ABSTRACT
Heterobimetallic tert-butoxides of alkali metal cations with tetravalent actinide centers exhibit two distinctive structural motifs, [AnM2(OtBu)6] and [AnM3(OtBu)7] (AnIV = Th, U and MI = Li, Na, K, Rb, Cs), evidently governed by the size of the alkali metal ions. Both [AnM3(OtBu)7] AnM3 (AnIV = U, MI = Li; AnIV = Th, MI = Li, Na) and [AnM2(OtBu)6] AnM2 (AnIV = U, MI = Na-Cs; AnIV = Th, MI = K-Cs) compounds are obtained in nearly quantitative yields by reacting actinide and alkali metal silyl amides with an excess of tert-butyl alcohol. The AnM3 complexes form a cubane-type coordination motif, whereas the AnM2 complexes display a geometry resembling two face-shared bipyramids. The sodium derivatives of thorium and uranium (ThNa3 and UNa2) allow the determination of the structural transition threshold as a function of the ratio of the ionic radii ri(AnIV)/ri(MI). The AnM3 complexes are formed for ratios above 0.92 and the AnM2 type is formed for ratios below 0.87. All compounds are unambiguously characterized in both solution and solid states by NMR and IR spectroscopic studies and single crystal X-ray diffraction analyses, respectively.
Subject(s)
Metals, Alkali , Uranium , Metals, Alkali/chemistry , Sodium/chemistry , Lithium/chemistry , Cations , Uranium/chemistryABSTRACT
Trivalent europium-based monochromatic red light-emitting phosphors are an essential component to realize high-performance smart lighting devices; however, the concentration and thermal quenching restrict their usage. Here, we report a series of efficient Eu3+-substituted Li3Y3BaSr(MoO4)8 red-emitting phosphors based on a stratified scheelite structure with negligible concentration and thermal quenching. All of the host and phosphor compositions crystallize in monoclinic crystal structure (space group C2/c). All of the phosphor compositions produce narrow-band red emission (FWHM â¼6 nm), which is highly apparent to the human eyes, and lead to exceptional chromatic saturation of the red spectral window. Concurrently, detailed investigations were carried out to comprehend the concentration and thermal quenching mechanism. Absolute quantum yields as high as 88.5% were obtained for Li3Y0.3Eu2.7BaSr(MoO4)8 phosphor with virtuous thermal stability (at 400 K, retaining 87% of its emission intensity). The light-emitting diodes were constructed by coupling Li3BaSrY0.3Eu2.7(MoO4)8 red phosphor with a near-UV LED chip (395 nm) operated at 20 mA forward bias, and the hybrid white LED (an organic yellow dye + red Li3Y3BaSr(MoO4)8:Eu3+ phosphor integrated with an NUV LED chip) showed a low CCT (6645 K), high CRI (83) values, and CIE values of x = 0.303; y = 0.368, which indicated that the synthesized phosphors can be a suitable red component for white LEDs. In addition, we have systematically investigated the Sm3+ and Sm3+, Eu3+ activation in Li3Y3BaSr(MoO4)8 to display the latent use of the system in plant growth applications and establish that the phosphor exhibits orange red emission with an intense deep-red emission (645 nm (4G5/2 â 6H9/2)). The phytochrome (Pr) absorption spectrum well matched the fabricated deep-red LED (by integrating a NUV LED + Li3Y3BaSr(MoO4)8:Sm3+ and Eu3+ phosphor) spectral lines.
Subject(s)
Color , Light , Luminescent Agents/pharmacology , Plants/drug effects , Barium/chemistry , Barium/pharmacology , Europium/chemistry , Europium/pharmacology , Humans , Lithium/chemistry , Lithium/pharmacology , Luminescent Agents/chemistry , Luminescent Measurements , Molybdenum/chemistry , Molybdenum/pharmacology , Phosphorus/chemistry , Phosphorus/pharmacology , Samarium/chemistry , Samarium/pharmacology , Strontium/chemistry , Strontium/pharmacology , TemperatureABSTRACT
Biomass-derived carbon-based energy materials are receiving extensive attention nowadays. With the widespread use of traditional Chinese medicines in the treatment of diseases and health care, a great deal of herb residues are thrown away after the unique decoction process. Here, through hydrothermal carbonization combined with KOH activation, a micropore-rich and nitrogen-doped porous carbon framework (MRNCF) is prepared from the waste roots of a kind of well-known and widely used traditional Chinese medicine, Acanthopanax senticosus. Compared with ordinary carbon-based sulfur host materials, the MRNCFs can effectively hinder the shuttling effect and dissolution of polysulfides through the synergistic action of physical confinement in micropores and chemical anchoring for nitrogen doping, and the lithium-sulfur batteries using MRNCF as the host present superior electrochemical performance. In a high sulfur content of over 75%, the as-prepared electrodes exhibit a highly reversible specific capacity of 540.4 mA h g-1 at a current density of 0.5C after 150 cycles and an excellent rate capability at different current densities.
