Resilient bismuthene-graphene architecture for multifunctional energy storage and wearable ionic-type capacitive pressure sensor device

Hierarchical Iontronic Flexible Sensor with High Sensitivity over Ultrabroad Range Enabled by Equilibration of Microstructural Compressibility and Stability

Despite improved sensitivity of iontronic pressure sensors with microstructures, structural compressibility and stability issues hinder achieving exceptional sensitivity across a wide pressure range. Herein, the interplay between ion concentration, mechanical properties, structural geometry, and aspect ratio (AR) on the sensitivity of lithium bis(trifluoromethanesulfonyl) imide/thermoplastic polyurethane (LiTFSI/TPU) ionogel is delved into. The results indicate that cones exhibit superior compressibility compared to pyramids and hemispheres, manifesting in an enhanced sensitivity toward the LiTFSI/TPU ionogel. Subsequently, by strategically combining cones with varying ARs, a harmonious balance between structural stability and compressibility is achieved, culminating in the fabrication of hierarchical iontronic flexible sensors (HIFS). Remarkably, HIFS-III with a three-level hierarchical conical microstructure demonstrates a preeminent sensitivity of 127.65 kPa-1 within ∼500 kPa. Even within the ultrabroad pressure range of 1500-3000 kPa, the sensitivity remains exceeding 10 kPa-1. Furthermore, HIFS-III boasts swift response and relaxation times (∼11 and 18 ms, respectively), a low detection limit (∼6.35 Pa), as well as remarkable durability (15,000 cycles). The exceptional sensing capabilities of HIFS-III underscore its emergence as a promising high-performance sensing and feedback solution tailored for applications in human-machine interaction and e-skin.

Recent Progress on Flexible Self-Powered Tactile Sensing Platforms for Health Monitoring and Robotics

Over the past decades, tactile sensing technology has made significant advances in the fields of health monitoring and robotics. Compared to conventional sensors, self-powered tactile sensors do not require an external power source to drive, which makes the entire system more flexible and lightweight. Therefore, they are excellent candidates for mimicking the tactile perception functions for wearable health monitoring and ideal electronic skin (e-skin) for intelligent robots. Herein, the working principles, materials, and device fabrication strategies of various self-powered tactile sensing platforms are introduced first. Then their applications in health monitoring and robotics are presented. Finally, the future prospects of self-powered tactile sensing systems are discussed.

Incorporating Machine Learning Strategies to Smart Gloves Enabled by Dual-Network Hydrogels for Multitask Control and User Identification

Smart gloves are often used in human-computer interaction scenarios due to their portability and ease of integration. However, their application in the field of information security has been less studied. Herein, we propose a smart glove using an iontronic capacitive sensor with significant pressure-sensing performance. Besides, an operator interface has been developed to match the smart glove, which is capable of multitasking integration of mouse movement, music playback, game control, and message typing in Internet chat rooms by capturing and encoding finger-tapping movements. In addition, by integrating machine learning, we can mine the characteristics of individual behavioral habits contained in the sensor signals and, based on this, achieve a deep binding of the user to the smart glove. The proposed smart glove can greatly facilitate people's lives, as well as explore a new strategy in research on the application of smart gloves in data security.

Tactile corpuscle-inspired piezoresistive sensors based on (3-aminopropyl) triethoxysilane-enhanced CNPs/carboxylated MWCNTs/cellulosic fiber composites for textile electronics

Recently, wearable electronic products and gadgets have developed quickly with the aim of catching up to or perhaps surpassing the ability of human skin to perceive information from the external world, such as pressure and strain. In this study, by first treating the cellulosic fiber (modal textile) substrate with (3-aminopropyl) triethoxysilane (APTES) and then covering it with conductive nanocomposites, a bionic corpuscle layer is produced. The sandwich structure of tactile corpuscle-inspired bionic (TCB) piezoresistive sensors created with the layer-by-layer (LBL) technology consists of a pressure-sensitive module (a bionic corpuscle), interdigital electrodes (a bionic sensory nerve), and a PU membrane (a bionic epidermis). The synergistic mechanism of hydrogen bond and coupling agent helps to improve the adhesive properties of conductive materials, and thus improve the pressure sensitive properties. The TCB sensor possesses favorable sensitivity (1.0005 kPa-1), a wide linear sensing range (1700 kPa), and a rapid response time (40 ms). The sensor is expected to be applied in a wide range of possible applications including human movement tracking, wearable detection system, and textile electronics.

Recent Trends in Supercapacitor Research: Sustainability in Energy and Materials

Supercapacitors (SCs) have emerged as critical components in applications ranging from transport to wearable electronics due to their rapid charge-discharge cycles, high power density, and reliability. This review offers an analysis of recent strides in supercapacitor research, emphasizing pivotal developments in sustainability, electrode materials, electrolytes, and 'smart SCs' designed for modern microelectronics with attributes such as flexibility, stretchability, and biocompatibility. Central to this discourse are two dominant electrode materials: carbon materials (CMs), primarily in electric double layer capacitors (EDLCs), and pseudocapacitive materials, involving oxides/hydroxides, chalcogenides, metal-organic frameworks, conductive polymers and metal nitrides such as MXene. Despite EDLCs' historical use, challenges such as low energy density persist, with heteroatom introduction into the carbon lattice seen as a solution. Concurrently, pseudocapacitive materials dominate recent studies, with efficiency enhancement strategies, such as the creation of hybrids based on different types of materials, surface structural engineering and doping, under exploration. Electrolyte innovation, especially the shift towards gel polymer electrolytes for flexible SCs, and the harmonization of electrode materials with SC designs are highlighted. Emphasis is given to smart SCs with novel attributes such as self-charging, self-healing, biocompatibility, and environmentally conscious designs. In summary, the article underscores the drive in sustainable supercapacitor research to achieve high energy and power density, steering towards SCs that are efficient and versatile and involving bioderived/biocompatible SC materials. This brief review is based on selected recent references, offering depth combined with an accessible overview of the SC landscape.

