MXene@c-MWCNT Adhesive Silica Nanofiber Membranes Enhancing Electromagnetic Interference Shielding and Thermal Insulation Performance in Extreme Environments

A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.

In Situ Polymer Gel Electrolyte in Boosting Scalable Fibre Lithium Battery Applications

The poor interfacial stability not only deteriorates fibre lithium-ion batteries(FLBs)performance but also impacts their scalable applications.To efficiently address these challenges,Prof.Huisheng Peng team proposed a generalized channel structures strategy with optimized in situ polymerization technology in their recent study.The resultant FLBs can be woven into different-sized powering textiles,providing a high energy density output of 128 Wh kg^(-1) and simultaneously demonstrating good durability even under harsh conditions.Such a promising strategy expands the horizon in developing FLB with particular polymer gel electrolytes,and significantly ever-deepening understanding of the scaled wearable energy textile system toward a sustainable future.

In-situ fabrication of on-chip 1T'-MoTe_(2)/Ge Schottky junction photodetector for self-powered broadband infrared imaging and position sensing

High-sensitivity room-temperature multi-dimensional infrared(IR)detection is crucial for military and civilian purposes.Recently,the gapless electronic structures and unique optoelectrical properties have made the two-dimensional(2D)topological semimetals promising candidates for the realization of multifunctional optoelectronic devices.Here,we demonstrated the in-situ construction of high-performance 1T’-MoTe_(2)/Ge Schottky junction device by inserting an ultrathin AlOx passivation layer.The good detection performance with an ultra-broadband detection wavelength range of up to 10.6 micron,an ultrafast response time of~160 ns,and a large specific detectivity of over 109 Jones in mid-infrared(MIR)range surpasses that of most 2D materials-based IR sensors,approaching the performance of commercial IR photodiodes.The on-chip integrated device arrays with 64 functional detectors feature high-resolution imaging capability at room temperature.All these outstanding detection features have enabled the demonstration of position-sensitive detection applications.It demonstrates an exceptional position sensitivity of 14.9 mV/mm,an outstanding nonlinearity of 6.44%,and commendable trajectory tracking and optoelectronic demodulation capabilities.This study not only offers a promising route towards room-temperature MIR optoelectronic applications,but also demonstrates a great potential for application in optical sensing systems.

One-step wet-spinning assembly of twisting-structured graphene/carbon nanotube fiber supercapacitor

Graphene fiber-based supercapacitors hold great promise as flexible energy-storage devices. However, simultaneously achieving high ion-transport ability in electrode and electrolyte layer, which is crucial for realizing the high electrochemical performance, still remains challenging. Here, a facile and effective strategy to solve the problem was proposed by developing a twisting-structured graphene/carbon nanotube(CNT) fiber supercapacitor via one-step wet-spinning process with customized multi-channel spinneret.The remarkable structure features of the resulting fiber supercapacitor with wrinkled and thin electrolyte layer, and well-developed porosity of fiber electrode favored the rapid infiltration and transport of electrolyte ions inside the electrode, as well as between electrode and electrolyte, thus boosting high specific capacitance of 187.6 mF cm^(-2) and energy density of 30.2 μWh cm^(-2), and featuring long cycling life(93%capacitance retention after 10,000 cycles) and excellent flexibility. Moreover, the specific capacitance and energy density could be further improved to 267.2 m F cm^(-2) and 66.8 μWh cm^(-2), respectively, when Mn O2 was incorporated into the fiber.

