Applications In Wearable Electronics Research Articles

Programmable and flexible wood-based origami electronics

Natural polymer substrates are gaining attention as substitutes for plastic substrates in electronics, aiming to combine high performance, intricate shape deformation, and environmental sustainability. Herein, natural wood veneer is converted into a transparent wood film (TWF) substrate. The combination of 3D printing and origami technique is established to create programmable wood-based origami electronics, which exhibit superior flexibility with high tensile strength (393 MPa) due to the highly aligned cellulose fibers and the formation of numerous intermolecular hydrogen bonds between them. Moreover, the flexible TWF electronics exhibit editable multiplexed configurations and maintain stable conductivity. This is attributed to the strong adhesion between the cellulose-based ink and TWF substrate by non-covalent bonds. Benefiting from its anisotropic structure, the programmability of TWF electronics is achieved through sequentially folding into predesigned shapes. This design not only promotes environmental sustainability but also introduces its customizable shapes with potential applications in sensors, microfluidics, and wearable electronics.

Robust and Reversible Thermal/Electro‐Responsive Supramolecular Polymeric Adhesives via Synergistic Hydrogen‐Bonds and Ionic Junctions

Adhesive conducting elastomers are rising materials towards cutting‐edge applications in wearable and implantable soft electronics. Yet, engineering the conductive adhesives with robust and tunable interfacial bonding strength is still in its infancy stage. We herein identify a structurally novel supramolecular polymer scaffold, characterized by synergistic coexistence of hydrogen‐bonding (H‐bonding) interactions and electrostatic ionic junctions, endowing the robust and tunable elastic conducting adhesives with remarkable thermal/electro‐responsive performance. H‐bonding association and electrostatic interaction play orthogonal yet synergistic roles in the strong supramolecular adhesive formation, serving as the leveraging forces for opposing both cohesion and adhesion energy. To do so, six‐arm star‐shaped random copolymers P(DAP‐co‐Thy‐co‐MBT)6 are strategically designed, bearing H‐bonding PDAP (poly(diaminopyridine acrylamide)) and PThy (poly(thymine)) segments, which can form hetero‐complementary DAP/Thy H‐bonding association, along with conductive poly(ionic liquid)s segment: PMBT, (poly(1‐[2‐methacryloylethyl]‐3‐methylimidazolium bis(trifluoromethane)‐sulfonamide)). DAP/Thy H‐bonding association, along with electrostatic ionic interaction, can yield dual supramolecular forces crosslinked polymeric networks with robust cohesion energy. Moreover, coexistence of poly(ionic liquid)s can impact and interfere the configuration of H‐bonding association, liberate more free DAP and Thy motifs to form H‐bonds towards substrate, affording strong surface adhesion in a synergistic manner. This work demonstrates a significant forward step towards potential adhesives devoted to hybrid electronic devices.

Robust and Reversible Thermal/Electro-Responsive Supramolecular Polymeric Adhesives via Synergistic Hydrogen-Bonds and Ionic Junctions.

Adhesive conducting elastomers are rising materials towards cutting-edge applications in wearable and implantable soft electronics. Yet, engineering the conductive adhesives with robust and tunable interfacial bonding strength is still in its infancy stage. We herein identify a structurally novel supramolecular polymer scaffold, characterized by synergistic coexistence of hydrogen-bonding (H-bonding) interactions and electrostatic ionic junctions, endowing the robust and tunable elastic conducting adhesives with remarkable thermal/electro-responsive performance. H-bonding association and electrostatic interaction play orthogonal yet synergistic roles in the strong supramolecular adhesive formation, serving as the leveraging forces for opposing both cohesion and adhesion energy. To do so, six-arm star-shaped random copolymers P(DAP-co-Thy-co-MBT)6 are strategically designed, bearing H-bonding PDAP (poly(diaminopyridine acrylamide)) and PThy (poly(thymine)) segments, which can form hetero-complementary DAP/Thy H-bonding association, along with conductive poly(ionic liquid)s segment: PMBT, (poly(1-[2-methacryloylethyl]-3-methylimidazolium bis(trifluoromethane)-sulfonamide)). DAP/Thy H-bonding association, along with electrostatic ionic interaction, can yield dual supramolecular forces crosslinked polymeric networks with robust cohesion energy. Moreover, coexistence of poly(ionic liquid)s can impact and interfere the configuration of H-bonding association, liberate more free DAP and Thy motifs to form H-bonds towards substrate, affording strong surface adhesion in a synergistic manner. This work demonstrates a significant forward step towards potential adhesives devoted to hybrid electronic devices.

