batterydata/paper-abstracts huggingface dataset:
The transient response of a proton exchange membrane fuel cell (PEMFC) supplied with pure hydrogen and oxygen was investigated by load step measurements assisted by electrochemical impedance spectroscopy and chronoamperometry. Using an in-house designed resistance board, the uncontrolled response in both cell voltage and current upon step changes in a resistive load was observed. The PEMFC was found to respond quickly and reproducibly to load changes. The transient PEMFC response was limited by a cathodic charge transfer process with a potential-dependent response time. For load steps to high-current densitities, a second transient process with a constant response time was observed. This transient was offset from the charge transfer transient by a temporarily stable plateau. Results from chronoamperometry indicated that the second transient could be related to a diffusion process. Transient paths were plotted in the V–i diagram, matching a predicted pattern with overshooting cell voltage and current during a load step.
Renewable energies in Spain have been promoted since 2002, proof of this lies in the fact that in 2007 renewable energy accounted for 6.9% of the consumption of primary energy. The renewable energies market is one of the sectors with the greatest growth in recent years in Spain and is key to the energy policies at national level. Both at national and regional level diverse targets have been set for the production of renewable energies, this article seeks to analyse the potential, current state, and perspectives of renewable energies in the Region of Murcia, investigating the possibilities of fulfilling the objectives established. The solar energy potential should be highlighted, where most of the territory has more than 5.0kWh/m2; also the wind power potential, where in certain areas there are winds of more than 6m/s; and the biogas potential due to the extensive livestock herds. With reference to the targets for photovoltaic and wind power, these have been reached; but in the rest of the energy sources the fulfilment of the objectives depends on favourable management and administration policies. Likewise, a comparative study of the state of the Region of Murcia has also been carried out, taking the national situation as the reference.
Detailed experimental conditions are added for the aging tests and electrochemical impedance spectroscopy measurements.
Introduction.– La voie transcalleuse interhémisphérique antérieure est une voie d’abord pour la chirurgie ventriculaire sustentorielle. Certaines études se sont intéressées à la répercussion cognitive de cette approche mais elles restent toutefois limitées en raison de petites casuistiques, de batteries de tests non exhaustives, de la présence de lésions associées extracalleuses, de lésions calleuses étendues (callosotomies totales ou des 4/5) ou par l’inclusion de patients avec agénésie calleuse. Nous avions pour objectif d’évaluer la compréhension verbale, l’efficience intellectuelle générale, les capacités d’exploration visuo-spatiale, les capacités visuo-constructives, les capacités mnésiques, le fonctionnement exécutif et la présence ou non de troubles comportementaux chez les patients callosotomisés. Patients et méthode.– Une étude radioanatomique grâce à l’IRM permettait de préciser la segmentation calleuse et les lésions extracalleuses associées. En outre, huit patients callosotomisés sur 16 participants ainsi que huit témoins appariés étaient évalués par une batterie de tests neuropsychologiques évaluant l’efficience intellectuelle globale, les fonctions mnésiques, les capacités exécutives et les capacités de transfert d’un apprentissage sériel. Résultats ou cas rapporté.– Soixante-trois pour cent des patients opérés par voie transcalleuse antérieure présentent un déficit mnésique verbal ou visuel, (quatre) 38 % des patients un syndrome dysexécutif cognitif (dont 25 % de fluences verbales), (cinq) 25 % des patients un syndrome dysexécutif comportemental et (six) des difficultés d’apprentissage sériel chez tous les patients. L’analyse de corrélations anatomocliniques montrait que parmi l’ensemble des lésions, celle du segment 3 du CC était le plus associée aux troubles mnésiques (RR=5 ; IC=0,87–28,9 ; p=0,001). Conclusion.– Les résultats de l’étude cognitive convergent avec les données anatomiques publiées récemment et d’IRM avec tractographie. Ils montrent que la connectivité des radiations calleuses ventrales entre les régions frontomédiales contribue à la coopération interhémisphérique des régions frontales qui seraient nécessaires à l’intégrité des fonctions mnésiques et exécutives.
