Se Loading Research Articles

Effect of inclusion of pentasulphate mixture and arsenic in diets given high level of selenium on feed intake and nutrient utilization in buffaloes

Sixteen Murrah buffalo male calves were divided into 4 groups with 4 animals in each group, based on their body weight and age. The animals were fed on rations to supply 15% less of CP requirements as per NRC (2001). Â All the animals were fed a basal diet (0.41 ppm Se) comprising of paddy straw, concentrate mixture and green maize (Control, group T1). The animals in groups T2, T3 and T4 were also supplemented with 10 ppm of Se in the form of sodium selenite after 60 d of feeding. Thereafter, animals were given supplementary arsenic (40 ppm of diet) in form of sodium arsenite and pentasulphate mixture (9 g/100 kg BW) in groups T3 and T4, respectively in addition to Se (10 ppm) being already given. After 85 days of feeding, a metabolism trial was conducted in order to determine DM intake, nutrient digestibility and balances of N and Se. DM Intake was similar in all the groups. Digestibility of nutrients (DM, OM, EE, CF, NFE, NDF) and nitrogen retention was also not affected by dietary treatments to any significant extent, however, digestibility of CP and ADF was lower (P<0.05) in group T2 compared to other groups. Supplementary pentasulphate mixture and As increased excretion of Se which paved the way for its less retention (P<0.01) in the body. Hence, supplementation of either pentasulphate mixture @ 9 g/100 kg BW or arsenic (40 ppm) to the diet already supplied with extra 10 ppm Se improved the digestibility of CP and ADF while reducing the Se load from the body considerably showing the positive effect of arsenic and pentasulphate supplementation in buffalo calves given high level of Se in paddy straw based rations.

A 3D-printed ultra-high Se loading cathode for high energy density quasi-solid-state Li–Se batteries

A quasi-solid-state Li–Se battery assembled with an ultra-high Se loading of 20 mg cm−2 delivers the highest reported areal capacity of 12.99 mA h cm−2 at 3 mA cm−2.

Selenium@Hollow mesoporous carbon composites for high-rate and long-cycling lithium/sodium-ion batteries

Abstract Selenium (Se) is a prospective candidate of electrode material for high-energy batteries. However, the low Se loading, volumetric expansion and polyselenide shuttling between cathode and anode are major factors to limit further development. To overcome above issues, the hollow carbon structure with interconnected mesopores is used to confine Se composite via a facile annealing treatment route. The Se/HMCS electrode exhibits excellent performance, including a long cycle life (710 mA h g−1 at the 800th cycle at 0.5 A g−1 for LIBs and 291 mA h g−1 at the 1500th cycle at 0.5 A g−1 for SIBs). When coupled with LiCoO2 and Na3V2(PO4)3/C in full cells, this electrode also exhibits superior rate capability (181 Wh kg−1total at 20 W kg−1 for LIBs and 130 Wh kg−1total at 52 W kg−1 for SIBs). The excellent electrochemical performance is attributed to the unique hollow structure of HMCS and a large amount of Se encapsulated within mesoporous, which not only promote electronic/ionic transport but also provide additional buffer space to adjust the volumetric expansion of Se and polyselenide during long cycling. This facile and novelty strategy could be easily extended to other materials with low electronic conductivity for advanced energy storage systems.

Synbiotic supplementation to decrease Salmonella colonization in the intestine and carcass contamination in broiler birds.

