High?Voltage Flexible Aqueous Zn?Ion Battery with Extremely Low Dropout Voltage and Super?Flat Platform

Flexible rechargeable aqueous zinc-ion batteries(ZIBs)have attracted extensive attentions in the energy storage field due to their high safety,environmental friendliness,and outstanding electrochemical performance while the exploration of high-voltage aqueous ZIBs with excellent rate capability is still a great challenge for the further application them in flexible and wearable electronics.Herein,we fabricated a 2.4 V high-voltage flexible aqueous ZIB,being among the highest voltage reported in aqueous ZIBs.Moreover,it exhibits extremely flat charging/discharging voltage platforms and the dropout voltage is only 0.1 V,which is the smallest gap in all aqueous batteries to our best knowledge.Furthermore,the prepared ZIB performs high rate capability of 25 C and energy density of 120 Wh kg?1 and exhibits excellent safety under various destructive conditions including hammering,sewing,punching,and soaking.These extraordinary results indicate the great application potential of our high-voltage flexible aqueous ZIB in wearable electronics.

Conformal manufacturing of soft deformable sensors on the curved surface

Health monitoring of structures and people requires the integration of sensors and devices on various 3D curvilinear,hierarchically structured,and even dynamically changing surfaces.Therefore,it is highly desirable to explore conformal manufacturing techniques to fabricate and integrate soft deformable devices on complex 3D curvilinear surfaces.Although planar fabrication methods are not directly suitable to manufacture conformal devices on 3D curvilinear surfaces,they can be combined with stretchable structures and the use of transfer printing or assembly methods to enable the device integration on 3D surfaces.Combined with functional nanomaterials,various direct printing and writing methods have also been developed to fabricate conformal electronics on curved surfaces with intimate contact even over a large area.After a brief summary of the recent advancement of the recent conformal manufacturing techniques,we also discuss the challenges and potential opportunities for future development in this burgeoning field of conformal electronics on complex 3D surfaces.

Hydroxyl Group Modifies Aggregation Behavior of a Non-ionic Hydro-fluorocarbon Hybrid Surfactant by Disrupting Interfacial Water

Two non-ionic hydro-fluorocarbon hybrid surfactants with and without hydroxyl groups were synthesized and compared.They exhibited good thermal stability and superior surface activity.It was observed that the hydroxyl group had a profound effect on modifying the surface tension of their solutions and the morphology of the formed micelles.This effect may be attributed to the rearranging of the alkane group from above the air/aqueous surface to below it and the disrupting of the interfacial water structure induced by the hydroxyl groups.This work provides a strategy to weaken the immiscibility between hydrocarbon and fluorocarbon chains by modifying their orientational structure at the interface,thus it is helpful for the design of surfactants with varied interfacial properties.

Nontrivial Topological States in BaSn5 Superconductor Probed by de Haas–van Alphen Quantum Oscillations

We report the nontrivial topological states in an intrinsic type-Ⅱ superconductor BaSn_(5)(T_(c)∼4.4 K)probed by measuring the magnetization,specific heat,de Haas–van Alphen(dHvA)effect,and by performing first-principles calculations.The first-principles calculations reveal a topological nodal ring structure centered at the H point in the k_(z)=πplane of the Brillouin zone,which could be gapped by spin-orbit coupling(SOC),yielding relatively small gaps below and above the Fermi level of about 0.04 eV and 0.14 eV,respectively.The SOC also results in a pair of Dirac points along theΓ–A direction,located at∼0.2 eV above the Fermi level.The analysis of the dHvA quantum oscillations supports the calculations by revealing a nontrivial Berry phase originating from the hole and electron pockets related to the bands forming the Dirac cones.Thus,our study provides an excellent avenue for investigating the interplay between superconductivity and nontrivial topological states.