CoNi nanoparticles anchored inside carbon nanotube networks by transient heating:Low loading and high activity for oxygen reduction and evolution

Transitional metal alloy and compounds have been developed as the low cost and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).However,a high mass loading of these catalysts is commonly needed to achieve acceptable catalytic performance,which could cause such problems as battery weight gain,mass transport blocking,and catalyst loss.We report herein the preparation of fine CoNi nanoparticles(5-6 nm)anchored inside a nitrogendoped defective carbon nanotube network(CoNi@N-DCNT)by a transient Joule heating method.When utilized as an electrocatalyst for oxygen reduction and evolution in alkaline media,the CoNi@N-DCNT film catalyst with a very low mass loading of 0.06 mg cm^(-2) showed excellent bifunctional catalytic performance.For ORR,the onset potential(Eonset)and the half-wave potential(E_(1/2))were 0.92 V versus reversible hydrogen electrode(vs.RHE)and 0.83 V(vs.RHE),respectively.For OER,the potential at the current density(J)of 10 mA cm^(-2)(E_(10))was 1.53 V,resulting in an overpotential of 300 mV much lower than that of the commercial RuO_(2) catalyst(320 mV).The potential gap between E_(1/2) and E_(10) was as small as 0.7 V.Considering the low mass loading,the mass activity at E_(10) reached at 123.2 A g^(-1),much larger than that of the RuO_(2) catalyst and literature results of transitional metal-based bifunctional catalysts.Moreover,the CoNi@N-DCNT film catalyst showed very good long-term stability during the ORR and OER test.The excellent bifunctional catalytic performance could be attributed to the synergistic effect of the bimetal alloy.

Hollow Gradient-Structured Iron-Anchored Carbon Nanospheres for Enhanced Electromagnetic Wave Absorption

In the present paper,a microwave absorber with nanoscale gradient structure was proposed for enhancing the electromagnetic absorption performance.The inorganic-organic competitive coating strategy was employed,which can effectively adjust the thermodynamic and kinetic reactions of iron ions during the solvothermal process.As a result,Fe nanoparticles can be gradually decreased from the inner side to the surface across the hollow carbon shell.The results reveal that it offers an outstanding reflection loss value in combination with broadband wave absorption and flexible adjustment ability,which is superior to other relative graded distribution structures and satisfied with the requirements of lightweight equipment.In addition,this work elucidates the intrinsic microwave regulation mechanism of the multiscale hybrid electromagnetic wave absorber.The excellent impedance matching and moderate dielectric parameters are exhibited to be the dominative factors for the promotion of microwave absorption performance of the optimized materials.This strategy to prepare gradient-distributed microwave absorbing materials initiates a new way for designing and fabricating wave absorber with excellent impedance matching property in practical applications.

Dual-Ion Co-Regulation System Enabling High-Performance Electrochemical Artificial Yarn Muscles with Energy-Free Catch States

Artificial yarn muscles show great potential in applications requiring low-energy consumption while maintaining high performance. However, conventional designs have been limited by weak ion-yarn muscle interactions and inefficient “rocking-chair” ion migration. To address these limitations, we present an electrochemical artificial yarn muscle design driven by a dual-ion co-regulation system. By utilizing two reaction channels, this system shortens ion migration pathways, leading to faster and more efficient actuation. During the charging/discharging process, PF_6~- ions react with carbon nanotube yarn, while Li~+ ions react with an Al foil. The intercalation reaction between PF_6~- and collapsed carbon nanotubes allows the yarn muscle to achieve an energy-free high-tension catch state. The dual-ion coordinated yarn muscles exhibit superior contractile stroke, maximum contractile rate, and maximum power densities, exceeding those of “rocking-chair” type ion migration yarn muscles. The dual-ion co-regulation system enhances the ion migration rate during actuation, resulting in improved performance. Moreover, the yarn muscles can withstand high levels of isometric stress, displaying a stress of 61 times that of skeletal muscles and 8 times that of “rocking-chair” type yarn muscles at higher frequencies. This technology holds significant potential for various applications, including prosthetics and robotics.

