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1.
J Biol Chem ; 295(18): 5970-5983, 2020 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-32184353

RESUMEN

Barttin is the accessory subunit of the human ClC-K chloride channels, which are expressed in both the kidney and inner ear. Barttin promotes trafficking of the complex it forms with ClC-K to the plasma membrane and is involved in activating this channel. Barttin undergoes post-translational palmitoylation that is essential for its functions, but the enzyme(s) catalyzing this post-translational modification is unknown. Here, we identified zinc finger DHHC-type containing 7 (DHHC7) protein as an important barttin palmitoyl acyltransferase, whose depletion affected barttin palmitoylation and ClC-K-barttin channel activation. We investigated the functional role of barttin palmitoylation in vivo in Zdhhc7-/- mice. Although palmitoylation of barttin in kidneys of Zdhhc7-/- animals was significantly decreased, it did not pathologically alter kidney structure and functions under physiological conditions. However, when Zdhhc7-/- mice were fed a low-salt diet, they developed hyponatremia and mild metabolic alkalosis, symptoms characteristic of human Bartter syndrome (BS) type IV. Of note, we also observed decreased palmitoylation of the disease-causing R8L barttin variant associated with human BS type IV. Our results indicate that dysregulated DHHC7-mediated barttin palmitoylation appears to play an important role in chloride channel dysfunction in certain BS variants, suggesting that targeting DHHC7 activity may offer a potential therapeutic strategy for reducing hypertension.


Asunto(s)
Aciltransferasas/metabolismo , Canales de Cloruro/metabolismo , Ácido Palmítico/metabolismo , Procesamiento Proteico-Postraduccional , Aciltransferasas/deficiencia , Aciltransferasas/genética , Animales , Perros , Técnicas de Inactivación de Genes , Células HEK293 , Humanos , Riñón/citología , Riñón/metabolismo , Células de Riñón Canino Madin Darby , Ratones , Mutación , Fenotipo
2.
Anal Chem ; 90(18): 10990-10999, 2018 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-30074391

RESUMEN

Chemical cross-linking combined with mass spectrometry (MS) is a powerful approach to identify and map protein-protein interactions. Its applications support computational modeling of three-dimensional structures and complement classical structural methodologies such as X-ray crystallography, NMR spectroscopy, and electron microscopy (EM). A plethora of cross-linkers, MS methods, and data analysis programs have been developed, but due to their methodological complexity application is currently reserved for specialized mass spectrometry laboratories. Here, we present a simplified single-step purification protocol that results in improved identifications of cross-linked peptides. We describe an easy-to-follow pipeline that combines the MS-cleavable cross-linker DSBU (disuccinimidyl dibutyric urea), a Q-Exactive mass spectrometer, and the dedicated software MeroX for data analysis to make cross-linking MS accessible to structural biology and biochemistry laboratories. In experiments focusing on kinetochore subcomplexes containing 4-10 subunits (so-called KMN network), one-step peptide purification, and enrichment by size-exclusion chromatography yielded identification of 135-228 non-redundant cross-links (577-820 cross-linked peptides) from each experiment. Notably, half of the non-redundant cross-links identified were not lysine-lysine cross-links and involved side chains with hydroxy groups. The new pipeline has a comparable potential toward the identification of protein-protein interactions as previously used pipelines based on isotope-labeled cross-linkers. A newly identified cross-link enabled us to improve our 3D-model of the KMN, emphasizing the power of cross-linking data for evaluation of low-resolution EM maps. In sum, our optimized experimental scheme represents a viable shortcut toward obtaining reliable cross-link data sets.

3.
Chemistry ; 22(20): 6808-14, 2016 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-26990320

RESUMEN

In this paper, we report an advanced long-life lithium ion battery, employing a Pyr14 TFSI-LiTFSI non-flammable ionic liquid (IL) electrolyte, a nanostructured tin carbon (Sn-C) nanocomposite anode, and a layered LiNi1/3 Co1/3 Mn1/3 O2 (NMC) cathode. The IL-based electrolyte is characterized in terms of conductivity and viscosity at various temperatures, revealing a Vogel-Tammann-Fulcher (VTF) trend. Lithium half-cells employing the Sn-C anode and NMC cathode in the Pyr14 TFSI-LiTFSI electrolyte are investigated by galvanostatic cycling at various temperatures, demonstrating the full compatibility of the electrolyte with the selected electrode materials. The NMC and Sn-C electrodes are combined into a cathode-limited full cell, which is subjected to prolonged cycling at 40 °C, revealing a very stable capacity of about 140 mAh g(-1) and retention above 99 % over 400 cycles. The electrode/electrolyte interface is further characterized through a combination of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) investigations upon cell cycling. The remarkable performances reported here definitively indicate that IL-based lithium ion cells are suitable batteries for application in electric vehicles.

