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Due to the unique safety qualities, solid composite polymer electrolyte (SCPE) has achieved considerable attentions to fabricate high-energy-density lithium metal batteries, but its overall performance still has to be improved. Herein, a high lithium salt content poly(vinylidene fluoride) (PVDF)-based SCPE was developed, enhanced by hexagonal boron nitride (h-BN) nanosheets, presenting perfect electrochemical performance, fast ion transport, and efficient inhibition of lithium dendrite growth. The optimized SCPE (PVDF-L70-B5) could deliver high ionic conductivity (2.98×10

Lithium-sulfur (Li-S) batteries have attracted considerable attention due to their high energy density (2600 Wh kg−1). However, its commercialization is hindered seriously by the low loading and utilization rate of sulfur cathodes. Herein, we designed the cellulose-based graphene carbon composite aerogel (CCA) self-standing electrode to enhance the performance of Li-S batteries. The CCA contributes to the mass loading and utilization efficiency of sulfur, because of its unique physical structure: low density (0.018 g cm−3), large specific surface area (657.85 m2 g−1), high porosity (96%), and remarkable electrolyte adsorption (42.25 times). Compared to Al (about 49%), the CCA displayed excellent sulfur use efficiency (86%) and could reach to high area capacity of 8.60 mAh cm−2 with 9.11 mg S loading. Meanwhile, the CCA exhibits the excellent potential for pulse sensing applications due to its flexibility and superior sensitivity to electrical response signals.

Currently, even though birefringent soft materials have attracted considerable attention for many sensors and optical devices, it is still difficult for most of them to achieve multiple responses. Herein, we have designed a multiple-responding birefringent elastomer with high birefringence but low modulus by using 2-phenoxy-ethanoacrylate (PHEA) as monomer and 4-cyano-4'pentylbiphenyl as solvent. The excellent transparency (~90%) exhibited by the designed birefringent elastomer allowed us to observe the change of interference color. The obtained birefringent elastomer not only can be used as a photoelastic strain sensor with high sensitivity and fast response but also show a very sensitive response to heat, particularly in the range of the human body temperature. More interestingly, it shows excellent dielectric properties with a strong correlation between the interference color and the applied electric field, which allows easily writing and erasing the encrypted information. These unique multi-signal response features of our obtained birefringent elastomer shed light on the multiple information encryptions, the anti-counterfeiting, and the multifunctional sensors.

Stretchable ionic conductors are considerable to be the most attractive candidate for next-generation flexible ionotronic devices. Nevertheless, high ionic conductivity, excellent mechanical properties, good self-healing capacity and recyclability are necessary but can be rarely satisfied in one material. Herein, we demonstrate a novel ionic conductor design, dynamic supramolecular ionic conductive elastomers (DSICE), via “phase-locked” strategy, wherein “locking soft phase” polyether backbone conducts lithium-ion (Li+) transport and the combination of dynamic disulfide metathesis and stronger supramolecular quadruple hydrogen bonds in the hard domains contributes to the self-healing capacity and mechanical versatility. The dual-phase design performs its own functions and the conflict among ionic conductivity, self-healing capability, and mechanical compatibility can be thus defeated. The well-designed DSICE exhibits high ionic conductivity (3.77×10−3 S m−1 at 30°C), high transparency (92.3%), superior stretchability (2615.17% elongation), strength (27.83 MPa) and toughness (164.36 MJ m−3), excellent self-healing capability (~99% at room temperature) and favorable recyclability. This work provides a new strategy for designing the advanced ionic conductors and offers promise for flexible iontronic devices or solid-state batteries.

Wearable devices have become a research hotspot due to their prospective applications in wireless sensor networks and the Internet of Things. However, these technologies demand the generation of new power sources, which are efficient, flexible, sustainable, and stable. Triboelectric nanogenerators (TENGs), as a new type of power supply, have been widely studied for environmental energy harvesting and self-powered sensing; however, they have vastly limited stretchability, flexibility, and stability. For the first time, we report a single-electrode TENG based on hydrophobic ionic liquid gel, which is simultaneously transparent (average transmittance of 89% for visible light), stretchable (400%), and has super-stability-up to 3 months in various weather conditions (from -25 to +60 °C and humidity up to 80%). This TENG was used to power a vast range of flexible electronics, including 30 green light-emitting diodes (LEDs), an arch-shaped finger-bending sensor, and a transparent keyboard. This work provides a creative platform to access the next-generation sustainable wearable electronics.