In vitro and in vivo experiments were conducted to study the effects of synbiotic supplementation on Salmonella enterica ser. Enteritidis (SE) proliferation, cecal content load, and broiler carcass contamination. Lactobacillus reuteri, Enterococcus faecium, Bifidobacterium animalis, and Pediococcus acidilactici culture supernatants decreased (P < 0.05) the in vitro proliferation of SE at 1:1 supernatant: pathogen dilution. A total of 240 Cobb-500 broiler chicks were randomly allotted to three treatment groups (8 replicates/group with 10 birds/replicate): control (basal diet), antibiotic (Virginiamycin at 20 mg/kg feed), synbiotic (PoultryStar® ME at 0.5 g/kg feed containing L. reuteri, E. faecium, B. animalis, P. acidilactici and a Fructooligosaccharide) from day of hatch. At 21 d of age, all birds in experimental groups were orally inoculated with 250 μl of 1 X 109 CFU SE. Antibiotic supplementation increased (P < 0.05) body weight and feed consumption, compared to the control group. Birds in the synbiotic supplementation had intermediate body weight and feed consumption that were not significantly different from both the control and antibiotic group at 42 d of age in SE infected birds. No significant effects were observed in feed efficiency at 42 d of age among the groups. Antibiotic and synbiotic supplementation decreased (P < 0.05) SE load in cecal contents by 0.90 and 0.85 log units/ g and carcass SE load by 1.4 and 1.5 log units/mL of rinsate compared to the control group at 42 d of age (21 dpi). The relative abundance of IL-10, IL-1, TLR-4, and IFNγ mRNA was decreased (P < 0.05) in the antibiotic and synbiotic supplementation groups compared to the control birds at 42 d of age (21 dpi). It can be concluded that synbiotic supplementation decreased SE proliferation in vitro and decreased SE load in the cecal contents and broiler carcass.

Material Design of New p-Type Tin Oxyselenide Semiconductor through Valence Band Engineering and Its Device Application.

This paper reports a new p-type tin oxyselenide (SnSeO), which was designed with the concept that the valence band edge from O 2p orbitals in the majority of metal oxides becomes delocalized by hybridizing Se 4p and Sn 5s orbitals. As the Se loading increased, the SnSeO film structures were transformed from tetragonal SnO to orthorhombic SnSe, which was accompanied by an increase in the amorphous phase portion and smooth morphologies. The SnSe0.56O0.44 film annealed at 300 °C exhibited the highest Hall mobility (μHall), 15.0 cm2 (V s)-1, and hole carrier density (nh), 1.2 × 1017 cm-3. The remarkable electrical performance was explained by the low hole effective mass, which was calculated by a first principle calculation. Indeed, the fabricated field-effect transistor (FET) with a p-channel SnSe0.56O0.44 film showed the high field-effect mobility of 5.9 cm2 (V s)-1 and an ION/OFF ratio of 3 × 102. This work demonstrates that anion alloy-based hybridization provides a facile route to the realization of a high-performance p-channel FET and complementary devices.

Selenium-Carbon Nanotubes Composite Cathode with Long Cycle Life for Rechargeable Li-Se Batteries

In the past two decades, lithium-ion batteries (LIBs) have been extensively utilized in portable electronic devices as well as electric vehicles (EVs). However, conventional LIBs depending on the lithium intercalation reactions of anode and transitional metal oxide cathode materials have limited capacities and low energy densities, which prevent their broader deployment as power sources for prolonged usage. High energy density and durable electrical energy storage devices are the key factors to meet the crucial demands for high-performance portable electronic devices and EVs. Selenium (Se), as a congener of sulfur in the periodic table, has been proposed as an alternative cathode material for rechargeable lithium batteries. Although Se has lower theoretical capacity (678 mAh g-1) than sulfur, it can provide a high volumetric capacity of 3253 mAh cm-3 because of its high mass density (4.8 g cm-3). In addition, selenium has a much higher electronic conductivity (1×10-3 S m-1), which implies that Se could provide better electrochemical activity. However, Se cathode is still facing similar challenges as sulfur such as poor cycling life and low Coulombic efficiency, which are attributed to the dissolution and shuttle effect of the formed high-order polyselenides as redox intermediates in the ether-based electrolyte. In addition, the significant volume change increases the difficulty for Li-Se batteries to be used in practical applications. During the last decade, lots of effort have been put into developing approaches to address these problems, thereby increasing energy density and cycle life of Li-Se batteries. In this contribution, we synthesized Se nanowires in the presence of carbon nanotubes (CNTs) by a facile method. The experimental process for preparing the Se/CNT composite consists of dissolving selenium oxide (SeO2) and beta-cyclodextrin (β-cyclodextrin) and dispersing the CNT bundles in an ethanolic mixture with de-ionized water. The vigorously stirring and ultrasonication procedure in the initial mixture cause fine dispersion of CNTs. In addition, the ethanol extenuates the hydrophobic activity of CNTs, and hence accelerates the dispersion-weave process by ultrasonication. The addition of ascorbic acid solution ensures the product of selenium nanowires. Upon another ultrasonication for selenium nanowires and CNTs to be perfectly woven, and then filtered and dried, the Se/CNT composite electrode was obtained. The filter paper has a diameter of 7 cm, which decides the overall size of the composite electrode. Se nanowires are weaved with CNTs to form a uniform binder-free composite electrode, which has superior electrical conductivity. This synthesis method provides a path for fabricating the Se cathodes with controllable mass loadings and thicknesses. At initial state, Se is in the form of branched nanowires with a diameter of <150 nm and length of 1-2 µm, interweaving with CNTs. By studying the composites electrodes with different mass loadings of active materials and different thicknesses, it is found that the electrode thickness has influence on the accumulation of redox products upon repeated cycling. The structural and morphological changes are analyzed by scanning electron microscope (SEM). Finally, the electrochemical phenomena are revealed experimentally, and enhanced cycling performance is achieved. The composite electrode with 23 µm thickness and 60% Se loading shows a high initial capacity of 537 mAh g-1, followed by stable cycling performance with a capacity of 401 mAh g-1 after 500 cycles at 1C rate. This study reports a synthesis strategy to obtain Se/CNT composite cathode with long cycle life for rechargeable Li-Se batteries. Figure 1