4.
Inorg Chem ; 54(19): 9393-400, 2015 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-26375476

RESUMEN

Here we report an in-depth structural characterization of transition metal-doped zinc oxide nanoparticles that have recently been used as anode materials for Li-ion batteries. Structural refinement of powder X-ray diffraction (XRD) data allowed the determination of small though reproducible changes in the unit cell dimensions of four ZnO samples (wurtzite structure) prepared with different dopants or different synthesis conditions. Moreover, large variations of the full width at half-maximum of the XRD reflections indicate that the crystallinity of the samples decreases in the order ZnO, Zn0.9Co0.1O, Zn0.9Fe0.1O/C, and Zn0.9Fe0.1O (the crystallite sizes as determined by Williamson-Hall plots are 42, 29, 15, and 13 nm, respectively). X-ray absorption spectroscopy data indicate that Co is divalent, whereas Fe is purely trivalent in Zn0.9Fe0.1O and 95% trivalent (Fe(3+)/(Fe(3+) + Fe(2+)) ratio = 0.95) in Zn0.9Fe0.1O/C. The aliovalent substitution of Fe(3+) for Zn(2+) implies the formation of local defects around Fe(3+) such as cationic vacancies or interstitial oxygen for charge balance. The EXAFS (extended X-ray absorption fine structure) data, besides providing local Fe-O and Co-O bond distances, are consistent with a large amount of charge-compensating defects. The Co-doped sample displays similar EXAFS features to those of pure ZnO, suggesting the absence of a large concentration of defects as found in the Fe-doped samples. These results are of substantial importance for understanding and elucidating the modified electrochemical lithiation mechanism by introducing transition metal dopants into the ZnO structure for the application as lithium-ion anode material.

5.
Macromol Rapid Commun ; 36(11): 1075-82, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25598387

RESUMEN

The synthesis of statistical and block copolymers based on polyacrylonitrile, as a source for carbonaceous materials, and thiol-containing repeating units as inorganic nanoparticle anchoring groups is reported. These polymers are used to coat Au@ZnO multipod heteroparticles with polymer brushes. IR spectroscopy and transmission electron microscopy prove the successful binding of the polymer onto the inorganic nanostructures. Thermogravimetric analysis is applied to compare the binding ability of the block and statistical copolymers. Subsequently, the polymer coating is transformed into a carbonaceous (partially graphitic) coating by pyrolysis. The obtained carbon coating is characterized by Raman spectroscopy and energy-dispersive X-ray (EDX) spectroscopy. The benefit of the conformal carbon coating of the Au@ZnO multipods regarding its application as lithium-ion anode material is revealed by performing galvanostatic cycling, showing a highly enhanced and stabilized electrochemical performance of the carbon-coated particles (still 831 mAh g(-1) after 150 cycles) with respect to the uncoated ones (only 353 mAh g(-1) after 10 cycles).


Asunto(s)
Suministros de Energía Eléctrica , Oro/química , Litio/química , Nanopartículas del Metal/química , Polímeros/química , Óxido de Zinc/química , Resinas Acrílicas/química , Carbono/química , Técnicas Electroquímicas , Electrodos , Iones/química , Microscopía Electrónica de Transmisión , Polímeros/síntesis química , Espectrometría por Rayos X
6.
Chemphyschem ; 15(10): 2177-85, 2014 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-24723308

RESUMEN

The electrochemical performance of nano- and micron-sized Co(3)O(4) is investigated, highlighting the substantial influence of the specific surface area on the obtainable specific capacities as well as the cycling stability. In fact, Co(3)O(4) materials with a high surface area (i.e. a small particle size) show superior specific features, which are, however, accompanied by a rapid capacity fading, owing to the increased formation of an insulating polymeric surface film that results from transition-metal-catalyzed electrolyte decomposition. The simultaneous coating with carbon of Co(3)O(4) nanoparticles and in situ reduction of the Co(3)O(4) by a carbothermal route yields a CoO-Co-C nanocomposite. The formation of this material substantially enhances the long-term cycling stability and coulombic efficiency of the lithium-ion active material used. Although the metallic cobalt enhances the electronic conductivity within the electrode and remains electrochemically inactive (as revealed by in situ powder X-ray diffraction analysis), it might have a detrimental effect on the long-term cycling stability by catalytically inducing continuous electrolyte decomposition.