Photoemission Spectroscopic Evidence of Multiple Dirac Cones in Superconducting BaSn_(3)

Signatures of topological superconductivity(TSC)in superconducting materials with topological nontrivial states prompt intensive researches recently.Utilizing high-resolution angle-resolved photoemission spectroscopy and first-principles calculations,we demonstrate multiple Dirac fermions and surface states in superconductor BaSn_(3) with a critical transition temperature of about 4.4 K.We predict and then unveil the existence of two pairs of type-Ⅰtopological Dirac fermions residing on the rotational axis.Type-ⅡDirac fermions protected by screw axis are confirmed in the same compound.Further calculation for the spin helical texture of the observed surface states originating from the Dirac fermions gives an opportunity for realization of TSC in one single material.Hosting multiple Dirac fermions and topological surface states,the intrinsic superconductor BaSn_(3) is expected to be a new platform for further investigation of topological quantum materials as well as TSC.

de Haas–van Alphen Quantum Oscillations in BaSn3 Superconductor with Multiple Dirac Fermions

Characterization of Fermi surface of the BaSn3 superconductor(Tc~ 4.4K)by de Haas–van Alphen(dHvA)effect measurement reveals its non-trivial topological properties.Analysis of non-zero Berry phase is supported by the ab initio calculations,which reveals a type-II Dirac point setting and tilting along the high symmetric K–H line of the Brillouin zone,about 0.13 eV above the Fermi level,and other two type-I Dirac points on the high symmetric Г–A direction,but slightly far below the Fermi level.The results demonstrate BaSn3 as an excellent example hosting multiple Dirac fermions and an outstanding platform for studying the interplay between nontrivial topological states and superconductivity.

Flexible aqueous Ca-ion full battery with super-flat discharge voltage plateau

Recently,multivalent metal-ion batteries have attracted considerable interests on the merits of their natural abundance and multielectron redox property.However,the development of Ca-ion battery is still in their preliminary stage because of the lack of suitable electrode material.The Ca-storage performance of the existing materials is still unsatisfactory with low capacity,poor cyclic stability,as well as sloping discharge profiles,which cannot provide stable energy output.In this work,transition metal oxide Sn-doped In2O3(ITO)has been explored as the aqueous Ca-ion battery anode,which could deliver a high discharge capacity of 71.2 mAh·g^(-1) with an ultra-flat discharge voltage plateau.The Ca storage mechanism was revealed to be reversible conversion reaction based on ex-situ X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron microscopy(TEM)characterizations.A flexible aqueous Ca-ion battery was subsequently assembled with zinc hexacyanoferrate(ZnHCF)cathode and ITO anode sandwiched by hydrogel electrolyte,which could deliver a high specific capacity of 75.3 mAh·g^(-1) at 0.4 A·g^(-1) with a flat output voltage plateau at around 0.8 V.The bendable and flexible Ca-ion battery with decent voltage output will pave the way for the energy storage devices towards practical applications in flexible and wearable electronics.

Migrating behaviors of interfacial elements and oxide layers during diffusion bonding of 6063Al alloys using Zn interlayer in air

The oxide layer on the surface has always been a key obstacle to achieving the diffusion bonding of Al alloys.It is a challenge for performing diffusion bonding without removing oxide layers.Herein,diffusion bonding of Al alloy retaining continuous oxide layers was successfully achieved in the air by a low-temperature and low-pressure diffusion bonding mothed using a Zn interlayer.During the bonding processes,conducted at 360℃ and 3 MPa,Zn diffused into Al through cracks of thin oxide layers to form the joint composed Al/(diffusion layer)/(oxide layer)/(Zn)/(oxide layer)/(diffusion layer)/Al.The diffusion layers were composed of Zn-Al eutectoid,and the oxide layer included nanocrystals and amorphous Al_(2)O_(3).The shear strength of joints containing continuous oxide layers was about 30 MPa.Interestingly,the migration behavior toward the joint center of the interfacial oxide layers was observed with consuming of the Zn interlayer.The cracking phenomenon,the“subcutaneous diffusion”and the migration behavior of oxide layers were verified and analyzed by the diffusion bonding of anodized 6063Al-6063Al.Subsequently,the dynamic migration mechanism of oxide layers with elements diffusion and bonding interface strengths were discussed in detail.The ability to join Al alloys in the air at low temperatures and low pressure suggests a highly practical and economic method for diffusion bonding.

