Se Particles Research Articles

Organ-specific mercury stable isotopes, speciation and particle measurements reveal methylmercury detoxification processes in Atlantic Bluefin Tuna

Identifying metabolism and detoxification mechanisms of Hg in biota has important implications for biomonitoring, ecotoxicology, and food safety. Compared to marine mammals and waterbirds, detoxification of MeHg in fish is understudied. Here, we investigated Hg detoxification in Atlantic bluefin tuna Thunnus thynnus using organ-specific Hg and Se speciation data, stable Hg isotope signatures, and Hg and Se particle measurements in multiple tissues. Our results provide evidence for in vivo demethylation and biomineralization of HgSe particles, particularly in spleen and kidney. We observed a maximum range of 1.83‰ for δ202Hg between spleen and lean muscle, whereas Δ199Hg values were similar across all tissues. Mean percent methylmercury ranged from 8% in spleen to 90% in lean muscle. The particulate masses of Hg and Se were higher in spleen and kidney (Hg: 61% and 59%, Se: 12% and 6%, respectively) compared to muscle (Hg: 2%, Se: 0.05%). Our data supports the hypothesis of an organ-specific, two-step detoxification of methylmercury in wild marine fish, consisting of demethylation and biomineralization, like reported for waterbirds. While mass dependent fractionation signatures were highly organ specific, stable mass independent fractionation signatures across all tissues make them potential candidates for source apportionment studies of Hg using ABFT.

2D Self-Assembly of Large-Sized Inorganic Nanosheets Leading to Enhanced Power Factors in Earth-Abundant Cu3SbSe4-Based Flexible Hybrid Films.

Fabrication of large-sized inorganic nanosheets is an efficient strategy to promote carrier transportation in flexible thermoelectric (TE) films. Herein, we report the self-assembly of large-sized Cu3SbSe4 nanosheets by using a Se nanowire template via wet chemical synthesis and then vacuum-assisted filter these plate-like microcrystals on nylon to prepare Cu3SbSe4 flexible thermoelectric (TE) hybrid films. SEM reveals that the as-synthesized Cu3SbSe4 powders by using Se nanowires as selenium sources presented 2D plate-like micron structures uniformly and tightly self-assembled by acute triangle-like nanoparticles. Furthermore, XPS evidences that extra Sb vacancies are generated in the unit cell of Cu3SbSe4 crystals synthesized by using the Se NW template, resulting in the shrinkage of the unit cell and the narrowing interplanar spacing, which are characterized by XRD and TEM. As a result, both carrier concentration and carrier mobility have been significantly improved. The high carrier concentration is proved to originate from the extra carriers induced by Sb vacancies, and the high carrier mobility of the film is mainly ascribed to its continuous grain boundaries in the plate-like microcrystal morphology. The large-sized nanosheet Cu3SbSe4/nylon hybrid film (CSS MPs) exhibits a high power factor (PF) of 235.45 μW m-1 K-2 at 400 K, which is 4.23 times higher than that of the Cu3SbSe4/nylon hybrid film (CSS NPs) where Cu3SbSe4 crystals are synthesized by using raw Se particles. This work reveals a novel approach to prepare plate-like Se-based semiconductors, which requires both high carrier concentration and high carrier mobility.

Optimization of the Conditions for the Transformation of a Bacillus subtilis Strain L11 to Prepare Nano Selenium and Its Preliminary Application in Sheep Feed

Selenium nanoparticles (SeNPs) have greater bioavailability and safety than inorganic selenium, and was widely used in medical, agricultural, nutritional supplements, and antibacterial fields. The present study screened a strain L11 producing SeNPs from a selenium rich dairy cow breeding base in Hubei Province, China. The strain was identified as Bacillus subtilis through physiological, biochemical, and molecular biology analysis. By adjusting the cultivation conditions, the experiment determined the ideal parameters for L11 to efficiently produce SeNPs. These parameters include a pH value of 6, a cultivation temperature of 37 °C, a concentration of 4 mmol/L Na2SeO3, and a cultivation of 48 h. X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), and Transmission Electron Microscopy (TEM) were used to verify that the Se particles produced by L11 are SeNPs with diameters ranging from 50 to 200 nm. The combination of the protein analysis of different cell components and TEM analysis showed that L11 mainly produces SeNPs through the transformation of the cell’s periplasmic space, cell membrane, and cell wall. Adding the L11 SeNPs complex to sheep feed can significantly enhance the antioxidant activity and immunity of sheep, and increase the Se content in the neck muscles, liver, and spleen tissues.