7.
Cell Metab ; 35(12): 2153-2164.e4, 2023 12 05.
Artículo en Inglés | MEDLINE | ID: mdl-37951214

RESUMEN

Nerve injuries cause permanent neurological disability due to limited axonal regeneration. Injury-dependent and -independent mechanisms have provided important insight into neuronal regeneration, however, common denominators underpinning regeneration remain elusive. A comparative analysis of transcriptomic datasets associated with neuronal regenerative ability revealed circadian rhythms as the most significantly enriched pathway. Subsequently, we demonstrated that sensory neurons possess an endogenous clock and that their regenerative ability displays diurnal oscillations in a murine model of sciatic nerve injury. Consistently, transcriptomic analysis showed a time-of-day-dependent enrichment for processes associated with axonal regeneration and the circadian clock. Conditional deletion experiments demonstrated that Bmal1 is required for neuronal intrinsic circadian regeneration and target re-innervation. Lastly, lithium enhanced nerve regeneration in wild-type but not in clock-deficient mice. Together, these findings demonstrate that the molecular clock fine-tunes the regenerative ability of sensory neurons and propose compounds affecting clock pathways as a novel approach to nerve repair.


Asunto(s)
Relojes Circadianos , Ratones , Animales , Relojes Circadianos/genética , Ritmo Circadiano , Regeneración Nerviosa/fisiología , Células Receptoras Sensoriales , Factores de Transcripción ARNTL/genética
8.
Front Neurol ; 13: 1023147, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36570440

RESUMEN

Objectives: Large vessel occlusion (LVO) stroke patients routinely undergo interhospital transfer to endovascular thrombectomy capable centers. Imaging is often repeated with residual intravenous (IV) iodine contrast at post-transfer assessment. We determined imaging findings and the impact of residual contrast on secondary imaging. Anterior circulation LVO stroke patients were selected out of a consecutive cohort. Directly admitted patients were contrast naïve, and transferred patients had previously received IV iodine contrast for stroke assessment at the referring hospital. Two independent readers rated the visibility of residual contrast on non-contrast computed tomography (CT) after transfer and assessed the hyperdense vessel sign. Multivariate linear regression analysis was used to investigate the association of the Alberta Stroke Program Early CT score (ASPECTS) with prior contrast administration, time from symptom onset (TFSO), and CTP ischemic core volume in both directly admitted and transferred patients. Results: We included 161 patients, with 62 (39%) transferred and 99 (62%) directly admitted patients. Compared between these groups, transferred patients had a longer TFSO-to-imaging at our institution (median: 212 vs. 75 min, p < 0.001) and lower ASPECTS (median: 8 vs. 9, p < 0.001). Regression analysis presented an independent association of ASPECTS with prior contrast administration (ß = -0.25, p = 0.004) but not with TFSO (ß = -0.03, p = 0.65). Intergroup comparison between transferred and directly admitted patients pointed toward a stronger association between ASPECTS and CTP ischemic core volume in transferred patients (ß = -0.39 vs. ß = -0.58, p = 0.06). Detectability of the hyperdense vessel sign was substantially lower after transfer (66 vs. 10%, p < 0.001). Conclusion: Imaging alterations due to residual IV contrast are frequent in clinical practice and render the hyperdense vessel sign largely indetectable. Larger studies are needed to clarify the influence on the association between ASPECTS and ischemic core.