A bifunctional wood membrane modified by MoS_(2)/covalent organic framework heterojunctions for effective solar-driven water evaporation and contaminant degradation

Interfacial solar evaporation technology is considered one of the most promising strategies for alleviating the scarcity of freshwater resources.However,solar-driven evaporation technology cannot eliminate the pollutants in the residual wastewater.To solve this problem,we have prepared a two-in-one solar-driven evaporation/photocatalysis system by decorating MoS_(2)/covalent organic framework(COF)heterojunctions on wood(MoS_(2)/COF-wood).Thanks to the unique porous structure of wood,it provides a strong guarantee for water transport and vapor release during the evaporation process.The introduction of MoS_(2) and COFs can promote the breaking of hydrogen bonds between water molecules,which leads to a significant decrease in the enthalpy of evaporation,achieving a water evaporation rate as high as 2.17 kg m^(-2)h^(-1)under 1 sun irradiation.Meanwhile,the resulting MoS_(2)/COF-wood exhibits good salt resistance and reusability.In addition,the heterojunctions formed between COFs and MoS_(2) can effectively inhibit charge carrier complexation and improve the photocatalytic degradation ability of pollutants(over 99%).This study highlights the construction strategy of bifunctional wood-based materials for freshwater production and wastewater remediation.

Modulating selective interaction of NiOOH with Mg ions for high-performance aqueous batteries

Aqueous Mg-ion batteries(AMIBs)featuring advantages of good safety,low cost,and high specific energy have been recognized as a promising energy-storage technology.However,the performance of AMIBs is consistently limited by sluggish diffusion kinetics and structural degradation of cathode materials arising from the strong electrostatic interactions between high-charge-density Mg2+and host materials.Here,layered-structured NiOOH,as traditional cathodes for alkaline batteries,is initially demonstrated to realize proton-assisted Mg-(de)intercalation chemistry with a high discharge platform(0.57V)in neutral aqueous electrolytes.Benefiting from the unique core/shell structure,the resulting NiOOH/CNT cathodes achieve a high capacity of 122.5 mAh g−1 and long cycle stability.Further theoretical calculations reveal that the binding energy of hydrated Mg2+is higher than that of Mg2+with NiOOH,resulting in that Mg2+is easily intercalated/de-intercalated into/from NiOOH.Benefiting from the freestanding design,the assembled fiber-shaped“rocking-chair”NaTi2(PO4)3//NiOOH AMIB shows a high energy density and satisfactory mechanical flexibility,which could be woven into a commercial fabric and power for fiber-shaped photoelectric sensors.

Understanding and unveiling the electro-chemo-mechanical behavior in solid-state batteries

Solid-state batteries(SSBs)are attracting growing interest as long-lasting,thermally resilient,and high-safe energy storage systems.As an emerging area of battery chemistry,there are many issues with SSBs,including strongly reductive lithium anodes,oxidized cathodes(state of charge),the thermodynamic stability limits of solid-state electrolytes(SSEs),and the ubiquitous and critical interfaces.In this Review,we provided an overview of the main obstacles in the development of SSBs,such as the lithium anode|SSEs interface,the cathode|SSEs interface,lithium-ion transport in the SSEs,and the root origin of lithium intrusions,as well as the safety issues caused by the dendrites.Understanding and overcoming these obstacles are crucial but also extremely challenging as the localized and buried nature of the intimate contact between electrode and SSEs makes direct detection difficult.We reviewed advanced characterization techniques and discussed the complex ion/electron-transport mechanism that have been plaguing electrochemists.Finally,we focused on studying and revealing the coupled electro-chemo-mechanical behavior occurring in the lithium anode,cathode,SSEs,and beyond.

A multifunctional flexible sensor based on PI-MXene/SrTiO_(3) hybrid aerogel for tactile perception