Insights into the impact of surfactants on the kinetics of selenium nanoparticles formation via lemon juice-assisted methodology, followed by their antibacterial and antioxidant assessment

Selenium nanoparticles (Se NPs) fabrication utilizing active species of natural lemon juice represents a promising pathway in the biosynthesis of nanoparticles. The reduction of Se4+ to Se(0) could be attributed to the presence of natural lemon juice, which was considered a supplier of vitamin C, polyphenolic compounds, flavonoids, and sugars. The synthesized spherical Se NPs exhibited a characteristic surface plasmon resonance band (SPR) at λ = 320 nm. The values of the rate constant for the reduction of Se (IV) to Se (0) by lemon juice were estimated to be kobs = 0.0011 s−1 for a Se concentration of 0.75 mmol.dm−3 and a lemon content of 0.001 mol.dm−3 at room temperature. Various conditions have been studied on the kinetics of Se NPs formation, such as the doses of SeO2 and lemon juice, and the presence of cationic and/or anionic surfactants like cetyltrimethyl ammonium bromide (CTABr) and sodium dodecyl sulfate (SDS), respectively. The synthesized Se particles were characterized by physicochemical techniques such as FT-IR, XRD, TEM, DLS, and zeta potential to investigate their main functional groups, crystallinity, chemical composition, particle size, and surface morphology. Moreover, the antioxidant power of Se NPs was tested in terms of their DPPH free radical scavenging activity. Finally, the antibacterial activity of the studied nanoparticles was confirmed against gram-positive and gram-negative bacteria (Staphylococcus aureus and Pseudomonas aeruginosa, respectively). In short, this study introduced the impact of surfactants on the formation of biocompatible Se NPs as an active antibacterial and antioxidant.

Biogenic Selenium Nanoparticles Synthesized with Alginate Oligosaccharides Alleviate Heat Stress-Induced Oxidative Damage to Organs in Broilers through Activating Nrf2-Mediated Anti-Oxidation and Anti-Ferroptosis Pathways.

Selenium (Se) is an essential trace element for maintaining health due to its ideal antioxidant properties. We previously prepared a new type of biogenic selenium nanoparticles based on alginate oligosaccharides (SeNPs-AOS), and this study aimed to investigate the protective effects of SeNPs-AOS (Se particle size = 80 nm, Se content = 8%) on organ health in broilers challenged with HS. A total of 192 21-day-old Arbor Acres broilers were randomly divided into four groups according to a 2 × 2 experimental design, including a thermoneutral zone group (TN, raised under 23 ± 1.5 °C); TN + SeNPs-AOS group (TN group supplemented 5 mg/kg SeNPS-AOS); HS group (HS, raised under 33 ± 2 °C for 10 h/day); and HS + SeNPs-AOS group (HS group supplemented 5 mg/kg SeNPS-AOS). There were six replicates in each group (eight broilers per replicate). The results showed that SeNPs-AOS improved the splenic histomorphology, enhanced the activity of catalase (CAT) and glutathione peroxidase (GSH-Px) of the spleen, as well as upregulating the splenic mRNA expression of antioxidant-related genes in broilers under HS. In addition, SeNPs-AOS reversed the pathological changes in bursa caused by HS increased the activity of GST, GSH-Px, and CAT and upregulated the mRNA expression of Nrf2 and antioxidant-related genes in the bursa of heat-stressed broilers. In addition, dietary SeNPs-AOS improved the hepatic damage, increased the activity of GSH-Px in the liver, and upregulated the mRNA expression of antioxidant-related genes while downregulating the Keap1 gene expression of the liver in broilers during HS. Moreover, dietary SeNPs-AOS upregulated the anti-ferroptosis-related genes expression of liver in broilers under HS. In conclusion, dietary SeNPs-AOS could relieve HS-induced oxidative damage to the spleen, bursa of Fabricius and liver in broilers by upregulating the Nrf2-mediated antioxidant gene expression and SeNPs-AOS could also upregulate the expression of hepatic Nrf2-related anti-ferroptosis genes in heat-stressed broilers. These findings are beneficial for the development of new nano-antioxidants in broilers.