Subject(s)
Carbon/chemistry , Drugs, Chinese Herbal/chemistry , Electric Power Supplies , Lithium/chemistry , Sulfur/chemistry , Medicine, Chinese Traditional , Particle Size , Plant Roots/chemistry , Porosity , Surface PropertiesABSTRACT
Controlling the microstructure and composition of electrodes is crucial to enhance their rate capability and cycling stability for lithium storage. Inspired by the highly interconnected network and good mechanical integrity of an ant-nest architecture, herein, a biomimetic strategy is proposed to enhance the electrochemical performance of Cu2-xSe. After facile carbonization and selenization treatments, the 3D Cu-MOF is successfully transformed into the final ant-nest-like Cu2-xSe@C (AN-Cu2-xSe@C). The AN-Cu2-xSe@C is composed of interconnected Cu2-xSe channels with amorphous carbon coated on the outer surface. The 3D interconnected channels within the AN-Cu2-xSe@C provide fast charge transport pathways and enhanced structural integrity to tolerate the large volume fluctuations of Cu2-xSe during cycling. When applied as the anode for lithium storage, the AN-Cu2-xSe@C shows remarkable electrochemical performance with a high capacity of 1452 mA h g-1 after 1200 cycles at 1.0 A g-1 and 879 mA h g-1 after 2500 cycles at 10.0 A g-1, respectively. Mechanism investigations demonstrate that the AN-Cu2-xSe@C experiences complicated conversion-intercalation co-existence reactions upon cycling. The existence of capacitive behaviour (74%) also contributes to the extended cycling performance. Our work offers a new avenue for designing a high performance electrode using the biomimetic concept.
Subject(s)
Biomimetic Materials/chemistry , Copper/chemistry , Lithium/chemistry , Selenium/chemistry , Carbon/chemistry , Electric Power Supplies , ElectrodesABSTRACT
Specific monovalent cation effects on the domain-domain interaction of heterogeneous dimeric protein were investigated using green fluorescent protein (GFP)-glutathione-s-transferase (GST) fusion protein as a model protein. Conjugating N-terminal of GST domain with a fluorescence probe Cyanine3, complementary increase and decrease of fluorescence intensities of Cyanine3 and GFP were recognized on the exclusive excitation of GFP and further the fluorescence decay of GFP was remarkably accelerated to show that an excellent Förster type of resonance excitation energy transfer (FRET) pair was constructed between GFP- and GST-domain. The spectral overlap integral and critical distance of the FRET pair were estimated to be 5.96×1013 M-1cm3 and 62.5 Å, respectively. The FRET rate and efficiency evaluated by fluorescence lifetime of the energy donor, GFP, were influenced by the monovalent cations included in the buffer solution to suggest that the domain-domain interactions of GFP-GST fusion protein would be susceptible to cation species and their concentrations. The order affecting the domain-domain interaction was estimated to be Li+>NH4+ >Na+>K+>Cs+, almost corresponding to the reverse Hofmeister series.
Subject(s)
Carbocyanines/chemistry , Fluorescence Resonance Energy Transfer , Fluorescent Dyes/chemistry , Glutathione Transferase/chemistry , Green Fluorescent Proteins/chemistry , Ammonium Chloride/chemistry , Cations/chemistry , Cesium/chemistry , Glutathione Transferase/metabolism , Lithium/chemistry , Potassium/chemistry , Protein Multimerization , Sodium/chemistryABSTRACT
BACKGROUND/AIM: The ketogenic diet has recently gained interest as potential adjuvant therapy for cancer. Many researchers have endeavored to support this claim in vitro. One common model utilizes treatment with exogenous acetoacetate in lithium salt form (LiAcAc). We aimed to determine whether the effects of treatment with LiAcAc on cell viability, as reported in the literature, accurately reflect the influence of acetoacetate. MATERIALS AND METHODS: Breast cancer and normal cell lines were treated with acetoacetate, in lithium and sodium salt forms, and cell viability was assessed. RESULTS: The effect of LiAcAc on cells was mediated by Li ions. Our results showed that the cytotoxic effects of LiAcAc treatment were significantly similar to those caused by LiCl, and also treatment with NaAcAc did not cause any significant cytotoxic effect. CONCLUSION: Treatment of cells with LiAcAc is not a convincing in vitro model for studying ketogenic diet. These findings are highly important for interpreting previously published results, and for designing new experiments to study the ketogenic diet in vitro.