Preparation and application of microfluidic SERS substrate:Challenges and future perspectives

Surface-enhanced Raman spectroscopy(SERS),as a highly sensitive molecular analysis technique,can realize fast and non-destructive detection of the information of molecular bonds to identify the component of analytes by"fingerprint"identification.The preparation of SERS substrates plays an extremely important role in the development of SERS technology and the application of SERS detection.By integrating SERS enhancement substrates into microfluidic chips,researchers have developed the microfluidic SERS chips which expand the function of microfluidic chips and provide an efficient platform for on-site biochemical analysis equipped with the powerful sensing capability of SERS technique.In this paper,we will first briefly give a review of the current microfluidic SERS-active substrates preparation technology and present the perspective on the application prospects of microfluidic SERS-active substrates.And then the challenges in the preparation of microfluidic SERS-active substrates will be pointed out,as well as realistic issues of using this technology for biochemical application.

Energy-dissipative dual-crosslinked hydrogels for dynamically super-tough sensors

In the fields of electronic skin and soft wearable sensors,intrinsically stretchable conductors undergo rapid development;however,practical applications of artificial skinlike materials/devices have not been realized because of the difficulty in combining the electromechanical properties and sensing performance.Contrarily,insoluble inorganic conductive domains in the hydrogel matrix are generally incompatible with surrounding elastic networks,decreasing the mechanical strength.Usually,the hydrogels are vulnerable either to severe mechanical stimuli or large deformation,especially when notches are induced.In this study,based on an energy-dissipative dual-crosslinked conductive hydrogel,a mechanically durable and super-tough strain sensor was developed.The highly soft yet dynamically tough hydrogel demonstrated high ionic conductivity(30.2 mS cm^(-1)),ultrastretchability(>600%strain),and superior linear dependence of strain sensitivity with a maximum gauge factor of 1.2 at 500%strain.Because of these advantageous synergistic effects,the resultant hydrogel strain sensor demonstrated reliable and stable detection of a large range of human motion and subtle vibrations.Moreover,it impressively exhibited super toughness that could endure consecutive treading pressure and even retain normal operation after 20 times of car run-over on the road.These demonstrations highly confirm the sensor’s superior mechanical durability and reliability,displaying great potential in developing next-generation mechanically adaptable sensors.

Performance enhancement of paper-based SERS chips by shell-isolated nanoparticle-enhanced Raman spectroscopy

Paper-based flexible surface-enhanced Raman scattering(SERS) chips have been demonstrated to have great potential for future practical applications in point-of-care testing(POCT) due to the potentials of massive fabrication, low cost, efficient sample collection and short signal acquisition time. In this work,common filter paper and Ag@Si O2 core-shell nanoparticles(NP) have been utilized to fabricate SERS chips based on shell-isolated nanoparticle-enhanced Raman spectroscopy(SHINERS). The SERS performance of the chips for POCT applications was systematically investigated. We used crystal violet as the model molecule to study the influence of the size of the Ag core and the thickness of the Si O2 coating layer on the SERS activity and then the morphology optimized Ag@Si O2 core-shell NPs was employed to detect thiram. By utilizing the smartphone as a miniaturized Raman spectral analyzer, high SERS sensitivity of thiram with a detection limit of 10^-9 M was obtained. The study on the stability of the SERS chips shows that a Si O2 shell of 3 nm can effectively protect the as-prepared SERS chips against oxidation in ambient atmosphere without seriously weakening the SERS sensitivity. Our results indicated that the SERS chips by SHINERS had great potential of practical application, such as pesticide residues detection in POCT.

Fundamentals and applications of enzyme powered micro/nano-motors

Micro/nanomotors(MNMs)are miniaturized machines that can convert many kinds of energy into mechanical motion.Over the past decades,a variety of driving mechanisms have been developed,which have greatly extended the application scenarios of MNMs.Enzymes exist in natural organisms which can convert chemical energy into mechanical force.It is an innovative attempt to utilize enzymes as biocatalyst providing driving force for MNMs.The fuels for enzymatic reactions are biofriendly as compared to traditional counterparts,which makes enzyme-powered micro/nanomotors(EMNMs)of great value in biomedical field for their nature of biocompatibility.Until now,EMNMs with various shapes can be propelled by catalase,urease and many others.Also,they can be endowed with multiple functionalities to accomplish on-demand tasks.Herein,combined with the development process of EMNMs,we are committed to present a comprehensive understanding of EMNMs,including their types,propelling principles,and potential applications.In this review,we will introduce single enzyme that can be used as motor,enzyme powered molecule motors and other micro/nano-architectures.The fundamental mechanism of energy conversion process of EMNMs and crucial factors that affect their movement behavior will be discussed.The current progress of proof-of-concept applications of EMNMs will also be elaborated in detail.At last,we will summarize and prospect the opportunities and challenges that EMNMs will face in their future development.

