Designing Textile Architectures for High Energy-Efficiency Human Body Sweat-and Cooling-Management

Thermal management of textiles requires local microclimate control over heat and wet dissipation to create a comfortable thermal-wet environment at the interface of the human body and clothing.Herein,we design a fabric capable of both sweat-and cooling-management using a knitted fabric featuring a bilayer structure consisting of hydrophobic polyethylene terephthalate and hydrophilic cellulose fibers to simultaneously achieve high infrared(IR)transmittance and good thermal-wet comfort.The IR transmission of this cooling textile increased by~twofold in the dry state and~eightfold in the wet state compared to conventional cotton fabric.When the porosity changes from 10 to 47%with the comparison of conventional cotton fabric and our cooling textile,the heat flux is increased from 74.4 to 152.3 W/cm^(2).The cooling effect of the cooling fabric is 105%greater than that of commercial cotton fabric,which displays a better thermal management capacity for personal cooling.This bilayer design controls fast moisture transfer from inside out and provides thermal management,demonstrating high impact not only for garments,but also for other systems requiring heat regulation,such as buildings,which could mitigate energy demand and ultimately contribute to the relief of global energy and climate issues.

Optical haze of transparent and conductive silver nanowire films

当代的 nanostructured 为在太阳能电池的使用的透明电极要求高发射度和高电导率，与高方面比率支配 nanostructures。光薄雾是在为被 nanostructures 的几何学也决定的太阳能电池的透明电极的一个同等地重要的还未学得的参数填写电极。在这个工作，在可见光谱的光薄雾价值上的银 nanowire 直径的效果用与小直径(60 nm ) 或大直径(150 nm ) 由电线组成的电影被调查。有限差别时间领域(FDTD ) 模拟和试验性的发射度数据证实更高根据优点的当前的数字的意见执行透明进行的电极(TCE ) 电影的那种更小的直径 nanowires 形式。当为每部电影在经常的发射度和电导率附近维持时，然而，电影与更大的直径银 nanowires 创作了，这试验性地被观察与更小的直径比电影有一个更高的薄雾因素。这与同样大、小的直径为单个 nanowires 证实薄雾因素的 FDTD 模拟。这是为被模仿了或试验性地测量了的 Ag NW 的薄雾性质的第一个记录，并且也，第一证实为 TCE 的优点的当前的数字是不够的在太阳能电池设备评估他们的表演。

A carbon-based 3D current collector with surface protection for Li metal anode

Lithium metal is considered the ideal anode material for Li-ion-based batteries because it exhibits the highest specific capacity and lowest redox potential for this type of cells. However, growth of Li dendrites, unstable solid electrolyte interphases, low Coulombic efficiencies, and safety hazards have significantly hindered the practical application of metallic Li anodes. Herein, we propose a three-dimensional （3D） carbon nanotube sponge （CNTS） as a Li deposition host. The high specific surface area of the CNTS enables homogenous charge distribution for Li nucleation and minimizes the effective current density to overcome dendrite growth. An additional conformal A1203 layer on the CNTS coated by atomic layer deposition （ALD） robustly protects the Li metal electrode/electrolyte interface due to the good chemical stability and high mechanical strength of the layer. The Li@ALD-CNTS electrode exhibits stable voltage profiles with a small overpotential ranging from 16 to 30 mV over 100 h of cycling at 1.0 mA·cm^-2. Moreover, the electrodes display a dendrite-free morphology after cycling and a Coulombic efficiency of 92.4% over 80 cycles at 1.0 mA·cm^-2 in an organic carbonate electrolyte, thus demonstrating electrochemical stability superior to that of planar current collectors. Our results provide an important strategy for the rational design of current collectors to obtain stable Li metal anodes.

Millisecond synthesis of CoS nanopartides for highly efficient overall water splitting

High performance and low-cost electrocatalysts for overall water splitting,i.e.,catalyzing hydrogen and oxygen evolution reactions with the same material,are of great importance for large-scale,renewable energy conversion processes.Here,we report an ultrafast(~7 ms)synthesis tech nique for tran sition metal chalcoge nide n anoparticles assisted by high temperature treatme nt.As a proof of con cept,we dem on strate that cobalt sulfide(~20 nm in diameter)@few-layer graphe ne(~2 nm in thick ness)core-shell nan oparticles embedded in RGO nano sheets exhibit remarkable bifunctional electrocatalytic activity and stability for overall water splitting,which is comparable to commercial 40 wt.%platinum/carbon(Pt/C)electrocatalysts.After 60 h of continuous operation,10 mA crrT?water splitting current density can still be achieved at a low potential of^1.77 V without any activity decay,which is among the most active for non-noble material based electrocatalysts.The presented study provides prospects in synthesizing highly efficient bifunctional electrocatalysts for large-scale energy conversion application via a simple yet efficient technique.