It is generally considered that the Al3Sc nanoprecipitates are highly thermal stable, mainly due to quite slow Sc diffusion in the α-Al matrix. In this paper, we demonstrate in an Al-Cu-Sc alloy that the Cu atoms have dual effect on the coarsening of Al3Sc nanoprecipitates. On the one hand, the Cu atoms with high diffusivity tend to accelerate the Al3Sc coarsening, which results from the Cu-promoted Sc diffusion. On the other hand, some Cu atoms will segregate at the Al3Sc/matrix interface, which further stabilizes the Al3Sc nanoprecipitates by reducing the interfacial energy. Competition between these two effects is tailored by temperature, which rationalizes the experimental findings that the coarsening kinetics of Al3Sc nanoprecipitate is greatly boosted at 300 °C-overaging while significantly suppressed at 400 °C-overaging.

A solid polymer electrolyte is expected to be useful for safe and high energy density lithium-metal batteries owing to its good flexibility and high degree of safety. The development of a polyethylene oxide (PEO) based solid electrolyte is still restrained by low ionic conductivity and unsatisfactory mechanical strength. Since MnO2 could combine with PEO chains and Li ions could undergo long-range migration on MnO2 nanosheets, MnO2 nanoflakes are chosen as fillers to improve the electrochemical and mechanical properties of a solid polymer electrolyte. A PEO/MnO2 composite solid polymer electrolyte (CSPE) displays a higher lithium ion transference number (0.378), higher ionic conductivity (1.5 times higher at 60 °C) and better tensile strength (2.3 times) than a PEO solid electrolyte. Density functional theory calculations reflect the fact that the binding energy between the PEO/Li complex and MnO2 is small and there is easy desorption of Li from PEO and migration on MnO2 nanosheets, indicating enhanced lithium ion transport in the electrolyte system. A solid-state lithium metal battery using a PEO/MnO2 CSPE delivers higher capacity (143.5 mA h g−1 after 300 cycles) than an electrolyte without fillers (61.2 mA h g−1 after 90 cycles). Soft-package lithium metal batteries with an MnO2 CSPE reveal high safety after cutting, nail and bending tests.

A satellite-based semi-mechanistic model was developed to estimate the sea surface partial pressure of CO2 (pCO2) on the river-dominated Louisiana Continental Shelf (LCS) in summer months using satellite-derived products including chlorophyll-a concentration (Chl-a_sat), sea surface salinity (SSS_sat), and sea surface temperature (SST_sat). The model analytically expresses pCO2 as the sum of physical (pCO2,mix) and biological (ΔpCO2,bio) contributions which are the primary controlling factors associated with the pCO2 variability on the LCS. The SSS_sat, derived from a locally calibrated retrieval algorithm, was used in a two-end member river-ocean mixing model to estimate the concentrations of dissolved inorganic carbon (DIC) and total alkalinity (TA) resulting from physical mixing. The mixing-induced DIC and TA were used together with SST_sat to calculate the pCO2,mix resulting from the mixing processes at the in situ temperature. The biological uptake of pCO2 through net community production (ΔpCO2,bio) was derived from a previously validated local Chl-a_sat product along with the difference between the pCO2,mix and the extensive in situ underway pCO2 data. The satellite-derived pCO2 agreed with in situ measurements with a median absolute difference of 37 μatm, mean difference of −5 μatm, and a root mean square difference of 58 μatm for five summer cruises spanning 2006–2009. The semi-mechanistic remote sensing model differentiates physical and biological influences on the pCO2 variability, which will help to better investigate the variability and the underlying controlling mechanisms of pCO2 and CO2 flux on the LCS. This study demonstrates that the use of locally calibrated satellite products (Chl-a_sat, SSS_sat) should be promoted to improve the satellite estimation of pCO2 in coastal waters. This method can potentially be applied in other river-dominated continental shelves with local tuning.

Stretchable ionic conductors with multiple functions provide new opportunities for flexible electronics, soft robots, and wearable devices. However, the practical applications of the existing stret...

The photoelastic effect has many uses in mechanics today, but it is usually disregarded in flexible materials. Using 2-phenoxyethyl acrylate as a monomer and 4-cyano-4'-pentylbiphenyl (5CB) as a solvent, a multiple responsive photoelastic organogel (PO) with strong birefringence but low modulus is created. 5CB is a liquid crystal molecule that does not participate in the polymerization process and is always present as tiny molecules in the polymer. It endows the PO low modulus and high birefringence, as well as the ability to drive the birefringence using an electric field. This PO not only has high sensitivity and fast response as a photoelastic strain sensor, but also has a very sensitive response to heat, especially in the range of human body temperature. It also has a high dielectric constant and a strong correlation between the interference color and the applied electric field, allowing for easy writing and erasure of encrypted data. This unique multisignal response feature and low modulus that mimics human skin bring up new opportunities in the potential applications such as multiple information encryption, anticounterfeiting, and multifunctional wearable sensors.