Using a simple mathematical model, we demonstrate that statistical kinetics of phase-transforming nanoparticles in porous electrodes results in macroscopic non-monotonic transient currents, which could be misinterpreted as the nucleation and growth mechanism by the Kolmogorov–Johnson–Mehl–Avrami (KJMA) theory. Our model decouples the roles of nucleation and surface reaction in the electrochemically driven phase-transformation process by a special activation rate and the mean particle-filling speed of active nanoparticles, which can be extracted from the responses of porous electrodes to identify the dynamics in single composing nanoparticles.
Hydrophilic poly(vinylidene fluoride) (PVDF) porous membranes are facilely fabricated via grafting polymerization and cross-linking reaction for vanadium flow battery (VFB) application. A solvent swelling pre-treatment is specifically carried out to introduce hydrophilic groups in the pores and on the surface, where they can form well connected ion transport networks. The modification is performed through chemical cross-linking and grafting of PVP by using potassium persulfate (K2S2O8) as a radical initiator. The effect of reaction condition on membrane morphology, hydrophilicity is characterized in detail. Meanwhile, the performance of modified membranes is detected in VFB single cell at a current density of 80 mA cm−2. It is found that more PVP is immobilized on membrane surface and in the pores with prolonging reaction time. Consequently, the membrane wetability and effective pore size change dramatically, resulting better hydrophilicity and higher ion selectivity. As a result, the VFBs assembled with these modified membranes show higher CE and overall better EE than unmodified ones. The optimized membrane shows CE of 94.4% and EE of 83.3%, which is comparable to commercial Nafion 115. Furthermore, the prepared hydrophilic PVDF membranes demonstrate excellent chemical stability through the long-term battery operation, showing great prospects in VFB applications.
A theoretical study of the structural, elastic and electronic properties of spinel LiTi2O4 anode has been performed by density functional theory (DFT) plane-wave pseudopotential method. The independent elastic constants, shear modulus (G), bulk modulus (B), and Young's modulus (E) are evaluated, respectively. The results suggest that cubic LiTi2O4 is mechanically stable. The G/B ratio of 0.584 indicates the ductility of LiTi2O4 is good. The electron density difference of LiTi2O4 shows that the O2p orbits overlap effectively with Ti3d ones, confirming the formations of strong covalent bonds between them, while Li is fully ionized in the lattice. The formation enthalpy for LiTi2O4 is calculated to be −2070.723±1.6kJmol−1. The strong covalent bonds between O and Ti atoms are not only responsible for the excellent mechanical stabilities but also very crucial for the thermodynamic stability of LiTi2O4 compound. Furthermore, in Li2Ti2O4 compound, the full occupation of 16(c) sites by Li+ not only leads to a smaller C 12 value but also leads to a much larger C 44 one. Therefore, the plasticity and ductility of the Li2Ti2O4 become poor in comparison to LiTi2O4, while the thermodynamic stability of Li2Ti2O4 can be further improved after the Li+ intercalation of LiTi2O4.
High-speed electron transfer channels and short Li ion transport distance are beneficial to improvement of Li ion battery properties. Here, a two-step solution phase synthesis method is developed to construct the V2O5 quantum dots/graphene hybrid nanocomposite by controlling nucleation and growth processes. It is demonstrated that the V2O5 quantum dots with an average size of 2-3 nm are uniformly anchored on the graphene sheets. The specific capacity can achieve 212mAhg−1 at 100mAg−1 after 100 cycles. Significantly, the novel V2O5 quantum dots/graphene shows a stable cycling performance with 89% capacity retention after 300 cycles. The improvement in electrochemical properties could be attributed to the short Li ion transfer distance, two-dimensional electron channels, homogeneous dispersion and immobilization of V2O5 quantum dots. Meanwhile, it indicates that V2O5 quantum dots/graphene is promising cathode material for use in long-life rechargeable lithium batteries. This design conception and synthesis strategy for V2O5 could also be extended to other electrode material systems.