Highly Stretchable Sensitive Multiscale Hydrogel Inspired by Biological Muscles for Wearing Sensors.

Hydrogels have attracted substantial research interest for application in wearable electronics due to their stretchability, elasticity, and compliance. However, most hydrogels could not satisfy the application requirements for high-performance wearable sensors due to their poor sensitivity, low mechanical properties, and sensing detection range until this day. Inspired by the fascia in biological muscles, we propose a strategy to form entangled "clusters" through the dense entanglement between highly cross-linked elastic hydrogel microspheres and polymer segments, and prepared a multiscale hydrogel with high sensitivity and mechanical toughness. This strategy embedded highly swollen hydrogel microspheres (with different pore sizes) to act as the microregions of dense entanglement in the soft matrix to adjust the microstructure of multiscale gel. When pressure was applied, this structure could provide a fast response due to the stack layer formed by microspheres and soft matrix produced effective stress distribution, resulting in the outstanding sensitivity of the multiscale hydrogel (S = 1.1 kPa-1) in the pressure range of 0-50 kPa. The distinct microspheres functioning as microscale joint areas significantly augment energy dissipation, culminating in exceptional mechanical stability, ultrastretchability (≈1050%), and high strength of the multiscale hydrogel. The most notable progress was that the synthesized multiscale hydrogel not only combined the above advantages but also simultaneously solved multiple dilemmas of tedious synthesis steps, high cost, and poor durability. Besides, the multiscale hydrogel also had excellent antibacterial properties and biocompatibility, which enabled them to have large-scale application potential in wearable and implantable electronic devices. Our research could provide a universal approach to the creation of robust, flexible, wearable, and sensitive sensors, significantly increasing the uses of stress sensors in wearable technology.

Dual‐active‐layer flexible piezoresistive sensor based on wrinkled microstructures and electrospun fiber network for human‐related motion sensing applications

AbstractFlexible pressure sensors with high sensitivity and a wide detection range must be developed for practical applications. In this study, a dual‐active‐layer flexible piezoresistive sensor was developed. A reduced graphene oxide film with wrinkled microstructures was prepared by a simple and low‐cost substrate pre‐stretching method and used as the first active layer. A thermoplastic polyurethane electrospun fiber membrane was modified by fast polydopamine coating and ultrasonication with multi‐walled carbon nanotubes and used as the second active layer. Owing to the continuously changing conductive pathways created by the wrinkled microstructures and fiber network under pressure deformation, the sensor achieved a detection range of 0–100 kPa, with sensitivities of 8.5, 1.35, and 0.39 kPa−1 in the ranges of 0–1, 1–20, and 20–100 kPa, respectively. Additionally, the sensor exhibited a low detection limit (2 Pa), response and recovery times of 105 and 85 ms, respectively, and reliable service performance over 10,000 loading/unloading cycles. The sensor enabled real‐time monitoring of finger and wrist bending, beaker‐holding, and fingertip‐sliding on a touch screen, demonstrating its feasible applications in wearable electronics and human–machine interface devices.

