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Thermal management through personal heating and cooling is a strategy by which to expand indoor temperature setpoint range for large energy saving.We show that nanoporous polyethylene (nanoPE) is transparent to mid-infrared human body radiation but opaque to visible light because of the pore size distribution (50 to 1000 nanometers).We processed the material to develop a textile that promotes effective radiative cooling while still having sufficient air permeability, water-wicking rate, and mechanical strength for wearability. We developed a device to simulate skin temperature that shows temperatures 2.7° and 2.0°C lower when covered with nanoPE cloth and with processed nanoPE cloth, respectively, than when covered with cotton.Our processed nanoPE is an effective and scalable textile for personal thermal management. [ABSTRACT FROM AUTHOR]

Transparent conductive film on plastic substrate is a critical componentin low-cost, flexible, and lightweight optoelectronics. Industrial-scalemanufacturing of high-performance transparent conductive flexibleplastic is needed to enable wide-ranging applications. Here, we demonstratea continuous roll-to-roll (R2R) production of transparent conductiveflexible plastic based on a metal nanowire network fully encapsulatedbetween graphene monolayer and plastic substrate. Large-area graphenefilm grown on Cu foil via a R2R chemical vapor deposition processwas hot-laminated onto nanowires precoated EVA/PET film, followedby a R2R electrochemical delamination that preserves the Cu foil forreuse. The encapsulated structure minimized the resistance of bothwire-to-wire junctions and graphene grain boundaries and strengthenedadhesion of nanowires and graphene to plastic substrate, resultingin superior optoelectronic properties (sheet resistance of ∼8 Ω sq–1at 94% transmittance), remarkable corrosion resistance, and excellentmechanical flexibility. With these advantages, long-cycle life flexibleelectrochromic devices are demonstrated, showing up to 10000 cycles. [ABSTRACT FROM AUTHOR]

The SnS absorber layer in solar cell devices was produced by vapor transport deposition (VTD), which is a low-cost manufacturing method for solar modules. The performance of solar cells consisting of Si/Mo/SnS/ZnO/indium tin oxide (ITO) was limited by the SnS layer's surface texture and fielddependent carrier collection. For improved performance, a fluorine doped tin oxide (FTO) substrate was used in place of the Mo to smooth the topography of the VTD SnS and to make bifacial solar cells, which are potentially useful for multijunction applications. A bifacial SnS solar cell consisting of glass/FTO/SnS/CdS/ZnO/ITO demonstrated front- and back-side power conversion efficiencies of 1.2% and 0.2%, respectively. [ABSTRACT FROM AUTHOR]

Metal nanowire (MNW) transparent electrodes have been widely developed for their promising sheet resistance (RS)—transmittance (T) performance, excellent mechanical flexibility, and facile synthesis. How to lower the junction resistance without compromising optical transmittance has become the key issue in enhancing their performance. Here we combine electrospinning and electroless deposition to synthesize interconnected, ultralong MNW networks. For both silver and copper nanowire networks, the RS and T values reach around 10 Ω /sq and 90%, respectively. This process is scalable and takes place at ambient temperature and pressure, which opens new opportunities for flexible electronics and roll-to-roll large-scale manufacturing. [ABSTRACT FROM AUTHOR]

The HadISST (Hadley Centre Sea Ice and Sea Surface Temperature) dataset is used to define the years of El Niño, El Niño Modoki, and La Niña events and to find out the impacts of these events on typhoon activity. The results show that the formation positions of typhoon are farther eastward moving in El Niño years than in La Niña years and much further eastward in El Niño Modoki years. The lifetime and the distance of movement are longer, and the intensity of typhoons is stronger in El Niño and in El Niño Modoki years than in La Niña years. The Accumulated Cyclone Energy of typhoon is highly correlated with the Oceanic Niño Index with a correlation coefficient of 0.79. We also find that the typhoons anomalously decrease during El Niño years but increase during El NiñoModoki years. Besides, there are two types of El Niño Modoki, I and II. The intensity of typhoon in El Niño Modoki I years is stronger than in El Niño Modoki II years. Furthermore, the centroid position of the Western Pacific Warm Pool is strongly related to the area of typhoon formation with a correlation coefficient of 0.95. [ABSTRACT FROM AUTHOR]

The article focuses on innovative textiles that help to cool the person who wears them. It discusses the impact of global warming on the textile industry. It is noted that the energy saving, challenges and opportunities exist for the radiative cooling textiles. It mentions that a radiative cooling textile with coupled dynamic evaporative cooling can cool the human body even when the ambient temperature is higher than the skin.

