Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxflow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are evaluated.It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups.The battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a specific capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs.Li/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species.The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory calculations.Therefore,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxflow batteries.

Advances in particulate matter filtration:Materials,performance,and application

Air-borne pollutants in particulate matter(PM)form,produced either physically during industrial processes or certain biological routes,have posed a great threat to human health.Particularly during the current COVID-19 pandemic,effective filtration of the virus is an urgent matter worldwide.In this review,we first introduce some fundamentals about PM,including its source and classification,filtration mechanisms,and evaluation parameters.Advanced filtration materials and their functions are then summarized,among which polymers and MOFs are discussed in detail together with their antibacterial performance.The discussion on the application is divided into end-of-pipe treatment and source control.Finally,we conclude this review with our prospective view on future research in this area.

Functionalized Fiber-Based Strain Sensors:Pathway to Next-Generation Wearable Electronics

Wearable strain sensors are arousing increasing research interests in recent years on account of their potentials in motion detection,personal and public healthcare,future entertainment,man-machine interaction,artificial intelligence,and so forth.Much research has focused on fiber-based sensors due to the appealing performance of fibers,including processing flexibility,wearing comfortability,outstanding lifetime and serviceability,low-cost and large-scale capacity.Herein,we review the latest advances in functionalization and device fabrication of fiber materials toward applications in fiber-based wearable strain sensors.We describe the approaches for preparing conductive fibers such as spinning,surface modification,and structural transformation.We also introduce the fabrication and sensing mechanisms of state-of-the-art sensors and analyze their merits and demerits.The applications toward motion detection,healthcare,man-machine interaction,future entertainment,and multifunctional sensing are summarized with typical examples.We finally critically analyze tough challenges and future remarks of fiber-based strain sensors,aiming to implement them in real applications.

Durable easy-cleaning and antibacterial cotton fabrics using fluorine-free silane coupling agents and CuO nanoparticles

Multifunctional fabrics of high durability through a scalable and eco-friendly technique remains a great challenge hindering their commercialization.In this work,we report a facile synthesis technique for the fabrication of superhydrophobic antibacterial fabrics by employing fluorine-free silane coupling agents as cross-linkers for enhanced durability.Three silane cross-linkers,Aminoethylaminopropyltrimethoxysilane(AEAPTMS),Aminopropyltriethoxysilane(APTES),and Methacryloyloxypropyltrimethoxysilane(MPTMS),have been investigated.During the fabrication,a low surface energy polymer,polydimethylsiloxane(PDMS)was first deposited on cotton fabrics.Subsequently,antibacterial copper oxide(CuO)nanoparticles were anchored on the PDMS coated fabrics using the silane cross-linkers.The as-prepared fabrics displayed high superhydrophobicity and antibacterial performance with water contact angle(WCA)>153
,water shedding angle(WSA)<5
,and up to 99%antibacterial efficiency.Additionally,the as-prepared fabrics displayed high durability against abrasion,ultrasonic washing,and soaking in harsh chemical environments.The air permeability and flexibility of the fabric was not compromised after the coating.The above-reported technique is simple,cost-effective and holds tremendous potential for large-scale production of energy-saving clothing and healthcare products.

Surface plasmon resonance metal-coupled biomass carbon modified TiO_(2) nanorods for photoelectrochemical water splitting

Exploring efficient and stable photoanode materials is a necessary link to realize the practical application of solar-driven photoelectrochemical(PEC)water splitting.Hence,we prepared rutile TiO_(2) nanorods,with a width of 50 nm,which was growth in situ on carbon cloth(TiO_(2)@CC)by hydrothermal reaction.And then,Ag nanoparticles(NPs)and biomass N,S-C NPs were chosen for the additional modification of the fabricated TiO_(2) nanorods to produce broccoli-like Ag-N,S-C/TiO_(2)@CC nanocomposites.According to the result of ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)and PEC water splitting performance tests,Ag-N,S-C/TiO_(2)@CC broadens the absorption region of TiO_(2)@CC from the ultraviolet region to the visible regio n.Under AM 1.5 G solar light irradiation,the photocurrent density of Ag-N,S-C/TiO_(2)@CC is 89.8μA·cm^(-2),which is 11.8 times higher than TiO_(2)@CC.Under visible light irradiation,the photocurrent density of Ag-N,S-C/TiO_(2)@CC reaches to 12.6μA·cm^(-2),which is 21.0 times higher than TiO_(2)@CC.Moreover,Ag-N,S-C/TiO_(2)@CC shows a photocurrent responses in full pH range.It can be found that Ag NPs and N,S-C NPs play key roles in broaden the absorption range of TiO_(2) nanorods to the visible light region and,promote the occurrence of PEC water oxidation reaction due to the surface plasmon resonance effect of Ag NPs and the synergistic effect of N,S-C NPs.The mechanism demonstrated that Ag-N,S-C/TiO_(2)@CC can separate the photogenerated electron-hole pairs effectively and transfer the photogenerated electrons to the photocathode(Pt plate)in time.This research provides a new strategy for exploration surface plasma metal coupled biomass carbon materials in the field of PEC water splitting.

