The integration of surface-regular micro/nanostructured electrodes within a limited footprint area is promising to enhance the electrochemical performance of planar micro-supercapacitors (P-MSCs), while developing simple yet efficient manufacturing methods for such electrodes remains a challenge. Here, we propose a universal strategy combining femtosecond laser plasma lithography with spatial light modulation (SLM-FPL), fabricating well-ordered sub-wavelength micro/nanostructured electrodes of interdigital P-MSCs (SEP-MSCs) on graphene oxide (GO) films. Achieving 500/50 µm finger widths/spacings and 680 nm internal grating periods, this method enables device densities >25 units inch−2 with processing efficiency orders of magnitude higher than conventional laser direct writing. Further performance optimizations via wettability modification, electric field engineering, and hybrid composites (GO-MXene/COF) yield outstanding specific capacitance ( 41.4 F cm−3) and cycling stability (93

Against the backdrop of increasingly severe electromagnetic pollution, fabricating high-performance, lightweight broadband electromagnetic wave-absorbing materials has become an exigent requirement. However, potential materials, such as MXene, suffer from critical bottlenecks in their traditional preparation methods, process hazards, time-consuming, and result in materials with poor microwave absorption performance. Herein, an innovative microwave-assisted molten salt synthesis strategy that employs ZnCl2 under microwave irradiation to obtain the TiO(2)nanoparticle-modified W-Ti3C2 composites. At a thickness of 2.53 mm, the lowest reflection loss (RLmin) is -64.2 dB. The effective absorption bandwidth (EAB) achieves 8.79 GHz when the thickness is 3.55 mm. The immense potential of a cost-efficient and environmentally friendly route of preparation can be applied in the construction of high-performance broadband microwave absorbers.

Asymmetric supercapacitors (ASCs) hold great promise as advanced energy storage components for future electronic devices. However, simultaneous modification of both positive and negative electrodes in ASCs remains underdeveloped. In this work, we have developed a laser-assisted reduction method to introduce heteroatoms (B, or B and N) into reduced graphene oxide (RGO), enabling synchronous dual-electrode modification and programmable patterning of graphene-based ASCs. The boron-doped and boron-nitrogen co-doped laser-reduced graphene oxide (B-LrGO, BN-LrGO) thin-film electrodes demonstrated significantly enhanced electrochemical performance compared to pure RGO electrodes, which stemmed from synergetic effect of laser reduction and heteroatom incorporation for introducing abundant micro-nano structure and defective sites. Furthermore, a solid-state BN-LrGO//B-LrGO ASC was assembled, including B-LrGO negative electrode and BN-LrGO positive electrode. Leveraging the programmable fabrication of laser reduction, we fabricated various patterned ASCs including interdigital, square and arch structures, overcoming the limited capacity of pure RGO. Notably, interdigital-structured ASC showed a maximum specific capacitance of 3.56 mF/cm2. This work presents a novel dual-electrode synchronous modification strategy for high-performance ASCs.

Laser-induced reduced graphene oxide (LIRGO) has exhibited great potential for energy storage device applications. However, challenges remain in regard to solving the restacking of graphene oxide (GO) sheets and conductivity differences after laser processing. In this study, we used direct laser writing (DLW) to fabricate self-assembled graphene oxide-Ti3C2Tx MXene (GO-M) composites on tag paper for planar supercapacitors. Due to the cooperation of interaction between electronegative GO and Ti3C2Tx MXene and introduction of paper substrate with cellulose network structure, the as-prepared composite (R-GO-M-P) based supercapacitor exhibits much higher specific capacitance (15.5 mF/cm2) than that of LIRGO on glass substrate (4.05 mF/cm2). We observed a good stability of 93.35% specific capacitance retention scores after 1,000 charge-discharge cycles. Moreover, the R-GO-M-P-based supercapacitor also displayed excellent flexibility due to the existence of paper substrate, with a 142% specific capacitance retention after 1,000 bending test cycles. The integrated R-GO-M-P-based supercapacitors were fabricated according to a programmable DLW pattern, that achieved an extended working potential of 2.4V and could power an LED. We hope that this study offers a new strategy for the development of high-performance LIRGO-based supercapacitors.