Aqueous Supercapacitors on Conductive Cotton

Wearable electronics offer the combined advantages of both electronics and fabrics.In this article,we report the fabrication of wearable supercapacitors using cotton fabric as an essential component.Carbon nanotubes are conformally coated onto the cotton fibers,leading to a highly electrically conductive interconnecting network.The porous carbon nanotube coating functions as both active material and current collector in the supercapacitor.Aqueous lithium sulfate is used as the electrolyte in the devices,because it presents no safety concerns for human use.The supercapacitor shows high specific capacitance(~70-80 F·g^(-1) at 0.1 A·g^(-1))and cycling stability(negligible decay after 35,000 cycles).The extremely simple design and fabrication process make it applicable for providing power in practical electronic devices.

Scalable nanomanufacturing of surfactant-free carbon nanotube inks for spray coatings with high conductivity

Spray-coated carbon nanotube films offer a simple and printable solution for fabricating low cost, lightweight, and flexible thin-film electronics. However, current nanotube spray inks require either a disruptive surfactant or destructive surface functionalization to stabilize dispersions at the cost of the electrical properties of the deposited film. We demonstrate that high-purity few-walled carbon nanotubes may be stabilized in isopropanol after surface functionalization and that optimizing the ink stability dramatically enhances the conductivity of subsequent spray-coated thin films. We consequently report a surfactant-free carbon nanotube ink for spray-coated thin films with conductivities reaching 2,100 S/cm. Zeta-potential measurements, used to quantify the nanotube ink dispersion quality, directly demonstrate a positive correlation with the spray- coated film conductivity, which is the key metric for high-performance printed electronics.

Garnet/polymer hybrid ion-conducting protective layer for stable lithium metal anode

Rechargeable Li metal batteries using Li metal anodes have attracted worldwide interest because of their high energy density. The critical barriers limiting their commercial application include uncontrolled dendritic Li growth and the unstable Li-electrolyte interface. Considerable efforts have been directed towards solving these problems, e.g., modifying the electrolyte, creating artificial interfacial layers for the Li metal, and constructing three-dimensional structures for the Li metal. However, stabilizing the Li metal interface remains challenging because of the highly reactive nature of the Li metal. In this study, we utilize a Li-ion conducting hybrid film comprising a garnet-type ion conductor and a poly（ethylene oxide）-based polymer electrolyte as a protective layer to stabilize the Li-electrolyte interface and mitigate the growth of Li dendrites. The hybrid ion-conducting layer can block Li dendrites from proliferating and accommodate Li volume expansion because of its robust mechanical properties. Moreover, the ion-conducting layer allows Li deposition only underneath it, rather than on the surface, functioning as a permanent protective layer to ensure the stability of the Li metal over a long cycling life. The dendrite-inhibiting effect of the ion-conducting protective layer is visually evidenced by in situ microscopy using planar batteries. The protective Li metal anode exhibits excellent cycling stability and low voltage hysteresis （-15 mV at 0.2 mA-cm-2） for a cycle life as long as 1,000 h. It also shows a high Coulombic efficiency （-99.5%） in a full cell against a LiFePO4 cathode, exhibiting promise for application in Li metal batteries. Our results imply that the ion-conducting protective layer markedly improves the metal anode, yielding safe, long-life, and high-energy-density batteries.

Catalyst-Free In Situ Carbon Nanotube Growth in Confined Space via High Temperature Gradient

Carbonaceous materials,such as graphite,carbon nanotubes(CNTs),and graphene,are in high demand for a broad range of applications,including batteries,capacitors,and composite materials.Studies on the transformation between diferent types of carbon,especially from abundant and low-cost carbon to high-end carbon allotropes,have received surging interest.Here,we report that,without a catalyst or an external carbon source,biomass-derived amorphous carbon and defective reduced graphene oxide(RGO)can be quickly transformed into CNTs in highly confned spaces by high temperature Joule heating.Combined with experimental measurements and molecular dynamics simulations,we propose that Joule heating induces a high local temperature at defect sites due to the corresponding high local resistance.Te resultant temperature gradient in amorphous carbon or RGO drives the migration of carbon atoms and promotes the growth of CNTs without using a catalyst or external carbon source.Our fndings on the growth of CNTs in confned spaces by fast high temperature Joule heating shed light on the controlled transition between diferent carbon allotropes,which can be extended to the growth of other high aspect ratio nanomaterials.