温度调控制备锡或二氧化锡@中空多孔碳纳米纤维电极用于个性化定制锂离子电池

锂离子电池广泛应用于电动汽车、混合动力汽车、便携式电子设备等储能系统,但由于电荷在活性材料中传输缓慢以及活性材料易粉碎等缺点,开发同时具有高容量以及快充性能的电极材料仍然是一个极大的挑战.针对这一问题,本文通过温度调控将SnO_(2)量子点或Sn纳米团簇均匀负载在中空多孔碳纳米纤维(HPCNFs)的内部,用于制备个性化定制锂离子电池.一方面,高度互联的碳纳米纤维形成三维网络,加快了电子传输,提高了电子导电性.另一方面,中空多孔结构缩短了锂离子传输路径,促进了锂离子的快速扩散,同时,抑制了Sn和SnO_(2)的体积膨胀.由于具有较高的锂离子吸附性能以及快的离子扩散速率,低碳化温度下(450℃)合成的SnO_(2)@HPCNFs复合电极在0.1 A g^(-1)的小电流密度下具有较高的放电比容量(899.3 mA h g~(-1)).此外,由于在大的电流密度下,Sn的大孔结构能够储存更多的锂离子,以及具有较高的电子电导率,因此,高碳化温度下(850℃)制备的Sn@HPCNFs复合电极展现出优异的快充性能,同时,在5 A g^(-1)(~10 C)的高电流密度下具有238.8 mA h g^(-1)的放电容量.本文通过调控碳化温度来研究SnO_(2)和Sn电极之间的电化学行为,为构建高性能储能器件提供了新的思路.

Flexible electrochromic fiber with rapid color switching and high optical modulation

Though flexible electrochromic devices have shown huge potential application in the fields of safety warning,display and smart windows,limited attention was paid on preparing flexible electrochromic fiber because of the difficulty in fabricating the multilayer electrochromic device structure in one-dimensional form.In this study,a flexible electrochromic nylon fiber based on Ag nanowires(NWs)/PEDOT:PSS/WO3 nanoparticles(NPs)(PEDOT:PSS=poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid)is successfully fabricated,delivering rapid color switching(2.5 and 9 s for bleaching and coloration)and high optical modulation(65.5%at 633 nm),and sustainable to repeated mechanical deformations.Ag NWs,PEDOT:PSS and WO3 NPs were dip-coated on the nylon fiber,resulting in an electrochromic fiber electrode with stable fiber resistance of 50-100Ω/10 cm,which can withstand mechanical deformation against 300 times of bending cycles with bending radius of 0.5 cm,and sustain 30 times of tape-peeling.During the galvanostatic tests,the capacitance of the electrochromic electrode can maintain 70%of the initial value even after 5,000 times of charge-discharge cycles.Even in knotted shape,the fiber still shows excellent color contrast.This study provides a novel method to construct flexible electrochromic fiber and pave the way for the development of flexible optoelectronic devices,such as flexible and wearable displays.

Rational designed ZIF-8@PDA@PDMS composite sponge for efficient and sustainable particulate matter filtering under harsh environment

Particulate matter(PM)is a significant danger to both environment and human health.Despite the development of a series of air filters,they do not work well in harsh environment such as high tem-perature,high humidity or long-time filtration.To make a three-dimensional(3D)particle capture de-vice,a sacrificial template approach was used to manufacture polydimethylsiloxane(PDMS)sponge,and then zeolite imidazole framework-8(ZIF-8)was grown in situ on the 3D network of PDMS sponge.The removal efficiency of PM_(2.5)or PM10 is greater than 99.8%because of the high specific surface area and porous network structure of PDMS sponge,as well as the large number of metal sites of ZIF-8.In addition,the sponge filter has long-term filtration stability and still achieves excellent performance after 65 h of filtration.The composite sponge can adapt to harsh environments such as high temperature(250℃)and high humidity(90%RH).Composite sponge filter has a regular shape,and it may be customized to any shape as required.This study provides a new idea for designing 3D high-efficiency air filters that can adapt to harsh environments.