The inadequacy of tactile perception systems in humanoid robotic manipulators limits the breadth of available robotic applications.Here,we designed a multifunctional flexible tactile sensor for robotic fingers that provides capabilities similar to those of human skin sensing modalities.This sensor utilizes a novel PI-MXene/SrTiO_(3) hybrid aerogel developed as a sensing unit with the additional abilities of electromagnetic transmission and thermal insulation to adapt to certain complex environments.Moreover,polyimide(PI)provides a high-strength skeleton,MXene realizes a pressure-sensing function,and MXene/SrTiO_(3) achieves both thermoelectric and infrared radiation response behaviors.Furthermore,via the pressure response mechanism and unsteady-state heat transfer,these aerogel-derived flexible sensors realize multimodal sensing and recognition capabilities with minimal cross-coupling.They can differentiate among 13 types of hardness and four types of material from objects with accuracies of 94%and 85%,respectively,using a decision tree algorithm.In addition,based on the infrared radiation-sensing function,a sensory array was assembled,and different shapes of objects were successfully recognized.These findings demonstrate that this PI-MXene/SrTiO_(3) aerogel provides a new concept for expanding the multifunctionality of flexible sensors such that the manipulator can more closely reach the tactile level of the human hand.This advancement reduces the difficulty of integrating humanoid robots and provides a new breadth of application scenarios for their possibility.

Water droplets play a role in Internet of Things applications

Water droplets help life in nature survive,thrive,and evolve.With water droplet serv-ing as one of the indispensable elements in the Internet of Things(IoT),many droplet-oriented technologies,such as microfluidics,droplet manipulation,electrowetting,and energy harvesting,make rapid progress driven by material science,computer science,and medicine.Droplet-based wearable devices are endowed with advantages such as flexibility,sensing ability,and automation for various parameter detection.Besides,the continuous exploration of droplet manipulation has led to the emergence of a wide variety of manipulation methods.Meanwhile,electrowetting that utilizes exter-nal fields modifying liquid–solid surfaces has found its applications in various areas,including droplet transportation,microfabrication,and healthcare.The energy gener-ation from water droplets also presents exciting opportunities for the development of novel electricity generators.These approaches for droplet utilization underscore the immense potentials and versatilities of droplet-based technologies in the IoT land-scape.Hence,this mini review presents the fundamental droplet-based technologies by summarizing their working mechanisms and methods,device structures,and appli-cations.Given the challenges in materials,fabrication,and system integration,this review shows the overall development roadmap in terms of improved functionality and performance and highlights the opportunities toward multifunctional,self-sustainable,and intelligent systems,which is called for IoT construction.

In-situ emb e dding zeolitic imidazolate framework derived Co–N–C bifunctional catalysts in carbon nanotube networks for flexible Zn–air batteries

Recently, the development of high-performance bifunctional oxygen catalysts integrated with flexible conductive scaffolds f or rechargeable metal-air batteries has attracted considerable interest, driving by fastgrowing wearable electronics. Herein, we report a flexible bifunctional oxygen catalyst thin film consisting of Co–N–C bifunctional catalysts embedding in carbon nanotube(CNT) networks. The catalyst is readily prepared by pyrolysis of cobalt-based zeolitic imidazolate frameworks(ZIF-67) that are in-situ synthesized in CNT networks. Such catalyst film demonstrates very high catalytic activities for oxygen reduction(onset potential: 0.91 V, and half-wave potential: 0.87 V vs. RHE) and oxygen evolution(10 m Acm^-2 at 1.58 V) reactions, high methanol tolerance property, and long-term stability(97% current retention). Moreover, our integrated catalyst film shows very good structure flexibility and robustness. Based on the obtained film air electrodes, flexible Zn–air batteries demonstrate low charging and discharging overpotentials(0.82 V at 1 m A cm^-1) and excellent structure stability in the bending tests. These results indicate that presently reported catalyst films are potential air electrodes for flexible metal–air batteries.