Efficient white light-emitting diodes (LEDs) with an efficacy of 200 lm W

In the United States National Science Foundation and the National Institutes of Health have mandated training STEM doctoral students in the ethical and responsible conduct of research to improve doctoral students' ethical decision-making skills; however, little is known about the process and factors that STEM faculty and graduate students use in their decision-making. This exploratory case study examined how four triads of chemistry faculty and their doctoral students recruited from three research universities in the eastern United States engaged in ethical decision-making on issues of authorship, assignment of credit, and plagiarism. A mixed-methods approach involving the administration of an online survey consisting of three open-ended case studies followed by a think-aloud interview was utilized. Participants were found to use analogical reasoning and base their decision-making on a common core set of considerations including fundamental principles, social contracts, consequences, and discussion with an advisor, often using prior personal experiences as sources. Co-authorship did not appear to impact the doctoral students' ethical decision-making. Gender may play a role in graduate students' decision-making; female doctoral students appeared to be less likely to consider prior experiences when evaluating the vignettes. Graduate students' lack of knowledge of the core issues in the responsible conduct of research, coupled with their lack of research experience, and inability to identify the core considerations may lead them to make bad judgments in specific situations. Our findings help explain the minimal impact that the current responsible conduct of research training methods has had on graduate students' ethical decision-making and should lead to the development of more effective approaches.

Cesium-lead halide perovskite nanoparticles are a promising class of luminescent materials for color and efficient displays. However, material stability is the key issue to solve before we can use these materials in modern displays. Encapsulation is one of the most efficient methods that can markedly improve the stability of perovskite nanoparticles against moisture, heat, oxygen, and light. Thus, we urgently need a low-cost, reliable, and device-compatible encapsulation method for the integration of nanomaterials into display devices. Here, we propose a facile encapsulation method to stabilize perovskite nanoparticles in thin polymer porous films. Using porous polymer films, we achieved good photoluminescence stability in the harsh environment of high temperature, high humidity and strong UV illumination. The good UV stability benefitted from the unique optical properties of the porous film. Besides, we observed photoluminescence enhancement of CsPbBr3 nanoparticle films in a high humidity environment. The stable CsPbBr3 nanoparticle thin porous film provides high brightness (236 nits) and great color enhancement for LCDs and is characterized by simple fabrication with easy scalability, thus it is very suitable for modern LCDs.

Organic quinone molecules are attractive electrochemical energy storage devices because of their high abundance, multielectron reactions, and structural diversity compared with transition metal-oxide electrode materials. However, they have problems like poor cycle stability and low rate performance on account of the inherent low conductivity and high solubility in the electrolyte. Solving these two key problems at the same time can be challenging. Herein, we demonstrate that using a nitrogen-doped hierarchical porous carbon (NC) with mixed microporous/low-range mesoporous can greatly alleviate the shuttle effect caused by the dissolution of organic molecules in the electrolyte through physical binding and chemisorption, thereby improving the electrochemical performances. Lithium-ion batteries based on the anthraquinone (AQ) electrode exhibit dramatic capacity decay (5.7% capacity retention at 0.2 C after 1000 cycles) and poor rate performance (14.2 mA h g-1 at 2 C). However, the lithium-ion battery based on the NC@AQ cathode shows excellent cycle stability (60.5% capacity retention at 0.2 C after 1000 cycles, 82.8% capacity retention at 0.5 C after 1000 cycles), superior rate capability (152.9 mA h g-1 at 2 C), and outstanding energy efficiency (98% at 0.2 C). Our work offers a new approach to realize the next-generation organic batteries for long life and high rate performance.

La2Ce2O7 (LC) is receiving increasing attention due to its lower thermal conductivity, better phase stability and higher sintering resistance than yttria partially stabilized zirconia (YSZ). However, the low fracture toughness and the sudden drop of CTE at approximately 350 °C greatly limit its application. In this study, the LC/50 vol.% YSZ composite TBC was deposited by supersonic atmospheric plasma spraying (SAPS). Compared to YSZ or double layered LC/YSZ coating, the thermal cycling life of LC/50 vol.% YSZ coating with CMAS attack increased by 93% or 91%. The latter possessed higher fracture toughness (1.48 ± 0.26 MPa m1/2) than LC (0.72 ± 0.15 MPa m1/2) and better CMAS corrosion resistance than YSZ owing to the formation of Ca2(LaxCe1-x)8(SiO4)6O6–4x with orientation perpendicular to the coating surface. The sudden CTE decrease of LC was fully suppressed in LC/50 vol.% YSZ coating due to the change of temperature dependent residual stresses induced by YSZ.

