batterydata/paper-abstracts huggingface dataset:
This work presents a novel binder-free nitrogen-doped carbon paper electrode (NCPE), which was derived from a N-rich polypyrrole (PPy)/cellulose-chopped carbon filaments (CCFs) composite, for Li–O2 batteries. The fabrication of NCPE involved cheap raw materials (e.g., Cladophora sp. green algae) and easy operation (e.g., doping N by a carbonization of N-rich polymer), which is especially suitable for large-scale production. The NCPE exhibited a bird's nest microstructure, which could provide the self-standing electrode with considerable mechanic durability, fast Li+ and O2 diffusion, and enough space for the discharge product deposition. In addition, the NCPE contained N-containing function groups, which may promote the electrochemical reactions. Furthermore, binder-free architecture designs can prevent binder-involved parasitic reactions. A Li–O2 cell with the NCPE displayed a cyclability of more than 30 cycles at a constant current density of 0.1 mA/cm2. The 1st discharge capacity for a cell with the NCPE reached 8040 mAh/g at a current density of 0.1 mA/cm2, with a cell voltage around 2.81 V. A cell with the NCPE displayed a coulombic efficiency of 81% on the 1st cycle at a current density of 0.2 mA/cm2. These results represent a promising progress in the development of a low-cost and versatile paper-based O2 electrode for Li–O2 batteries.
Here we show that the intrinsic low electrical conductivity of LiFePO4 which seriously hinders the application of LiFePO4 for Li-ion batteries is overcome with conductive metallic NiP nano-coating. High resolution transmission electron microscopy image reveals that the NiP coating is a nanoscale amorphous layer, which was deposited on the LiFePO4 particles to form a so-called core/shell structure via electroless plating at room temperature. The electrochemical performances of NiP coated LiFePO4 show that both of the rate performance and cycleability of LiFePO4 against graphite anode are improved by the NiP coating. Analysis of electrochemical impedance spectra of the LiFePO4/graphite cells demonstrates that the NiP coating decreases both of the surface film resistance and charge transfer resistance. The dissolution of Fe from LiFePO4 in the LiPF6 based electrolyte is remarkably suppressed by the protective NiP coating.
LiNi0.5Mn1.5O4 (LNMO) nanostructures (microspheres composed of nanoparticles) are prepared from urchin-like γ-MnO2 by calcinating under 800°C, the product shows Fd3m-based phase involving minor rock salt phase and Mn3+ ions confirmed by its Raman spectra, X-ray diffraction pattern and electrochemical activities. Furthermore, HRTEM images and EDS line-scanning spectroscopy patterns focusing on a single nanoparticle provide direct observation of intergrowth of two phases that minor P4332 phase is found on the edge of Fd3m body coupled with the varying Mn/Ni ratio. In comparison, the other sample is obtained by adding an annealing treatment at 700°C after calcinating at 800°C, which preserves the nanostructured architecture of C800 and displays all the structural characteristics of pure P4332 phase. As cathode materials for lithium-ion batteries, merely calcined sample receives discharge capacities of 91 mAh•g−1 even at 50C, and 100.5 mAh•g−1 after 300 cycles at 5C, which shows better combination of rate and cycling performances than its counterpart with pure P4332 phase.
Battery powered energy systems such as electric vehicles utilize power electronics for controlling energy flows between the battery and the load or generation, respectively. Therefore, the battery is under high frequency stress due to fast switching power electronic devices. However, most battery models throughout the literature are not able to cope with high frequency excitation. This paper proposes an easy to implement equivalent circuit model that covers aforementioned frequency regions with a series of inductors that are each connected in parallel with an ohmic resistance. This circuit is parameterized by electrochemical impedance spectroscopy (EIS) up to 100 kHz. For further regions that reach regions of megahertz a skin effect model is investigated and compared to the RL-model. It is shown that such semi-empirical models can be motivated by geometrical considerations that can be found in the literature. Moreover, the proposed model is validated by simulating the voltage response from an input current that originates from an actual back-to-back half bridge DC/DC converter. The promising results indicate that such models might be implemented in future battery energy systems to improve insights on how batteries react to perturbations such as EMI noise or high frequency current ripple.