In Situ Wood Delignification toward Sustainable Applications

CONSPECTUS:As one of the most abundant and versatile natural materials on Earth,recently wood has attracted tremendous attention from scientists and engineers due to its outstanding advantages,including hierarchically porous microstructure,high mechanical strength,environmental friendliness,renewability,and biodegradability.Wood’s hierarchically porous structure and chemical components(e.g.,cellulose,hemicelluloses,and lignin)enable its mechanical,ionic,optical,and thermal properties to be tuned via physical,chemical,and/or thermal modifications.Among these various approaches,the chemical delignification of bulk wood is the most fascinating,in which the majority of lignin and hemicelluloses is removed while leaving the cellulose intact,maintaining wood’s physical integrity and hierarchical structure.This delignified structure is unique,composed of hollow,aligned channels made up of cellulose microfibrils,and particularly attractive given its origin from a sustainable and renewable resource.As a result,delignified wood has attracted increasing attention for applications that go far beyond traditional wood utilization,such as lightweight yet strong structural materials,energy storage and conversion,environmental remediation,flexible electronics,and bioengineering.This Account reviews recent developments in bulk wood delignification strategies toward the achievement of such advanced wood technologies for sustainable applications,with a focus on the research in our group.Similar to chemical pulping and bleaching,wood delignification involves a series of nucleophilic reactions based on alkaline Na2SO3 or Na2S systems(i.e.,chemical pulping)or electrophilic,radical,and oxidation reactions based on H2O2,ClO2,or NaClO systems(i.e.,chemical bleaching)to deconstruct,fragment,and promote the hydrophilicity of lignin macromolecules,which finally make lignin easier to be removed.We discuss the structure and properties of partially and near-completely delignified wood,with a focus on process-structure−property relationships.The resulting delignified wood materials,with tunable structure and properties,demonstrate various advanced functions,in a wide range of advanced applications,such as building and construction,green energy,and electronics.Finally,the potential challenges and appealing perspectives of in situ wood delignification are discussed.In situ wood delignification,as a powerful modification strategy,has speeded up the development of advanced wood technologies and wood-based functional materials and products.

Strong and Superhydrophobic Wood with Aligned Cellulose Nanofibers as a Waterproof Structural Material

Lightweight structural materials are important for the energy efficiency of applications,particularly those in the building sector.Here,inspired by nature,we developed a strong,superhydrophobic,yet lightweight material by simple in situ growth of nano-SiO2 and subsequent densification of the wood substrate.In situ generation of SiO2 nanoparticles both inside the wood channels and on the wood surfaces gives the material superhydrophobicity,with static and dynamic contact angles of 159.4°and 3°,respectively.Densification of the wood to remove most of the spaces among the lumen and cell walls results in a laminated,dense structure,with aligned cellulose nanofibers,which in turn contributes to a high mechanical strength up to 384.2 MPa(7-times higher than natural wood).Such treatment enables the strong and superhydrophobic wood(SH-Wood)to be stable and have excellent water,acid,and alkaline resistance.The high mechanical strength of SH-Wood combined with its excellent structural stability in harsh environments,as well its low density,positions the strong and superhydrophobic wood as a promising candidate for strong,lightweight,and durable structural materials that could potentially replace steel.

Electrochemical measurement of serotonin by Au-CNT electrodes fabricated on microporous cell culture membranes

Gut–brain axis(GBA)communication relies on serotonin(5-HT)signaling between the gut epithelium and the peripheral nervous system,where 5-HT release patterns from the basolateral(i.e.,bottom)side of the epithelium activate nerve afferents.There have been few quantitative studies of this gut-neuron signaling due to a lack of real-time measurement tools that can access the basolateral gut epithelium.In vitro platforms allow quantitative studies of cultured gut tissue,but they mainly employ offline and endpoint assays that cannot resolve dynamic molecular-release patterns.Here,we present the modification of a microporous cell culture membrane with carbon nanotube-coated gold(Au-CNT)electrodes capable of continuous,label-free,and direct detection of 5-HT at physiological concentrations.Electrochemical characterization of single-walled carbon nanotube(SWCNT)-coated Au electrodes shows increased electroactive surface area,5-HT specificity,sensitivity,and saturation time,which are correlated with the CNT film drop-cast volume.Two microliters of CNT films,with a 10-min saturation time,0.6μA/μM 5-HT sensitivity,and reliable detection within a linear range of 500 nM–10μM 5-HT,can be targeted for high-concentration,high-time-resolution 5-HT monitoring.CNT films(12.5μL)with a 2-h saturation time,4.5μA/μM 5-HT sensitivity,and quantitative detection in the linear range of 100 nM–1μM can target low concentrations with low time resolution.These electrodes achieved continuous detection of dynamic diffusion across the porous membrane,mimicking basolateral 5-HT release from cells,and detection of cell-released 5-HT from separately cultured RIN14B cell supernatant.Electrode-integrated cell culture systems such as this can improve in vitro molecular detection mechanisms and aid in quantitative GBA signaling studies.