Self-configuration and autonomy are key features required for the next generation of gadgets and networks, since regular users are willing to have computationally enabled devices pervasively spread into their environment. Sensors are among the most promising devices into this new scenario. However, their low battery and processing power raise several issues to these autonomy requirements. This paper presents BiO4SeL (Bio-Inspired Optimization for Sensor Network Lifetime), a swarm intelligence-based algorithm to perform self-organization and optimization of lifetime by means of routing into a Wireless Sensor Network. Results show that BiO4SeL achieves its objectives when compared to similar approaches: ARAMA (Ant-based Routing Algorithm for MANETs), EAR (Energy-Aware Routing) and AODV (Ad-hoc On-demand Distance Vector).
The performance of high-silicon-content anodes was tested as a function of silicon particle-size (44μm, 1.8μm and 70–100nm), surface pre-treatment and solvent chosen for anode preparation. Two simple procedures, leading to significant improvements in electrode performance are reported. First, pre-treatment of nano-Si in ethanol which unexpectedly yields functionalised surfaces improving cycling stability. Second, the use of a 30:70 solution of ethanol and water to dissolve the CMC-binder for the electrode preparation boosts specific battery capacity. Ethanol pre-treatment of nano-Si also resulted in improved adhesion of the electrode to the current collector as well as in de-agglomeration of nano-Si powder. All these treatments improved capacity stability during cycling. Changes in surface chemistry of nano-Si before and after ethanol treatment have been analysed by XPS. A stable capacity of about 1630mAhg−1 was obtained after 25 cycles for an electrode containing 80% silicon using ethanol during electrode coating preparation.
Bipolar rechargeable alkaline manganese dioxide–zinc (RAM) batteries are produced in the laboratory. These are obtained through minimizing the passivation problems associated with the zinc electrode, which is considered to have a limiting effect on the charge–discharge cycle performance. To overcome this, different tin alloys are employed in the zinc negative electrode (anode). A relationship is observed between the tin alloying elements, as current-collectors, and gas evolution during the cycling. A copper–tin–zinc ternary alloy (trademark: Optalloy) displays better corrosion resistance and a higher hydrogen overvoltage, when used as the anode current-collector. To increase the electrochemical reversibility and electronic conductivity of the anode mass, porous zinc is treated with Optalloy. This is to obtain a modified zinc electrode, which is found to be effective in terms of raising the cycle performance of the bipolar RAM batteries. Moreover, optimum electrical contact between the electroactive materials and the conductive carbon-filled polyethylene matrix is achieved through coating graphite on the cathode as well as electroless plating of copper on the anode side. It is evident that copper acts as an underlayer for the current-collector.
Silicon is considered to be one of the most promising substitutes for tradition graphite anode due to its highest theoretical specific capacity (4200 mAh g−1) in nature. However, the poor electronic conductivity and huge volume change during lithiation/delithiation process cause serious electrode polarization and the active particle cracking, resulting in significant capacity fading and therefore greatly limit their commercial application. Herein, we report a novel method—electrophoretic deposition (EPD) to prepare the CNFs/Si film with honeycomb structure as an integrated anode electrode without additional binders and conductive agents. The electrode film can be formed by the codeposition of CNFs and Si nanospheres onto the copper foil. Moreover, lithium tetraborate (Li2B4O7) has been proved to play a critical role on the structure and morphology of the electrode by influencing the migration rate and double electric layer of charged particles during the EPD process. As a result, the CNFs/Si electrode with nanosized Si particles homogeneously distributed in the CNFs matrix prepared by EPD method exhibits excellent capacity retention with a reversible capacity of 670 mAh g−1 after 100 cycles at a current density of 400 mA g−1 and good rate performance.
The goal of this narrative review was to give an up-to-date overview of the peripheral and central neurostimulation methods that can be used to treat chronic pain. Special focus has been given to three pain conditions: neuropathic pain, nociplastic pain and primary headaches. Both non-invasive and invasive techniques are briefly presented together with their pain relief potentials. For non-invasive stimulation techniques, data concerning transcutaneous electrical nerve stimulation (TENS), transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), remote electrical neuromodulation (REN) and vagus nerve stimulation (VNS) are provided. Concerning invasive stimulation techniques, occipital nerve stimulation (ONS), vagus nerve stimulation (VNS), epidural motor cortex stimulation (EMCS), spinal cord stimulation (SCS) and deep brain stimulation (DBS) are presented. The action mode of all these techniques is only partly understood but can be very different from one technique to the other. Patients’ selection is still a challenge. Recent consensus-based guidelines for clinical practice are presented when available. The development of closed-loop devices could be of interest in the future, although the clinical benefit over open loop is not proven yet.