Lung injury caused by both inhaled dusts and infectious agents depends on increased availability of iron and metal-catalyzed oxidative stress. Because inhaled particles, such as silica, and certain infections can cause secondary pulmonary alveolar proteinosis (PAP), we tested the hypothesis that idiopathic PAP is associated with an altered iron homeostasis in the human lung.
Two ionic liquids (ILs), which are functionalized with bis(oxalato)borate (BOB) and diﬂuoro(oxalato)borate (DFOB) as the anion, have been synthesized and applied as additives for the battery grade electrolyte 1 M LiPF6 in an equivolume mixture of EC-DEC-DMC (LP71). When 0.3 M IL was added to LP71, peaks attributed to the formation of solid electrolyte interface (SEI) were observed during cyclic voltammetry for both cathodic and anodic sides. The presence of peaks during anodic scans suggests that the ILs possess the ability to form SEI on cathode surfaces. The high voltage Li | LiNi0.5Mn1.5O4 (LNMO) cells, employing the integrated electrolytes, exhibited a discharge capacity of around 120 mAh g−1. The retention rates of discharge capacity after 100 cycles were found to be 99.2% and 98.1% for the solution with 0.3 M of BOB-IL and DFOB-IL, respectively. By means of impedance analysis during the galvanostatic cycling, the growth of SEI was confirmed when BOB-IL was used as the additive. In this case, in the infrared spectra of the cycled LNMO electrodes, peaks related to borate compounds and polycarbonate were observed. This confirms that the BOB-IL promotes the formation of stable interfaces between the electrolyte and LNMO.
The electrochemical properties of a thin-film LiMn2O4 electrode were studied in an aqueous medium. The studies were done in a saturated aqueous medium to increase similarity of the electrolyte solution with a non-aqueous medium. The apparent diffusion coefficient was calculated and discussed for different potentials at the aqueous electrolyte. In addition, stability of the thin solid film was investigated during potential cycling, which indicates that the electrode is highly stable in aqueous medium as well as in non-aqueous media. The obtained results from electrochemical measurements indicate that the properties of the thin-film LiMn2O4 electrode in aqueous medium are similar to those that have been found in non-aqueous media.
Composites comprising silicon (Si), graphite (C) and polyacrylonitrile-based disordered carbon (PAN-C), denoted as Si/C/PAN-C, have been synthesized by thermal treatment of mechanically milled silicon, graphite, and polyacrylonitrile (PAN) powder of nominal composition C–17.5wt.% Si–30wt.% PAN. PAN acts as a diffusion barrier to the interfacial diffusion reaction between graphite and Si to form the electrochemically inactive SiC during prolonged milling of graphite and Si, which could be easily formed in the absence of PAN. In addition, graphite, which contributes to the overall capacity of the composite and suppresses the irreversible loss, retains its graphitic structure during prolonged milling in the presence of PAN. The resultant Si/C/PAN-C based composites exhibit a reversible capacity of ∼660mAhg−1 with an excellent capacity retention displaying almost no fade in capacity when cycled at a rate of ∼C/4. Scanning electron microscopy (SEM) analysis indicates that the structural integrity and microstructural stability of the composite during the alloying/dealloying process appear to be the main reasons contributing to the good cyclability observed in the above composites.