Flexible tactile sensing of magnetic hydrogel composites based on electrical impedance tomography

Flexible and stretchable tactile sensors show promising applications in robotics, prosthetics, and wearable electronics. This paper demonstrates an electrical impedance tomography (EIT) based highly flexible, touch-sensitive pressure sensor using magnetic hydrogels. EIT technology has been explored for continuous distributed strain sensing and tactile imaging. Magnetic hydrogel composites are synthesized by simultaneous polymerization and crosslinking of acrylamide with magnetic carbonyl iron particles (CIPs). The effects of CIPs percentage on morphology, sensitivity, and electrical/mechanical properties is investigated. EIT accurately discerns pressure quantity, shape, and spatial distribution. Lower CIPs volume fractions (3%) exhibit maximum sensitivity to strain fields. Mechanical testing show the hydrogels have excellent fatigue resistance, ideal for repeated compression loading. The results demonstrate the potential of EIT with magnetic hydrogel composites for tactile sensing and imaging, with applications in soft robotics, prosthetics, and wearable electronics. The tunable sensitivity and multifunctionality make these soft composites promising materials for flexible electronics.

Nitrogen Doping Engineering of V2CTx based Zinc Ion Hybrid Microcapacitors with Quadruple High Energy Density

To accommodate the long-term and stable energy supply requirements for wearable electronics, the reported flexible zinc ion hybrid microcapacitor (ZIHMC) needs to further increase the energy density. So, a nitrogen doped V2CTx (N-V2CTx) based ZIHMC was proposed to achieve high electrochemical performance. The introduction of N heteroatoms by NH3 annealing can dramatically increase the electrical conductivity of V2CTx and simultaneously widen the voltage window to 1.9 V. In detail, the doped nitrogen atoms in V2CTx based device has a maximum capacity of 293.0 mF cm–2, four times higher than that of pure V2CTx based ZIHMC. The mechanism of the enhanced electrochemical performance by nitrogen doped V2CTx was revealed by the experimental analysis and theoretical simulation. And the N-V2CTx based ZIHMC demonstrated high energy density with 150.0 μWh cm–2 at a power density of 380.0 μW cm–2 and excellent stability with 94.80% capacitance retention after 3000 charge-discharge cycles. The N-V2CTx based ZIHMC also presents excellent flexibility without virtually capacity loss after 3000 bending cycles. The good electrochemical performance and flexibility of N-V2CTx ZIHMC make it has potential applications in flexible wearable electronics.

Room temperature self-healing and reprocessing elastomer with dynamic bonds for flexible wearable sensor

The production of room-temperature (RT) self-healing elastomers with good mechanical properties is significant for application in soft electronics, yet remains a challenge in material design. Herein, we present an effective and feasible approach to create RT self-healing cross-linked elastomers (CEs) through photo-initiated copolymerization. A key feature is the incorporation of 2,7-dihydroxynaphthalene and alicyclic diisocyanate into the polymer backbone as hard domains, along with the rational optimization of the soft segments. In addition, urethane-based H-bonding interactions, acting as sacrificial bond, contribute to the high toughness of the CEs. The resulting CEs exhibit desirable mechanical performances, including a tensile strength of 12.9 MPa, an elongation at break of approximately 1243 %, and a high toughness of 68.64 MJ m–3. Furthermore, by integrating a flexible PTMEG-based polymeric chain and hindered urea bonds into the backbone, the chain mobility and dynamic nature of the CEs are improved. The CEs are capable of reprocessing and self-healing at RT within 30 min upon scratching, with a self-healing efficiency in toughness reaching 99.64 %. The dynamic networks are evidenced by rheological test, stress relaxation analysis, as well as creep and recovery experiments. These CEs, characterized by their superior properties, hold promise for applications in flexible wearable electronics.