Subject(s)
Acetoacetates/pharmacology , Breast Neoplasms/drug therapy , Lithium Compounds/pharmacology , Lithium/pharmacology , Acetoacetates/chemistry , Adenosine Triphosphate/metabolism , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cations, Monovalent/chemistry , Cations, Monovalent/pharmacology , Cell Growth Processes/drug effects , Cell Line, Tumor , Humans , Lithium/chemistry , Lithium Chloride/chemistry , Lithium Chloride/pharmacology , Lithium Compounds/chemistry , MCF-7 CellsABSTRACT
We report the building, validation and release of QSPR (Quantitative Structure Property Relationship) models aiming to guide the design of new solvents for the next generation of Li-ion batteries. The dataset compiled from the literature included oxidation potentials (Eox ), specific ionic conductivities (κ), melting points (Tm ) and boiling points (Tb ) for 103 electrolytes. Each of the resulting consensus models assembled 9-19 individual Support Vector Machine models built on different sets of ISIDA fragment descriptors.(1) They were implemented in the ISIDA/Predictor software. Developed models were used to screen a virtual library of 9965 esters and sulfones. The most promising compounds prioritized according to theoretically estimated properties were synthesized and experimentally tested.
Subject(s)
Computer Simulation , Drug Evaluation, Preclinical , Electrolytes/chemistry , Electrolytes/chemical synthesis , Solvents/chemistry , Solvents/chemical synthesis , Electric Conductivity , Electric Power Supplies , Electrochemical Techniques , Electrolytes/analysis , Esters/chemical synthesis , Esters/chemistry , Lithium/chemistry , Models, Molecular , Molecular Structure , Quantitative Structure-Activity Relationship , Software , Solvents/analysis , Sulfones/chemical synthesis , Sulfones/chemistry , Support Vector MachineABSTRACT
Lithium (Li) could be much safer and successful approach to supply Li via Li-fortified food products. This study is highlighting the potential scope of Li supply via Li-biofortification of Luobuma tea (made from Apocynum venetum leaves), which is a very popular beverage in Asia with several medical properties. We explored the possibility of A. venetum as Li-enriched tea and investigated plant growth, Li accumulation, total flavonoids (TFs), rutin and hyperoside concentrations, and the antioxidant capacity of A. venetum. With the increase of additional Li, Li concentration in roots, stems and leaves increased gradually. Compared with the control treatment, 10-15 mg kg-1 Li addition stimulated the growth of A. venetum and 25 mg kg-1 Li addition significantly increased the Li concentration in leaves by 80 mg kg-1. Li application did not decrease TFs, rutin, hyperoside and antioxidant capacity of this medicinal herb. A daily consumption of 10 g Li-biofortified A. venetum leaves (cultivated with 25 mg kg-1 LiCl) can give 592 µg Li intake and would constitute 59% of the provisional recommended dietary daily intake of Li. Our results showed that Li-biofortified A. venetum leaves can be used as Li-fortified tea to enhance Li supply and to improve human health when it was used as daily drink.
