Design and practice of an emergency blood allocation system based on radiofrequency identification technology.

BACKGROUND AND OBJECTIVES: Currently, blood allocation is solely done by scanning barcode labels for each bag of blood, with low efficiency. However, the rapid allocation of emergency blood is required owing to the rapid increase in blood consumption during unconventional emergencies. This study aimed to design and apply radiofrequency identification (RFID) technology for the rapid allocation of blood in batches with advantages in time, efficiency and accuracy. MATERIALS AND METHODS: A blood emergency allocation system based on RFID technology was designed using a multi-label anti-collision algorithm and tested with automatic information check, a comparative study of scanning speed and accuracy, data analysis and other methods. RESULTS: The optimal packing quantities of suspended red blood cells and fresh frozen plasma were 40 and 50 bags per box, respectively. The application of rapid batch allocation of blood using RFID technology was performed, and the data sent and received by RFID scanning and barcode scanning were compared. CONCLUSION: The designed RFID blood emergency allocation system could effectively achieve the rapid and batch allocation of emergency blood and has the advantages of stability, efficiency and accuracy in blood emergency allocation and management.

Spatiotemporally Correlated Imaging of Interfacial Defects and Photocurrents in High Efficiency Triple-Cation Mixed-Halide Perovskites.

Triple-cation mixed-halide perovskites have attracted considerable attention due to their excellent photovoltaic properties and enhanced stability, though the power conversion efficiency (PCE) is still far below the theoretical expectation. In order to understand the microscopic mechanisms responsible for the gap, a Cs0.05 (FA0.85 MA0.15 )0.95 Pb(I0.85 Br0.15 )3 (CsFAMA)-based solar cell with respectful efficiency over 20% is examined, and distinct high- and low-current regions are observed in photoconductive atomic force microscopy (pc-AFM) mapping. Simulations attribute the difference in local photocurrents to interfacial donor defect densities at the NiO/CsFAMA interface, which is supported by electrochemical strain microscopy (ESM) mapping, revealing a negative correlation between ionic defects and photocurrents. The interfacial defects can be further manipulated by external bias upon relaxation study, resulting in reduced photocurrents accompanied by topography change when positive ions are driven toward the NiO/CsFAMA interface. It is also observed that both structure variation and photocurrent degradation upon accelerated aging test initiate at grain boundaries, which gradually expand at the expense of grain interior, suggesting that ionic defects are most active at grain boundaries. These findings render a direct correlation between interfacial defects and photocurrents while revealing degradation evolution, and if such interfacial defects heterogeneity can be mitigated, PCE toward the theoretical limit with enhanced stability can be envisioned.

Highly Flexible Freestanding BaTiO3 -CoFe2 O4 Heteroepitaxial Nanostructure Self-Assembled with Room-Temperature Multiferroicity.

Multiferroics with simultaneous electric and magnetic orderings are highly desirable for sensing, actuation, data storage, and bio-inspired systems, yet developing flexible materials with robust multiferroic properties at room temperature is a long-term challenge. Utilizing water-soluble Sr3 Al2 O6 as a sacrificial layer, the authors have successfully self-assembled a freestanding BaTiO3 -CoFe2 O4 heteroepitaxial nanostructure via pulse laser deposition, and confirmed its epitaxial growth in both out-of-plane and in-plane directions, with highly ordered CoFe2 O4 nanopillars embedded in a single crystalline BaTiO3 matrix free of substrate constraint. The freestanding nanostructure enjoys super flexibility and mechanical integrity, not only capable of spontaneously curving into a roll, but can also be bent with a radius as small as 4.23 µm. Moreover, piezoelectricity and ferromagnetism are demonstrated at both microscopic and macroscopic scales, confirming its robust multiferroicity at room temperature. This work establishes an effective route for flexible multiferroic materials, which have the potential for various practical applications.

Three-dimensional mesoporous γ-Fe2O3@carbon nanofiber network as high performance anode material for lithium- and sodium-ion batteries.