Radiative cooling textiles hold promise for achieving personal thermal comfort under increasing global temperature. However, urban areas have heat island effects that largely diminish the effectiveness of cooling textiles as wearable fabrics because they absorb emitted radiation from the ground and nearby buildings. We developed a mid-infrared spectrally selective hierarchical fabric (SSHF) with emissivity greatly dominant in the atmospheric transmission window through molecular design, minimizing the net heat gain from the surroundings. The SSHF features a high solar spectrum reflectivity of 0.97 owing to strong Mie scattering from the nano-micro hybrid fibrous structure. The SSHF is 2.3°C cooler than a solar-reflecting broadband emitter when placed vertically in simulated outdoor urban scenarios during the day and also has excellent wearable properties. [ABSTRACT FROM AUTHOR]

Here, we developed high-efficiency (<99.5%) polyimide-nanofiber air filters for the high temperature PM2.5 removal. The polyimide nanofibers exhibited high thermal stability, and the PM2.5 removal efficiency was kept unchanged when temperature ranged from 25-370 °C. These filters had high air flux with very low pressure drop. They could continuously work for <120 h for PM2.5 index <300. A field-test showed that they could effectively remove <99.5% PM particles from car exhaust at high temperature. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) pollution in air has become a serious environmental issue calling for new type of filter technologies. Recently, we have demonstrated a highly efficient air filter by direct electrospinning of polymer fibers onto supporting mesh although its throughput is limited. Here, we demonstrate a high throughput method based on fast transfer of electrospun nanofiber film from roughed metal foil to a receiving mesh substrate. Compared with the direct electrospinning method, the transfer method is 10 times faster and has better filtration performance at the same transmittance, owing to the uniformity of transferred nanofiber film (>99.97% removal of PM2.5 at ~73% of transmittance). With these advantages, large area freestanding nanofiber film and roll-to-roll production of air filter are demonstrated. [ABSTRACT FROM AUTHOR]

Graphene nanoribbons (GNRs) are promising building blocks for high-performance electronics due to their high electron mobility and dimensionality-induced bandgap. Despite many past efforts, direct synthesis of GNRs with controlled dimensions and scalability remains challenging. Here we report the scalable synthesis of GNRs using electrospun polymer nanofiber templates. Palladium-incorporated poly(4-vinylphenol) nanofibers were prepared by electrospinning with controlled diameter and orientation. Highly graphitized GNRs as narrow as 10 nm were then synthesized from these templates by chemical vapor deposition. A transport gap can be observed in 30 nm-wide GNRs, enabling them to function as field-effect transistors at room temperature. Our results represent the first success on the scalable synthesis of highly graphitized GNRs from polymer templates. Furthermore, the generality of this method allows various polymers to be explored, which will lead to understanding of growth mechanism and rational control over crystallinity, feature size and bandgap to enable a new pathway for graphene electronics. [ABSTRACT FROM AUTHOR]

By harnessing the oxidative power of microorganisms, energy can be recovered from reservoirs of less-concentrated organic matter, such as marine sediment, wastewater, and waste biomass. Left unmanaged, these reservoirs can become eutrophic dead zones and sites of greenhouse gas generation. Here, we introduce a unique means of energy recovery from these reservoirs―a microbial battery (MB) consisting of an anode colonized by microorganisms and a reoxidizable solid-state cathode. The MB has a single-chamber configuration and does not contain ion-exchange membranes. Bench-scale MB prototypes were constructed from commercially available materials using glucose or domestic wastewater as electron donor and silver oxide as a coupled solid-state oxidant electrode. The MB achieved an efficiency of electrical energy conversion of 49% based on the combustion enthalpy of the organic matter consumed or 44% based on the organic matter added. Electrochemical reoxidation of the solid-state electrode decreased net efficiency to about 30%. This net efficiency of energy recovery (unoptimized) is comparable to methane fermentation with combined heat and power. [ABSTRACT FROM AUTHOR]

The article presents a study that explores the metalized polyamide heterostructure as a moisture-responsive actuator for multimodal adaptive personal heat management . It mentions that personal thermal management textile/wearable as an effective strategy to expand the indoor temperature set point range to reduce a building's energy consumption.