High-loading Co-doped NiO nanosheets on carbon-welded carbon nanotube framework enabling rapid charge kinetic for enhanced supercapacitor performance

Developing high power and energy supercapacitors(SCs)is a long-pursued goal for the application in transportation and energy storage station.Herein,a rationally-designed Co-doped nickel oxide nanosheets@carbon-welded carbon nanotube foam(Co-doped NiO@WCNTF)as freestanding electrode is successfully prepared for high power and energy SCs.The WCNTF framework with high specific surface area provides three dimensional highly conductive network for fast charge transport and ensures high loading of active materials(9.2 mg/cm2).Moreover,porous Co-doped NiO nanosheets uniformly anchored on the WCNTF framework enable rapid charge kinetics due to the high intrinsic conductivity of Co-doped Ni O nanosheets and their good contact with conductive WCNTF substrate.As a result,the unique integrated electrode with 3D architecture exhibits an ultrahigh specific capacitance of 11.45 F/cm2 at 5 mA/cm2,outstanding rate capability(11.45 F/cm2 at 5 mA/cm2 and a capacitance retention of 86.2%at 30 mA/cm2)and good cycling stability,suggesting great potential for high performance supercapacitor.

Negative photoconductivity in low-dimensional materials

In recent years,low-dimensional materials have received extensive attention in the field of electronics and optoelectronics.Among them,photoelectric devices based on photoconductive effect in low-dimensional materials have a broad development space.In contrast to positive photoconductivity,negative photoconductivity(NPC)refers to a phenomenon that the conductivity decreases under illumination.It has novel application prospects in the field of optoelectronics,memory,and gas detection,etc.In this paper,we review reports about the NPC effect in low-dimensional materials and systematically summarize the mechanisms to form the NPC effect in existing low-dimensional materials.

Van der Waals integration inch-scale 2D MoSe_(2) layers on Si for highly-sensitive broadband photodetection and imaging

As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable bandgap,high carrier mobility,and excellent air stability.Although 2D MoSe_(2)-based photodetectors have been reported to exhibit admired performance,the large-area 2D MoSe_(2)layers are difficult to be achieved via conventional synthesis methods,which severely impedes its future applications.Here,we present the controllable growth of large-area 2D MoSe_(2)layers over 3.5-inch with excellent homogeneity by a simple post-selenization route.Further,a high-quality n-MoSe_(2)/p-Si van der Waals(vdW)heterojunction device is in-situ fabricated by directly growing 2D n-MoSe_(2)layers on the patterned p-Si substrate,which shows a self-driven broadband photoresponse ranging from ultraviolet to mid-wave infrared with an impressive responsivity of 720.5 mA·W^(−1),a high specific detectivity of 10^(13) Jones,and a fast response time to follow nanosecond pulsed optical signal.In addition,thanks to the inch-level 2D MoSe_(2)layers,a 4×4 integrated heterojunction device array is achieved,which has demonstrated good uniformity and satisfying imaging capability.The large-area 2D MoSe_(2)layer and its heterojunction device array have great promise for high-performance photodetection and imaging applications in integrated optoelectronic systems.

Layer-controlled nonlinear terahertz valleytronics in two-dimensional semimetal and semiconductor PtSe_(2)

Platinum diselenide(PtSe_(2))is a promising two-dimensional(2D)material for the terahertz(THz)range as,unlike other transition metal dichalcogenides(TMDs),its bandgap can be uniquely tuned from a semiconductor in the nearinfrared to a semimetal with the number of atomic layers.This gives the material unique THz photonic properties that can be layer-engineered.Here,we demonstrate that a controlled THz nonlinearity—tuned from monolayer to bulk PtSe_(2)—can be realized in wafer size polycrystalline PtSe_(2)through the generation of ultrafast photocurrents and the engineering of the bandstructure valleys.This is combined with the PtSe_(2)layer interaction with the substrate for a broken material centrosymmetry,permitting a second order nonlinearity.Further,we show layer dependent circular dichroism,where the sign of the ultrafast currents and hence the phase of the emitted THz pulse can be controlled through the excitation of different bandstructure valleys.In particular,we show that a semimetal has a strong dichroism that is absent in the monolayer and few layer semiconducting limit.The microscopic origins of this TMD bandstructure engineering are highlighted through detailed DFT simulations,and shows the circular dichroism can be controlled when PtSe_(2)becomes a semimetal and when the K-valleys can be excited.As well as showing that PtSe_(2)is a promising material for THz generation through layer controlled optical nonlinearities,this work opens up a new class of circular dichroism materials beyond the monolayer limit that has been the case of traditional TMDs,and impacting a range of domains from THz valleytronics,THz spintronics to harmonic generation.