A highly stretchable and self-adhesive cellulose complex hydrogels based on PDA@Fe3+ mediated redox reaction for strain sensor

As the application of conductive hydrogels in the field of wearable smart devices is gradually deepening, a variety of hydrogel sensors with high mechanical properties, strong adhesion, fast self-healing, and excellent conductivity are emerging. However, it is still a great challenge to manufacture hydrogel sensors combining multiple properties. Herein, we leveraged the dynamic redox reaction occurring between polydopamine (PDA) and Fe3+ to induce ammonium persulfate (APS) to generate free radicals, thereby initiating the copolymerization of hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) monomers. Then, polypyrrole-encapsulated cellulose nanofibers (PPy@CNF) and carboxymethylcellulose (CMC) were incorporated as conductive reinforced nanofillers and interpenetrating network skeleton. The obtained hydrogel cross-linked through reversible metal-ligand bonds, π-π stacking and abundant hydrogen bonding demonstrated great mechanical properties (strength 240.4 kPa, strain 1175 %) and self-healing ability (88.96 %). Particularly, the gel displayed ultrahigh durability and skin adhesive ability (75 kPa after 10 cycles), surpassing previous skin adhesion hydrogels. Furthermore, through the synergistic conductive effect of PPy@CNF and Fe3+, the prepared hydrogel sensor possessed high sensitivity (GF = 1.89) with a wide sensing range (~1000 %), which could realize the human body's daily motion detection, and had a promising application in flexible wearable electronics.

Fluorine-free biomimetic membranes with leaf vein-like and lotus leaf dual structure for high-performance waterproof and breathable textiles

Intelligent microporous membranes with excellent water resistance and moisture permeability have a huge market demand owing to their wide applications in personal protection, outdoor equipment and wearable electronics. However, the construction of such high-performance waterproof and moisture-permeable membranes (WBMs) based on a simple preparation process without post-coating treatment presents significant challenges. Herein, we present a simple strategy for constructing a fluorine-free polyethylene terephthalate (PET)-based WBM with a novel composite structure by combining a leaf vein-like nanofibrous substrate membrane and lotus leaf-inspired biomimetic nanofibrous skin using multi-needle electrospinning and heat treatment techniques. Surface hydrophobicity, along with the stable crosslinked structure of PET-based membranes, was achieved by in-suit doping of fluorine-free two-component reactive silicone rubber (PDMS). In addition, the small pore size and high porosity of the composite membranes were regulated by co-assembling PET/PDMS fibers and microspheres with different morphologies and structures. The resulting composite membranes based on substrate membrane-1:3 (BNFM-1:3) achieved excellent waterproof performance of 90.3 kPa, good moisture permeability of 5116 g m−2 d−1, and air permeability of 1.82 mm s−1. The WBMs based on novel composite structures are expected to be applied in various fields because of their ideal comprehensive performance.

Room-Temperature Flexible CNT/Fe2O3 Film Sensor for ppb-Level H2S Detection.

Carbon nanotubes (CNTs) had room temperature response, large surface area, and excellent mechanical properties, making them favorable for the design of flexible, wearable, and portable gas sensors. However, CNTs were lacking in response and selective response to different gases, such as H2S. Here, we demonstrated a flexible H2S ppb-level gas sensor based on a carbon nanotube/amorphous Fe2O3 (CNT/Fe2O3) film at room temperature, which was fabricated via a simple one-step solvent-thermal method. The CNT/Fe2O3 film gas sensor exhibited a high selective response to H2S (with a response of 55.1% to 100 ppb H2S), rapid reversible response at room temperature (with a response time of ∼127 s to 100 ppb H2S), and low limit of detection to about 2 ppb. Additionally, the CNT/Fe2O3 film maintained good sensing performance under various bending conditions and could be further fabricated into the fiber gas sensor device via wet stretching, retaining response at the ppb level (with a response of 18.6% to 100 ppb H2S). This research on a flexible gas sensor device based on the CNT film/fiber opened up new possibilities for wearable portable electronic device applications.

Flexible Single Microwire X-Ray Detector with Ultrahigh Sensitivity for Portable Radiation Detection System.