Annealing Temperature Effect on the Surface Properties of the MoSe Thin Films

2D transition metal dichalcogenides have been studied extensively in the field of electronics and photonics. Among them, the molybdenum chalcogenides have been receiving considerable attention due to their potential usage in field‐effect transistors and biosensors. Despite such promising aspects of these materials, studies regarding temperature effects on MoSe remain relatively rare. Herein, MoxSey (x = 0 ≈ 10, y = 0 ≈ 2) thin films are fabricated by radio frequency (RF) magnetron cosputtering on silicon and investigated using scanning electron microscopy for various atomic ratios and annealing temperatures from room temperature to 500 °C. Above the melting point of Se, Se evaporates and forms a layer, subsequently leading Mo to be exposed on the surface of the thin films. From the X‐ray diffraction and X‐ray photoelectron spectroscopy results, silicon peaks are observed due to the evaporation of Se. In addition, both Mo and Se are oxidized at above 300 °C. The work functions of the MoxSey thin films show the highest value at 200 °C measured by ultraviolet photoelectron spectroscopy and a Kelvin probe. Above the melting point of Se, there is a tendency for the work function to decrease due to the influence of Mo.

3D Porous Biomass Derived Carbon Composite Modified with (Ni,Co)Se Particles for High‐Performance Supercapacitors

AbstractModification with transition metal compounds is an effective strategy to improve the capacitance of biomass derived carbon. In this work, high‐performance (Ni,Co)Se/banana leaves derived carbon ((Ni,Co)Se/BLC) composite with 3D porous structure was prepared by two‐step carbonization and subsequent hydrothermal reaction process. The prepared (Ni,Co)Se/BLC exhibits a high specific capacitance of 840.6 F/g at a current density of 1 A/g, which is more than five times comparing with the carbon matrix. Asymmetric supercapacitor, assembled with the (Ni,Co)Se/BLC composite as the positive electrode and BLC as the negative electrode, exhibits a wide potential window of 1.5 V, delivers a high energy density of 34.3 Wh/kg at a power density of 749.8 W/kg, and the power density can reach 7500 W/kg at the energy density of 19.4 Wh/kg. The results reveal that the modification of metal selenide can greatly improve the electrochemical properties of biomass derived carbon, which is significant for the application of biowaste in supercapacitor electrode materials.

A green and fast microwave-assisted synthesis of selenium nanoparticles and their characterization under gastrointestinal conditions using mass spectrometry.

We present a novel microwave-assisted green synthesis of selenium nanoparticles (SeNPs) using yeast extract as source of a non-toxic reducing and capping agents. Effects of synthesis and gastrointestinal digestion conditions on the biogenic Se particle size distribution and number concentration using SP ICP MS were evaluated. The median equivalent diameter of SeNPs varied depending on the synthesis conditions. Upon incubation in simulated gastric juice, the increase of SeNPs size was observed, whereas after simulated intestinal juice addition, their size came back close to the initial value. The biomolecules contained in yeast extract, which play predominant role in the synthesis of SeNPs, were identified by non-targeted qualitative analysis using LC Orbitrap ESI MS. The use of the state-of-the-art MS techniques allowed both the comprehensive assessment of the processes leading to the SeNPs formation and the evaluation of their behavior under gastrointestinal conditions which is of utmost importance for their use as a novel selenium source.

Biogenic synthesis of selenium nanoparticles using Hibiscus esculentus L. extract: Catalytic degradation of organic dye and its anticancer, antibacterial and antifungal activities