Selenium Nanocomposite Cathode with Long Cycle Life for Rechargeable Lithium‐Selenium Batteries

AbstractSelenium (Se) is a potential cathode material for high energy density rechargeable lithium batteries. In this study, a binder‐free Se‐carbon nanotube (CNT) composite electrode has been prepared by a facile chemical method. At initial state, Se is present in the form of branched nanowires with a diameter of &lt;150 nm and a length of 1–2 μm, interwoven with CNTs. After discharge and re‐charge, the Se nanowires are converted to nanoparticles embedded in the CNT network. This synthesis method provides a path for fabricating the Se cathodes with controllable mass loading and thickness. By studying the composite electrodes with different Se loading and thickness, we found that the electrode thickness has a critical impact on the distribution of Se during repeated cycling. Promising cycling performance was achieved in thin electrodes with high Se loading. The composite electrode with 23 μm thickness and 60 % Se loading shows a high initial capacity of 537 mAh g−1 and stable cycling performance with a capacity of 401 mAh g−1 after 500 cycles at 1 C rate. This study reports a synthesis strategy to obtain Se/CNT composite cathode with long cycle life for rechargeable Li−Se batteries.

Freestanding layer-structure selenium cathodes with ultrahigh Se loading for high areal capacity Li-Se batteries

In this work, a freestanding layer-structure Se cathode, composed of alternant barrier layers and active layers, is synthesized via a facile syringe-filtration strategy. With employing the barrier layers simultaneously acting as polyselenide-interception barriers and as highly conductive current collectors, the active layers with 3D porous architecture are endowed with strong polyselenide-trapping capability and fast redox-conversion capability. Such novel Se cathode readily achieves a high Se loading up to 13.5 mg cm−2. The optimized Se cathode with a high Se loading of 4.5 mg cm−2 exhibits high specific capacity/areal capacity (794 mA h g−1/3.6 mA h cm−2), excellent cycling stability (508 mA h g−1@300 cycles), and remarkable rate capability (389 mA h g−1@800 mA g−1), which is superior to conventional Se cathodes.

Calibration of foundation movements for AASHTO LRFD bridge design specifications

ABSTRACTIn the bridge design specifications of the American Association of State Highway and Transportation Officials using the Load and Resistance Factor Design method, the loads and resulting force effects are given two-letter designations, e.g. “SE” for “force effects due to settlement”. The same two-letter designation is used as a subscript to distinguish load factors, γ, to be applied to loads and other actions acting on the bridge. Thus, the load factor γSE is used to develop factored values of the additional induced force effects such as moments and shears in a bridge structure due to foundation movements. This paper presents the process to calibrate the SE load factor as a function of the target reliability index based on structural service limit states such as cracking in a bridge superstructure. In this process, the target reliability index, uncertainty in predicted movements, and user-specified deterministic tolerable movements are considered in a unified manner. The calibration process can be used for any analytical method and any pattern of movement. The calibration process is demonstrated by an example of immediate settlement for five analytical methods using a dataset based on 20 instrumented spread footings from 10 bridges in the northeast USA.