Multifunctional hydrophobic fabric-based strain sensor for human motion detection and personal thermal management

Multifunctional flexible devices for human motion detection and thermal management raised great at-tention as the problem of the aging population is becoming more and more serious.However,it is still a challenge to endow the devices with excellent stability and wide application scope.Here we prepared a hydrophobic and conductive fabric-based strain sensor for smart fabric via successively coating with poly-dopamine(PDA),polyaniline(PANI),polypyrrole(PPy),and polydimethylsiloxane(PDMS)through in-situ polymerization and dip-coating,which could be used for strain sensor and wearable heater both in air and underwater.The obtained sample exhibited a fast electrical response in 500 ms and could withstand 10,000 times stretching-releasing cycles,additionally,the sample exhibited satisfactory electro-thermal and photo-thermal performances.As a whole,the multifunctional fabric-based devices with excellent performances show great potential to be applied in medical monitoring and personal care,especially for aged and disabled persons.

Electrospun Nanocomposite Fibrous Membranes for Sustainable Face Mask Based on Triboelectric Nanogenerator with High Air Filtration Efficiency

Air pollution caused by the rapid development of industry has always been a great issue to the environment and human being’s health.However,the efficient and persistent filtration to PM_(0.3) remains a great challenge.Herein,a self-powered filter with micro-nano composite structure composed of polybutanediol succinate(PBS)nanofiber membrane and polyacrylonitrile(PAN)nanofiber/polystyrene(PS)microfiber hybrid mats was prepared by electrospinning.The balance between pressure drop and filtration efficiency was achieved through the combination of PAN and PS.In addition,an arched TENG structure was created using the PAN nanofiber/PS microfiber composite mat and PBS fiber membrane.Driven by respiration,the two fiber membranes with large difference in electronegativity achieved contact friction charging cycles.The open-circuit voltage of the triboelectric nanogenerator(TENG)can reach to about 8 V,and thus the high filtration efficiency for particles was achieved by the electrostatic capturing.After contact charging,the filtration efficiency of the fiber membrane for PM_(0.3) can reach more than 98%in harsh environments with a PM_(2.5) mass concentration of 23,000µg/m^(3),and the pressure drop is about 50 Pa,which doesn’t affect people’s normal breathing.Meanwhile,the TENG can realize self-powered supply by continuously contacting and separating the fiber membrane driven by respiration,which can ensure the long-term stability of filtration efficiency.The filter mask can maintain a high filtration efficiency(99.4%)of PM_(0.3) for 48 consecutive hours in daily environments.

Namib desert beetle inspired special patterned fabric with programmable and gradient wettability for efficient fog harvesting

Efficient collection of water from fog provides a potential solution to solve the global freshwater shortage problem, particularly in the desert or arid regions. In this work, a flexible and highly efficient fog collector was prepared by mimicking the back exoskeleton structure of the Namib desert beetle. The improved fog collector was constructed by a superhydrophobic-superhydrophilic patterned fabric via a simple weaving method, followed by in-situ deposition of copper particles. Compared with the conventional fog collector with a plane structure, the fabric has shown a higher water-harvesting rate at 1432.7 mg/h/cm2,owing to the biomimetic three-dimensional structure, its enhanced condensation performance enabled by the copper coating and the rational distribution of wetting units. The device construction makes use of the widely available textile materials through mature manufacturing technology, which makes it highly suitable for large-scale industrial production.

TiO2 nanotube arrays decorated with Au and Bi2S3 nanoparticles for efficient Fe3+ ions detection and dye photocatalytic degradation