Subject(s)
Antioxidants/pharmacology , Apocynum/chemistry , Biofortification , Lithium/chemistry , Antioxidants/chemistry , Flavonoids/chemistry , Flavonoids/metabolism , Humans , Lithium/pharmacology , Plant Leaves/chemistry , Plant Roots/chemistry , Plants, Medicinal/chemistry , Teas, MedicinalABSTRACT
Highly efficient fluorescent and biocompatible europium doped sodium zinc molybdate (NZMOE) nanoprobes were successfully synthesized via Polyol method. Non-radiative defect centres get reduced with Li+ co-doping in NZMOE nanoprobes. XRD spectra and Rietveld refinement confirmed successful incorporation of lithium ion and crystallinity was also improved with Li+ co-doping. The shape of phosphor is rod shaped, as determined by TEM. Significant enhancement in photoluminescence intensity was observed with 266, 395 and 465 nm excitations. Profound red emission was recorded for 5 at% Li+ co-doped NZMOE nanoprobes with 266 nm excitation. It shows high asymmetry ratio (~15), color purity (94.90%) and good quantum efficiency (~70%). Judd Ofelt parameters have been calculated to measure intensity parameters and radiative transition rates. In order to measure biocompatibility of the nanoprobes, cytotoxicity assays were performed with HePG2 cells. The fluorescence emitted from phosphor material treated HePG2 cells was also measured by Laser Scanning Confocal Microscopy. The bright red fluorescence in HePG2 cells treated with very low concentration (20 µg/ml) of phosphor material indicates that it could be a promising phosphor for biological detection or bio-imaging.
Subject(s)
Europium/chemistry , Lithium/chemistry , Luminescent Agents/chemical synthesis , Molybdenum/chemistry , Zinc/chemistry , Cell Proliferation/drug effects , Cell Survival/drug effects , Hep G2 Cells , Humans , Luminescent Agents/chemistry , Luminescent Agents/pharmacology , Metal Nanoparticles , Microscopy, Confocal , Phosphorus/chemistryABSTRACT
Pleurotus ostreatus is a white-rot mushroom that bioaccumulates metals in basidiocarps and vegetative mycelia. This fungus has been used in soil and water bioremediation of several heavy metals; however, there are few studies of lithium mycelial bioaccumulation for pharmacological use. The aim of this study was to evaluate lithium bioaccumulation in P. ostreatus mycelia grown in a liquid malt extract cultivation medium with Li2CO3 or LiCl. Each lithium source was added to the medium to obtain a concentration of 0, 5, 10, 15, 20, 25, 30, 40, 50, 100, or 200 mg · L-1 lithium. The highest bioaccumulation of lithium in mycelia was 1575.29 µg · g-1 upon treatment with 40 mg · L-1 Li2CO3. P. ostreatus mycelia produce biomass and bioaccumulate both lithium sources, but more lithium bioaccumulates when in the form of Li2CO3. This study provides a prospective for the development of biotechnological products with high aggregate values and alternative ways to deliver lithium and eventually other salts for pharmacological use.
Subject(s)
Lithium Carbonate/metabolism , Lithium/metabolism , Mycelium/metabolism , Pleurotus/metabolism , Dose-Response Relationship, Drug , Lithium/chemistry , Lithium Carbonate/chemistry , Mycelium/chemistry , Pleurotus/chemistryABSTRACT
The study examined the effects of a novel neurotropic medication based on a lithium complex composed of lithium citrate, polymethylsiloxane, and aluminum oxide on electrophysiological parameters of the rat brain. In contrast to lithium carbonate (the reference drug), the novel preparation resulted in a wave-like dynamics of electrical activity in the visual cortex. Rhythmic photic stimulation of the rats treated with lithium carbonate resulted in appearance of the signs attesting to up-regulation of excitability of cerebral cortex in all examined ranges. In contrast, the complex lithium preparation diminished the delta power spectrum, which was the only affected frequency band. It is hypothesized that the complex lithium medication induces milder activation of the cerebral cortex in comparison with lithium carbonate. The novel medication composed of lithium citrate, aluminum oxide, and polymethylsiloxane, is characterized by greater efficacy and safety than the preparation based on inorganic lithium salt (lithium carbonate).