Paper-based supercapacitors (P-SCs) exhibit superior electrochemical performance owing to the flexibility and unique surface properties of paper substrates. Currently, most P-SCs adopt a sandwich structure that is limited by electrode fabrication methods. However, the development of planar paper-based devices is crucial to satisfy the tremendous demand for wearable electronics. Herein, based on the mechanism of interaction between the laser and material, we used direct laser writing (DLW) techniques to fabricate in-plane P-SCs based on graphene oxide (GO) and manganese dioxide (MnO2) composite-covered paper substrates. Owing to the in-plane device structure and pseudocapacitive MnO2, the acquired rGO-MnO2-based planar P-SCs possessed a much higher specific capacitance value (17.7 mF/cm2) than that based on sandwich-structured reduced GO (rGO) (1.71 mF/cm2). In addition, three in-series integrated devices can be easily achieved via the DLW fabrication method, which shows potential for practical applications such as powering a light emitting diode. In addition, by carefully designing the paper substrate structure, the paper-based device exhibited excellent stretching stability. A specific capacitance retention of 86.8% remained after 5000 stretch cycles. Therefore, this study provides valuable insights into the design and fabrication of wearable paper-based electronics.

Graphene-based planar microsupercapacitors are promising energy storage devices for microelectromechanical systems. However, the capacitance and energy density of such graphene-based microsupercapacitors cannot achieve further promotion because of the lack of strategies that permit tailoring both chemical and geometric structures of graphene at the nanoscale. In this study, supercapacitors on hairs with quantum capacitancedominant extraordinary capacitance are found. Simulations reveal that the record high capacitance and energy density are attributed to the enhanced quantum capacitance effect. The graphene electrodes are prepared by femtosecond laser direct writing-assisted reduction and N-doping of graphene oxides on the human hair surface. Due to the distinct quantum capacitance dominance, the microsupercapacitors exhibit extremely high capacitance ( 3000 mF/cm2) and energy density ( 417 mu Wh/cm2). We hope that this work will promote the development of microsupercapacitors with high capacitance and energy density.

Lithium metal batteries specialize in energy density, while the immoderate dendrite growth and solid electrolyte interphase (SEI) proliferation have been impeding their practical application. The key is the regulation of Li+ diffusion/nucleation behaviors toward a dense deposition. Herein, Li9Al4/Li3N energized mixed ionic/electronic conductive (MIEC) interfaces are pre-implanted in both the surface and bulk of the lithium metal anode. Such MIEC interfaces are activated from the in situ conversion and nano-alloying reactions between AlN and metallic Li and are uniformly dispersed via facile mechanical kneading. In vitro, MIEC interfaces participate in the formation of an inorganic-enriched SEI that balances ionic transport, electron blocking, and mechanical strength to guarantee homogeneous ion fluxes and structural integrity. In vivo, a unique nanorod-array architecture enables a released internal stress and rapid diffusion kinetics, affording a dense and large granular plating manner. As a result, the symmetric cell delivers a striking cumulative capacity of >120000 mAh cm(-2) at 20 mA cm(-2)@20 mAh cm(-2) with a prolonged lifespan of over 6000 h. The improved machinability also enables a scalable fabrication of ultrathin foil to achieve a stable high-areal-capacity full cell for 320 cycles with enhanced energy density characteristics both gravimetrically and volumetrically.