Due to increasingly serious environmental problems,many researchers are investigating green cleanenergy to solve the world’s energy supply issues.So the strategy that Au nanoparticles(Au NPs)and bismuth sulfide(Bi2S3)NPs are used to evenly decorate TiO2 nanotube arrays(TiO2 NTAs)was carried out.Composite materials demonstrated enhanced solar light absorption ability and excellent photoelectrochemical performance.This was attributed to the presence of Bi2S3 NPs with a narrow band gap and the decoration with noble metallic Au NPs which resulted in local surface plasmon resonance(LSPR)effects.The Au/Bi2S3@TiO2 NTAs composites exhibit improved photocatalytic activity for the degradation of methylene blue(MB)under irradiation of UV and visible light.Moreover,the Au/Bi2S3@TiO2 NTAs exhibits high fluorescence emission at 822 nm.Due to the better binding affinity between Bi2S3,TiO2 and Fe3+ions,the synthesized nanocomposites exhibit high selectivity to Fe3+ions.The number of binding sites for Au/Bi2S3@TiO2 NTAs was estimated to be 1.41 according to the double logarithmic regression method.The calculated value of"K"was 1862 M-1.Fluorescence emission intensity decreases with increasing concentration(30μM–5000μM).The detection limit of the synthesized sensor is 0.221μM.

Hydroxyapatite-modified micro/nanostructured titania surfaces with different crystalline phases for osteoblast regulation

Surface structures and physicochemical properties critically influence osseointegration of titanium(Ti)implants.Previous studies have shown that the surface with both micro-and nanoscale roughness may provide multiple features comparable to cell dimensions and thus efficiently regulate cell-material interaction.However,less attention has been made to further optimize the physicochemical properties(e.g.,crystalline phase)and to further improve the bioactivity of micro/nanostructured surfaces.Herein,micro/nanostructured titania surfaces with different crystalline phases(amorphous,anatase and anatase/rutile)were prepared and hydroxyapatite(HA)nanorods were deposited onto the as-prepared surfaces by a spin-assisted layer-by-layer assembly method without greatly altering the initial multi-scale morphology and wettability.The effects of crystalline phase,chemical composition and wettability on osteoblast response were investigated.It is noted that all the micro/nanostructured surfaces with/without HA modification presented superamphiphilic.The activities of MC3T3-E1 cells suggested that the proliferation trend on the micro/nanostructured surfaces was greatly influenced by different crystalline phases,and the highest proliferation rate was obtained on the anatase/rutile surface,followed by the anatase;but the cell differentiation and extracellular matrix mineralization were almost the same among them.After ultrathin HA modification on the micro/nanostructured surfaces with different crystalline phases,it exhibited similar proliferation trend as the original surfaces;however,the cell differentiation and extracellular matrix mineralization were significantly improved.The results indicate that the introduction of ultrathin HA to the micro/nanostructured surfaces with optimized crystalline phase benefits cell proliferation,differentiation and maturation,which suggests a favorable biomimetic microenvironment and provides the potential for enhanced implant osseointegration in vivo.

Rational designed microstructure pressure sensors with highly sensitive and wide detection range performance

Highly sensitive pressure sensors are often deployed in human-machine interaction area,touch screen and human motion detection.However,there are still great challenges to fabricating with high sensitivity pressure sensor with wide-range detection.Herein,we developed a new strategy to fabricate a highly sensitive pressure sensor using sandpaper and improve its detection range using a sacrificial template.It was the fthatirst time to combine microstructure processing with the sacrificial template method to fabricate pressure sensor.The microstructure of sandpaper endowed the sensor with high sensitivity,and the elastic substrate enhanced the sensor ability to resist high pressure without being damaged.The fabricated sensor device exhibits a superior sensitivity of 39.077 kPa-1in the range from 50 kPa to 110 kPa with a broad linear response.Remarkably,high pressure ceiling(<160 kPa) ensures that the sponge could be applied in different practical conditions to monitor a range of subtle human motions including finger,wrist bending,and pulse.For applications,the sensor device can not only detect the foot stepping behavior(0.7 MPa) but also produce an obvious response to an extremely slight paper(9 mg,~0.9 Pa).The successful preparation of this micro-structured elastic sponge material provided new ideas for exploring its potential applications in pressure sensors and flexible wearable electronic devices.

Oxygen-deficient bismuth tungstate and bismuth oxide composite photoanode with improved photostability

A homogeneous layer of Bi_2O_3-Bi_(14)WO_(24) composite(BWO/Bi_2O_3) thin film was fabricated using a combination of electrodeposition and thermal treatment. The evenly distributed Bi14 WO24 component within the Bi_2O_3 layer was found to be important in stabilising the photoelectrochemical performances of Bi_2O_3 photoanode by promoting the photoelectron transport. The unmodified Bi_2O_3 suffered from severe photocorrosion as proven by X-ray diffraction(XRD) and inductively coupled plasma(ICP) analyses while the composite thin film was active without noticeable activity decay for at least 3 h of illumination. This strategy might be applicable to other photocatalysts with stability issues.