Aerosol-induced haze problem has become a serious environmental concern. Filtration is widely applied to remove aerosols from gas streams. Despite classical filtration theories, the nanoscale capture and evolution of aerosols is not yet clearly understood. Here we report an in situ investigation on the nanoscale capture and evolution of aerosols on polyimide nanofibers. We discovered different capture and evolution behaviors among three types of aerosols: wetting liquid droplets, nonwetting liquid droplets, and solid particles. The wetting droplets had small contact angles and could move, coalesce, and form axisymmetric conformations on polyimide nanofibers. In contrast, the nonwetting droplets had a large contact angle on polyimide nanofibers and formed nonaxisymmetric conformations. Different from the liquid droplets, the solid particles could not move along the nanofibers and formed dendritic structures. This study provides an important insight for obtaining a deep understanding of the nanoscale capture and evolution of aerosols and benefits future design and development of advanced filters. [ABSTRACT FROM AUTHOR]

Face masks are widely used to filter airborne pollutants, especially when particulate matter (PM) pollution has become a serious concern to public health. Here, the concept of thermal management is introduced into face masks for the first time to enhance the thermal comfort of the user. A system of nanofiber on nanoporous polyethylene (fiber/nanoPE) is developed where the nanofibers with strong PM adhesion ensure high PM capture efficiency (99.6% for PM2.5) with low pressure drop and the nanoPE substrate with high-infrared (IR) transparency (92.1%, weighted based on human body radiation) results in effective radiative cooling. We further demonstrate that by coating nanoPE with a layer of Ag, the fiber/Ag/nanoPE mask shows a high IR reflectance (87.0%) and can be used for warming purposes. These multifunctional face mask designs can be explored for both outdoor and indoor applications to protect people from PM pollutants and simultaneously achieve personal thermal comfort. [ABSTRACT FROM AUTHOR]

Lithium metal is an attractive anode for the next generation of high energy density lithium-ion batteries due to its high specific capacity (3,860 mAh g–1) and lowest overall anode potential. However, the key issue is that the static solid electrolyte interphase cannot match the dynamic volume changes of the Li anode, resulting in side reactions, dendrite growth, and poor electrodeposition behavior, which prevent its practical applications. Here, we show that the “solid-liquid” hybrid behavior of a dynamically cross-linked polymer enables its use as an excellent adaptive interfacial layer for Li metal anodes. The dynamic polymer can reversibly switch between its “liquid” and “solid” properties in response to the rate of lithium growth to provide uniform surface coverage and dendrite suppression, respectively, thereby enabling the stable operation of lithium metal electrodes. We believe that this example of engineering an adaptive Li/electrolyte interface brings about a new and promising way to address the intrinsic problems of lithium metal anodes. [ABSTRACT FROM AUTHOR]

High ionic conductivity solid polymer electrolyte (SPE) has long been desired for the next generation high energy and safe rechargeable lithium batteries. Among all of the SPEs, composite polymer electrolyte (CPE) with ceramic fillers has garnered great interest due to the enhancement of ionic conductivity. However, the high degree of polymer crystallinity, agglomeration of ceramic fillers, and weak polymer-ceramic interaction limit the further improvement of ionic conductivity. Different from the existing methods of blending preformed ceramic particles with polymers, here we introduce an in situ synthesis of ceramic filler particles in polymer electrolyte. Much stronger chemical/mechanical interactions between monodispersed 12 nm diameter SiO2 nanospheres and poly(ethylene oxide) (PEO) chains were produced by in situ hydrolysis, which significantly suppresses the crystallization of PEO and thus facilitates polymer segmental motion for ionic conduction. In addition, an improved degree of LiClO4 dissociation can also be achieved. All of these lead to good ionic conductivity (1.2 × 10-3 S cm-1 at 60 °C, 4.4 × 10-5 S cm-1 at 30 °C). At the same time, largely extended electrochemical stability window up to 5.5 V can be observed. We further demonstrated all-solid-state lithium batteries showing excellent rate capability as well as good cycling performance. [ABSTRACT FROM AUTHOR]

Lithium metal is one of the most promising candidatesas an anode material for next-generation energy storage systems dueto its highest specific capacity (3860 mAh/g) and lowest redox potentialof all. The uncontrolled lithium dendrite growth that causes a poorcycling performance and serious safety hazards, however, presentsa significant challenge for the realization of lithium metal-basedbatteries. Here, we demonstrate a novel electrode design by placinga three-dimensional (3D) oxidized polyacrylonitrile nanofiber networkon top of the current collector. The polymer fiber with polar surfacefunctional groups could guide the lithium ions to form uniform lithiummetal deposits confined on the polymer fiber surface and in the 3Dpolymer layer. We showed stable cycling of lithium metal anode withan average Coulombic efficiency of 97.4% over 120 cycles in ether-basedelectrolyte at a current density of 3 mA/cm2for a totalof 1 mAh/cm2of lithium. [ABSTRACT FROM AUTHOR]