Sensitive, flexible, and low false alarm rate X-ray detector is crucial for medical diagnosis, industrial inspection, and scientific research. However, most semiconductors for X-ray detectors are susceptible to interference from ambient light, and their high thickness hinders their application in wearable electronics. Herein, a flexible visible-blind and ultraviolet-blind X-ray detector based on Indium-doped Gallium oxide (Ga2O3:In) single microwire is prepared. Joint experiment-theory characterizations reveal that the Ga2O3:In microwire possess a high crystal quality, large band gap, and satisfactory stability, and reliability. On this basis, an extraordinary sensitivity of 5.9×105µCGyair -1cm-2 and a low detection limit of 67.4nGyairs-1 are achieved based on the prepared Ag/Ga2O3:In/Ag device, which has outstanding operation stability and excellent high temperature stability. Taking advantage of the flexible properties of the single microwire, a portable X-ray detection system is demonstrated that shows the potential to adapt to flexible and lightweight formats. The proposed X-ray detection system enables real-time monitor for X-rays, which can be displayed on the user interface. More importantly, it has excellent resistance to natural light interference, showing a low false alarm rate. This work provides a feasible method for exploring high-performance flexible integrated micro/nano X-ray detection devices.

A wearable cotton fiber-based supercapacitor electrode material with outstanding stability and photothermal performance utilizing AgNWs, NiCoAl-LDH, and PPy-NWs.

Designing cotton fiber (CF) based flexible electrode materials with both electrochemical energy storage and structural stability is crucial for the utilization of flexible supercapacitors in wearable devices. Nevertheless, the electrochemical properties of such materials are often constrained by suboptimal ion diffusion, a limited electroactive surface area, and inadequate structural integrity. Herein, Silver nanowires (AgNWs), NiCoAl hydrotalcite (NCA-LDH), and polypyrrole nanowires (PPy-NWs) are employed to construct a CF-based electrode material (PNHAS/CF) with high stability through a layer-by-layer self-assembly method. The PNHAS/CF with a high capacitance of 1207.58 mF cm-2 at 5mAcm-2 due to the faster electronic transmission paths of AgNWs and PPy-NWs, and the high specific capacitance of NCA-LDHs. The NCA-LDH stabilizes the PPy-NWs molecular chain, and the PPy-NWs winding structure can further enhance the PNHAS/CF's structural stability and prevent the AgNWs network from being destroyed, which guarantees the exceptional 87.5% capacitance retention after 2000cycles. The constructed symmetrical supercapacitor shows an energy density of 36.28 μWh cm-2 at 0.31mWcm-2 power density. The PNHAS/CF exhibits superb solar spectral absorptivity (~94.8%) and outstanding solar heating performance. Surprisingly, the fiber-based flexible electrode material and the assembled supercapacitor are expected to find applications in wearable intelligent electronics.

Environmentally stable, Adhesive, Self-healing, Stretchable and Transparent Gelatin based Eutectogels for Self-Powered Humidity Sensors

Intrinsic environmental and stability limitations of hydrogels have inhibited their practical applications as a flexible wearable device due to water evaporation or freezing in complex environments such as low temperatures and arid environments. In this work, a multifunctional gelatin based ionic conductive eutectogel with double network structure is designed via ternary deep eutectic solvent (DES) (acrylic acid (AA), choline chloride (ChCl) and ethylene glycol (EG)). In this system, the introduction of ethylene glycol (EG) can be used to dissolve gelatin. The resulting DESG eutectogel exhibited excellent adhesion, mechanical robustness, anti-freeze, anti-drying, and self-healing. Interestingly, the DESG gels showed high humidity sensitivity in a wide humidity detection range (11 %–83 %), which can be assembled as a self-powdered humidity sensor to monitor human mouth and nose breathing. This work is expected to bring new prospect to construct high performance humidity sensors using gelatin based humidity-responsive materials for a wide range of potential applications in respiratory diagnostics, sleep monitoring, electronic skin and wearable electronics.