In this work, we develop the synthesis of selenium nanoparticles (B@SeNPs) using a green method using the aqueous extract of Hibiscus esculentus L. Various techniques were used to characterize bio-synthesized B@SeNPs. The mixture color was clearly changed to reddish at 45-50 °C and the extract pH = 6. According to Fourier transform infrared spectroscopy (FT-IR), the B@SeNPs were produced, capped, and stabilized using biomolecules found in plant extracts. The energy dispersive X-ray (EDX) analysis profile revealed an atomic Se signal (1.39 mV). The powder X-ray diffraction (PXRD) pattern confirmed the hexagonal phase crystalline form of B@SeNPs. The zeta potential for SeNPs was determined to be -51.3 mV. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) micrographs revealed spherical Se particles with sizes of roughly 62 nm. Furthermore, B@SeNPs can degrade methylene blue dye by 98.3% at 21 min with a rate constant of 0.1023 min-1 in the presence of NaBH4. In biological evaluation, the synthesized nanoparticles have been proven to be effective against two human cancers (AGS and MCF-7 cells) with IC50 values of 20.46 and 88.43 µg/mL, respectively. Additionally, B@SeNPs showed high safety in the Beas cell line (normal) at 123 µg/mL as the highest concentration. The biofabricated SeNPs had a moderate antibacterial effect against ATCC and multidrug-resistant clinical isolates. They had no antifungal activity against the tested fungus strains except C. albicans (IFRC 1873), with a MIC value of 138.75 µg/mL. Finally, the green-synthesized B@SeNPs could be a contender for further testing as a chemotherapeutic agent in the treatment of some human cancers.

Evaluating Kinetics of Composite Cathodes of All-Solid-State Batteries

ASSBs (all-solid-state batteries) are promoted as an energy dense and safe alternative to current Li-ion batteries (LIBs) and attract great interest from academia and industry. In contrast to LIBs, which employ a liquid organic electrolyte, they utilize a solid electrolyte. This substitution promises to eliminate the flammability of the battery and to simplify the cell design.While recent research efforts have concentrated on miniaturizing and eventually even removing the anode host material in batteries, the relative portion of the cathode needs to be maximized, as cathodes are the only component that can increase energy density by increasing its fraction. In a simplified view, the cathode kinetics are determined by the cathode microstructure, the volume fractions of the constituents and the properties of electrolyte and cathode active material (CAM).Liquid electrolytes can easily penetrate porous composite cathodes, but rigid SEs can not do the same, resulting in residual porosity in the cathode. This porosity can lower active interface area between CAM and SE, and increase tortuosity of ionic and electronic charge transport pathways. Sufficient ionic and electronic transport pathways in composite cathode structures are, however, essential because cathode active material particles that are either electronically or ionically isolated cannot contribute to the charging or discharging process.We analyse the requirements for SSB cathodes and determine charge transport bottlenecks by impedance spectroscopy of a reference system consisting of a thiophosphate based solid electrolyte and a nickel rich layered CAM. Different cathode microstructures are analysed and their charge transport properties are quantified as partial conductivities. From the obtained partial conductivities, we calculated tortuosity factors and correlated them to cell performance with complementary cycling data of all-solid-state batteries in order to determine charge transport bottlenecks. We find, that ionic charge transport and consequently cathode kinetics are highly dependent on the SE particle size distributionIn addition, we analyse the requirements for CAMs for SSBs and develop design principles for different CAM types that aim to further increase cathode performance.

Tailoring shape and exposed crystal facet of single-crystal layered-oxide cathode particles for all-solid-state batteries

The design of composite cathode microstructures is important for improving the performance of all-solid-state batteries (ASSBs). The microstructural properties can provide efficient ionic/electronic percolation, good cathode/solid electrolyte (SE) contact, and minimal void spaces. Although the effects of the size of cathode and SE particles have been extensively investigated, the shape effects of cathode particles remain unexplored. Here, we demonstrate that the shape and exposed crystal facet of cathode particles affect the electrochemical performance of ASSBs using crack-free single-crystalline LiNi0.6Co0.2Mn0.2O2 (NCM) as the cathode and oxidation-tolerant Li3YCl6 as the SE. Systematic studies using five particle shapes (octahedra, plates, rods, spherical single crystals, and spherical polycrystals) reveal the important effects of the shape and exposed facets on the solid–solid contact as well as Li+ ion diffusion in composite cathodes. Single-crystalline octahedral NCM particles have a higher rate capability than that of their counterparts because their wide planar surface promoted plane-to-plane contact with the SE and the (012) facets provided straightforward 3D Li+ transfer channels between the surface and the center. These results suggest that single-crystal NCM cathodes with advanced shapes and exposed facets can enable the fabrication of ASSBs with superior performance.