Subject(s)
Cerebral Cortex/drug effects , Cerebral Cortex/metabolism , Lithium/pharmacology , Aluminum Oxide/pharmacology , Animals , Brain/drug effects , Brain/metabolism , Citrates/pharmacology , Electrophysiological Phenomena/drug effects , Lithium/chemistry , Lithium Carbonate/pharmacology , Male , Rats , Silicones/pharmacologyABSTRACT
Adenosine triphosphate (ATP) and guanosine triphosphate (GTP) exist in physiological solution mostly bound to cations. Interestingly, their cellular Mg2+-bound forms have been shown to bind Li+, a first-line drug for bipolar disorder. However, solution structures of NTP/NDP (N = A or G) bound to Li+ and/or Mg2+ have not been solved, thus precluding knowledge of how the native Mg2+-bound cofactor conformation changes upon binding non-native Li+ and/or switching its environment from aqueous solution to proteins. Using well-calibrated methods that reproduce experimental structural and thermodynamic parameters of several Mg2+/Li+-nucleotide complexes, we show that the native NTP/NDP-Mg2+ cofactor adopts a "folded" conformation in water that remains unperturbed upon Li+ binding. We further show that the ATP-binding pockets of receptors such as P2X are complementary in shape to the "folded" ATP-Mg2+ solution structure, whereas the elongated GTP-binding pockets found in G-proteins necessitate the GTP-Mg2+ cofactor to undergo a conformational change from its "folded" conformation in solution to an extended one upon G-protein binding. Implications of the findings on how Li+, in its bound state, can manifest its therapeutic effects are discussed.
Subject(s)
Adenosine Triphosphate/metabolism , Guanosine Triphosphate/metabolism , Adenosine Triphosphate/chemistry , Cations/chemistry , Guanosine Triphosphate/chemistry , Lithium/chemistry , Lithium/metabolism , Magnesium/chemistry , Magnesium/metabolism , Magnetic Resonance Spectroscopy , Protein Binding , Proteins/chemistry , Proteins/metabolism , Thermodynamics , Water/chemistryABSTRACT
INTRODUCTION: Obtaining suitable results unaffected by pre- or postanalytical phases is pivotal for clinical chemistry service. We aimed comparison and stability of nine biochemical analytes after centrifugation using Barricor™ plasma tubes with mechanical separator vs standard Vacutainer® lithium heparin tubes. MATERIALS AND METHODS: We collected samples on six healthy volunteers and nine patients from intensive care units into 6 mL plastic Vacutainer® lithium heparin tubes and 5.5 mL plastic Barricor™ plasma tubes. All tubes were centrifuged within 30 minutes after venipuncture. First, we compared results of nine biochemical analytes from lithium heparin tubes with Barricor™ tubes for each analyte using Passing-Bablok and Bland-Altman analyses. Second, we calculated the difference of analyte concentrations between baseline and time intervals in tubes stored at + 4 °C. Based on the total change limit we calculated the maximum allowable concentrations percentage change from baseline. RESULTS: The majority of correlation coefficients were close to 0.99 indicating good correlation in the working range. Bland-Altman analyses showed an acceptable concordance for all analytes. In consequence, the Barricor™ tube might be an alternative to regular lithium heparin tube. Stability with this new generation tube is improved for eight analytes (except for aspartate aminotransferase) in comparison with regular lithium heparin tubes. CONCLUSIONS: By using Barricor™ tubes and prompt centrifugation, supplemental analysis or re-analysis for eight analytes including alanine aminotransferase, alkaline phosphatase, C-reactive protein, high sensitivity troponin T, lactate dehydrogenase, NT-pro BNP, potassium and sodium could be performed within 72 h of specimen collection.
Subject(s)
Blood Specimen Collection/instrumentation , Centrifugation/instrumentation , Alanine Transaminase/blood , Alkaline Phosphatase/blood , Anticoagulants/chemistry , Biomarkers/blood , Blood Specimen Collection/standards , C-Reactive Protein/metabolism , Case-Control Studies , Cations, Monovalent , Critical Illness , Heparin/chemistry , Humans , Intensive Care Units , L-Lactate Dehydrogenase/blood , Lithium/chemistry , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Potassium/blood , Sodium/blood , Troponin T/bloodABSTRACT
Zeolites are often used as adsorbents materials and their loaded cations can be exchanged with metal ions in order to add antimicrobial properties. The aim of this study was to use the 4A zeolite and its derived ion-exchanged forms with Zn2+, Li+, Cu2+ and Co2+ in order to evaluate their antifungal properties against Fusarium graminearum, including their capacity in terms of metal ions release, conidia germination and the deoxynivalenol (DON) adsorption. The zeolites ion-exchanged with Li+, Cu2+, and Co2+ showed an excellent antifungal activity against F. graminearum, using an agar diffusion method, with a zone of inhibition observed around the samples of 45.3 ± 0.6 mm, 25.7 ± 1.5 mm, and 24.7 ± 0.6 mm, respectively. Similar results using agar dilution method were found showing significant growth inhibition of F. graminearum for ion-exchanged zeolites with Zn2+, Li+, Cu2+, and Co2+. The fungi growth inhibition decreased as zeolite-Cu2+>zeolite-Li+>zeolite-Co2+>zeolite-Zn2+. In addition, the conidia germination was strongly affected by ion-exchanged zeolites. With regard to adsorption capacity, results indicate that only zeolite-Li+ were capable of DON adsorption significantly (P < 0.001) with 37% at 2 mg mL-1 concentration. The antifungal effects of the ion-exchanged zeolites can be ascribed to the interactions of the metal ions released from the zeolite structure, especially for zeolite-Li+, which showed to be a promising agent against F. graminearum and its toxin.