Electrode materials that can function well in both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) are desirable for electrochemical energy storage applications, especially under high rate. In this work, a three-dimensional (3D) mesoporous γ-Fe2O3@carbon nanofiber (γ-Fe2O3@CNF) mat has been successfully synthesized by sol-gel based electrospinning and carbonization. It delivers a specific capacity of 820 mAh g-1 at 0.5 C after 250 cycles, 430 mAh g-1 at 6 C after 1000 cycles, and 222 mAh g-1 at ultrahigh rate of 60 C for LIBs, while for SIBs it delivers a specific capacity of 360 mAh g-1 at 1 C after 1000 cycles and 130 mAh g-1 at 60 C. Besides, the result of ex situ microstructure examination shows the polycrystalline nature of γ-Fe2O3 nanoparticle still exists in LIB even after 1000 cycles, while it vanishes in SIB, suggesting that the relatively larger volume expansion occurred during Na+ insertion/deinsertion, resulting in pulverization of the particles. The CNFs maintained their pristine 3D network structure after the charge/discharge, which demonstrated the critical role of a robust conductive electrode in promoting fast Li+/Na+ transportation. More importantly, they act as an electrical bridge between Li+/Na+ and γ-Fe2O3 nanoparticles, therefore suppressing the cell impedance growth and γ-Fe2O3 volume expansion, resulting in the enhancement in both cyclic and rate capability.

Resolving fine electromechanical structure of collagen fibrils via sequential excitation piezoresponse force microscopy.

Collagen is the main protein in extracellular matrix that is found in many connective tissues, and it exhibits piezoelectricity that is expected to correlate with its hierarchical microstructure. Resolving fine electromechanical structure of collagen, however, is challenging, due to its weak piezoresponse, rough topography, and microstructural hierarchy. Here we adopt the newly developed sequential excitation strategy in combination with piezoresponse force microscopy to overcome these difficulties. It excites the local electromechanical response of collagen via a sequence of distinct frequencies, minimizing crosstalk with topography, followed by principal component analysis to remove the background noise and simple harmonic oscillator model for physical analysis and data reconstruction. These enable us to acquire high fidelity mappings of fine electromechanical response at the nanoscale that correlate with the gap and overlap domains of collagen fibrils, which show substantial improvement over conventional piezoresponse force microscopy techniques. It also embodies the spirit of big data atomic force microscopy that can be readily extended into other applications with targeted data acquisition.

Calcium supplementation reducing the risk of hypertensive disorders of pregnancy and related problems: A meta-analysis of multicentre randomized controlled trials.

Hypertensive disorders of pregnancy are closely related to maternal mortality and morbidity. Calcium supplementation during pregnancy seems to reduce the risk of hypertensive disorders. No systematic review on multicentre RCTs of calcium supplementation during pregnancy has been published. The purpose of this study was to report a quantitative systematic review of the effectiveness of calcium supplementation during pregnancy on reducing the risk of hypertensive disorders of pregnancy and related problems. Publications over the years of 1991-2012 were searched through PubMed, Science Direct, EMBASE, CINAHL and Web of Science. The literatures were selected of the multicentre RCTs on calcium supplementation during pregnancy in prevention of hypertensive disorders and related problems. Reference lists from the studies were also examined for additional references. Studies were critically appraised by three independent reviewers, and the Cochrane Handbook was used to assess the quality of those included trials. Four studies were included in this systematic review. All included studies were high quality, with low risk of bias. There was an observed risk reduction in hypertension in calcium group. However, there was no reduction in the risk of severe gestational hypertension, pre-eclampsia, severe pre-eclampsia, preterm birth and low birthweight. Calcium supplementation appears to reduce the risk of hypertension in pregnancy.

A high-performance TPGDA/PETEA composite gel polymer electrolyte for lithium metal batteries.

A gel polymer electrolyte (GPE) supported by a polyimide (PI) nanofiber membrane with Li6.5La3Zr1.5Ta0.5O12 (LLZTO) nanoparticles (PI/LLZTO/GPE) shows excellent flexibility and electrochemical properties, the ionic conductivity is 1.87 mS cm-1 and the Li+ transfer number is 0.64 at room temperature. The assembled Li metal battery with a LiFePO4 (LFP) cathode retains a 56.4 mA h g-1 discharge capacity at 10C.

Unveiling the Nature of Ultrastable Potassium Storage in Bi0.48Sb1.52Se3 Composite.