Lead acid batteries are still widely used for SLI (Starting–Lighting–Ignition) systems in vehicles because of the cost advantage. The batteries are frequently charged and discharged under different operation conditions, which continuously changes distribution of inner temperature of batteries. Variation of the temperature distributions significantly affects performance and durability of the battery. We developed a one-dimensional dynamic model based on the first principle of thermal dynamics and electrochemistry. The thermal model incorporates control volumes for each of the major constituents of the battery cells that is casing, electrolyte, and electrodes. The model was extended for a six-cell battery and used to analyze effects of discharging currents on the performances and temperature, compared with results from a three-dimensional finite element analysis and tested against experimental results obtained from a thermal chamber and using thermal imaging.
Pyrite FeS2 has long been used as commercial primary lithium batteries at room temperature. To achieve rechargeable FeS2 battery, biomass-carbon@FeS2 composites are prepared using green and renewable auricularia auricula as carbon source through the process of carbonization and sulfuration. The auricularia auricula has strong swelling characteristics to absorb aqueous solution which can effectively absorb Fe ions into its body. FeS2 homogeneously distributed in biomass carbon matrix performs high electronic and ionic conductivity. The specific capacity of biomass-carbon@FeS2 composites remains 850 mAh g−1 after 80 cycles at 0.5C and 700 mAh g−1 at the rate of 2C after 150 cycles. Biomass-carbon@FeS2 composites exhibit high-rate capacity in lithium-ion battery.
Groundwater flow exerts a crucial control on the boundary between the sea and freshwater and is thus a key factor for preserving groundwater resources and preventing seawater intrusion in coastal areas. Although it is highly probable that geological faults in coastal areas affect groundwater flow patterns, the effect has not been described yet in detail. This study is aimed at detecting and imaging groundwater flow and its temporal change around a fault in a coastal area through resistivity and chargeability distributions using electrical sounding. The Okoshiki area in central Kyushu, southwest Japan, was selected as a case study area, because of the presence of Kamiouda Fault. The measurements were conducted along six lines of both parallel and perpendicular orientations to the coastline. A feature suggesting a fault zone was evident on two lines. Through the temporal change of resistivity, movement and mixing processes of the seawater and freshwater during the ebb, low and flood tides were interpreted. A conceptual model of the processes was constructed in which a fault zone and the configuration of bedrock are dominant elements by acting as a selective path and a barrier to the groundwater flow, respectively.
Different solvent mixtures were investigated for non-aqueous vanadium acetylacetonate (V(acac)3) redox flow batteries with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. The aim of this study was to increase the energy density of the non-aqueous redox flow battery. A mixture of acetonitrile, dimethyl sulfoxide and 1-3-dioxolane nearly doubles the solubility of the active species. The proposed electrolyte system was characterized by Raman and FT-IR spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and charge–discharge set-up. Spectroscopic methods were applied to understand the interactions between the solvents used and their impact on the solubility. The potential difference between oxidation and reduction of V(acac)3 measured by cyclic voltammetry was about 2.2 V. Impedance spectroscopy showed an electrolyte resistance of about 2400 Ω cm2. Experiments in a charge–discharge test cell achieved coulombic and energy efficiencies of ∼95% and ∼27% respectively. The highest discharge power density was 0.25 mW cm−2.