9.
Sci Adv ; 7(3)2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33523899

RESUMEN

SMAC/DIABLO and HTRA2 are mitochondrial proteins whose amino-terminal sequences, known as inhibitor of apoptosis binding motifs (IBMs), bind and activate ubiquitin ligases known as inhibitor of apoptosis proteins (IAPs), unleashing a cell's apoptotic potential. IBMs comprise a four-residue, loose consensus sequence, and binding to IAPs requires an unmodified amino terminus. Closely related, IBM-like N termini are present in approximately 5% of human proteins. We show that suppression of the N-alpha-acetyltransferase NatA turns these cryptic IBM-like sequences into very efficient IAP binders in cell lysates and in vitro and ultimately triggers cellular apoptosis. Thus, amino-terminal acetylation of IBM-like motifs in NatA substrates shields them from IAPs. This previously unrecognized relationship suggests that amino-terminal acetylation is generally protective against protein degradation in human cells. It also identifies IAPs as agents of a general quality control mechanism targeting unacetylated rogues in metazoans.


Asunto(s)
Proteínas Inhibidoras de la Apoptosis , Proteína Inhibidora de la Apoptosis Ligada a X , Acetilación , Apoptosis/fisiología , Humanos , Proteínas Inhibidoras de la Apoptosis/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Ubiquitina/metabolismo , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo
10.
ESC Heart Fail ; 8(2): 1253-1262, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33480186

RESUMEN

AIMS: Heart transplantation (HTx) represents optimal care for advanced heart failure. Left ventricular assist devices (LVADs) are often needed as a bridge-to-transplant (BTT) therapy to support patients during the wait for a donor organ. Prolonged support increases the risk for LVAD complications that may affect the outcome after HTx. METHODS AND RESULTS: A total of 342 patients undergoing HTx after LVAD as BTT in a 10-year period in two German high-volume HTx centres were retrospectively analysed. While 73 patients were transplanted without LVAD complications and with regular waiting list status (T, n = 73), the remaining 269 patients were transplanted with high urgency status (HU) and further divided with regard to the observed leading LVAD complications (infection: HU1, n = 91; thrombosis: HU2, n = 32; stroke: HU3, n = 38; right heart failure: HU4, n = 41; arrhythmia: HU5, n = 23; bleeding: HU6, n = 18; device malfunction: HU7, n = 26). Postoperative hospitalization was prolonged in patients with LVAD complications. Analyses of perioperative morbidity revealed no differences regarding primary graft dysfunction, renal failure, and neurological events except postoperative infections. Short-term survival, as well as Kaplan-Meier survival analysis, indicated comparable results between the different study groups without disadvantages for patients with LVAD complications. CONCLUSIONS: Left ventricular assist device therapy can impair the outcome after HTx. However, the occurrence of LVAD complications may not impact on outcome after HTx. Thus, we cannot support the prioritization or discrimination of HTx candidates according to distinct mechanical circulatory support-associated complications. Future allocation strategies have to respect that device-related complications may define urgency but do not impact on the outcome after HTx.


Asunto(s)
Trasplante de Corazón , Corazón Auxiliar , Humanos , Estudios Retrospectivos , Resultado del Tratamiento , Listas de Espera
11.
Front Neurol ; 12: 651387, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33776900

RESUMEN

Background and Purpose: Acute ischemic stroke of the anterior circulation due to large vessel occlusion (LVO) is a multifactorial process, which causes neurologic symptoms of different degree. Our aim was to examine the impact of neuromorphologic and vascular correlates as well as clinical factors on acute symptom severity in LVO stroke. Methods: We selected LVO stroke patients with known onset time from a consecutive cohort which underwent multiparametric CT including non-contrast CT, CT angiography and CT perfusion (CTP) before thrombectomy. Software-based quantification was used to calculate CTP total ischemic and ischemic core volume. Symptom severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) upon admission. Multivariable regression analysis was performed to determine independent associations of admission NIHSS with imaging and clinical parameters. Receiver operating characteristics (ROC) analyses were used to examine performance of imaging parameters to classify symptom severity. Results: We included 142 patients. Linear and ordinal regression analyses for NIHSS and NIHSS severity groups identified significant associations for total ischemic volume [ß = 0.31, p = 0.01; Odds ratio (OR) = 1.11, 95%-confidence-interval (CI): 1.02-1.19], clot burden score (ß = -0.28, p = 0.01; OR = 0.76, 95%-CI: 0.64-0.90) and age (ß = 0.17, p = 0.04). No association was found for ischemic core volume, stroke side, collaterals and time from onset. Stroke topography according to the Alberta Stroke Program CT Score template did not display significant influence after correction for multiple comparisons. AUC for classification of the NIHSS threshold ≥6 by total ischemic volume was 0.81 (p < 0.001). Conclusions: We determined total ischemic volume, clot burden and age as relevant drivers for baseline NIHSS in acute LVO stroke. This suggests that not only mere volume but also degree of occlusion influences symptom severity. Use of imaging parameters as surrogate for baseline NIHSS reached limited performance underlining the need for combined clinical and imaging assessment in acute stroke management.

