[en] Highlights: •Co–Sn/CNF was prepared by electrospinning and thermal process. •CoSn alloy formation influenced on performance of Co–Sn/CNF. •Co–Sn/CNF composites exhibited the fully interconnected structure. •The discharge capacity for Co–Sn/CNF-800 was 560 mA h g⁻¹ at 80th cycle. -- Abstract: Co–Sn alloy embedded carbon nanofiber (Co–Sn/CNF) composites functioning as anode materials were prepared by using electrospinning technique followed with stabilization and carbonization with heat treatments. Co–Sn/CNF carbonized at 800 °C (Co–Sn/CNF-800) was composed of large amounts of CoSn alloy compared to CoSn₂ alloy and Sn crystalline phases both embedded in carbon nanofibers (CNF). The 80th discharge capacity of Co–Sn/CNFs were ranked by their preparation temperature: 800 °C (560 mA h g⁻¹) > 900 °C (504 mA h g⁻¹) > 700 °C (501 mA h g⁻¹). The excellent specific discharge capacity and cycle retention of the sample prepared at 800 °C were attributed to the abundant formation of CoSn facilitating the reversible reaction, the presence of Sn, the buffering role of CNF, and the excellent distribution of nanoparticles by electrospinning. The electrochemical performance for Co–Sn/CNF-900 is lower than that of Co–Sn/CNF-800 because of the formation of CoSn₂ showing a two-step mechanism involving irreversible reaction

[en] The objective of this study is to assess human exposure to phthalates and its associations with demographic characteristics of the subjects in the Korean National Human Biomonitoring Survey. The subjects aged between 18 and 69 were selected through nationwide stratified sampling. A total of 1874 urine samples were collected and stored at −20 °C until measurement for ten selected metabolites of phthalates (MnBP, MiBP, MBzP, MCHP, MnOP, MEHP, MEOHP, MEHHP, MiNP, and MiDP) using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The difference in the level of urinary phthalate metabolites by the characteristics of the subjects was tested for statistical significance using SAS Surveyreg procedure. The coefficients and standard errors from multiple linear regressions were exponentiated to estimate the adjusted proportional change (APC) and 95% CIs compared with a referent level. The proportion of data above LOQ was less than 20% for MCHP, MnOP, MiNP, and MiDP. Geometric means of creatinine-adjusted concentrations (unit: μg/g creatinine) of six other phthalate metabolites among Korean adults were 41.7 (95% CI 39.6–43.9) for MnBP, 17.1 (95% CI 16.1–18.1) for MiBP, 15.7 (95% CI 14.4–17.1) for MBzP, 8.65 (95% CI 8.10–9.22) for MEHP, 17.5 (95% CI 16.8–18.3) for MEOHP, and 38.1 (95% CI 36.2–40.2) for MEHHP. Urinary level of phthalates tended to be higher among subjects with older age, females, and those with vigorous daily physical activity and tended to be lower among drinkers and those with higher income. Our results suggest that the level of phthalate exposure is significant among Korean adults and thus warrants further studies to identify major source and route of exposure to phthalates.

[en] Cu₂O–SnO/poly(3,4-ethylenedioxythiophene, PEDOT) nanocomposites (CSPs) were synthesized by polymerizing a mixture consisting of Sn(II) acetate and Cu(II) acetate as metal precursors, EDOT as the monomer, and cerium(IV) sulfate as the oxidant. Three kinds of CSPs (SnO-rich, homo-phase, and Cu₂O-rich CSP) with different contents of metal precursors formed the core-shell structures, in which the metal oxides and metals were encapsulated by PEDOT. The homo-phase CSP consisted of low crystalline Cu₂O, amorphous SnO, and nanosized Cu within PEDOT, while both the SnO-rich CSP and Cu₂O-rich CSP were composed of high crystalline SnO and Cu₂O without Cu nanoparticles. The homo-phase CSP showed excellent discharge and charge capacities of 988.38 and 876 mAh g⁻¹ in the second cycle, representing high reversibility compared to the other two samples. This is caused by (i) the nanostructured formation by low crystalline Cu₂O, amorphous SnO, and nanosized Cu, (ii) the increase of electrical conductivity by nanosized Cu, (iii) the buffering role by PEDOT, and (iv) the formation of a fully interconnected pore structure. -- Highlights: ► Cu₂O–SnO/PEDOT (CSP) composites form core-shell structures, encapsulating nanoparticles by PEDOT. ► Homo-phase CSP consists of nanosized Cu₂O, SnO, and Cu in PEDOT. ► Its morphology leads to high electrical conductivity and electrochemical performance.

[en] Hollow activated carbon nanofibers (H-ACNF) were prepared by concentric electrospinning of poly(methyl methacrylate) (PMMA) as a pyrolytic core precursor and polyacrylonitrile (PAN) as a carbon shell precursor, followed by stabilization, carbonization, and activation. The H-ACNF with 190 and 270 nm for core and shell diameter showed excellent mesoporous structure, and 1-D conducting pathway in employing as catalysts of counter electrodes (CEs) for dye-sensitized solar cells (DSCs). The mesoporous structure of H-ACNF represented surface area of 1037.5 m² g⁻¹ with average mesopore diameter of 17.4 nm. The overall conversion efficiency of H-ACNF is comparable to that of Pt CE because its characteristics promotes the electron and ion transfer, decreases the resistance of charge transfer, and increases the contact area between liquid electrolyte and H-ACNF

[en] Highlights: • An electrospun self-supported CNF membrane used as a conductive framework. • Pulse electrodeposition forms a uniform V₂O₅ shell on the continuous CNF framework. • Proper thermal annealing yields an amorphous CNFV₂O₅ core-shell structure. • Near theoretical capacity with high stability for both 2 and 3 Li⁺/V₂O₅ insertion. • High degree of stability and capacity retentions at high rates up to 1500 mA g⁻¹. This study reports an approach to achieving stable 2 and 3 Li⁺ insertion, respectively, into vanadium pentoxide (V₂O₅) as lithium-ion battery (LIB) cathode materials using a core-shell structure based on a self-standing carbon nanofiber (CNF) membrane fabricated by an electrospinning process. Uniform coaxial V₂O₅ shells are coated onto continuous CNF cores via a pulsed electrodeposition. The materials analyses confirm that the V₂O₅ shell after 4 h of thermal annealing at 300 °C forms a partially hydrated amorphous structure. SEM and TEM images indicate that the uniform 30–50 nm thick V₂O₅ shell forms an intimate interface with the CNF core. Lithium insertion capacities up to 291 and 429 mAh g⁻¹ are achieved in the voltage ranges of 4.0–2.0 V and 4.0–1.5 V, respectively, which are in good agreement with the theoretical values of 294 mAh g⁻¹ for 2 Li⁺/V₂O₅ insertion and 441 mAh g⁻¹ for 3 Li⁺/V₂O₅ insertion into crystalline V₂O₅ materials. Moreover, after 100 cycles, remarkable retention rates of 97% and 70% are obtained for 2 Li⁺/V₂O₅ and 3 Li⁺/V₂O₅ insertion, respectively. These results reveal that it is potentially feasible to fabricate the core-shell structure with electrospinning and electrodeposition processes to break the intrinsic limits of V₂O₅ and enabling this high-capacity cathode materials for future LIBs.