The conversion and alloying-type anodes for potassium-ion batteries (PIBs) have drawn attention. However, it is still a challenge to relieve the huge volume expansion/electrode pulverization. Herein, we synthesized a composite material comprising Bi0.48Sb1.52Se3 nanoparticles uniformly dispersed in carbon nanofibers (Bi0.48Sb1.52Se3@C). Benefiting from the synergistic effects of the high electronic conductivity of Bi0.48Sb1.52Se3 and the mechanical confinement of the carbon fiber that buffers the large chemomechanical stress, the Bi0.48Sb1.52Se3@C//K half cells deliver a high reversible capacity (491.4 mAh g-1, 100 cycles at 100 mA g-1) and an extraordinary cyclability (80% capacity retention, 1000 cycles at 1000 mA g-1). Furthermore, the Bi0.48Sb1.52Se3@C-based PIB full cells achieve a high energy density of 230 Wh kg-1. In situ transmission electron microscopy (TEM) reveals an intercalation, conversion, and alloying three-step reaction mechanism and a reversible amorphous transient phase. More impressively, the nanofiber electrode can almost return to its original diameter after the potassiation and depotassiation reaction, indicating a highly reversible volume change process, which is distinct from the other conversion type electrodes. This work reveals the stable potassium storage mechanisms of Bi0.48Sb1.52Se3@C composite material, which provides an effective strategy to enable conversion/alloying-type anodes for high performance PIBs for energy storage applications.

High S-doped amorphous carbon/carbon quantum dots coupled micro-frame for highly efficient potassium storage.

Anode materials with excellent rate capability, capacity, and cycle life have been a challenge in obtaining cost-effective K-ion batteries (KIBs). Based on the concept of waste recycling, we prepared the S-doped (21.5%) amorphous carbon/carbon quantum dots coupled micro-frame (SCMF) by combining chemical exfoliation and S/Se-assisted carbonization. SCMF exhibited the advantages of integrating amorphous carbon and carbon quantum dots (CQDs). The CQDs serve as fast electron channels, while amorphous carbon can accommodate more large-size K-ions and mitigate volume expansion. In KIBs, SCMF maintained a high reversible capacity (414.0 mAh g-1, after 100 cycles at 100 mA g-1), a good rate capability (224.0 mAh g-1, 2000 mA g-1), and excellent capacity retention (208.9 mAh g-1, after 2000 cycles at 1000 mA g-1). The molecular dynamic simulation revealed that CQDs provided fast electron transport channels and that C, O and S atoms had suitable interactions with K, facilitating potassium storage. Moreover, the potassium-ion capacitor (PIC) assembled from SCMF and activated carbon exhibited stable electrochemical performance, proving its potential for application. The research provided valuable insights into the reuse of biomass waste in new secondary batteries.

Mechanically Gated Transistor.

Silicon-based field effect transistors have underpinned the information revolution in the last 60 years, and there is a strong desire for new materials, devices, and architectures that can help sustain the computing power in the age of big data and artificial intelligence. Inspired by the Piezo channels, a mechanically gated transistor abandoning electric gating altogether, achieving an ON/OFF ratio over three orders of magnitude under a mechanical force of hundreds of nN is developed. The two-terminal device utilizes flexoelectric polarization induced by strain gradient, which modulates the carrier concentration in a Van der Waals structure significantly, and it mimics Piezo channels for artificial tactile perception. This simple device concept can be easily adapted to a wide range of semiconducting materials, helping promote the fusion between mechanics and electronics in a similar way as mechanobiology.

Composition-Driven Polarization Distribution in Poly(vinylidene fluoride)-Based Copolymer Blends for High Power Density Capacitors.

High power density capacitors have been highly demanded in modern electronics and pulsed power systems. Yet the long-standing challenge that restricts achieving high power in capacitors lies in the inverse relationship between the breakdown strength and permittivity of dielectric materials. Here, we introduce poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) into the host poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) to produce PVDF-based copolymer blends, resulting in composition-driven 0-3 type microstructures, featuring nanospheres of P(VDF-TrFE) lamellar crystals dispersed homogeneously in a P(VDF-HFP) matrix together with crystalline phase evolution from the γ-phase to the α-phase. At the critical composition, the TrFE/HFP mole ratio is equal to 1, and the blend film achieves maximum energy storage performance with discharged energy density (Udis) ∼ 24.3 J/cm3 at 607 MV/m. Finite element analyses reveal the relationship between microstructures, compositions, and the distribution of local electric field and polarization, which provide an in-depth understanding of the microscopic mechanism of the enhancement in energy storage capability of the blend films. More importantly, in a practical charge/discharge circuit, the blend film could deliver an ultrahigh energy density of 20.4 J/cm3, i.e., 88.3% of the total stored energy to 20 kΩ load in 2.8 µs (τ0.9), resulting a high power density of 7.29 MW/cm3, outperforming the reported dielectric polymer-based composites and copolymer films in both energy and power densities. The study thus demonstrates a promising strategy to develop high-performance dielectrics for high power capacitors.

