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Laser‐induced graphene (LIG) technology has provided a new manufacturing strategy for the rapid and scalable assembling of triboelectric nanogenerators (TENG). However, current LIG‐based TENG commonly rely on polymer films, e.g., polyimide (PI) as both friction material and carbon precursor of electrodes, which limit the structural diversity and performance escalation due to its incapability of folding and creasing. Using specialized PI paper composed of randomly distributed PI fibers to substantially enhance its foldability, this work creates a new type of TENG, which are structurally foldable and stackable, and performance tailorable. First, by systematically investigating the laser power‐regulated performance of single‐unit TENG, the open‐circuit voltage can be effectively improved. By further exploiting the folding process, multiple TENG units can be assembled together to form multi‐layered structures to continuously expand the open‐circuit voltage from 5.3 to 34.4 V cm−2, as the increase of friction units from 1 to 16. Last, by fully utilizing the unique structure and performance, representative energy‐harvesting and smart‐sensing applications are demonstrated, including a smart shoe to recognize running motions and power LEDs, a smart leaf to power a thermometer by wind, a matrix sensor to recognize writing trajectories, as well as a smart glove to recognize different objects. [ABSTRACT FROM AUTHOR]

Smart honeycombs are becoming the novel structural strategy for next‐generation devices and equipments. Unfortunately, traditional surface‐coating, structural immersing, and 3D printing approaches still face significant challenges in combining structural customization and performance multifunctionality. Herein, a brand‐new processing strategy is developed to construct graphene‐based smart honeycombs by stacking and deploying laser‐induced graphene (LIG) layers with alternatively inserted adhesives. Through tuning key parameters, various LIG‐enabled smart honeycombs (LIG‐HC) can be assembled with scalable areal dimension and thickness, variable cell sizes and shapes, as well as patternable graphene clusters. By further understanding the process‐dependent structural stability and electrical conductivity, multifunctional characteristics are systematically explored, including anisotropic mechanical, electrical, piezoresistive, and electromagnetic performance. To finally demonstrate the unique honeycomb multifunctionally applied in fields of aviation, an intelligent LIG‐HC enabled aircraft‐wing model is representatively constructed for performing anti‐/de‐icing, high‐temperature warning, flame retardancy, pressure and vibration monitoring, as well as electromagnetic shielding and stealth. [ABSTRACT FROM AUTHOR]

3D printing has become an important strategy for constructing graphene smart structures with arbitrary shapes and complexities. Compared with graphene oxide ink/gel/resin based manners, laser‐induced graphene (LIG) is unique for facile and scalable assembly of 1D and 2D structures but still faces size and shape obstacles for constructing 3D macrostructures. In this work, a brand‐new LIG based additive manufacturing (LIG‐AM) protocol is developed to form bulk 3D graphene with freeform structures without introducing extra binders, templates, and catalysts. On the basis of selective laser sintering, LIG‐AM creatively irradiates polyimide (PI) powder‐bed for triggering both particle‐sintering and graphene‐converting processes layer‐by‐layer, which is unique for assembling varied types of graphene architectures including identical‐section, variable‐section, and graphene/PI hybrid structures. In addition to exploring combined graphitizing and fusing discipline, processing efficiency and assembling resolution of LIG‐AM are also balanceable through synergistic control of lasing power and powder‐feeding thickness. By further studying various process dependent properties, a LIG‐AM enabled aircraft‐wing section model is finally printed to comprehensively demonstrate its shiftable process, hybridizable structure, and multifunctional performance including force‐sensing, anti‐icing/deicing, and microwave shielding and absorption. [ABSTRACT FROM AUTHOR]