12.
ChemSusChem ; 13(13): 3504-3513, 2020 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-32286730

RESUMEN

Conversion/alloying materials (CAMs) are a potential alternative to graphite as Li-ion anodes, especially for high-power performance. The so far most investigated CAM is carbon-coated Zn0.9 Fe0.1 O, which provides very high specific capacity of more than 900 mAh g-1 and good rate capability. Especially for the latter the optimal particle size is in the nanometer regime. However, this leads to limited electrode packing densities and safety issues in large-scale handling and processing. Herein, a new synthesis route including three spray-drying steps that results in the formation of microsized, spherical secondary particles is reported. The resulting particles with sizes of 10-15 µm are composed of carbon-coated Zn0.9 Fe0.1 O nanocrystals with an average diameter of approximately 30-40 nm. The carbon coating ensures fast electron transport in the secondary particles and, thus, high rate capability of the resulting electrodes. Coupling partially prelithiated, carbon-coated Zn0.9 Fe0.1 O anodes with LiNi0.5 Mn1.5 O4 cathodes results in cobalt-free Li-ion cells delivering a specific energy of up to 284 Wh kg-1 (at 1 C rate) and power of 1105 W kg-1 (at 3 C) with remarkable energy efficiency (>93 % at 1 C and 91.8 % at 3 C).

13.
Neuroimage Clin ; 27: 102329, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32629166

RESUMEN

PURPOSE: Ipsilateral thalamic diaschisis (ITD) refers to the phenomenon of thalamic hypoperfusion or hypometabolism due to a distant cerebral injury. To further investigate the characteristics and spectrum of ITD, we analyzed quantitative measurements of thalamic hypoperfusion in acute anterior circulation stroke. METHODS: We selected consecutive patients with large-vessel occlusion (LVO) anterior circulation stroke and available CT perfusion (CTP) examination on admission who underwent endovascular thrombectomy. Thalamic perfusion parameters on CTP were tested between ipsi- and contralesional thalamus and ischemic territory. Values were compared with thresholds from CTP analysis software. Associations of thalamic perfusion parameters with acute imaging and clinical data were determined in uni- and multivariate logistic regression analyses. RESULTS: Ninety-nine patients were included. All perfusion parameters indicated significant non-ischemic hypoperfusion of the thalamus, not reaching the levels of ischemia in the middle cerebral artery territory due to LVO (all p < 0.002). Multiple perfusion parameters exhibited significant association with ischemic lesion extent (relative cerebral blood flow [CBF]: ß =  - 0.23, p = 0.022; Δtime to drain: ß = 0.33, p < 0.001; ΔTmax: ß =  - 0.36, p < 0.001) and involvement of the Lentiform Nucleus (Δmean transit time: ß = 0.64, p = 0.04; Δtime to drain: ß = 0.81, p = 0.01; ΔTmax: ß =  - 0.82, p = 0.01). Symptom severity on admission exhibited minor significant association with reduction of thalamic CBF in uncorrected analysis (Odds ratio: 0.05, p = 0.049), but short- and long-term outcomes were unaffected by perfusion status. ITD reached guideline-based software-threshold levels in only one patient. CONCLUSIONS: ITD in acute stroke is a non-binary phenomenon affected by lesion extent and involvement of the lentiform nucleus. We found uncorrected association of ITD with early clinical presentation, but no association with short- or long-term outcome was evident. Relevant misclassification of ITD by guideline-based CTP software was not indicated, which needs further dedicated testing.