Fabrication and Characterization of an Optimized Low-Loss Two-Mode Fiber for Optoacoustic Sensing.

An optimized multi-step index (MSI) 2-LP-mode fiber is proposed and fabricated with low propagation loss of 0.179 dB/km, low intermodal crosstalk and excellent bend resistance. We experimentally clarified the characteristics of backward Brillouin scattering (BBS) and forward Brillouin scattering (FBS) induced by radial acoustic modes (R0,m) in the fabricated MSI 2-LP-mode fiber, respectively. Via the use of this two-mode fiber, we demonstrated a novel discriminative measurement method of temperature and acoustic impedance based on BBS and FBS, achieving improved experimental measurement uncertainties of 0.2 °C and 0.019 kg/(s·mm2) for optoacoustic chemical sensing. The low propagation loss of the sensing fiber and the new measurement method based on both BBS and FBS may pave the way for long-distance and high spatial resolution distributed fiber sensors.

Ultrafast Li/Fluorinated Graphene Primary Batteries with High Energy Density and Power Density.

Lithium/fluorinated carbon (Li/CFx) primary batteries have essential applications in consumer electronics and medical and high-power military devices. However, their application is limited due to the difficulty in achieving simultaneous high power density and high energy density in the CFx cathode. The tradeoff between conductivity and fluorine content is the decisive factor. Herein, by rational design, 3D porous fluorinated graphene microspheres (FGS-x) with both high conductivity and a high F/C ratio are successfully synthesized for the first time. FGS-x possesses an F/C ratio as high as 1.03, a nanosheet structure with hierarchical pores, abundant C═C bonds, few inactive C-F2 bonds, and electrochemically active C-F bonds. The beneficial features that can increase discharge capacity, shorten the diffusion length for both ions and electrons, enhance the Li+ intercalation kinetics, and accommodate the volume change are demonstrated. The Li/FGS-1.03 coin cell delivers an unprecedented power density of 71,180.9 W/kg at an ultrahigh rate of 50 C (43.25 A/g), coupled with a high energy density of 830.7 Wh/kg. Remarkably, the Li/FGS-1.03 pouch cell exhibits a record cell-level power density of 12,451.2 W/kg at 20 C. The in-depth investigation by the ex situ method on structural evolution at different discharge depths reveals that the excellent performance benefits from the structural stability and the uniform formation of LiF. The FGS-1.03 cathode also has excellent performance in extreme operating temperatures (0 to 100 °C) and high active material mass loading (4.3 mg/cm2). These results indicate that the engineered fluorinated graphene developed here has great potential in applications requiring both high power density and high energy density.

A large-scale, multicentered trial evaluating the sensitivity and specificity of digital PCR versus ARMS-PCR for detecting ctDNA-based EGFR p.T790M in non-small-cell lung cancer patients.

BACKGROUND: Developing liquid biopsy technology with higher sensitivity and specificity especially for low-frequency mutations remains crucial. This study demonstrated superior performance of the newly developed digital PCR (dPCR) kit for ctDNA-based EGFR p.T790M detection in metastatic non-small-cell lung cancer (NSCLC) against ARMS-PCR. METHODS: This large-scale, multi-centered diagnostic study recruited 1,045 patients including 1,029 patients diagnosed with advanced NSCLC and 16 patients with specific samples between April 1st 2018 and November 30th 2019. EGFR p.T790M in plasma samples from mNSCLC patients were tested using dPCR with ADx-ARMS PCR and Cobas® EGFR Mutation Test V2 as comparator assays to confirm cut-off value for dPCR and evaluate its performance against ARMS-PCR-based assays. Efficacy was evaluated for patients with EGFR p.T790M detected by dPCR or ARMS-PCR, who underwent Osimertinib treatment. RESULTS: The sensitivity, specificity, and concordance of dPCR against ADx-ARMS PCR was 98.15%, 88.66% and 90.16%, respectively for 1,026 plasma samples. Additional 9.26% patients were detected positive by dPCR. The majority of those samples had a mutation allele frequency between 0.1% and 1%. In 45 paired tissue and plasma samples, the sensitivity improved from 30.77% to 53.85% by dPCR with the specificity over 90%. The response of Osimertinib in 74 EGFR p.T790M-positive patients detected by dPCR, including 26 determined as negative by ARMS-PCR, were evaluated to have an ORR of 44.59% and a DCR of 90.54%. CONCLUSIONS: dPCR is a sensitive and accurate tool for ctDNA-based EGFR p.T790M detection due to its significantly improved sensitivity without compromising specificity, and dPCR is equivalent to ARMS-PCR as a companion diagnostic tool while benefiting more patients under Osimertinib treatment. TRIAL REGISTRATION: Chinese Clinical Trial Registry identifier: ChiCTR2100043147.