Here, we have proposed a new scheme to enhance the electrochemical performance of LIG-based supercapacitors by combining the advantages of pseudocapacitive MnO2 nanoparticles, easy-removed GO precursors, and programmable processing of LIG. The formation of GO-MnO2 precursor with proper GO content not only preserves the abundant active sites of MnO2 nanoparticles, but also ensures better ion transportation properties by adjusting the distribution of easy-stacking MnO2 nanoparticles. Therefore, the as-prepared LIG-GO-MnO2 films possess more active sites, better and more plentiful microstructures, and lower sheet resistance than solo LIG films, and the resultant LIG-GO-MnO2-based supercapacitors exhibit enhanced electrochemical performance compared with LIG based supercapacitors. Moreover, the LIG-GO-MnO2-based supercapacitors also display good cycling stability, with at least 92.59 % specific capacitance retention after 1000 cycling tests. And after more than nine months later, the LIG-GO-MnO2 based-supercapacitor still shows a specific capacitance retention of similar to 100 %. What's more, the need for additive connections. In-series LIG-GO-MnO2-based supercapacitors could be obtained by a single laser induced process owing to the performance uniformity of a single supercapacitor, which realize the voltage extension from 0.8 to 2. 4 V and power an LED. In this work, we have demonstrated the possibility of using GO as an auxiliary agent instead of routine roles as active materials and we hope this proposal will help expand the diversity of easy-removed nano-composite precursors in developing LIG-based devices in practical applications.

In-plane asymmetric supercapacitors not only have high energy and power delivery, but also have flexible form factors.This technology allows for high performance, miniaturization and integration, and greatly satisfies the need for future developments in portable and wearable electronic devices.In the process of achieving in-plane asymmetric supercapacitors, the techniques used to design the device in-plane will determine the ultimate range of applications.Here, the recent progress in the preparation of in-planar asymmetric supercapacitor encompassing electrode materials, production techniques and electrolyte was introduced, and the operation methods and practical performance of each planarization means was mainly introduced.The characteristics of different production techniques and the matters that should be paid attention to during operation was analysed, and the current key problems and future development trends of various technologies was disscussed.By summarizing current technological developments and experimental results at home and abroad, the paper analysed the limitations to in-planar energy storage devices and next steps to overcome these issues through the development of new materials or new structures.

Graphene-based supercapacitors are powerful devices for supporting smart wearable electronics. However, the properties of the as-prepared graphene and its analogues differ from the expected characteristics, which hinder the development of graphene-based energy storage devices. Herein, we demonstrated the fabrication of planar supercapacitors based on laser-induced electrostatic self-assembled graphene oxide-MXene (GO-M) composites. Owing to the synergetic effect of the laser-matter interaction and electrostatic self-assembly, the as-prepared reduced GO-M (R-GO-M) showed good conductivity and a better layered micro-/nanostructure than reduced graphene oxide (RGO). Moreover, in this laser-induced process, MXene was introduced in R-GO-M, which offered more active sites. Therefore, the supercapacitor based on R-GO-M exhibited noticeable capacity enhancement, five times more than the value of the RGO-based supercapacitor. Furthermore, after comprehensive electrochemical performance analysis, the proper electrostatic self-assembly ratio was confirmed to be 10:1. We believe that the laser fabrication technique combined with a simple electrostatic self-assembly mechanism will promote the development of graphenebased energy storage devices using a simple but effective method.

Since pure laser-induced graphene (LIG)-based supercapacitors suffer poor capacity, additional active materials need to be introduced to promote the capacitive performance of LIG-based electrodes. However, the effective introduction and the removal of redundant active materials remain challenging during the fabrication of planar LIG-based supercapacitors. Here we propose the easy-removed self-assembled MXene-graphene oxide composite (C) for the preparation of LIG-based supercapacitors. Owing to the combination of homogeneous C solution and programmable laser-induced process, the as-prepared supercapacitor based on laser-induced C covered polyimide (PI) films (LIG-C) showed enhanced capacity and improved ion transportation characteristics due to the low sheet resistance (15.0 ohm sq(-1)) and homogenous microstructures. What's more, the LIG-C-based supercapacitor prepared under laser power of 3 W exhibited good stability including a specific capacitance retention of 98.9% after six months and 102.4% after 1000 cycles charge-discharge process. Additionally, LIG-C-based supercapacitors also showed good performance uniformity, and series LIG-C-based supercapacitors could power a LED because of a voltage expansion. At the same time, LIG-C-based supercapacitors possessed good deformation-resisting properties under different bending states, which showed promising potential for future conformal electronics device applications. And we hope that this work will pave a new way for LIG-based material in the energy storage field.