The effect of LaMnO3 with high electronic conductivity on the fast charge-discharge rate performance of LiMn2O4 is studied. X-ray diffraction patterns confirm the existence of LaMnO3 and also indicate LaMnO3 has no influence on the crystal structure of pristine LiMn2O4. The transmission electron microscopy (TEM) images indicate that LaMnO3 coating layer, about 15nm thickness, covers the surface of LiMn2O4 well. The electrochemical performances are evaluated by galvanostatic charge/discharge tests and electrochemical impedance spectroscopy (EIS). At 0.5C/0.5C, LaMnO3 coated LiMn2O4 delivers an initial capacity of about 114mAhg−1 along with the coulombic efficiency of 95.0%, which are higher than those of uncoated LiMn2O4 (106mAhg−1 and 89.1%). Furthermore, LaMnO3 coated LiMn2O4 can exhibit higher capacities at high charge-discharge rates than uncoated LiMn2O4. It can deliver about 90.6mAhg−1 at 10C/10C and 68.0mAhg−1 at 20C/20C, but there are only 53.6mAhg−1 and 43.3mAhg−1 for bare LiMn2O4. Electrochemical impedance spectroscopy (EIS) demonstrates that LaMnO3 coating layer can effectively reduce the electrodes' resistances and improve the kinetics of electrodes. The improved high rate properties of LaMnO3 coated LiMn2O4 are ultimately ascribed to the easier phase conversion from λ-MnO2 to Li0·5Mn2O4 which is related to LaMnO3 coating layer with high electronic conductivity.
Various aspects of stability of composite polymer gel electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF/HFP) polymeric matrix and functionalized precipitated silicas have been studied. The silica fillers have been surface modified with methacryloxy or vinyl groups by partially replacing silanol groups, so that bi-functional (hydrophilic/hydrophobic) character of the inorganic fillers was created. Compatibility of the gel electrolytes with lithium electrode has been examined by means of EIS technique. Electrochemical stability window has been studied with the application of cyclic voltammetry technique with fast sweeping rate. Passive layer formation on graphite electrode has been investigated for all the gel electrolytes by means of cyclic voltammetry with slow scan rate and galvanostatic charging/discharging technique. It has been shown that stability of the interface between lithium and gel electrolyte is significantly improved when bi-functional silicas are used as fillers. The phenomenon has been ascribed to more effective scavenging of trace impurities as well as to better shielding of the electrode surfaces. Cyclic voltammetry on platinum has revealed excessive electrochemical redox processes upon prolonged cycling for all the gel electrolytes. It has been demonstrated that stable passive layers are formed on graphite electrodes upon electrochemical reduction in the presence of the studied composite polymer gel electrolytes.
Pd nanoparticle catalysts supported by multiwall carbon nanotubes (Pd/MWNTs) prepared using a complexation–reduction method are used in this study for the electrochemical determination of hydrazine. The physico-chemical properties of the Pd/MWNT catalyst were characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and scanning electron microscopy physico-chemical (SEM). These structural analyses reveal that the Pd/MWNTs-modified glassy carbon electrode possesses a three-dimensional network structure in which the Pd nanoparticles, with an average size of 5nm, are uniformly distributed on the surface of the MWNTs. After Nafion solution was coated on the surface of the Pd/MWNT layer, the resulting Pd/MWNT–Nafion modified electrode retained the three-dimensional network structure. Electrochemical measurements show that the oxidation peak current of hydrazine decreases with increasing pH. Under optimum conditions, the Pd/MWNT–Nafion-based hydrazine sensor exhibits a broad linear calibration range (2.5–700μM) and a low detection limit of 1.0μM for hydrazine.
In Germany, the laender hold most of the powers relevant for protecting the population. After the end of the Cold War, they had realized a substantial peace dividend. Yet after 9/11, they have been confronted with a number of new (or newly realized) challenges, and a new governance pattern evolved that requires more intense co-operation between the laender and other levels of the political system. Furthermore, in the light of fiscal austerity and a certain euphoria for privatization, the private sector has become very much involved in formal and informal disaster management networks with state actors on all levels. Our paper traces this development in detail, explains its causes and gauges its impacts in terms of both effectiveness and democratic accountability. It is based on twenty expert interviews with state representatives on all levels of government as well as private actors representing different types of companies, and it especially focuses on the involvement of hospitals in emergency planning, electrical power network management (including reactions to blackouts), recent changes at firefigthers’ co-ordination centers, and, as a cross-cutting issue, the role of Information Technology (IT).