Large-scale multiferroic complex oxide epitaxy with magnetically switched polarization enabled by solution processing.

Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi(1-y)/2Fe y Mg(1-y)/2O3-(x)CaTiO3 (BTFM-CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 µB/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7-3.0 × 10-7 s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM-CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications.

Preparation Methods of Polypropylene/Nano-Silica/Styrene-Ethylene-Butylene-Styrene Composite and Its Effect on Electrical Properties.

Compared with traditional insulation materials, such as cross-linked polyethylene (XLPE), polypropylene (PP) is famous for its better recyclable and thermal properties, as well as its good electrical performance. However, the problem of poor impact strength has restricted the application of pure PP in high-voltage, direct current (HVDC) cables. In this paper, styrene-ethylene-butylene-styrene block copolymer (SEBS) was used as a toughening filler, and nano-SiO2 was expected to improve the electric properties of the nano-composite. By controlling the masterbatch system, the dispersion characteristics of nano-SiO2 in the ternary composite system were changed. When PP/SiO2 was used as the masterbatch and then blended with SEBS, nano-SiO2 tended to disperse in the PP phase, and the number of nano-particles in the SEBS phase was lower. When PP/SEBS was used as the masterbatch, nano-SiO2 was distributed in both the PP phase and the SEBS phase. When SEBS/SiO2 was used as the masterbatch, nano-SiO2 tended to be dispersed in the SEBS phase. The different dispersion characteristics of nano-SiO2 changed the crystallization and mechanical properties of the ternary composite system and produced different electrical performance improvement effects. The results of our experiment revealed that the space charge suppression capability was positively correlated with the direct current (DC) breakdown strength improvement effect. Compared with the DC performance of 500 kV commercial XLPE materials, the self-made PP-based ternary composite system has better space charge suppression effects and higher DC breakdown strength. When nano-SiO2 was more dispersed in the PP phase, the space charge improvement effect was best. When the nano-SiO2 particles were more dispersed in the SEBS phase, the expected electrical property improvement was not obtained. Scanning electron microscopy showed that the nano-SiO2 particles in the SEBS phase were more dispersed at the interface than in the SEBS matrix, indicating that the nano-particles were poorly dispersed, which may be a reason why the electrical properties of the composite system were not significantly improved.

Improved DC Dielectric Performance of cPP-g-MAH/iPP/SEBS Composite with Chemical Graft Modification.

In order to achieve both high toughness and favorable dielectric properties of polypropylene materials, a styrene⁻butadiene⁻styrene block copolymer (SEBS) was employed as a toughening filler, in addition to a copolymerized polypropylene grafted by maleic anhydride (cPP-g-MAH) as a compatibilization modifier, to develop a novel isotactic polypropylene (iPP) composite (cPP-g-MAH/iPP/SEBS composite) with significantly improved direct-current (DC) dielectric performance and tenacity. The underlying physical and chemical mechanisms of modifying electric insulation were studied utilizing micro-structure characterization methods in combination with multiple thermal⁻mechanic⁻electric tests. The SEBS phase islands are uniformly distributed in the PP matrix with evidently improved dispersion due to cPP-g-MAH compatibilization. Compared with iPP, the elastic modulus of cPP-g-MAH/iPP/SEBS composites can be reduced by 58% with doubled thermal elongation, which is still superior to that of cross-linked polyethylene (XLPE), implying that the composites are qualified in terms of mechanical properties for use as power cables. The space charge accumulation and electric conduction are considerably suppressed in comparison with pure iPP and the iPP/SEBS composite. In the interest of charge-trapping characteristics modified by chemically grafting MAH, the deep traps introduced into polypropylene by grafting MAH were measured with a thermal stimulation current experiment to be 1.2 and 1.6 eV of energy level in trapping depth, verified through the first-principles electronic structure calculations with an all-electron numerical orbital scheme. It was concluded that the acquired high density of deep traps can effectively restrict the carrier transport and suppress the injection of space charge, resulting in a remarkable improvement of DC dielectric properties for the MAH grafted composites. The present work demonstrates that the cPP-g-MAH/iPP/SEBS composites are eligible to be applied to polypropylene-based high-voltage DC cables due to their excellent DC insulation performance, together with the appropriate mechanical properties.