Enhancement of the thermoelectric performance of Cu3SbSe4 particles by controlling morphology using exfoliated selenium nanosheets.

Copper antimony selenide (Cu3SbSe4), a ternary Cu-based material, is a promising p-type thermoelectric material. In this study, the morphology of Cu3SbSe4 particles was controlled using the shape of Se during the synthesis process. To this end, Se particles with a size of 20 μm were exfoliated to form nanosheets through an ultrasonication process without the oxidation of Se. The variation in the morphology of Cu3SbSe4 nanoparticles and nanosheets affected their grain size, thus affecting their electrical conductivity and lattice thermal conductivity owing to the phonon and electron scattering at the interface of the grains. By combining the effects of the morphological variation with the electrical and lattice thermal conductivity, the Cu3SbSe4 synthesized using Se nanosheets exhibited improved thermoelectric performance. The synthesized Cu3SbSe4 nanosheets achieved a maximum thermoelectric figure of merit value of 0.40, which was 1.41 times higher than that of Cu3SbSe4 nanoparticles.

Selenium bioconcentration in Canadian oat (Avena sativa) from soils treated with nanoscale elemental selenium

Development of selenium (Se)-enriched agricultural products can increase human daily dietary Se intake in Se-deficient areas. Canadian oat (Avena sativa L. cv. Saddle) is one of the common cereal grains in the world. Previous studies have shown that Se accumulation in oat can be significantly affected by soil Se, but few have dealt with different chemical forms of Se, including emerging nanoscale elemental Se particles (SeNPs). Because SeNPs have unique chemical and physical properties in comparing with bulk elemental Se, this laboratory study determined the effects of soil SeNP treatments of 0, 1, 5, and 10 mg/kg on Se bioconcentration in oat grain, compared with bulk elemental Se or selenate (Na2SeO4). The results showed that the soil SeNP treatments significantly increased Se concentrations in oat grain with an increase in the treatment level from 1 to 10 mg/kg (P < 0.05). The distribution of Se accumulated in oat tissues followed a descending order of root and grain > husk > stem and leaf. While the grain yield was reduced with the higher soil selenate treatments of 5–10 mg/kg, the soil SeNP treatment of 1–10 mg/kg significantly enhanced the oat grain yield, compared with the control. Concentrations of Se in oat grains in the soil SeNP treatments were approximately 7–20-fold higher than were the concentrations of those in the soil bulk elemental Se treatments, but were about 7–26% of the concentrations in oat grains in the soil selenate treatments. This study demonstrated that nanoscale elemental Se particles could be used for development of soil Se-amended fertilisers for Se-biofortified oat.

Macrophage-biomimetic porous Se@SiO2 nanocomposites for dual modal immunotherapy against inflammatory osteolysis

BackgroundInflammatory osteolysis, a major complication of total joint replacement surgery, can cause prosthesis failure and necessitate revision surgery. Macrophages are key effector immune cells in inflammatory responses, but excessive M1-polarization of dysfunctional macrophages leads to the secretion of proinflammatory cytokines and severe loss of bone tissue. Here, we report the development of macrophage-biomimetic porous SiO2-coated ultrasmall Se particles (porous Se@SiO2 nanospheres) to manage inflammatory osteolysis.ResultsMacrophage membrane-coated porous Se@SiO2 nanospheres(M-Se@SiO2) attenuated lipopolysaccharide (LPS)-induced inflammatory osteolysis via a dual-immunomodulatory effect. As macrophage membrane decoys, these nanoparticles reduced endotoxin levels and neutralized proinflammatory cytokines. Moreover, the release of Se could induce macrophage polarization toward the anti-inflammatory M2-phenotype. These effects were mediated via the inhibition of p65, p38, and extracellular signal-regulated kinase (ERK) signaling. Additionally, the immune environment created by M-Se@SiO2 reduced the inhibition of osteogenic differentiation caused by proinflammation cytokines, as confirmed through in vitro and in vivo experiments.ConclusionOur findings suggest that M-Se@SiO2 have an immunomodulatory role in LPS-induced inflammation and bone remodeling, which demonstrates that M-Se@SiO2 are a promising engineered nanoplatform for the treatment of osteolysis occurring after arthroplasty.Graphical