Metal Oxide Interlayer for Long-Lived Lithium-Selenium Batteries.

A lithium-selenium (Li-Se)-alkali activated carbon hybrid cell with a tungsten oxide interlayer is implemented for the first time. The Se hybrid at a Se loading of 70 % in the full Li-Se cell delivers a large reversible capacity of 625 mA h gSe -1 , in comparison with 505.8 mA h gSe -1 achieved for the pristine Se cell. This clearly shows the advantage of the carbon in improving the capacity of the Li-Se cell. A tungsten oxide interlayer is drop-cast over the battery separator to further circumvent the issues of polyselenide dissolution and shuttle, which cause severe capacity fading. The oxide layer conducts Li ions, as evidenced from the Li-ion diffusion coefficient of 4.2×10-9 cm2 s-1 , and simultaneously blocks the polyselenide crossover, as it is impermeable to polyselenides, thereby reducing the capacity fading with cycling. The outcome of this unique approach is reflected in the reversible capacities of 808 and 510 mA h gSe -1 achieved for the Li-oxide@separator/Se-alkali activated carbon cell before and after 100 cycles, respectively, thus demonstrating that carbon and oxide can efficiently restrict the capacity fading and improve the performances of Li-Se cells.

Carbon black free Selenium/CTAB decorated carbon nanotubes composite with high selenium content for Li-Se batteries

A cost effective, low temperature, scalable route is presented for the synthesis of Selenium nanoparticles-cetyltrimethylammonium bromide-decorated multiwalled carbon nanotubes (Se NPs@CTAB-MWCNTs) composite. The Se content in the carbon black (CB) free Li-Se NPs@CTAB-MWCNTs cell is ∼72 wt%, which is much higher than that reported in previous studies on Li-Se composite cells, where the Se loadings typically vary between 40 and 50 wt% in full cells. The high loading of Se imparts a high capacity to the composite cell due to a high electrical conductivity of Se NPs (∼0.1 S cm−1). The initial Li-ion storage capacity delivered by the same CB free cell is ∼709 mAh gSe−1 (at 0.5 current (C)-rate), and a reversible capacity of 157 mAh gSe−1 is retained after 500 cycles. In comparison, the reversible capacities offered by the Li-Se NPs-CB cell (at 80 wt% Se loading), and the Li-Se NPs@CTAB-MWCNTs-CB cell (at 64 wt% Se loading) are 13.8 and 172.5 mAh gSe−1 at the same C-rate, after 500 cycles. For the CB free cell, the capacity decay is 0.14% per cycle from 8th to 500th cycle. Though present in small quantities of 18 and 16 wt% in the two composite based cells without and with CB, CTAB-MWCNTs confer the following functional attributes to the cells. They (a) restrict polyselenide shuttle, (b) buffer the volume expansion during discharge and (c) allow Li-ion storage, without the use of any conducting CB additive (due to the composite's high inherent electrical conductivity). The electrochemical performance of the CB free Li-Se composite cell opens up opportunities to develop eco-friendly and robust Li-Se batteries.

Metal-organic complex derived hierarchical porous carbon as host matrix for rechargeable Na-Se batteries

The low Se loading, volumetric expansion and polyselenide shuttling between cathode and anode are major factors to limit the further development of Na-Se batteries. To overcome above issues, metal-organic complex derived hierarchical porous carbon (HPC) was synthesized as host matrix for Se via a facile synthesis combined with annealing treatment. The unique hollow structure holds numerous micropores and mesopores for Se loading to form Se-HPC composite. The Se-HPC electrode shows outstanding rate capabilities of 330 and 260 mA h g-1 at 1 C and 5 C, respectively. It also exhibits a stable cycling performance for 1000 cycles at 2 C with a small capacity decay rate of 0.04% per cycle. Such good performance demonstrates the viability of Na-Se batteries with high Se loading of 56%, which may be attributed to the unique hollow structure of HPC with Se encapsulated within micropores and mesopores. This attractive structure not only promotes electrolyte infiltration and electron transfer but also provides additional buffer space to buffer volumetric expansion of Se and suppress polyselenides dissolution in carbonate electrolyte during cycling.