Asunto(s)
Isquemia Encefálica , Accidente Cerebrovascular , Isquemia Encefálica/diagnóstico por imagen , Circulación Cerebrovascular , Humanos , Imagen de Perfusión , Estudios Retrospectivos , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Tálamo/diagnóstico por imagen , Trombectomía , Tomografía Computarizada por Rayos X
14.
Arch Pharm (Weinheim) ; 342(10): 557-68, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19714675

RESUMEN

We have presented the synthesis of novel thiazolo- and isothiazolo-apomorphines 12-17 resulting-in part-from an unexpected isomerization step occurred during the acid-catalyzed rearrangement of precursor thiazolo-morphinandienes 3-5. These 2,3-disubstituted apomorphines represent a new group of A-ring substituted aporphines. The receptor binding studies revealed that with the exception of two derivatives all the tested compounds have limited affinity for dopamine-receptor subtypes. Functional calcium assay for the most active isothiazolo-apomorphine showed higher affinities for D(1) and D(2L) subtypes. The docking of these ligands has been modelled to human D(2) and D(3 )receptors. On the basis of the predicted models, we identified an important cation-p interaction for the binding of isothiazolo-apomorphine 16.


Asunto(s)
Apomorfina/farmacología , Diseño Asistido por Computadora , Agonistas de Dopamina/farmacología , Diseño de Fármacos , Receptores Dopaminérgicos/efectos de los fármacos , Tiazoles/farmacología , Apomorfina/análogos & derivados , Apomorfina/síntesis química , Apomorfina/metabolismo , Sitios de Unión , Señalización del Calcio/efectos de los fármacos , Línea Celular , Simulación por Computador , Agonistas de Dopamina/síntesis química , Agonistas de Dopamina/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Isomerismo , Modelos Moleculares , Estructura Molecular , Conformación Proteica , Ensayo de Unión Radioligante , Receptores Dopaminérgicos/química , Receptores Dopaminérgicos/genética , Receptores Dopaminérgicos/metabolismo , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D3/agonistas , Tiazoles/síntesis química , Tiazoles/metabolismo , Transfección
15.
ChemSusChem ; 11(1): 229-236, 2018 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-28960847

RESUMEN

The room-temperature molten salt mixture of N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis(trifluoromethanesulfonyl) imide ([DEME][TFSI]) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is herein reported as electrolyte for application in Li-O2 batteries. The [DEME][TFSI]-LiTFSI solution is studied in terms of ionic conductivity, viscosity, electrochemical stability, and compatibility with lithium metal at 30 °C, 40 °C, and 60 °C. The electrolyte shows suitable properties for application in Li-O2 battery, allowing a reversible, low-polarization discharge-charge performance with a capacity of about 13 Ah g-1carbon in the positive electrode and coulombic efficiency approaching 100 %. The reversibility of the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) is demonstrated by ex situ XRD and SEM studies. Furthermore, the study of the cycling behavior of the Li-O2 cell using the [DEME][TFSI]-LiTFSI electrolyte at increasing temperatures (from 30 to 60 °C) evidences enhanced energy efficiency together with morphology changes of the deposited species at the working electrode. In addition, the use of carbon-coated Zn0.9 Fe0.1 O (TMO-C) lithium-conversion anode in an ionic-liquid-based Li-ion/oxygen configuration is preliminarily demonstrated.


Asunto(s)
Suministros de Energía Eléctrica , Electrólitos/química , Éteres/química , Líquidos Iónicos/química , Compuestos de Litio/química , Oxígeno/química , Conductividad Eléctrica , Técnicas Electroquímicas/métodos , Microscopía Electrónica de Rastreo
16.
Materials (Basel) ; 11(1)2017 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-29286315

RESUMEN

In order to further improve the energy and power density of state-of-the-art lithium-ion batteries (LIBs), new cell chemistries and, therefore, new active materials with alternative storage mechanisms are needed. Herein, we report on the structural and electrochemical characterization of Fe-doped ZnO samples with varying dopant concentrations, potentially serving as anode for LIBs (Rechargeable lithium-ion batteries). The wurtzite structure of the Zn1-xFexO samples (with x ranging from 0 to 0.12) has been refined via the Rietveld method. Cell parameters change only slightly with the Fe content, whereas the crystallinity is strongly affected, presumably due to the presence of defects induced by the Fe3+ substitution for Zn2+. XANES (X-ray absorption near edge structure) data recorded ex situ for Zn0.9Fe0.1O electrodes at different states of charge indicated that Fe, dominantly trivalent in the pristine anode, partially reduces to Fe2+ upon discharge. This finding was supported by a detailed galvanostatic and potentiodynamic investigation of Zn1-xFexO-based electrodes, confirming such an initial reduction of Fe3+ to Fe2+ at potentials higher than 1.2 V (vs. Li⁺/Li) upon the initial lithiation, i.e., discharge. Both structural and electrochemical data strongly suggest the presence of cationic vacancies at the tetrahedral sites, induced by the presence of Fe3+ (i.e., one cationic vacancy for every two Fe3+ present in the sample), allowing for the initial Li⁺ insertion into the ZnO lattice prior to the subsequent conversion and alloying reaction.