Carbon nanotube fibers with excellent mechanical and electrical properties by structural realigning and densification

Floating catalysis chemical vapor deposition(FCCVD)direct spinning process is an attractive method for fabrication of carbon nanotube fibers(CNTFs).However,the intrinsic structural defects,such as entanglement of the constituent carbon nanotubes(CNTs)and inter-tube gaps within the FCCVD CNTFs,hinder the enhancement of mechanical/electrical properties and the realization of practical applications of CNTFs.Therefore,achieving a comprehensive reassembly of CNTFs with both high alignment and dense packing is particularly crucial.Herein,an efficient reinforcing strategy for FCCVD CNTFs was developed,involving chlorosulfonic acid-assisted wet stretching for CNT realigning and mechanical rolling for densification.To reveal the intrinsic relationship between the microstructure and the mechanical/electrical properties of CNTFs,the microstructure evolution of the CNTFs was characterized by cross-sectional scanning electron microscopy(SEM),wide angle X-ray scattering(WAXS),polarized Raman spectroscopy and Brunauer–Emmett–Teller(BET)analysis.The results demonstrate that this strategy can improve the CNT alignment and eliminate the inter-tube voids in the CNTFs,which will lead to the decrease of mean distance between CNTs and increase of inter-tube contact area,resulting in the enhanced inter-tube van der Waals interactions.These microstructural evolutions are beneficial to the load transfer and electron transport between CNTs,and are the main cause of the significant enhancement of mechanical and electrical properties of the CNTFs.Specifically,the tensile strength,elastic modulus and electrical conductivity of the high-performance CNTFs are 7.67 GPa,230 GPa and 4.36×10^(6)S/m,respectively.It paves the way for further applications of CNTFs in high-end functional composites.

Spin orbit torques in Pt-based heterostructures with van der Waals interface

Spin orbit torques(SOTs)in ferromagnet/heavy-metal heterostructures have provided great opportunities for efficient manipulation of spintronic devices.However,deterministically field-free switching of perpendicular magnetization with SOTs is forbidden because of the global two-fold rotational symmetry in conventional heavy-metal such as Pt.Here,we engineer the interface of Pt/Ni heterostructures by inserting a monolayer MoTe_(2)with low crystal symmetry.It is demonstrated that the spin orbit efficiency,as well as the out-of-plane magnetic anisotropy and the Gilbert damping of Ni are enhanced,due to the effect of orbital hybridization and the increased spin scatting at the interface induced by MoTe_(2).Particularly,an out-of-plane damping-like torque is observed when the current is applied perpendicular to the mirror plane of the MoTe_(2)crystal,which is attributed to the interfacial inversion symmetry breaking of the system.Our work provides an effective route for engineering the SOT in Pt-based heterostructures,and offers potential opportunities for van der Waals interfaces in spintronic devices.

Electrical manipulation of lightwaves in the uniaxially strained photonic honeycomb lattices under a pseudomagnetic field

The realization of pseudomagnetic fields for lightwaves has attained great attention in the field of nanophotonics.Like real magnetic fields,Landau quantization could be induced by pseudomagnetic fields in the strainengineered graphene.We demonstrated that pseudomagnetic fields can also be introduced to photonic crystals by exerting a linear parabolic deformation onto the honeycomb lattices,giving rise to degenerate energy states and flat plateaus in the photonic band structures.We successfully inspire the photonic snake modes corresponding to the helical state in the synthetic magnetic heterostructure by adopting a microdisk for the unidirectional coupling.By integrating heat electrodes,we can further electrically manipulate the photonic density of states for the uniaxially strained photonic crystal.This offers an unprecedented opportunity to obtain on-chip robust optical transports under the electrical tunable pseudomagnetic fields,opening the possibility to design Si-based functional topological photonic devices.