MXene based layered materials have exhibited excellent performance in supercapacitor applications owing to their high conductivity. However, device planarization hinders their broader ability in a film-based energy storage device. Here, we have demonstrated the fabrication of self-assembled MXene–graphene oxide (M-GO) composites based on the electrostatic interaction between MXene and GO solutions. The as-prepared M-GO composite possessed homogeneous structures and tunable conductivities according to different GO contents, which benefit both charge storage and ions transmission. The first-assembly sandwiched supercapacitors based on these M-GO composites showed a maximum specific capacitance value of 39.0 mF/cm2 (10.9 mF/cm2 for MXene based devices). The enhanced electrochemical performance after self-assembly was due to the improved interface effect between electrodes and electrolytes. Additionally, the introduction of GO guarantees the completeness of designed M-GO patterns without the need for additives, and it is worth noting that with the assistance of a laser fabrication technique, planar supercapacitors based on the most suitable M-GO (with mass ratio of M:GO = 1:1) composite could be obtained by ablating the unwanted areas. Additionally, planar M-GO based supercapacitors also exhibited excellent electrochemical performance, which demonstrated the great potential of M-GO composite supercapacitors in wearable electronic applications.

The development of laser-induced graphene (LIG) has been regarded as an effective method for satisfying the substantial requirements for the scalable fabrication of graphene-based electrode materials. Despite the rapid progress in fabricating LIG-based supercapacitors, the incompatibility between material modification and the device planarization process remains a challenging problem to be resolved. In this study, we demonstrate the attributes of novel LIG-MXene (LIG-M) composite electrodes for flexible planar supercapacitors fabricated by direct laser writing (DLW) of MXene-coated polyimide (PI) films. During the DLW process, PI was transformed into LIG, while MXene was simultaneously introduced to produce LIG-M. Combining the porous structure of LIG and the high conductivity of MXene, the as-prepared LIG-M-based supercapacitor exhibited superior specific capacitance, five times higher than that of the pristine LIG-based supercapacitor. The enhanced capacitance of LIG-M also benefited from the pseudocapacitive performance of the abundant active sites offered by MXene. Moreover, the planar LIG-M-based device delivered excellent cycling stability and flexibility. No significant performance degradation was observed after bending tests. Arbitrary electrode patterns could be obtained using the DLW technique. The patterned in-series LIG-M supercapacitor was able to power a light-emitting diode, demonstrating significant potential for practical applications.

Stretchable supercapacitor with two-dimensional (2D) stretchability had high received attention for its practical applications such as wearable electronics and electronic skins. However, mechanical strength of devices and stretchable stability during repetitive movement have been seriously affected the device performance, which is all caused by the device structural design. Herein, we report a simple laser holography technology for periodic elastic substrate with 500-800μm microgrooved structures, and laser holography technology not only structured the elastic substrate but also could provide synchronous photoreduction of grapheme oxides (GO) for graphene electrodes. When the scan speed of 50mV/s, the tensile of devices is 54%, the area specific capacitance is 0.96mF/cm2, which shows less significant changes to area specific capacitance of 0.79mF/cm2 (0% tensile ratio). This work may hold great promise for production of stretchable grapheme supercapacitor that can be used in wearable electronic devices.

In view of the bulk production, resolvability, dispersibility of aqueous solution, graphene oxides (GO) prepared by strong chemical oxidation of graphite flakes have been widely used for the production of graphene-like materials. However, because of the insulating nature caused by amounts of defects on its surface, the application of GO material is greatly constrained. Hence, effective reduction of GO becomes critical. The photoreduction of GO showed more attractive properties than conventional thermal/chemical routes due to its synchronous reduction and flexible patterning, which facilitates a number of applications, such as the electrochemical energy storage devices, electronic devices, and biomimetic substrates. In this review, we dedicatedly summarized the latest advances in photoreduction including the fabrications and applied values in multiple fields. We deem that the photoreduction and synchronous patterning of GO will have very prospects in the development of graphene devices.