Subject(s)
Fungicides, Industrial/pharmacology , Fusarium/drug effects , Trichothecenes/chemistry , Zeolites/chemistry , Zeolites/pharmacology , Adsorption , Drug Evaluation, Preclinical/methods , Fungicides, Industrial/chemistry , Fusarium/growth & development , Lithium/chemistry , Lithium/pharmacology , Metals/chemistryABSTRACT
Sr3 (PO4 )2 :Dy3+ ,Li+ phosphors were prepared using a simple high temperature solid method for luminescence enhancement. The structures of the as-prepared samples agreed well with the standard phase of Sr3 (PO4 )2 , even when Dy3+ and Li+ were introduced. Under ultraviolet excitation at 350 nm, the Sr3 (PO4 )2 :Dy3+ sample exhibited two emission peaks at 483 nm and 580 nm, which were due to the 4 F9/2 â 6 H15/2 and 4 F9/2 â 6 H13/2 transitions of Dy3+ ions, respectively. A white light was fabricated using these two emissions from the Sr3 (PO4 )2 :Dy3+ phosphors. The luminescence properties of Sr3 (PO4 )2 :Dy3+ ,Li+ phosphors, including emission intensity and decay time, were improved remarkably with the addition of Li+ as the charge compensator, which would promote their application in near-ultraviolet excited white-light-emitting diodes.
Subject(s)
Dysprosium/chemistry , Light , Lithium/chemistry , Luminescence , Phosphates/chemistry , Phosphorus/chemistry , Strontium/chemistryABSTRACT
Phototherapy is a renowned treatment for curing skin diseases since ancient times. Phototherapeutic treatment for psoriasis and many other diseases require narrow band ultra violet-B (NB-UVB) light with peak intensity at 313nm to be exposed to the affected part of body. In this paper, we report combustion synthesis of NB-UVB -313nm emitting Ca9Mg(PO4)6F2 phosphors doped with Gd3+, Pr3+ and Li+ ions. The phase formation was confirmed by obtaining X-ray diffraction (XRD) pattern and morphology was studied with the Scanning electron microscopy (SEM) images. Photoluminescence (PL) emission spectra show intense narrow band emission at 313nm under 274nm excitation wavelengths. Emission intensity was enhanced when Ca9Mg(PO4)6F2 compound is co-doped with Pr3+ ions. Excitation spectra of Ca9Mg(PO4)6F2:Gd3+, Pr3+ doped samples shows broad excitation in ultra violet C (UVC) region. Diffuse reflectance spectra (DRS), obtained by UV-visible spectrophotometer, measures the absorption properties of the material. By applying Kubelka Munk function on the diffuse reflectance spectra, band gap of the material is determined. PL decay curves were examined which indicates efficient energy transfer between Pr3+ and Gd3+ ions. Charge compensation effect was also studied by co-doping Li+ ion in host. Emission intensity was found to increase with the addition of charge compensator. The prepared phosphor has potential to convert UVC light into NB-UVB. The luminescence intensity of Gd3+ shows remarkable increase when it is sensitized with Pr3+, and an addition of charge compensator in the form of Li+, show even better results. This phosphor surely has the potential to be used as phototherapy lamp phosphor.