Encapsulation of selenium in MOF-derived N,O-codoped porous flower-like carbon host for Na-Se batteries

Na-Se batteries have their drawbacks such as large volumetric expansion and shuttle effect related to generation of soluble sodium polyselenides. To address these issues, a nitrogen and oxygen codoped flower-like porous carbon host is derived from a Ni-based metal–organic framework (MOF) for Se storage. The use of 4,4′-oxybisbenzoic acid and 4,4′-dimethyl-2,2′-bipyridyl ligands ensure the in-situ doping of the carbon host with oxygen and nitrogen upon carbonization of MOF, which increases its polarity and restricts the diffusion of selenium. Highly porous microflower-like carbon morphology provides sufficient space for Se storage. To avoid undesirable aggregation of Se particles which happens when using conventional melt-diffusion method, we employed a vapor-infiltration method for Se loading, which ensures the homogeneous dispersion of selenium and high utilization of pores in the carbon host. Density functional theory calculations confirmed that the increased polarity of the carbon host due to N,O codoping promotes the adsorption of polyselenides. When tested as a cathode for sodium-selenium battery, the optimized carbon/selenium composite shows an excellent electrochemical performance.

Synthesis of C:Se nanoparticles via laser ablated with magnetic field on porous silicon for gas sensor applications

The presented study synthesized C:Se NPs via a combination of the laser along with magnetic field at various laser pulse energies 200, 600 and 1000mJ with 100 shots, have been deposited on the porous silicon (PS) through the use of drop-casting method. The pattern of the X-ray diffraction (XRD) had indicated the nanocrystaline of specimens. In Atomic force microscopy (AFM), which shows agglomeration of C:Se NPs increased, the distribution of the granularity showed that the distribution of part was almost Gaussian, also the transmission electron microscope (TEM) indicated that the synthesized C:Se particles have an average particle size of 35 nm. Bright-field TEM images show complementary contrast, confirming the formation of core/shell structures. The optical measurements in wavelength range ultraviolet-visible near infrared (UV–vis–NIR) as well as a transition of indirect type with 4 eV band gap is specified. Also, the electrical characteristics like barrier height (ΦB), ideal factor (n) for Al/C:Se NPs/PS/Si/Al heterojunction were concluded with measurements of current-voltage (I-V). Lastly, the operation temperature variations associated with NO2 and NH3 gas sensors are subjected to fabrication from the prepared samples on response time, sensor sensitivity and recover time was examined. The maximum sensitivity of C:Se/PS at 1000 mJ gas sensor to 60 ppm of NO2 about 202.5% at around 100 °C,also the maximum sensitivity of C:Se/PS at 1000mJgas sensor to 200 ppm of NH3 can reach 17.9%, and the optimum sensing temperature of C: Se/PS sensor is at around 150 °C.

Synthesis of C:Se nanoparticles ablated on porous silicon for sensing NO2 and NH3 gases

In this work, synthesis and characterizing of carbon: selenium nanoparticles (C:Se NPs) are synthesized by laser ablation Q-switched Nd:YAG laser with wavelength of 1064 nm at different laser pulses energy 200, 600 and 800 mJ with 100 shots and porous silicon (PS) was presented. X-ray diffraction (XRD) was utilized for examining the structural properties. In addition, the results of the Atomic force microscope (AFM) analysis an 39.76 nm as average diameter which is coordinated in rod-like shape appearing for C:Se NPs, also the transmission electron microscope (TEM) indicated that the synthesized C:Se particles have been spherical with average particle size in range of (25 and 75) nm. Lastly, the variations of operation temperature related toNH3 and NO2 gas sensors that are fabricated from prepared samples on the sensor sensitivity, recover time and response time were examined, the maximum sensitivity is approximately 205% with regard to (C:Se NPs) ablated via laser energy 800mJ on PS of gas NO2, also the maximum sensitivity is approximately 43% in terms of(C:Se NPs) ablated via laser energy 200mJ on PS of gas NH3.

Co0.85Se particles encapsulated in the inner wall of nitrogen-doped carbon matrix nanotubes with rational interfacial bonds for high-performance lithium-ion batteries.