The design and implementation of innovation policy funding programmes has been the subject of scientific and political debate for decades. Especially the increasingly popular approach of mission-oriented innovation policies is a much discussed subject. The question of how missions arise, what rhetoric accompanies them and how they are eventually implemented has not yet been sufficiently clarified and specification is lacking. Whether mission-oriented innovation policy actually follows a strict top-down logic, or whether the policymaking process rather resembles a certain evolutionary scheme is questioned in this study. On the basis of the change within many policy strategy papers from biotechnology to a much broader bioeconomy, it is shown that, in reality, the transition does not follow a linear sequence. Neither excessive prioritisation nor neglect of a selected sector can be confirmed in this analysis. Within the bioeconomy, however, a clear change can be identified. Biotechnology funding was visibly reduced as part of the change of leitmotif while R&D increased in the agricultural sector in particular. Furthermore, it becomes clear that the issue of missing markets, which is predicted in theoretical studies, can also be confirmed empirically. So far, in terms of public involvement, little effort has been invested in the practical application of bioeconomical knowledge, which is why the intended transition towards bio-based economic activities is lagging behind expectations.
Following from the classical work of Hubel and Wiesel, it has been recognized that the orientation and the on- and off-zones of receptive fields of layer 4 simple cells in the visual cortex are linked to the spatial alignment and properties of the cells in the visual thalamus that relay the retinal input. Here we present evidence showing that the orientation and the on- and off-zones of receptive fields of layer 6 simple cells in cat visual cortex that provide feedback to the thalamus are similarly linked to the alignment and properties of the receptive fields of the thalamic cells they contact. However, the pattern of influence linked to on- and off-zones is phase-reversed. This has important functional implications.
Some aspects of the influence on the electrochemical mechanisms of the anion and structure in tin based negative materials are presented. Li insertion mechanisms in SnS and tin composite oxides (TCO) are analysed by 119Sn Mössbauer spectroscopy. For SnS, Mössbauer experiments were combined with in situ X-ray diffraction in order to determine tin oxidation states and identify the phases occurring during the discharge. The Mössbauer recoil-free fraction has been determined for TCO and the Debye temperature is found to be lower than that of crystalline SnO in good agreement with the lower network rigidity of the glass.
Amorphous silicon (α-Si) films are deposited on LiFePO4@C electrode by using vacuum thermal evaporation deposition technique and the effect of α-Si film on electrochemical performance of LiFePO4@C cells is investigated systematically by the charge–discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. The results reveal that the present of α-Si film on electrode surface could remarkably improve the electrochemical performance at high charge/discharge rate, especially at elevated temperature. This enhancement may be attributed to the amelioration of the electrochemical dynamics on the electrode/electrolyte interface resulting from the beneficial effects of α-Si film, which might significantly suppress the rise of both of the surface film resistance and charge transfer resistance.
Introduction Persistent air leaks (PAL) is the most frequent post-operative complication in Thoracic Surgery, leading to a longer hospital stay and an increase in patient morbidity. We present a prospective study conducted in the Dr. Josep Trueta University Hospital in Gerona, involving a portable chest drainage system (PCDS) connected to a pleural drainage which allowed air leaks to be treated ambulatorily. Our aim is to demonstrate that by using this system hospital stay is reduced without increasing post-operative morbidity, and improves the quality of life of the patient. Material and methods The Thoracic Surgery Department of Gerona Hospital collected the data on 33 patients with PAL in the post-surgical period and who were treated ambulatorily with a PCDS. Post-operative complications were recorded, along with the mean days of ambulatory treatment with the PCDS and the hospital days saved. Results The mean hospital stay of the 33 patients was 7.03 days. The mean number of days that the 33 patients were treated ambulatorily with the PCDS was 9.33 days. It was calculated that there was a saving of 308 hospital days. The ambulatory treatment of PAL did not increase post-operative morbidity. Conclusions The clinical results and the management of the PCDS support the treatment of this problem in patients who do not have any other causes to remain in hospital. The study shows a saving in a considerable number of hospital days stay, with no increase in patient morbidity. All the patients preferred this system to hospital admission.