Subject(s)
Gadolinium/chemistry , Lithium/chemistry , Luminescent Agents/chemistry , Energy Transfer , Ions/chemistry , Spectrum AnalysisABSTRACT
A rod-like Cu2-x Se is synthesized by a facile water evaporation process. The electrochemical reaction mechanism is investigated by exâ situ X-ray diffraction (XRD). By adopting an ether-based electrolyte instead of a carbonate-based electrolyte, the electrochemical performance of Cu2-x Se electrodes improved significantly. The Cu2-x Se electrodes exhibit outstanding cycle performance: after 1000â cycles, 160â mA h g-1 can be maintained with a retention of 80.3 %. At current densities of 100, 200, 500, and 1000â mA g-1 , the capacity of a Cu2-x Se/Li battery was 208, 202, 200, and 198â mA h g-1 , respectively, showing excellent rate capability. The 4-probe conductivity measurements along with electrochemical impendence spectroscopy (EIS) and cyclic voltammetry (CV) tests illustrate that the Cu2-x Se electrodes display high specific conductivity and impressive lithium-ion diffusion rate, which makes the Cu2-x Se a promising anode material for lithium-ion batteries.
Subject(s)
Copper/chemistry , Electric Power Supplies , Lithium/chemistry , Selenium/chemistry , Microscopy, Electron , Spectrum Analysis, Raman , X-Ray DiffractionABSTRACT
A novel photoelectrochemical sensor was developed for determination of tert-butyl-hydroquinone (TBHQ) in edible vegetable oils, based on CdSe/ZnS core-shell quantum dots sensitized with lithium tetracyanoethylenide (LiTCNE). The CdSe/ZnS/LiTCNE photoelectrochemical sensor presented a TBHQ photocurrent about 13-fold higher and a charge transfer resistance 62-fold lower than observed for a CdSe/ZnS sensor. The photoelectrochemical sensor showed selectivity to TBHQ, with a high photocurrent for this antioxidant compared to the photocurrent responses for other phenolic antioxidants. The CdSe/ZnS/LiTCNE photoelectrochemical sensor presented a linear range from 0.6 to 250µmolL-1, sensitivity of 0.012µALµmol-1, and a limit of detection of 0.21µmolL-1 for TBHQ, under optimized experimental conditions. The sensor was successfully employed in the analysis of edible oil samples, with recoveries of between 98.25% and 99.83% achieved.
Subject(s)
Antioxidants/chemistry , Food Additives/chemistry , Food Analysis/methods , Hydroquinones/chemistry , Plant Oils/chemistry , Food Analysis/instrumentation , Lithium/chemistry , Quantum Dots/chemistryABSTRACT
A ternary CuO-Fe2 O3 -mesocarbon microbeads (MCMB) conversion anode was characterized and combined with a high-voltage Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 spinel cathode in a lithium-ion battery of relevant performance in terms of cycling stability and rate capability. The CuO-Fe2 O3 -MCMB composite was prepared by using high-energy milling, a low-cost pathway that leads to a crystalline structure and homogeneous submicrometrical morphology as revealed by XRD and electron microscopy. The anode reversibly exchanges lithium ions through the conversion reactions of CuO and Fe2 O3 and by insertion into the MCMB carbon. Electrochemical tests, including impedance spectroscopy, revealed a conductive electrode/electrolyte interface that enabled the anode to achieve a reversible capacity value higher than 500â mAh g-1 when cycled at a current of 120â mA g-1 . The remarkable stability of the CuO-Fe2 O3 -MCMB electrode and the suitable characteristics in terms of delivered capacity and voltage-profile retention allowed its use in an efficient full lithium-ion cell with a high-voltage Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 cathode. The cell had a working voltage of 3.6â V and delivered a capacity of 110â mAh gcathode-1 with a Coulombic efficiency above 99 % after 100 cycles at 148â mA gcathode-1 . This relevant performances, rarely achieved by lithium-ion systems that use the conversion reaction, are the result of an excellent cell balance in terms of negative-to-positive ratio, favored by the anode composition and electrochemical features.
Subject(s)
Aluminum Oxide/chemistry , Copper/chemistry , Electric Power Supplies , Ferric Compounds/chemistry , Lithium/chemistry , Magnesium Oxide/chemistry , Microspheres , Electrodes , Green Chemistry TechnologyABSTRACT
A novel porous carbon material using the spongy tissue of sunflower as raw material is reported for the first time. The obtained porous carbon has an extremely high surface area of 2493.0m2g-1, which is beneficial to focus on encapsulating selenium in it and have an inhibiting effect about diffusion of polyselenides over the charge/discharge processes used as the host matrix for Li-Se battery. The porous carbon/Se composite electrode with 63wt% selenium delivers a high specific capacitance of 319mAhg-1 of the initial capacity, and maintains 290mAhg-1, representing an extremely high capacity retention of 90.9% after 840 cycles with the rate of 1C.