The reduction and patterning of graphene oxides (GOs) have broad applications in gene transfection, cell differentiation control, etc. However, two-dimensional (2D) photoreduction technologies (such as UV lithography) fail to realize the three-dimensional (3D) reduction and patterning of GO, limiting its applications in 3D electronic device interconnection and 3D graphene organ-on-a-chip. Here we developed 3D reduction and patterning of GO by femtosecond laser direct writing (FsLDW) technology. FsLDW has been adopted for 3D structure fabrication and 2D/3D micropatterning of reduced GOs on GO films. We deem that this technology will advance GO in the evolution of future electronics.

Herein, we report a simple laser holography technology for hierarchically structuring and synchronous photoreduction of graphene oxides (GO), toward the development of efficient graphene-based electrodes for supercapacitor applications in cost effectively manners. Hierarchical micro-nanostructures, formed due to laser treatment induced photoreduction and ablation effect. Interestingly, both the morphology and reduction degree of the laser holography reduced GO (LHRGO) show strong dependence on the laser intensity, providing the feasibility for controlling the micro-nanostructures, chemical composition, and the conductivity of the graphene electrodes. Furthermore, the supercapacitors based on LHRGO show higher capacitance values and better electrochemical performance compared to that based on thermal reduced GO (TRGO) of same reduction level. Photoredution and micro-nanostructuring of GO using laser holography may hold great promise for production of effective carbon-based electrodes towards practical applications in energy storage devices.

Inspired from fish scales that exhibit unique underwater superoleophobicity, artificial porous membranes featuring similar wettability have been successfully developed for oil-water separation. However, most of the superoleophobic meshes are workable only for underwater oil/water separation and become disabled in air. In this article, we reported the facile fabrication of underwater super-oleophobic kraft mesh and demonstrated efficient oil-water separation using kraft mesh origamis. Kraft paper that features porosity, natural hydrophilicity, and relatively high elasticity and tear resistance has been found to be an ideal candidate for developing underwater super-oleophobic origami. Direct laser drilling has been employed to make microhole arrays on the kraft paper, forming a flexible mesh. The hydrophilic nature and the hierarchical microstructures that consist of microhole arrays and porous microfiber networks make the resultant kraft mesh superoleophobic underwater, enabling oil-water separation. More importantly, the kraft mesh can retain a large amount of water (2.5 times its weight under dry conditions) owing to its porous and hydrophilic structure. Thus, the wet kraft mesh became a slippery surface for oil droplets when it was taken out of the water. This unique feature makes it possible to directly fish out oil droplets from water using a simple kraft mesh origami. Direct laser drilling of paper mesh for flexible origami may open up a new route to the rational design and fabrication of oil-water separation devices.

Here, we reported an ingenious fabrication of moisture responsive graphene-based actuator via unilateral two-beam laser interference (TBLI) treatment of graphene oxide (GO) papers. TBLI technique has been recognized as a representative photoreduction and patterning strategy for hierarchical structuring of GO. The GO paper can be reduced and cut into grating-like periodic reduced graphene oxide (RGO) microstructures due to laser ablation effect. However, the lower light transmittance of the thick GO paper and the corresponding thermal relaxation phenomenon make it impossible to trigger complete reduction, leading to the formation of the anisotropic GO/reduced GO (RGO) bilayer structure. Interestingly, the RGO side that feature lower OCGs and higher roughness shows strong water adsorption due to the formation of micronanostructures. Due to the different water adsorption capacities of the two sides, a flower moisture-responsive actuator has been fabricated, which exhibits “opening” and “closing” behavior under different humidity conditions.