The scalable and sustainable manufacture of thick electrode films with high energy and power densities is critical for the large-scale storage of electrochemical energy for application in transportation and stationary electric grids. Two-dimensional nanomaterials have become the predominant choice of electrode material in the pursuit of high energy and power densities owing to their large surface-area-to-volume ratios and lack of solid-state diffusion. However, traditional electrode fabrication methods often lead to restacking of two-dimensional nanomaterials, which limits ion transport in thick films and results in systems in which the electrochemical performance is highly dependent on the thickness of the film. Strategies for facilitating ion transport-such as increasing the interlayer spacing by intercalation or introducing film porosity by designing nanoarchitectures-result in materials with low volumetric energy storage as well as complex and lengthy ion transport paths that impede performance at high charge-discharge rates. Vertical alignment of two-dimensional flakes enables directional ion transport that can lead to thickness-independent electrochemical performances in thick films. However, so far only limited success has been reported, and the mitigation of performance losses remains a major challenge when working with films of two-dimensional nanomaterials with thicknesses that are near to or exceed the industrial standard of 100 micrometres. Here we demonstrate electrochemical energy storage that is independent of film thickness for vertically aligned two-dimensional titanium carbide (TiCT ), a material from the MXene family (two-dimensional carbides and nitrides of transition metals (M), where X stands for carbon or nitrogen). The vertical alignment was achieved by mechanical shearing of a discotic lamellar liquid-crystal phase of TiCT . The resulting electrode films show excellent performance that is nearly independent of film thickness up to 200 micrometres, which makes them highly attractive for energy storage applications. Furthermore, the self-assembly approach presented here is scalable and can be extended to other systems that involve directional transport, such as catalysis and filtration.
It is a challenge to manufacture pressure‐sensing materials that possess flexibility, high sensitivity, large‐area compliance, and capability to detect both tiny and large motions for the development of artificial intelligence products. Herein, a very simple and low‐cost approach is proposed to fabricate versatile pressure sensors based on microcrack‐designed carbon black (CB)@polyurethane (PU) sponges via natural polymer‐mediated water‐based layer‐by‐layer assembly. These sensors are capable of satisfying the requirements of ultrasmall as well as large motion monitoring. The versatility of these sensors benefits from two aspects: microcrack junction sensing mechanism for tiny motion detecting (91 Pa pressure, 0.2% strain) inspired by the spider sensory system and compressive contact of CB@PU conductive backbones for large motion monitoring (16.4 kPa pressure, 60% strain). Furthermore, these sensors exhibit excellent flexibility, fast response times (<20 ms), as well as good reproducibility over 50 000 cycles. This study also demonstrates the versatility of these sensors for various applications, ranging from speech recognition, health monitoring, bodily motion detection to artificial electronic skin. The desirable comprehensive performance of our sensors, which is comparable to the recently reported pressure‐sensing devices, together with their significant advantages of low‐cost, easy fabrication, especially versatility, makes them attractive in the future of artificial intelligence.
Soft actuation materials are highly desirable in flexible electronics, soft robotics, etc. However, traditional bilayered actuators usually suffer from poor mechanical properties as well as deteriorated performance reliability. Here, inspired by the delicate architecture of natural bamboo, we present a hierarchical gradient structured soft actuator via mesoscale assembly of micro–nano-scaled two-dimentional MXenes and one-dimentional cellulose nanofibers with molecular-scaled strong hydrogen bonding. The resultant actuator integrates high tensile strength (237.1 MPa), high Young’s modulus (8.5 GPa), superior toughness (10.9 MJ/m3), and direct and fast hygroscopic actuation within a single body, which is difficult to achieve by traditional bilayered actuators. The proof-of-concept prototype robot is demonstrated to emphasize its high mechanical robustness even after bending 100 000 times, kneading, or being trampled by an adult (7 500 000 times heavier than a crawling robot). This bioinspired mesoscale assembly strategy provides an approach for soft materials to the application of next-generation robust robotics.
Progress toward the integration of electronic sensors with a signal processing system is important for artificial intelligent and smart robotics. It demands mechanically robust, highly sensitive, and self-healable sensing materials which could generate discernible electric variations responding to external stimuli. Here, inspired by the supramolecular interactions of amino acid residues in proteins, we report a self-healable nanostructured Ti3C2MXenes/rubber-based supramolecular elastomer (NMSE) for intelligent sensing. MXene nanoflakes modified with serine through an esterification reaction assemble with an elastomer matrix, constructing delicate dynamic supramolecular hydrogen bonding interfaces. NMSE features desirable recovered toughness (12.34 MJ/m3) and excellent self-healing performance (∼100%) at room temperature. The NMSE-based sensor with high gauge factor (107.43), low strain detection limit (0.1%), and fast responding time (50 ms) can precisely detect subtle human motions (including speech, facial expression, pulse, and heartbeat) and moisture variations even after cut/healing processes. Moreover, NMSE-based sensors integrated with a complete signal process system show great feasibility for speech-controlled motions, which demonstrates promising potential in future wearable electronics and soft intelligent robotics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.