Selenium Impregnated Monolithic Carbons as Free-Standing Cathodes for High Volumetric Energy Lithium and Sodium Metal Batteries

Energy density (energy per volume) is a key consideration for portable, automotive and stationary battery applications. We created selenium (Se) lithium and sodium metal cathodes that are monolithic and free-standing, and with record Se loading of 70 wt%. The carbon host is derived from nanocellulose, an abundant and sustainable forestry product. The composite is extremely dense (2.37 g cm-3), enabling theoretical volumetric capacity of 1120 mAh cm-3. Such architecture is fully distinct from previous Se – carbon nano or micropowders, intrinsically offering up to 2X higher energy density. For Li storage, the cathode delivered reversible capacity of 1028 mAh cm-3 (620 mAh g-1) and 82% retention over 300 cycles. For Na storage 848 mAh cm-3 (511 mAh g-1) was obtained with 98% retention after 150 cycles. The electrodes yield superb volumetric energy densities, being 1727 Wh L-1 for Li-Se and 980 Wh L-1 for Na-Se normalized by total composite mass and volume. Despite the low surface area, over 60% capacity is maintained as the current density is increased from 0.1 to 2 C (30 min charge) with Li or Na. Remarkably, the electrochemical kinetics with Li and Na are comparable, including the transition from interfacial to diffusional control.

Seasonal Effects on Leachate Quality from an Ozark Highlands Managed Grassland Using Automated, Equilibrium‐Tension Lysimeters

Core Ideas Lysimeters aid subsurface water quality assessments in long‐term nutrient management plots. Broiler litter rates affected few leachate quality parameters during a continuous 8‐yr period. Leachate water quality was affected by season during a continuous 8‐yr period. In regions with concentrated broiler (Gallus gallus) production, land application is a useful means of managing broiler litter (BL). However, surface and subsurface water quality issues may arise when continued annual BL application to fields occurs for extended periods. The application of manure follows seasonal guidelines for surface water quality protection. The objective of this study was to evaluate the effects of BL rate (0, 5.6, and 11.2 Mg litter ha−1) and season on drainage and leachate water quality over an 8‐yr period (2003–2011) in the Ozark Highlands with karst geology using automated, equilibrium‐tension lysimeters. During the 8‐yr period, seasonal drainage was unaffected by season or BL rate, averaging 118 mm per season. Averaged across BL rates, seasonal leachate pH, electrical conductivity (EC), flow‐weighted mean (FWM) NO3–N, dissolved organic C, S, and Zn concentrations, and NH4–N, Cu, Fe, and Se loads differed (P &lt; 0.05) among seasons. Averaged across seasons, seasonal leachate EC, FWM PO4–P, total P, and S concentrations, and Ni load differed (P &lt; 0.05) among BL rates. With the exception of As and Se, seasonal FWM leachate Cd, Cr, Cu, and NO3–N concentrations were at least five times smaller than their maximum contaminant level for drinking water during any of the four seasons. Since rainfall patterns seasonally change in many regions of concentrated poultry production, seasonal differences in the leachate water quality response to continuous annual application of BL are important to help tailor best management practices to protect soil and water resources in regions underlain by karst geology.