Photocatalytic Enhancement Strategy with the Introduction of Metallic Bi: A Review on Bi/Semiconductor Photocatalysts

Semiconductor photocatalysis has great potential in the fields of solar fuel production and environmental remediation. Nevertheless, the photocatalytic efficiency still constrains its practical production applications. The development of new semiconductor materials is essential to enhance the solar energy conversion efficiency of photocatalytic systems. Recently, the research on enhancing the photocatalytic performance of semiconductors by introducing bismuth (Bi) has attracted widespread attention. In this review, we briefly overview the main synthesis methods of Bi/semiconductor photocatalysts and summarize the control of the micromorphology of Bi in Bi/semiconductors and the key role of Bi in the catalytic system. In addition, the promising applications of Bi/semiconductors in photocatalysis, such as pollutant degradation, sterilization, water separation, CO2 reduction, and N2 fixation, are outlined. Finally, an outlook on the challenges and future research directions of Bi/semiconductor photocatalysts is given. We aim to offer guidance for the rational design and synthesis of high-efficiency Bi/semiconductor photocatalysts for energy and environmental applications.

Recent Development Strategies for Bismuth-Driven Materials in Sustainable Energy Systems and Environmental Restoration

Bismuth(Bi)-based materials have gained considerable attention in recent decades for use in a diverse range of sustainable energy and environmental applications due to their low toxicity and eco-friendliness. Bi materials are widely employed in electrochemical energy storage and conversion devices, exhibiting excellent catalytic and non-catalytic performance, as well as CO₂ /N₂ reduction and water treatment systems. A variety of Bi materials, including its oxides, chalcogenides, oxyhalides, bismuthates, and other composites, have been developed for understanding their physicochemical properties. In this review, a comprehensive overview of the properties of individual Bi material systems and their use in a range of applications is provided. This review highlights the implementation of novel strategies to modify Bi materials based on morphological and facet control, doping/defect inclusion, and composite/heterojunction formation. The factors affecting the development of different classes of Bi materials and how their control differs between individual Bi compounds are also described. In particular, the development process for these material systems, their mass production, and related challenges are considered. Thus, the key components in Bi compounds are compared in terms of their properties, design, and applications. Finally, the future potential and challenges associated with Bi complexes are presented as a pathway for new innovations.

2D Layers of Group VA Semiconductors: Fundamental Properties and Potential Applications

Members of the 2D group VA semiconductors (phosphorene, arsenene, antimonene, and bismuthine) present a new class of 2D materials, which are recently gaining a lot of research interest. These materials possess layered morphology, tunable direct bandgap, high charge carrier mobility, high stability, unique in-plane anisotropy, and negative Poisson's ratio. They prepare the ground for novel and multifunctional applications in electronics, optoelectronics, and batteries. The most recent analytical and empirical developments in the fundamental characteristics, fabrication techniques, and potential implementation of 2D group VA materials in this review, along with presenting insights and concerns for the field's future are analyzed.

Multifunctional Integrated Interdigital Microsupercapacitors and Self-Powered Iontronic Tactile Pressure Sensor for Wearable Electronics

Multifunctionality and self-powering are key technologies for next-generation wearable electronics. Herein, an interdigitated MXene/TiS₂-based self-powered intelligent pseudocapacitive iontronic sensor system is designed, realizing integration of energy storage and pressure-sensitive sensing function into one device. The intercalation of TiS₂ nanosheet can effectively prevent self-stacking of MXene and results in mesoporous cross-linked framework, therefore exposing more active sites and broadening the electron/ion transport channels. The pressure sensing performance together with developed all-solid-state microsupercapacitor is explored systematically. When applied in a symmetrical microsupercapacitor, it presents a satisfactory energy density of 31.6 Wh/kg at 400 W/kg and 79.8% capacitance retention after 10 000 cycles. Meanwhile, with MXene/TiS₂//MXene/TiS₂ interdigitated structure as flexible self-powering pressure sensor, it illustrates outstanding pressure-sensing response toward external pressure, realizing accurate and continuous detection of human body motion signals. It is believed that this work proposes a feasible strategy by integrating pressure-sensing with a self-powering function for the next-generation self-powered E-skin electronics.

Highly Compressible Elastic Aerogel Spring-Based Piezoionic Self-Powering Pressure Sensor for Multifunctional Wearable Electronics

To meet the rapid development of wearable flexible electronics, the multifunctional integrations into singe device are in extreme demand. In this paper, we developed novel self-powering multifunctional pressure sensors and supercapacitor-integrated device based on highly elastic silver nanowires@reduced graphene aerogel, being conductive to reduce integration difficulties and device size. Serving as an energy device, it behaves with a prominent specific capacitance of 146.6 F g−1, and excellent rate capability even at 500 mV s−1. The fabricated sensor demonstrates an excellent sensitivity of 2.54 kPa−1 and superior pressure-sensing stability up to 1000 compressive cycles. Piezoionization effect is suggested to reveal the sensing mechanism. Our research provides a new research direction in designing the integration of self-driving wearable electronics.