Solid-stateelectrolytes provide substantial improvements to safety and electrochemicalstability in lithium-ion batteries when compared with conventionalliquid electrolytes, which makes them a promising alternative technologyfor next-generation high-energy batteries. Currently, the low mobilityof lithium ions in solid electrolytes limits their practical application.The ongoing research over the past few decades on dispersing of ceramicnanoparticles into polymer matrix has been proved effective to enhanceionic conductivity although it is challenging to form the efficiencynetworks of ionic conduction with nanoparticles. In this work, wefirst report that ceramic nanowire fillers can facilitate formationof such ionic conduction networks in polymer-based solid electrolyteto enhance its ionic conductivity by three orders of magnitude. Polyacrylonitrile-LiClO4incorporated with 15 wt % Li0.33La0.557TiO3nanowire composite electrolyte exhibits an unprecedentedionic conductivity of 2.4 × 10–4S cm–1at room temperature, which is attributed to the fast ion transporton the surfaces of ceramic nanowires acting as conductive networkin the polymer matrix. In addition, the ceramic-nanowire filled compositepolymer electrolyte shows an enlarged electrochemical stability windowin comparison to the one without fillers. The discovery in the presentwork paves the way for the design of solid ion electrolytes with superiorperformance. [ABSTRACT FROM AUTHOR]

The ability to intercalate guest species into the van der Waals gap of 2D layered materials affords the opportunity to engineer the electronic structures for a variety of applications. Here we demonstrate the continuous tuning of layer vertically aligned MoS2 nanofilms through electrochemical intercalation of Li+ ions. By scanning the Li intercalation potential from high to low, we have gained control of multiple important material properties in a continuous manner, including tuning the oxidation state of Mo, the transition of semiconducting 2H to metallic 1T phase, and expanding the van der Waals gap until exfoliation. Using such nanofilms after different degree of Li intercalation, we show the significant improvement of the hydrogen evolution reaction activity. A strong correlation between such tunable material properties and hydrogen evolution reaction activity is established. This work provides an intriguing and effective approach on tuning electronic structures for optimizing the catalytic activity. [ABSTRACT FROM AUTHOR]

Complex fluctuations within physiological signals can be used to evaluate the health of the human body. This study recruited four groups of subjects: young healthy subjects (Group 1, n = 32), healthy upper middle-aged subjects (Group 2, n = 36), subjects with well-controlled type 2 diabetes (Group 1, n = 31), and subjects with poorly controlled type 2 diabetes (Group 4, n = 24). Data acquisition for each participant lasted 30 minutes.We obtained data related to consecutive time series with R-R interval (RRI) and pulse transit time (PTT). Usingmultiscale cross-approximate entropy (MCE), we quantified the complexity between the two series and thereby differentiated the influence of age and diabetes on the complexity of physiological signals. This study usedMCE in the quantification of complexity between RRI and PTT time series. We observed changes in the influences of age and disease on the coupling effects between the heart and blood vessels in the cardiovascular system, which reduced the complexity between RRI and PTT series. [ABSTRACT FROM AUTHOR]

Aligned ZnO nanopagoda arrays have been grown on the silicon substrate with ZnO nanorod arrays by a hydrothermal and downward growth process. The concentration of ascorbic acid was used to control the growth direction and the degree of lamination of the ZnO nanostructure with a vastly reduced reaction time (from 24 to 2 h). Low turn-on and threshold fields indicate that ZnO nanopagodas are promising for applications in field emission devices. The ZnO nanopagodas exhibit a very prominent blue shift (10 nm) of UV emission and almost no green emission attributed to singly ionized oxygen vacancies at room temperature. The enhancement in deep-UV optical properties shall be advantageous in applications for nanoscale light-emitting devices. The polar surface concept can be used to understand the ZnO growth mechanism of nanopagodas. The appropriate substrates and reaction conditions lead to the growth of ZnO nanopagoda arrays with wafer-scale production. The large-scale ZnO nanopagoda arrays shall be beneficial in fabricating the novel devices, such as field emitters, ultraviolet lasers, and dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]