Space Charge Characteristics of Polypropylene Modified by Rare Earth Nucleating Agent for ß Crystallization.

Compared to cross-linked polyethylene, polypropylene has a thermoplastic property and the advantage of recycling. However, the poor impact resistance at low temperature and the corresponding space charge problem restrict the application of polypropylene with the extruded high voltage direct current (HVDC) cable. Sufficient introduction of the ß form of the polypropylene crystal can significantly improve impact resistance at low temperatures. Although it has been widely applied in insulation engineering, the effect of ß-crystal on the space charge characteristics of polypropylene has rarely been researched until now. In this paper, a rare earth nucleating agent of ß-crystal is employed to modify the performance of polypropylene to investigate the effects of nucleating agent content on ß-crystalline, mechanical relaxation, trap, and space charge characteristics of polypropylene. The results of differential scanning calorimeter (DSC) and X-ray diffraction (XRD) tests indicate that the relative content of ß-crystal in modified polypropylene increases gradually with the increasing concentration of the nucleating agent, approaching 43.5% when the nucleating agent content has been raised to 0.2 wt %, suggesting appreciable efficiency of the nucleating agent utilized in our research. Scanning electron microscopy (SEM) is utilized to characterize the morphology of ß-crystal spherulites, which illustrates that the ß-spherulites are in bunchy shape, and the lamellar crystals are parallel to each other without an obvious boundary between them. The results of the space charge test demonstrate that the modified polypropylene can substantially suppress space charge accumulation, which is attributed to an increment of ß-crystal content by adopting a rare earth nucleating agent. It is indicated from dynamic mechanical analysis (DMA) measurements that the enhancement of ß-crystalline in modified polypropylene can distinctly increase and decrease the ß and α relaxation losses, respectively, which proves that the defects in ß-crystal and amorphous regions are reduced and increased respectively. Thermally stimulated depolarization current tests further confirm that the number of traps caused by defects in the ß-form of polypropylene crystal declines definitely, which dominantly accounts for the suppression of space charge accumulation.

Sepiolite/CNT/S@PANI composite with stable network structure for high performance lithium sulfur batteries.

Composite materials with a stable network structure consisting of natural sepiolite (Sep) powders, carbon nanotubes (CNTs) and conductive polymer (PANI) have been successfully synthesized using a simple vacuum heat treatment and chemical oxidation method, and they have been used as cathode materials for lithium sulfur batteries. It is found that Sep/CNT/S@PANI composites possess high initial discharge capacity, good cyclic stability and good rate performance. The initial discharge capacity of the Sep/CNT/S@PANI-II composite is about 1100 mA h g-1 at 2C, and remained at 650 mA h g-1 after 300 cycles, and the corresponding coulombic efficiency is above 93%. Such performance is attributed to specific porous structure, outstanding adsorption characteristics, and excellent ion exchange capability of sepiolite, as well as excellent conductivity of CNT. Furthermore, the PANI coating has a pinning effect for sulfur, which enhances the utilization of the active mass and improves the cycling stability and the coulombic efficiency of the composites at high current rates.

Deterministic, Reversible, and Nonvolatile Low-Voltage Writing of Magnetic Domains in Epitaxial BaTiO3/Fe3O4 Heterostructure.

The ability to electrically write magnetic bits is highly desirable for future magnetic memories and spintronic devices, though fully deterministic, reversible, and nonvolatile switching of magnetic moments by electric field remains elusive despite extensive research. In this work, we develop a concept to electrically switch magnetization via polarization modulated oxygen vacancies, and we demonstrate the idea in a multiferroic epitaxial heterostructure of BaTiO3/Fe3O4 fabricated by pulsed laser deposition. The piezoelectricity and ferroelectricity of BaTiO3 have been confirmed by macro- and microscale measurements, for which Fe3O4 serves as the top electrode for switching the polarization. X-ray absorption spectroscopy and X-ray magnetic circular dichroism spectra indicate a mixture of Fe2+ and Fe3+ at O h sites and Fe3+ at T d sites in Fe3O4, while the room-temperature magnetic domains of Fe3O4 are revealed by microscopic magnetic force microscopy measurements. It is demonstrated that the magnetic domains of Fe3O4 can be switched by not only magnetic fields but also electric fields in a deterministic, reversible, and nonvolatile manner, wherein polarization reversal by electric field modulates the oxygen vacancy distribution in Fe3O4, and thus its magnetic state, making it attractive for electrically written magnetic memories.