Macroscopic 3D graphene has become a significant topic for satisfying the continuously upgraded smart structures and devices. Compared with liquid assembling and catalytic templating methods, laser‐induced graphene (LIG) is showing facile and scalable advantages but still faces limited sizes and geometries by using template induction or on‐site lay‐up strategies. In this work, a new LIG protocol is developed for facile stacking and shaping 3D LIG macrostructures by laminating layers of LIG papers (LIGPs) with combined resin infiltration and hot pressing. Specifically, the constructed 3D LIGP composites (LIGP‐C) are compatible with large area, high thickness, and customizable flat or curved shapes. Additionally, systematic research is explored for investigating critical processing parameters on tuning its multifunctional properties. As the laminated layers are stacked from 1 to 10, it is discovered that piezoresistivity (i.e., gauge factor) of LIGP‐C dramatically reflects an ≈3900% improvement from 0.39 to 15.7 while mechanical and electrical properties maintain simultaneously at the highest levels, attributed to the formation of densely packed fusion layers. Along with excellent durability for resisting multiple harsh environments, a sensor‐array system with 5 × 5 LIGP‐C elements is finally demonstrated on fiber‐reinforced polymeric composites for accurate strain mapping. [ABSTRACT FROM AUTHOR]

Abstract Carbon nanomaterials (CNM) based technology has offered a variety of promising strategies for self-sensing and diagnosing functionalities in polymeric composites. In comparison with studies about detecting deformations and cracks, monitoring the manufacturing stage of composites using CNMs is rather limited. Based on continuous fabrication, we systematically investigated carbon nanotubes (CNTs) coated, graphene coated and carbon fiber sensors for monitoring complete molding process of composites through the real-time resistance change. Comparing to graphene-coated and carbon fibers with densely and continuously packed graphitic structures, the CNT fiber sensor with entangled and loosely packed porous network shows far superior performance for sensing different processing stages of composites, including resin infusion, gelation and curing. The resistance decay of the CNT sensor agrees well with curing kinetics measured by differential scanning calorimetry. Versatile capabilities of the CNT sensor were further explored for identifying various flowing defects such as dry spots and partially infiltrated areas. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) technology featuring low-cost, high-efficiency and scalability has presented great advantages in micro-supercapacitors (MSCs) fabrication. However, the limited capacitance of LIG based MSCs is still hindering their further development. Herein, we introduce joule heating as a critical in-situ treatment merged with the assembly of laser-induced graphene paper based MSCs (LIGP-MSCs) toward capacitive enhancement. By increasing heating-treatment temperature from ∼20 to 500 °C, the number of nanopores in LIGP continuously increases, attributed to the gradual decomposition of amorphous carbon components. The resulting joule-heated LIGP (J-LIGP) with improved specific surface area (160.97–533.49 m2/g) and pore volume (0.179–0.553 cm3/g) as well as superhydrophilic surface is highly suitable to be employed as J-LIGP-MSCs microelectrodes. By investigating process dependent performance, the J-LIGP-MSCs heated at 500 °C for 60 min delivers a significantly improved specific areal capacitance (C A) of 13.71 mF/cm2 at 10 mV/s, which is approximately six-fold higher than that of unheated LIGP-MSCs. By further exploring and optimizing the process efficiency, J-LIGP-MSCs with a C A of 12.61 mF/cm2 has been achieved by 550 °C heating for only 5 min. Along with superior mechanical flexibility, cyclability and structural modularity, the proposed in-situ joule heating treatment is finally proved to be a universal approach for consistently enhancing the C A of LIG based MSCs processed under various chemical modifications. A facile and general approach for enhancing the capacitance performance of laser-induced graphene paper based MSCs (LIGP-MSCs) are creatively proposed and demonstrated by an in-situ joule heating processing strategy, revealing outstanding potential for fabrication of high-performance LIG based MSCs. [Display omitted] [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is a highly promising technology for assembling thin-film electronics with miniaturized surficial patterns, although hard to guarantee both high-quality formation of raw materials and high resolution of feature size. In this study, a combined microcontact printing (μCP) and LIG protocol is creatively utilized to fabricate ultra-thin graphene films with highly ordered micro-stripe arrays. In addition to realize various patterned structures with unique scalable and stackable characteristics, PAA concentration (4–8 wt%) is systematically investigated as a critical parameter to precisely control the feature size of micro-patterns before and after the irradiation process, including line width (before: 5.37–22.44 μm, after: 4.83–22.32 μm) and average height (before: 69.81–187.39 nm, after: 5.72–48.61 nm). By further exploring a defocused multi-lasing strategy, sheet resistance of the graphene array could be optimized dramatically from 634.1 kΩ/sq to 1.9 kΩ/sq, while maintaining low ablation (45.38 % porosity) and high carbon content (84.2 wt%). Lastly, the process is demonstrated to assemble different graphene based electronic devices with miniaturized sizes, including liquid sensors with sensitivity of 2.7 % μL−1 and electrothermal heaters with temperature-ramping rate as high as 24.7 °C/s and working temperature as high as 248 °C. A combined microcontact printing (μCP) and laser-induced graphene (LIG) protocol is creatively developed to assemble ultra-thin graphene film based devices with highly-ordered and stackable micro-stripe-array patterns, tunable feature width (4.83–22.32 μm) and height (5.72–48.61 nm), optimized sheet resistance (1.9 kΩ/sq), and functions of liquid-sensing (sensitivity of 2.7 % μL−1) and joule-heating (working temperature of 248 °C). [Display omitted] [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is a newly-emergent processing strategy for assembling graphene-based structures and devices with low-cost, high-efficiency and high-customizability. However, with the limitation of positioning accuracy, the application of LIG for swift and continuous production of 1D graphene-fiber based electronics is still vacant. Considering the unique 1D geometry with prominent advantages for flexible and wearable devices, in this work, we adventurously proposed and investigated a vertically-oriented laser-sweeping strategy to continuously convert the ∼16.5 μm diameter polyimide monofilament into freestanding graphene fibers. Based on process-structure-property relationship modulated precisely by varied combinations of lasing power and pulse resolution, the LIG enabled fiber electronics (LIGFE) could simultaneously exhibit small diameter (<20 μm), high strength (56.49 MPa), electrical conductivity (306.45 S/m), gauge sensitivity (5.43), joule-heated temperature (71.3 °C), and capacitive performance (0.26 μF/cm2). Taking advantage of computer-aided design and manufacture along with the variously excellent properties, we lastly demonstrated the LIGFE as multimodal sensors for liquid sensing, airflow & respiration monitoring, ultrasonic frequency capturing, as well as functional element embedded in polymer composites for varied types of structural health monitoring from manufacturing to failure stages. A vertically-oriented laser-sweeping strategy has been innovatively proposed for manufacturing LIG enabled 1D fiber electronics (LIGFE) with tunable characteristics and multimodal sensing capabilities. Image 1 [ABSTRACT FROM AUTHOR]