Cobalt selenides based on the conversion reaction have been widely applied in lithium-ion batteries (LIBs) due to their high conductivity and high specific capacity. However, effectively suppressing the fast capacity fade caused by the irreversible Se/Co dissolution and serious volume change during the cycling process is still a challenge. Herein, a facile and efficient self-generated sacrificial template method is used to prepare Co0.85Se nanoparticles encapsulated in the inner wall of N-doped carbon matrix nanotubes (Co0.85Se@NCMT). In this strategy, the formation of stable Co-N/C and Se-C as well as enhancing the mechanical strength between active materials and N-doped carbon matrix nanotubes can critically affect the performance through suppressing the dissolution of Se/Co, decreasing energy band, promoting the shuttling of the ions/e- moving and mitigating the volume expansion during the charge-discharge process, which play a key role in improving the structure stability and electrochemical performance. Besides, Co0.85Se nanoparticles encapsulated in the robust carbon matrix inner wall can ensure good electron transfer and prevent the aggregation of nanoparticles, leading to superior electrochemical reversibility. Finally, carbon matrix nanotubes can provide sufficient space to effectively accommodate the volume changes of encapsulated Co0.85Se nanoparticles, thereby improving the cyclic stability. Based on the above advantages, as expected, the electrochemical investigations exhibited that the Co0.85Se@NCMT anode performs a stable reversible capacity of 462.9 mA h g-1 at a large current density of 5 A g-1 and a remarkable capacity retention of 99.5% after 800 cycles, suggesting its promising potential for the anode of LIBs.

Lignin derived hierarchical porous carbon with extremely suppressed polyselenide shuttling for high-capacity and long-cycle-life lithium–selenium batteries

A low-cost scalable strategy is developed to fabricate lignin derived hierarchical porous carbon as a high-loading Se host. When combined with carbonate-based electrolyte, the high-capacity and long-term cycling Li–Se batteries were obtained. Lithium–selenium (Li–Se) batteries have attracted considerable attentions for next-generation energy storage systems owing to high volumetric capacity of 3265 mAh cm −3 and excellent electronic conductivity (~10 −5 S cm −1 ) of selenium. However, the shuttling effect and capacity fading prevent their wide applications. Herein we report a low-cost strategy for scalable fabrication of lignin derived hierarchical porous carbon (LHPC) as a new high-loading Se host for high-capacity and long-term cycling Li–Se batteries in carbonate electrolyte. The resulting LHPC exhibits three-dimensional (3D) hierarchically porous structure, high specific surface area of 1696 m 2 g −1 , and hetero-atom doping (O, S), which can effectively confine the Se particles into the micropores, and meanwhile, offer effective chemical binding sites for selenides from hetero-atoms (O, S). As a result, our Li–Se batteries based on Se@LHPC demonstrate high capacity of 450 mAh g −1 at 0.5 C after 500 cycles, with a low capacity fading rate of only 0.027%. The theoretical simulation confirmed the strong affinity of selenides on the O and S sites of LHPC effectively mitigating the Se losing. Therefore, our strategy of using lignin as the low-cost precursor of hierarchically porous carbon for high-loading Se host offers new opportunities for high-capacity and long-life Li–Se batteries.

Porous nanofibers comprised of hollow SnO2 nanoplate building blocks for high-performance lithium ion battery anode

Hollow nanoplates-aggregated SnO2 nanofibers were fabricated from electrospinning process and two-step heat treatment. Se particles were dissolved in electrospinning solution and played a critical role in the formation of small-sized SnSe nanoplates during the selenization heat treatment. During the oxidation heat treatment, due to the well-known Kirkendall diffusion process, the dense SnSe nanoplates were transformed into hollow SnO2 nanoplates. Three other SnO2 nanostructures including SnO2 hollow nanoplates, hollow nanofiber with hierarchical SnO2 nanocrystals, and SnO2 hollow nanofibers were prepared as comparison. The capacity of hollow nanoplate-aggregated SnO2 nanofibers after the 700th discharge process was 375 mA h g−1 when cycled at a high current density of 3 A g−1, whereas those of the comparison SnO2 nanostructured electrodes in the order listed were 78, 277, and 262 mA h g−1, respectively. The high structural stability of the synthesized hollow nanoplate-aggregated SnO2 nanofiber during repeated lithiation and delithiation processes resulted in lithium-ion battery anode with longer cycle life.