Improved thermoelectric properties of metal ion doped aniline tetramer/carbon nanotube composite films

Carbon nanotubes and their composites have attracted much attention in the field of thermoelectric conversion for potential application in wearable electronics owing to their good electrical conductivity and excellent mechanical properties. However, low Seebeck coefficient of carbon nanotubes limit the improvement of their thermoelectric properties. In this work, metal ions (Mn+ = Fe3+, Ni2+, Cu2+) are used to further improve the thermoelectric properties of aniline tetramer (ANIT)/single-walled carbon nanotubes (SWCNT) composites, and Mn+@ANIT/SWCNT films are prepared by physical mixing and vacuum filtration method. The metal ions and concentrations for improving Mn+@ANIT/SWCNT thermoelectric films are optimized, and the metal ions doping optimizes carrier concentration and promotes carrier transport of the composites appropriately, which increased the Seebeck coefficient. Amone the prepared Mn+@ANIT/SWCNT films, the Cu2+@ANIT/SWCNT demonstrates the highest PF value of 145.3 ± 3.9 μW m−1 K−2 at the molar ratio of Cu2+/ANIT to being 5:100 with the σ of 560.1 ± 22.1 S cm−1, and the S of 51.0 ± 1.3 μV K−1 at room temperature. Finally, five pairs of p-type Cu2+@ANIT/SWCNT films and n-type copper sheets are connected in series to assemble a self-powered thermoelectric device, which demonstrates an actual output power of about 426 nW under a temperature difference of 50 K. Therefore, this work offers a metal ions doping strategy to improve the SWCNT composites with enhanced thermoelectric properties.

Highly mechanically stable and intrinsically stretchable large-area organic photovoltaics using nanoporous bulk-heterojunction

It is important to develop bulk-heterojunction films that simultaneously exhibit good photovoltaic properties and mechanical robustness to realize intrinsically stretchable organic photovoltaics (IS-OPVs). We developed a strategy for preparing nanoporous bulk-heterojunction (np-BHJ) films at a large area by nonsolvent-induced phase separation assisted by thermoplastic polyurethane. The resulting np-BHJ can form much improved adhesive interfaces with a neighbored stretchable layer in OPV devices and effectively dissipate applied mechanical stress. IS-OPVs using the np-BHJ films showed efficiency of 12.0 %, which is comparable performance to 12.4 % of the controlled BHJ. The IS-OPV device using np-BHJ films much improved mechanical stability and maintained 89 % of its initial efficiency under applied strain of 40 %. The corresponding module showed only 10 % decrease in efficiency after 1,000 cycles in stretching tests at 10 % strain. Because of high scalability of the np-BHJ morphology, IS-OPV modules with efficiency of 7.06 % and active area of 10.17 cm2 and were successfully demonstrated. Photoplethysmography sensors prepared using the IS-OPV module showed strong potential for application in wearable electronics.

Ultrasensitive and wide-range MXene/PDMS piezoresistive sensors inspired by rose petals

Flexible pressure sensors are crucial in a variety of applications, including artificial intelligence (AI), the Internet of Things (IoT), and electronic skin (e-Skin), due to their ability to convert mechanical stimuli into electrical signals. However, achieving both high sensitivity and a wide detection range simultaneously remains challenging, often limiting their practical applications. To address this, we designed a three-dimensional contact interface with Ti3C2 MXene/polydimethylsiloxane (MP) inspired by rose petals, which allows for significant strain and resistance changes across a broad range of stress levels. The innovative design significantly extends the pressure detection range (0.033–535 kPa), enhances pressure sensitivity (0.432 kPa−1), offers a fast response/recovery times (57/4 ms), and ensures exceptional long-term durability (up to 2950 cycles). The structured MP sensor demonstrates the capability to detect human physiological movements, distinguish various voices and map real-time pressure distributions. Notably, it achieves real-time tracking of handwriting processes with high recognition accuracy through a machine learning module. The work offers a new strategy and inspiration for designing and manufacturing innovative structured pressure sensors with reliable performance, paving the way for their application in next-generation wearable and portable electronics.