17.
ACS Appl Mater Interfaces ; 9(5): 4570-4576, 2017 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-28084724

RESUMEN

Advanced metal oxide electrodes in Li-ion batteries usually show reversible capacities exceeding the theoretically expected ones. Despite many studies and tentative interpretations, the origin of this extra-capacity is not assessed yet. Lithium storage can be increased through different chemical processes developing in the electrodes during charging cycles. The solid electrolyte interface (SEI), formed already during the first lithium uptake, is usually considered to be a passivation layer preventing the oxidation of the electrodes while not participating in the lithium storage process. In this work, we combine high resolution soft X-ray absorption spectroscopy with tunable probing depth and photoemission spectroscopy to obtain profiles of the surface evolution of a well-known prototype conversion-alloying type mixed metal oxide (carbon coated ZnFe2O4) electrode. We show that a partially reversible layer of alkyl lithium carbonates is formed (∼5-7 nm) at the SEI surface when reaching higher Li storage levels. This layer acts as a Li reservoir and seems to give a significant contribution to the extra-capacity of the electrodes. This result further extends the role of the SEI layer in the functionality of Li-ion batteries.

18.
Chem Commun (Camb) ; 52(20): 3970-3, 2016 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-26883178

RESUMEN

The (de)lithiation process of carbon-coated ZnFe2O4 has been investigated by in situ Raman spectroscopy. Solid electrolyte interphase (SEI) products were detected. Their detection may result from a temporary surface enhancement Raman effect from Zn nanoparticles formed in the conversion reaction at a potential that coincides with SEI formation.

19.
ChemSusChem ; 9(1): 42-9, 2016 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-26611916

RESUMEN

As existing battery technologies struggle to meet the requirements for widespread use in the field of large-scale energy storage, novel concepts are urgently needed concerning batteries that have high energy densities, low costs, and high levels of safety. Here, a novel eco-friendly energy storage system (ESS) using seawater and an ionic liquid is proposed for the first time; this represents an intermediate system between a battery and a fuel cell, and is accordingly referred to as a hybrid rechargeable cell. Compared to conventional organic electrolytes, the ionic liquid electrolyte significantly enhances the cycle performance of the seawater hybrid rechargeable system, acting as a very stable interface layer between the Sn-C (Na storage) anode and the NASICON (Na3 Zr2 Si2 PO12) ceramic solid electrolyte, making this system extremely promising for cost-efficient and environmentally friendly large-scale energy storage.


Asunto(s)
Suministros de Energía Eléctrica , Electrólitos/química , Líquidos Iónicos/química , Agua de Mar/química , Cerámica , Electroquímica , Electrodos , Microscopía Electrónica de Rastreo , Propiedades de Superficie
20.
ChemSusChem ; 9(10): 1112-7, 2016 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-27098345

RESUMEN

The aqueous processing of lithium-ion battery (LIB) electrodes has the potential to notably decrease the battery processing costs and paves the way for a sustainable and environmentally benign production (and recycling) of electrochemical energy storage devices. Although this concept has already been adopted for the industrial production of LIB graphite anodes, the performance decay of cathode electrodes based on transition metal oxides processed in aqueous environments is still an open issue. In this study, we show that the addition of small quantities of phosphoric acid into the cathodic slurry yields Li[Ni0.33 Mn0.33 Co0.33 ]O2 electrodes that have an outstanding electrochemical performance in lithium-ion cells.


Asunto(s)
Cobalto/química , Litio/química , Manganeso/química , Níquel/química , Óxidos/química , Agua/química , Suministros de Energía Eléctrica , Electroquímica , Electrodos
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