Pristine spinel lithium manganese oxide (LiMn2O4) and zinc- and cerium-doped lithium manganese oxide [LiZn x Ce y Mn2−x−y O4 (x =0.01–0.10; y =0.10–0.01)] are synthesized for the first time via the sol–gel route using p-amino benzoic acid as a chelating agent to obtain micron-sized particles and enhanced electrochemical performance. The sol–gel route offers shorter heating time, better homogeneity and control over stoichiometry. The resulting spinel product is characterized through various methods such as thermogravimetic and differential thermal analysis (TG/DTA), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and electrochemical galvanostatic cycling studies. Charge–discharge studies of LiMn2O4 samples heated at 850°C exhibit a discharge capacity of 122mAhg−1 and a corresponding 99% coulombic efficiency in the 1st cycle. The discharge capacity and cycling performance of LiZn0.01Ce0.01Mn1.98O4 is found to be superior (124mAhg−1), with a low capacity fade (0.1mAhg−1 cycle−1) over the investigated 10 cycles.
The performance of materials for electrochemical energy conversion and storage depends upon the number of electrocatalytic sites available for reaction and their accessibility by the transport of reactants and products. For solid oxide fuel/electrolysis cell materials, standard 3-D measurements such as connected triple-phase boundary (TPB) length and effective transport properties partially inform on how local geometry and network topology causes variability in TPB accessibility. A new measurement, the accessible TPB, is proposed to quantify these effects in detail and characterize material performance. The approach probes the reticulated pathways to each TPB using an analytical electrochemical fin model applied to a 3-D discrete representation of the heterogeneous structure provided by skeleton-based partitioning. The method is tested on artificial and real structures imaged by 3-D x-ray and electron microscopy. The accessible TPB is not uniform and the pattern varies depending upon the structure. Connected TPBs can be even passivated. The sensitivity to manipulations of the local 3-D geometry and topology that standard measurements cannot capture is demonstrated. The clear presence of preferential pathways showcases a non-uniform utilization of the 3-D structure that potentially affects the performance and the resilience to alterations due to degradation phenomena. The concepts presented also apply to electrochemical energy storage and conversion devices such as other types of fuel cells, electrolyzers, batteries and capacitors.
The shuttle effect of lithium polysulfides (LiPSs) seriously affects the cycle and rate capability performances of lithium sulfur batteries (LSBs) and restricts their commercial application. In order to suppress availably the shuttle effect of LiPSs, herein a holistic design strategy for using tin disulfide nanosheet wrapped with interconnected carbon nanotube networks (SnS2@CNT) as the sulfur host and separator of LSBs is put forward. Based on the advantages of physical internment and chemistry absorption for LiPSs as well fast electron/lithium ion transport of SnS2@CNT, the LSBs with SnS2@CNT/S-SnS2@CNT release a high initial discharge specific capacity of 1375 mAh g−1 at 0.1C. After 800 cycles a high reversible specific capacity of 555 mAh g−1 can still be obtained even at a high current density of 2C. Besides, the LSBs with the high sulfur loading of 4.8 mg cm−2 can exhibit a reversible areal capacity of 4.5 mAh cm−2 after 50 cycles. Therefore, the design strategy provides a beneficial exploration for the commercialization of high-performance LSBs.
Fuel cell power for locomotives combines the environmental benefits of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. A North American consortium, a public–private partnership, is developing a prototype hydrogen-fueled fuel cell-battery hybrid switcher locomotive for urban and military-base rail applications. Switcher locomotives are used in rail yards for assembling and disassembling trains and moving trains from one point to another. At 127tonnes (280,000lb), continuous power of 250kW from its (proton exchange membrane) PEM fuel cell prime mover, and transient power well in excess of 1MW, the hybrid locomotive will be the heaviest and most powerful fuel cell land vehicle yet. This fast-paced project calls for completion of the vehicle itself near the end of 2007. Several technical challenges not found in the development of smaller vehicles arise when designing and developing such a large fuel cell vehicle. Weight, center of gravity, packaging, and safety were design factors leading to, among other features, the roof location of the lightweight 350bar compressed hydrogen storage system. Harsh operating conditions, especially shock loads during coupling to railcars, require component mounting systems capable of absorbing high energy. Vehicle scale-up by increasing mass, density, or power presents new challenges primarily related to issues of system layout, hydrogen storage, heat transfer, and shock loads.