The aim of this study was to perform psychometric testing of the Growth Hormone Deficiency-Child Impact Measure (GHD-CIM): a patient-reported outcome (PRO) for children with GHD aged 9 to < 13 years and an observer-reported outcome (ObsRO) for parents/guardians of children who are unable to answer for themselves.
We investigated the ability to perform solfeggio, i.e. oral reading of musical notes in MP, a 65 year-old female professional musician, who, following a left temporoparietal ischemia, showed a complex pattern of amusia. The deficit on which we focused was her inability to read orally the bass (F) clef, often substituting it with the violin (G) clef. This problem could not be attributed to a lack of comprehension. The patient could in fact correctly perform on the piano the same sequences she erroneously read aloud; she was also able to correctly judge whether two strings, one in bass clef and the other in violin clef, represented the same sequence of notes. The problem seems to lie in the inability to retrieve note names keeping into account the clef-rule. It is hypothesized that, in the production of note names, this function requires the identification and application of syntactic-like information, in analogy with what is thought to happen in the retrieval of other words.
The coulomb counting method is expedient for state-of-charge (SOC) estimation of lithium-ion batteries with high charging and discharging efficiencies. The charging and discharging characteristics are investigated and reveal that the coulomb counting method is convenient and accurate for estimating the SOC of lithium-ion batteries. A smart estimation method based on coulomb counting is proposed to improve the estimation accuracy. The corrections are made by considering the charging and operating efficiencies. Furthermore, the state-of-health (SOH) is evaluated by the maximum releasable capacity. Through the experiments that emulate practical operations, the SOC estimation method is verified to demonstrate the effectiveness and accuracy.
A novel redox-mediated aqueous electrolyte is prepared by adding sodium persulfate (Na2S2O8) into KOH alkaline electrolyte for the application in most metal oxide based supercapacitors. The electrochemical behaviors of nickel oxide (NiO) electrode in 2M KOH and 2M KOH containing different concentration of Na2S2O8 electrolytes, respectively, were characterized by cyclic voltammetry and electrochemical impedance spectroscopy methods. The results indicate that the reaction mechanism of NiO electrode in Na2S2O8 mixed electrolytes appears to be the reversible redox of Ni2+ to Ni3+ on two different channels, which is different with that in KOH electrolyte. Charge-discharge experiments show that the discharge ability of the NiO electrode in redox electrolyte is excellent. When added Na2S2O8 into KOH electrolyte, the charge time is shorted and the discharge time is increased sharply. The specific capacitance was up to 6317.5Fg−1 at 0.5Ag−1 in mixed 2M KOH and 0.03M Na2S2O8, more than 100% coulombic efficiency. Fortunately, this new redox-mediated aqueous electrolyte not only suitable for the metal oxide based electrode, but also have much effect to the metal sulfide, vanadate, and phosphate electrode et al.
Nowadays, wide temperature range and high-energy Li-ion batteries are increasingly required. However, it is difficult to get a compromise between subzero temperature performance and high temperature performance. Herein, methyl acetate co-solvent with a freezing point of −98.1 °C (50% by volume) is blended with carbonates to obtain a high-conductivity LiPF6-based electrolyte, which contains tris(trimethylsilyl) phosphite and 1,3-propanediolcyclic sulfate binary functional additives to significantly enhance cycling performance of a challenging high-voltage (5 V-class) battery system using a LiNi0.5Mn1.5O4 cathode and a graphitic mesocarbon microbead anode, unprecedentedly ranging from −60 °C to 50 °C. High reactivity between methyl acetate co-solvent and graphitic mesocarbon microbead anode is innovatively proposed to be associated with graphitic mesocarbon microbead anode catalytic formation of methoxy free radical. More importantly, high reactivity between methyl acetate co-solvent and graphitic mesocarbon microbead anode can be greatly suppressed by species derived from functional additives. This paper highlights the crucial rule of both high Li+ conductivity and favorable graphite anode interface layer for achieving high performance wide temperature range Li-ion batteries.