Selenium Impregnated Monolithic Carbons as Free‐Standing Cathodes for High Volumetric Energy Lithium and Sodium Metal Batteries

AbstractEnergy density (energy per volume) is a key consideration for portable, automotive, and stationary battery applications. Selenium (Se) lithium and sodium metal cathodes are created that are monolithic and free‐standing, and with record Se loading of 70 wt%. The carbon host is derived from nanocellulose, an abundant and sustainable forestry product. The composite is extremely dense (2.37 g cm−3), enabling theoretical volumetric capacity of 1120 mA h cm−3. Such architecture is fully distinct from previous Se–carbon nano‐ or micropowders, intrinsically offering up to 2× higher energy density. For Li storage, the cathode delivers reversible capacity of 1028 mA h cm−3 (620 mA h g−1) and 82% retention over 300 cycles. For Na storage, 848 mA h cm−3 (511 mA h g−1) is obtained with 98% retention after 150 cycles. The electrodes yield superb volumetric energy densities, being 1727 W h L−1 for Li–Se and 980 W h L−1 for Na–Se normalized by total composite mass and volume. Despite the low surface area, over 60% capacity is maintained as the current density is increased from 0.1 to 2 C (30 min charge) with Li or Na. Remarkably, the electrochemical kinetics with Li and Na are comparable, including the transition from interfacial to diffusional control.

Long Cycle Life, Low Self‐Discharge Sodium–Selenium Batteries with High Selenium Loading and Suppressed Polyselenide Shuttling

AbstractThe use of selenium as a cathode in rechargeable sodium–selenium batteries is hampered by low Se loading, inferior electrode kinetics, and polyselenide shuttling between the cathode and anode. Here a high‐performance sodium–selenium cell is presented by coupling a binder‐free, self‐interwoven carbon nanofiber–selenium cathode with a light‐weight carbon‐coated bifunctional separator. With this strategy, electrodes with a high Se mass loading (4.4 mg cm−2) render high reversible capacities of 599 mA h g−1 at 0.1C rate and 382 mA h g−1 at 5C rate. In addition, this novel cell offers good shelf‐life with a low self‐discharge, retaining 93.4% of its initial capacity even after resting for six months. As evidenced by experimental and density functional theory analysis, the remarkable dynamic (cycle life) and static (shelf‐life) stabilities originate from the high electrical conductivity, improved Na‐ion accessibility through the 3D interconnected open channels, and highly restrained polyselenide shuttle. The results demonstrate the viability of high‐performance sodium–selenium batteries with high selenium loading.

Protective Effects of Dietary Garlic Powder Against Cadmium-induced Toxicity in Sea Bass Liver: a Chemical, Biochemical, and Transcriptomic Approach.

To investigate the protective effect of garlic powder on cadmium-induced toxicity sea bass liver, juvenile fishes where maintained under three food diets (diet 1: normal without garlic supply, diet 2: 2% garlic powder; diet 3: 6% garlic powder). After 30days of specific diets, each group was injected with 500μgkg-1of Cd. The control group was the one fed with normal diet and not injected with Cd. Liver Cd, Zn, and Se loads was assessed after 1 and 3days of Cd injections. Moreover, antioxidant enzymes activities termed as catalase, superoxide dismutase, and glutathione peroxydase as well as their gene expression levels were monitored. Finally, metallothionein protein accumulation and its gene expression regulation (MTa) were determined. In fish fed with 2 and 6% garlic powder, the amounts of Cd, Zn, and Se significantly increase in liver tissues. Two percent garlic powder specific diet reversed the Cd-induced inhibition of catalase (CAT), superoxide dismutase (SOD), and gluthathione peroxydase (GPx) and restored the Cd-induced lipid peroxidation (MDA). The increase of liver metallothionein proteins as well as the MTa gene expression level under Cd influence was more pronounced in animals maintained for 30days under garlic power 2% diet. Our data must be carefully considered in view of the garlic powder introduction in sea bass food composition at 2% since it is an efficient prevention against Cd-induced alterations.

Exceptional Energy and New Insight with Sodium – Selenium Battery Based on Carbon Nanosheet Cathode and Pseudographite Anode