Rechargeable quasi-solid-state aqueous hybrid Al^(3+)/H^(+) battery with 10,000 ultralong cycle stability and smart switching capability

Safe and long lifespan batteries facilitate the development of portable electronics and electric vehicles.Owing to the low-cost,naturally abundance,and trivalent charge carrier of aluminum with the highest theoretical volumetric capacity,rechargeable aqueous aluminum-ion-based batteries are considered as promising next-generation secondary batteries.However,traditional electrolytes and frequent collapse of the host structure of electrode materials greatly jeopardize the cycle stability of the batteries.Here,we develop a novel hydrogel-based electrolyte coupled with stable layered intercalation electrodes for the first time to fabricate a highly safe and flexible rechargeable hybrid Al^(3^(+))/H^(+)battery.The as-fabricated hybrid-ion battery(HIB)delivers a high specific capacity of 125 mAh·g^(−1) at 0.1 A·g^(−1) and exhibits an unprecedented super long-term cycling stability with no capacity fading over 10,000 cycles at 2 A·g^(−1).In addition,the hydrogel-based electrolyte possesses smart function of thermoresponsive switching,which can effectively prevent thermal runaway for the batteries.The unprecedented long cycle stability,highly intrinsic safety as well as low-cost indicate that the flexible aqueous HIBs are promising for applications.

Versatile Ti_(3)C_(2)T_(x)MXene for free-radical scavenging

MXene,as an emerging two-dimensional(2D)material with ultrathin structure and fascinating physiochemical properties,has been widely explored in broad applications.Versatile functions of MXenes are continuously explored.This work presents distinctive feature of MXene-Ti_(3)C_(2)T_(x)nanosheets for free-radical(FRs)scavenging that never reported before.We demonstrated the mechanism and equation in regard to the reaction between Ti_(3)C_(2)T_(x)and H_(2)O_(2),which was applied to design colorimetric H_(2)O_(2)strip assay with good performance.The good FRs scavenging capability of Ti_(3)C_(2)T_(x),including a series of reactive oxygen species(ROS)and reactive nitrogen species(RNS),was systemically confirmed.The antioxidation capability of Ti_(3)C_(2)T_(x)for protecting cells from oxidative damage was demonstrated using the oxidative damage model of alpha mouse liver 12(AML-12)cells.This original work provides huge opportunities for MXenes in FR-related biomedical applications.

Magnetic Nanomotor-Based Maneuverable SERS Probe

Surface-enhanced Raman spectroscopy(SERS)is a powerful sensing technique capable of capturing ultrasensitive fingerprint signal of analytes with extremely low concentration.However,conventional SERS probes are passive nanoparticles which are usually massively applied for biochemical sensing,lacking controllability and adaptability for precise and targeted sensing at a small scale.Herein,we report a“rod-like”magnetic nanomotor-based SERS probe(MNM-SP)that integrates a mobile and controllable platform of micro-/nanomotors with a SERS sensing technique.The“rod-like”structure is prepared by coating a thin layer of silica onto the self-assembled magnetic nanoparticles.Afterwards,SERS hotspots of silver nanoparticles(AgNPs)are decorated as detecting nanoprobes.The MNM-SPs can be navigated on-demand to avoid obstacles and target sensing sites by the guidance of an external gradient magnetic field.Through applying a rotating magnetic field,the MNM-SPs can actively rotate to efficiently stir and mix surrounding fluid and thus contact with analytes quickly for SERS sensing.Innovatively,we demonstrate the self-cleaning capability of the MNM-SPs which can be used to overcome the contamination problem of traditional single-use SERS probes.Furthermore,the MNM-SPs could precisely approach the targeted single cell and then enter into the cell by endocytosis.It is worth mentioning that by the effective mixing of intracellular biocomponents,much more informative Raman signals with improved signal-to-noise ratio can be captured after active rotation.Therefore,the demonstrated magnetically activated MNM-SPs that are endowed with SERS sensing capability pave way to the future development of smart sensing probes with maneuverability for biochemical analysis at the micro-/nanoscale.