Functional electrodes with unique ion storage and rapid ion migration properties through microstructure and chemical-doping modulation are always crucial for rapid charging devices such as micro-supercapacitors (MSCs). In this work, proton exchange membrane named phosphoric acid (PA) doped polybenzimidazole membrane (PA-PBI) is studied as a unique precursor for assembling laser induced graphene (LIG) based electrodes (PA-PBI-LIG) in MSCs, toward the enhancement of energy storage performance via simultaneous heteroatoms doping, microporous structure improving and proton-conducting substrate introducing. By tuning PA concentration, the microporous structures perform adjustable specific surface area from 20.2 to 384.46 m2 g−1, thereby enhancing changeable capacitance from 2.44 mF cm−2 to 149 mF cm−2, with highest specific energy density of 20.7 μWh cm−2. To understand the mechanism, PA and the initiated free radicals are proposed to motivate microporous formation and heteroatoms doping during laser fabrication via unique laser absorption properties of PA. Additionally, PA-PBI substrates work synergistically on ions migration with microporous graphene, potentially promoting energy storage efficiency especially in the acid-based electrolyte. Overall, the raised PA-PBI-LIG electrodes simultaneously promote microporous, heteroatomic and multilayered graphene with proton conducting substrate, which show great potentials in micro energy storage devices. [Display omitted] • Phosphoric acid involved PBI-LIG improve micro pores, heteroatoms & ions transfer. • Phosphoric acid tunes the LIG specific surface area from 384.46 to 20.2 m2 g−1. • The optimized capacitance and energy density reach 149 mF cm−2 and 20.7 μWh cm−2. [ABSTRACT FROM AUTHOR]