP in 120 min under visible light irradiation. Furthermore, the filter-membrane-shaped CFC/UiO-66-NH₂/AgI can be utilized to treat the flowing sewage (CIP, 10 mg/L, ~1 L/h), and the removing efficiency of CIP reached 71.0% after 10 grades. Therefore, this work demonstrates the huge application prospect of recyclable CFC/UiO-66-NH₂/AgI with high adsorption and photocatalytic capacity in flowing sewage treatment under visible light illumination.

Application-Driven Carbon Nanotube Functional Materials

Carbon nanotube functional materials (CNTFMs) represent an important research field in transforming nanoscience and nanotechnology into practical applications, with potential impact in a wide realm of science, technology, and engineering. In this review, we combine the state-of-the-art research activities of CNTFMs with the application prospect, to highlight critical issues and identify future challenges. We focus on macroscopic long fibers, thin films, and bulk sponges which are typical CNTFMs in different dimensions with distinct characteristics, and also cover a variety of derived composite/hierarchical materials. Critical issues related to their structures, properties, and applications as robust conductive skeletons or high-performance flexible electrodes in mechanical and electronic devices, advanced energy conversion and storage systems, and environmental areas have been discussed specifically. Finally, possible solutions and directions are proposed for overcoming current obstacles and promoting future efforts in the field.

Superelastic and ultralight electrospun carbon nanofiber/MXene hybrid aerogels with anisotropic microchannels for pressure sensing and energy storage

As ultralight and superelastic aerogels are quite desirable for pressure sensing and energy storage applications, superelastic and ultralight carbon nanofiber (CNF)/transition metal carbides and carbonitrides (MXenes) hybrid aerogels with anisotropic microchannels are thus fabricated by liquid nitrogen-assisted unidirectional-freezing followed by freeze-drying. The CNFs with high aspect ratios entangle and assemble into the interconnected scaffolds, while the MXene sheets enhance structural stability of the framework of CNFs and endow the aerogels with satisfactory electronic conductivities. Benefiting from the stable architecture with orientated microchannels, the CNF/MXene aerogel (CNF/MX) with an ultralow density of 4.87 mg cm^-3 exhibits superb compressible resilience at the strain of 50% for at least 5000 cycles and a high strain of 95% for 500 cycles. Importantly, the outstanding strain- or pressure-responses endow the CNF/MX aerogel sensor with high sensitivity (65 kPa^-1), ultralow detection limit (<5 Pa), rapid response (26 ms), large workable strain range (0-95%), and superb response stability. Furthermore, the presence of MXene with excellent electrochemical activity makes the binder-free CNF/MX electrode exhibit a high rate performance with 80% capacitance retention when the current density increases by 100 times and a high cycling stability with capacitance retention of 90% after 20,000 cycles at 5 A g^-1.

Breakdown of Native Oxide Enables Multifunctional, Free-Form Carbon Nanotube-Metal Hierarchical Architectures

Passive oxide layers on metal substrates impose remarkable interfacial resistance for electron and phonon transport. Here, a scalable surface activation process is presented for the breakdown of the passive oxide layer and the formation of nanowire/nanopyramid structured surfaces on metal substrates, which enables high-efficiency catalysis of high-crystallinity carbon nanotubes (CNTs) and the direct integration of the CNT-metal hierarchical architectures with flexible free-form configurations. The CNT-metal hierarchical architecture facilitates a dielectric free-energy-carrier transport pathway and blocks the reformation of passive oxide layer, and thus demonstrates a 5-fold decrease in interfacial electrical resistance with 66% increase in specific surface area compared with those without surface activation. Moreover, the CNT-metal hierarchical architectures demonstrate omnidirectional blackbody photoabsorption with the reflectance of 1 × 10^-5 over the range from ultraviolet to terahertz region, which is 1 order of magnitude lower than that of any previously reported broadband absorber material. The synergistically incorporated CNT-metal hierarchical architectures offer record-high broadband optical absorption with excellent electrical and structural properties as well as industrial-scale producibility.

Temperature-Dependent Morphologies of Precursors: Metal-Organic Framework-Derived Porous Carbon for High-Performance Electrochemical Double-Layer Capacitors

In this work, three Cu metal-organic framework samples with tunable rhombic, squama, and trucated bipyramid morphologies have been synthesized at 0, 25, and 60 °C, respectively, and further employed as precursors to initially prepare Cu@C composites by the calcination-thermolysis procedure. Then Cu@C composites have been etched with HCl and subsequently activated with KOH to obtain activated porous carbon (APC-0, -25, and -60). Interestingly, APC-25 presents a loose multilevel morphology of cabbage and possesses the largest specific surface area (1880.4 m² g^-1) and pore volume (0.81 cm³ g^-1) among these APC materials. Consequently, APC-25 also exhibits the highest specific capacitance of 196 F g^-1 at 0.5 A g^-1, and the corresponding symmetric supercapacitor cell (SSC) achieves a remarkable energy density of 11.8 Wh kg^-1 at a power density of 350 W kg^-1. Furthermore, APC-25 shows excellent cycling stability, and the loss of capacitance is only 7.7% even after 10000 cycles at 1 A g^-1. Significantly, five light-emitting diodes can be lit by six SSCs, which proves that APC-25 can be used in energy storage devices.

High-performance supercapacitors based on hierarchically porous carbons with a three-dimensional conductive network structure

Novel clews of carbon nanobelts (CsCNBs), which have high specific surface area, three-dimensional conductive network structure, hierarchically porous framework and excellent hydrophilicity, have been successfully prepared by carbonization and KOH activation.