Graphene supported transition metal oxides (TMOs) nanocomposites have been recognized as an advisable strategy to develop the advanced electrodes for lithium-ion batteries (LIB) recently, yet the long-term cyclic stability could not be well maintained mainly due to the severe structural collapse and continuous exfoliation of active TMOs from graphene support. Herein, we successfully designed a novel sandwich-type hybrid nanostructure of reduced graphene oxide (rGO) enwrapped MnO nanooctahedra like a blanket (MnO@rGO NO) via a facile solution reflux and a post-annealing. The XRD patterns and FESEM images confirm that octahedral Mn3O4 precursor embedded among GO interlayers could be easily reduced into conformal MnO nanocrystal whilst the full reduction of GO into rGO during the subsequent calcination at 700 °C in N2. When used as a promising anode for LIBs, the sandwiched MnO@rGO NO manifests excellent lithium storage capability with high reversible discharge capacity, long-term cyclic stability and superb rate performance, mainly benefiting from the robust structure and good conductivity enhanced by rGO matrix. Even undergoing 600 cycles at the current densities of 400 and 800 mA g−1, the hybrid sandwiched MnO@rGO NO anodes could still deliver stable discharge capacities of 838 and 687 mAh g−1, respectively.

Progress in the design and fabrication of thermal barrier coating (TBC) is strongly dependent on the application of new materials and deposition methods. In this work, one novel and efficient plasma spraying method was employed to deposit a La2Ce2O7 (LC)/YSZ gradient TBC using a synchronous dual powder feeding system, in which the melting state and feeding rate of LC or YSZ feedstock powder can be precisely controlled. The experimental and simulation results suggested that the as-sprayed LC/YSZ TBC presented an obvious gradient change along the coating thickness direction. The heat insulation temperature and thermal cycling property of gradient TBC were greatly improved compared to its double-layer-structured counterpart due to the increased interfaces and deflection of fatigue cracks resulted from the gradient structure.

Carbonaceous hybrid nanocomposites with a porous flaky structure hold great promise as high-performance electrodes for lithium-ion batteries (LIBs); yet large-scale synthesis is still a challenge. In this work, we successfully develop a novel carbon hybrid structure of carbon-coated ZnFe2O4 nanoflakes (ZnFe2O4@C NFs) through a fast ethylene glycol (EG)-mediated metal alkoxide method, refluxing at 200 °C in EG and a post-calcination at 500 °C in a N2 atmosphere. The organic components in the pre-synthesized ZnFe-alkoxide precursor (ZnFe2(OCH2CH2O)4) can be transferred into an amorphous carbon layer easily surrounding the crystalline ZnFe2O4 subunits during the annealing process. The flaky morphologies of the as-prepared ZnFe2O4@C hybrids are highly dependent on the refluxing temperature. Upon increasing the refluxing temperature from 140 °C to 200 °C, the sphere-like morphology of the ZnFe2O4@C composites gradually evolves into microflowers and separate nanoflakes. When used as an anode for LIBs, the hybrid ZnFe2O4@C NFs present excellent electrochemical performance with high discharge capacity, long-term cyclic stability and superior high-rate capability. Even after 1000 cycles at 0.5 A g−1, the hybrid ZnFe2O4@C NFs still deliver a stable reversible discharge capacity of 778.6 mA h g−1.

Efficient white light-emitting diodes (LEDs) with an efficacy of 200 lm W-1 are much desirable for lighting and displays. The phosphor-based LEDs in use today for display applications offer poor color saturation. Intensive efforts have been made to replace the phosphor with quantum-dot-based downconverters, but the efficiency and stability of these devices are still in their infancy. Quantum rods (QRs), nanoparticles with an elongated shape, show superior properties such as relatively larger Stokes shifts, polarized emission, and high light out-coupling efficiency in the solid-state. However, these QRs usually suffer from poor optical quality for PL wavelengths

In the present work, one new technique named as supersonic suspension plasma spraying (SSPS) is employed to fabricate high-performance yttria-stabilized zirconia (YSZ) based thermal barrier coatings (TBCs). The typical microstructures, such as vertical-cracked and columnar-structured coatings, were tailored by controlling the key spray parameters. The process-microstructure-property relationship of SPPS-coating was investigated. It was found that the deposition rate was significantly improved by reducing the stand-off distance or increasing the solid content and spray power. The columnar-structured coating exhibited the longest thermal cycling life at 1300 °C, which was approximately 7 times longer than that of coating with wide vertical cracks. Both the simulation and experimental results showed that the failure of SPPS-coating occurred near the top coat/bond coat interface. However, the failure modes were largely dependent on its microstructure. For the coating with wide vertical cracks, the oxidation of bond coat was the main reason that caused its spallation, while the failure of columnar-structured coating was attributed to the accumulation of sintering stress.