Functional 2D MXene Inks for Wearable Electronics

MXene-Based Micro-Supercapacitors: Ink Rheology, Microelectrode Design and Integrated System

MXenes have shown great potential for micro-supercapacitors (MSCs) due to the high metallic conductivity, tunable interlayer spacing and intercalation pseudocapacitance. In particular, the negative surface charge and high hydrophilicity of MXenes make them suitable for various solution processing strategies. Nevertheless, a comprehensive review of solution processing of MXene MSCs has not been conducted. In this review, we present a comprehensive summary of the state-of-the-art of MXene MSCs in terms of ink rheology, microelectrode design and integrated system. The ink formulation and rheological behavior of MXenes for different solution processing strategies, which are essential for high quality printed/coated films, are presented. The effects of MXene and its compounds, 3D electrode structure, and asymmetric design on the electrochemical properties of MXene MSCs are discussed in detail. Equally important, we summarize the integrated system and intelligent applications of MXene MSCs and present the current challenges and prospects for the development of high-performance MXene MSCs.

Large-Scale Fabrication of Tunable Sandwich-Structured Silver Nanowires and Aramid Nanofiber Films for Exceptional Electromagnetic Interference (EMI) Shielding

The recent advancements in communication technology have facilitated the widespread deployment of electronic communication equipment globally, resulting in the pervasive presence of electromagnetic pollution. Consequently, there is an urgent necessity to develop a thin, lightweight, efficient, and durable electromagnetic interference (EMI) shielding material capable of withstanding severe environmental conditions. In this paper, we propose an innovative and scalable method for preparing EMI shielding films with a tunable sandwich structure. The film possesses a nylon mesh (NM) backbone, with AgNWs serving as the shielding coating and aramid nanofibers (ANFs) acting as the cladding layer. The prepared film was thin and flexible, with a thickness of only 0.13 mm. AgNWs can easily form a conductive network structure, and when the minimum addition amount was 0.2 mg/cm2, the EMI SE value reached 28.7 dB, effectively shielding 99.884% of electromagnetic waves and thereby meeting the commercial shielding requirement of 20 dB. With an increase in dosage up to 1.0 mg/cm2, the EMI SE value further improved to reach 50.6 dB. The NAAANF film demonstrated remarkable robustness in the face of complex usage environments as a result of the outstanding thermal, acid, and alkali resistance properties of aramid fibers. Such a thin, efficient, and environmentally resistant EMI shielding film provided new ideas for the broad EMI shielding market.

Advances in the application of Mxene nanoparticles in wound healing

Skin is the largest organ of the human body. It plays a vital role as the body's first barrier: stopping chemical, radiological damage and microbial invasion. The importance of skin to the human body can never be overstated. Delayed wound healing after a skin injury has become a huge challenge in healthcare. In some situations, this can have very serious and even life-threatening effects on people's health. Various wound dressings have been developed to promote quicker wound healing, including hydrogels, gelatin sponges, films, and bandages, all work to prevent the invasion of microbial pathogens. Some of them are also packed with bioactive agents, such as antibiotics, nanoparticles, and growth factors, that help to improve the performance of the dressing it is added to. Recently, bioactive nanoparticles as the bioactive agent have become widely used in wound dressings. Among these, functional inorganic nanoparticles are favored due to their ability to effectively improve the tissue-repairing properties of biomaterials. MXene nanoparticles have attracted the interest of scholars due to their unique properties of electrical conductivity, hydrophilicity, antibacterial properties, and biocompatibility. The potential for its application is very promising as an effective functional component of wound dressings. In this paper, we will review MXene nanoparticles in skin injury repair, particularly its synthesis method, functional properties, biocompatibility, and application.

Papertronics: Marriage between Paper and Electronics Becoming a Real Scenario in Resource-Limited Settings

Integrating electronic applications with paper, placed next to or below printed images or graphics, can further expand the possible uses of paper substrates. Consuming paper as a substrate in the field of electronics can lead to significant innovations toward papertronics applications as paper comprises various advantages like being disposable, inexpensive, biodegradable, easy to handle, simple to use, and easily available. All of these advantages will definitely spur the advancement of the electronics field, but unfortunately, putting electronics on paper is not an easy task because, compared to plastics, the paper surface is not just rough but also porous. For example, in the case of lateral flow assay testing the sensor response is delayed if the pore size of the paper is enormous. This might be a disadvantage for most electrical devices printed directly on paper. Still, some methods make it compatible when fit with a rough, absorbent surface of the paper. Building electronic devices on a standard paper substrate have sparked much interest because of its lightweight, environmental friendliness, minimal cost, and simple fabrication. A slew of improvements have been achieved in recent years to make paper electronics perform better in various applications, including transistors, batteries, and displays. In addition, flexible electronics have gained much interest in human-machine interaction and wireless sensing. This review briefly examines the origins and fabrication of paper electronics and then moves on to applications and exciting possible paths for paper-based electronics.

Application of Titanium Carbide MXenes in Chemiresistive Gas Sensors

The titanium carbide MXenes currently attract an extreme amount of interest from the material science community due to their promising functional properties arising from the two-dimensionality of these layered structures. In particular, the interaction between MXene and gaseous molecules, even at the physisorption level, yields a substantial shift in electrical parameters, which makes it possible to design gas sensors working at RT as a prerequisite to low-powered detection units. Herein, we consider to review such sensors, primarily based on Ti₃C₂T_x and Ti₂CT_x crystals as the most studied ones to date, delivering a chemiresistive type of signal. We analyze the ways reported in the literature to modify these 2D nanomaterials for (i) detecting various analyte gases, (ii) improving stability and sensitivity, (iii) reducing response/recovery times, and (iv) advancing a sensitivity to atmospheric humidity. The most powerful approach based on designing hetero-layers of MXenes with other crystals is discussed with regard to employing semiconductor metal oxides and chalcogenides, noble metal nanoparticles, carbon materials (graphene and nanotubes), and polymeric components. The current concepts on the detection mechanisms of MXenes and their hetero-composites are considered, and the background reasons for improving gas-sensing functionality in the hetero-composite when compared with pristine MXenes are classified. We formulate state-of-the-art advances and challenges in the field while proposing some possible solutions, in particular via employing a multisensor array paradigm.