Flexible All-Inorganic Thermoelectric Yarns.

Achieving both formability and functionality in thermoelectric materials remains a significant challenge due to their inherent brittleness. Previous approaches, such as polymer infiltration, often compromise thermoelectric efficiency, underscoring the need for flexible, all-inorganic alternatives. This study demonstrates that the extreme brittleness of thermoelectric bismuth telluride (Bi2Te3) bulk compounds can be overcome by harnessing the nanoscale flexibility of Bi2Te3 nanoribbons and twisting them into a yarn structure. The resulting Bi2Te3 yarn, with a Seebeck coefficient of -126.6µVK-1, exhibits remarkable deformability, enduring extreme bending curvatures (down to 0.5mm-1) and tensile strains of ≈5% through over 1000 cycles without significant resistance change. This breakthrough allows the yarn to be seamlessly integrated into various applications-wound around metallic pipes, embedded within life jackets, or woven into garments-demonstrating unprecedented adaptability and durability. Moreover, a simple 4-pair thermoelectric generator comprising Bi2Te3 yarns and metallic wires generates a maximum output voltage of 67.4mV, substantiating the effectiveness of thermoelectric yarns in waste heat harvesting. These advances not only challenge the traditional limitations posed by the brittleness of thermoelectric materials but also open new avenues for their application in wearable and structural electronics.

Oxygen vacancies enhancing hierarchical NiCo2S4@MnO2 electrode for flexible asymmetric supercapacitors

The limited energy density of supercapacitors hampers their widespread application in electronic devices. Metal oxides, employed as electrode materials, suffer from low conductivity and stability, prompting extensive research in recent years to enhance their electrochemical properties. Among these efforts, the construction of core–shell heterostructures and the utilization of oxygen vacancy (VO) engineering have emerged as pivotal strategies for improving material stability and ion diffusion rates. Herein, core–shell composites comprising NiCo2S4 nanospheres and MnO2 nanosheets are grown in situ on carbon cloth (CC), forming nanoflower clusters while introducing VO defects through a chemical reduction method. Density functional theory (DFT) results proves that the existence of VO effectively enhances electronic and structural properties of MnO2, thereby enhancing capacitive properties. The electrochemical test results show that NiCo2S4@MnO2-V3 exhibits excellent 1376 F g−1 mass capacitance and 2.06 F cm−2 area capacitance at 1 A g−1. Moreover, NiCo2S4@MnO2-V3//activated carbon (AC) asymmetric supercapacitor (ASC) can achieve an energy density of 39.7 Wh kg−1 at a power density of 775 W kg−1, and maintains 15.5 Wh kg−1 even at 7749.77 W kg−1. Capacitance retention is 73.1 % after 10,000 cycles at 5 A g−1, and coulombic efficiency reaches 100 %, demonstrating satisfactory cycle stability. In addition, the device’s excellent flexibility offers broad application prospects in wearable electronic applications.

Recyclable and Stable Strain Sensors Based on Semi‐Wrapped Structure of Silver Nanowires in Polyvinyl Alcohol for Human Motion Monitoring

AbstractHighly sensitive strain sensors have been widely used in human motion monitoring, medical treatment, soft robots, and human–computer interaction, and the recycling of functional materials is in a huge demand for eco‐friendly and sustainable electronics. However, the manufacturing of recyclable strain sensors still remains challenging. Here, a semi‐wrapped structure based on silver nanowires and polyvinyl alcohol is proposed to realize a recyclable and stable strain sensor. It has shown excellent sensitivity, fast response, high stretchability and good environmental stability, and is successfully applied for human motion monitoring. In addition, a simple strategy is developed to effectively recycle silver nanowires in an eco‐friendly manner. The recyclable and stable strain sensor demonstrates potential applications in wearable and stretchable electronics, and the recycling strategy can be extended to other noble metal nanomaterials.