We created a unique sodium ion battery (NIB, SIB) cathode based on selenium in cellulose-derived carbon nanosheets (CCN), termed Se-CCN. The elastically compliant two-dimensional CCN host incorporates a high mass loading of amorphous Se (53wt.%), which is primarily impregnated into the 1 cm3g-1 of the nanopores. This results in facile sodiation kinetics due to short solid-state diffusion distances and large charge transfer area of the nanosheets. The architecture also leads to an intrinsic resistance to polyselenide shuttle and to disintegration/coarsening. As a Na half-cell, the Se-CCN cathode delivers a reversible capacity of 613 mAh g-1 with 88% retention over 500 cycles. The exceptional stability is achieved employing a standard electrolyte (1M NaClO4 EC-DMC), without secondary additives or high salt concentrations. The rate capability is also superb, achieving 300 mAhg-1 at 10C. Compared to recent state-of-the-art literature, the Se-CCN is the most cyclically stable and offers the highest rate performance. As a Se-Na battery, the system achieves 992 Wh/kg at 68 W/kg and 384 Wh/kg at 10144 W/kg (by active mass in cathode). We are the first to fabricate and test a Se-based full NIB, which is based on Se-CCN coupled to a Na intercalating pseudographitic carbon anode (PGC). It is demonstrated that the PGC anode increases its structural order in addition to dilating as a result of Na intercalation at voltages below 0.2 V vs. Na/Na+. The {110} Na reflections are distinctly absent from the XRD patterns of PGC sodiated down to 0.001 V, indicating that Na metal pore filling is not significant for pseudographitic carbons. The battery delivers highly promising Ragone chart characteristics, for example yielding 203 and 50 Wh kg-1 at 70 and 14000 W kg-1 (by total material mass in anode and cathode).

Designed Formulation of Se-Impregnated N-Containing Hollow Core Mesoporous Shell Carbon Spheres: Multifunctional Potential Cathode for Li-Se and Na-Se Batteries.

Nitrogen-containing carbon spheres with hollow core and mesoporous shell (NHCS), capable of confining Se at levels as high as 72 wt % has been demonstrated to exhibit appreciable electrochemical behavior with 52 and 61 wt % Se loading. In particular, 52 wt % Se confined NHCS cathode exhibits 265 mAh/g at 10C rate and retains 75% of initial capacity at 2C rate up to 10 000 cycles with an insignificant decay of 0.0025% per cycle, which is an ever first report on the extended cycle life of Li-Se batteries. Due to the negligible difference found between the transport kinetics of Se and that of Li2Se, irrespective of the cycling rate, 52 wt % Se @ NHCS performs better at high rates. Furthermore, capacity is governed by the extent of utilization of confined Se and cycle life by the extent of mitigation of volume expansion. Accordingly, rate capability studies recommend 52 wt % Se loaded cathode above 2C rate and 61 wt % Se loading up to 2C rate. Furthermore, NHCS/Se-52 cathode demonstrates suitability for Na-Se batteries by exhibiting 339 and 219 mAh/g of capacity at rates of C/5 and 2C rates, respectively. NHCS with select Se concentration could thus be exploited for multifunctional cathode behavior in Li-Se and Na-Se systems.

Three-dimensional hierarchical C-Co-N/Se derived from metal-organic framework as superior cathode for Li-Se batteries

Three-dimensional, porous graphitic carbon co-doped with cobalt and nitrogen (C-Co-N) is prepared with metal-organic framework (MOF) and employed as Lewis base matrix to host selenium. Owing to the unique structure with abundant micro/meso-pores, the highly-conductive C-Co-N matrix provides highly-efficient channels for electron transfer and ionic diffusion, and sufficient surface area for loading of selenium nanoparticles while mitigating dissolution of polyselenides and suppressing volume expansion. The homogenous distribution of cobalt nanoparticles and nitrogen-group in C-Co-N composite immobilize polyselenides through strong chemical interaction in the operation of Li-Se batteries. With a very high Se loading of 76.5 wt%, the C-Co-N/Se cathode delivers superior electrochemical performance with an ultrahigh reversible capacity of 672.3 mAh g−1 (99.6% of the theoretical value) and a capacity of 574.2 mAh g−1 after 200 cycles, giving a capacity fading of only 0.07% per cycle and a nearly 100% Columbic efficiency. In-situ Raman spectroscopy and density functional theory simulations are employed to investigate the Se (de)lithiation mechanism at the electrolyte/cathode interface, and confirm that the structure and composition of C-Co-N scaffold give rise to efficient cathode host for high-performance Se-based cathodes with dramatically reduced capacity fading.