1,721,415 research outputs found
Sodium induced morphological changes of carbon coated TiO2 anatase nanoparticles High performance materials for na ion batteries
Full text linkThe most promising candidate as an everyday alternative to lithium ion batteries LIBs are sodium ion batteries NIBs . This is not only due to Na abundance, but also because the main principles and cell structure are very similar to LIBs. Due to these benefits, NIBs are expected to be used in applications related to large scale energy storage systems and other applications not requiring top performance in terms of volumetric capacity. One important issue that has hindered the large scale application of NIBs is the anode material. Graphite and silicon, which have been widely applied as anodes in NIBs, do not show great performance. Hard carbons look very promising in terms of their abundance and low cost, but they tend to suffer from instability, in particular over the long term. In this work we explore a carbon coated TiO2 nanoparticle system that looks very promising in terms of stability, abundance, low cost, and most importantly that safety of the cell, since it does not suffer from potential sodium plating during cycling. Maintaining a nano size and consistent morphology of the active material is a crucial parameter for maintaining a well functioning cell upon cycling. In this work we applied Anomalous Small Angle X Ray Scattering ASAXS for the first time at the Ti K edge of TiO2 anatase nanoparticles on different cycled composite electrodes in order to have a complete morphological overview of the modifications induced by sodiation and desodiation. This work also demonstrates for the first time that the nanosize of the TiO2 is maintained upon cycling, which is in agreement with the electrochemical stabilit
Innovative control strategy for fast runback operational transient applied to SMRs
No full textThe recent interest in the Small Modular Reactor (SMR) for its potential increased economic competitiveness has focused attention in part on reducing operational costs to offset those plant costs that do not benefit from the economies of scale of large traditional units. Plant operation and maintenance economics are significantly driven by plant availability, which can be enhanced by means of innovative control strategies by avoiding unnecessary plant or unit trips. In this context, an effective strategy for achieving fast runback of a sodium-cooled SMR has been developed. In this work, after having defined and modeled a suitable control strategy by adopting the Petri nets formalism, a Model-based Predictive Control regulator has been developed in order to reduce as promptly as possible the power level, without scramming the reactor (fast runback) and possibly limiting the control rod contribution. Such flexibility could lead to significant savings in the operational costs of the reactor while also improving the system availability. The proposed procedure has been characterized by simulating the operational transients on both an oxide-fueled reactor and on a metal-fueled reactor, comparing the responses of the two different configurations and the respectively needed control rod contribution
Absorption of polarized X-rays by V2O5-based cathodes for lithium batteries: An application
No full textVanadium pentoxide materials prepared through sol-gel processes (xerogel, aerogel and aerogel-like) act as excellent intercalation hosts for lithium as well as for polyvalent cations. The large lithium insertion capacity of these materials makes them attractive for use as cathodes in high capacity lithium batteries. This paper describes the utility of X-Ray absorption spectroscopy (XAS) for the investigation of gel-based V2O5 materials. In particular, X-ray near edge structure (XANES) and polarized EXAFS experiments are highlighted. © 2002 Elsevier Science Ltd. All rights reserved
Natural Polymers as Green Binders for High-Loading Supercapacitor Electrodes
Full text linkThe state-of-the-art aqueous binder for supercapacitors is carboxymethyl cellulose (CMC). However, it limits the mass loading of the coatings owing to shrinkage upon drying. In this work, natural polymers, that is, guar gum (GG), wheat starch (WS), and potato starch (PS), were studied as alternatives. The flexibility and adhesion of the resulting coatings and electrochemical performance was tested. The combination of 75:25 (w/w) ratio PS/GG showed a promising performance. Electrodes were characterized by SEM, thermal, adhesion, and bending tests. Their electrochemical properties were determined by cyclic voltammetry, electrochemical impedance spectroscopy, and cycling experiments. The PS/GG mixture conformed well to criteria for industrial production, enabling mass loadings higher than CMC (7.0 mg cm−2) while granting the same specific capacitance (26 F g−1) and power performance (20 F g−1 at 10 A g−1). Including the mass of the current collector, this represents a +45 % increase in specific energy at the electrode level
Istigazione e misura della Condotta Aggressiva e dell'Ostilità Interpersonale: Contributo metodologico.
No full textAssessing n-type organic materials for lithium batteries: A techno-economic review
Full text linkThe high demand for critical minerals such as lithium, copper, nickel, and cobalt, required for lithium-ion batteries, has raised questions regarding the feasibility of maintaining a steady and affordable supply of raw materials for their production. In the last years, researchers have shifted their attention toward organic materials, which are potentially more widely available, affordable, and sustainable due to the ubiquitous presence of the constituent organic elements. The n-type materials have a redox mechanism analogous to that of lithium-ion cathodes and anodes, hence they are suitable for a meaningful comparison with the state-of-the-art technology. While many reviews have evaluated the properties of organic materials at the material or electrode level, herein, the properties of n-type organic materials are assessed in a complex system, such as a full battery, to evaluate the feasibility and performance of these materials in commercial-scale battery systems. The most relevant cathode materials for organic batteries are reviewed, and a detailed cost and performance analysis of n-type material-based battery packs using the BatPaC 5.0 software is presented. The analysis considers the influence of electrode design choices, such as the conductive carbon content, active material mass loading, and electrode density, on energy density and cost. The potential of n-type organic materials as a low-cost and sustainable solution for energy storage applications is highlighted, while emphasizing the need for further advancements of organic materials for energy storage applications
Evaluation of counter and reference electrodes for the investigation of Ca battery materials
Full text linkThe growing needs for electrochemical storage systems are pushing the research community to explore alternatives to Li-ion technology. Ca-based chemistry is attracting more and more attention and expectation. However, the unsuitability of Ca metal as counter and reference electrodes limits the research activity on the topic. Herein we propose a simple electrochemical cell configuration employing activated carbon as counter and reference electrodes, which is suitable for positive electrode screening. The feasibility of this cell configuration has been confirmed by evaluating the electrochemical activity of bilayered-V2O5 in the Ca-ion system
Introduction to the special Issue: Focus review - New and emerging battery technologies
No full textDriven by the ongoing global target of transitioning to a low-carbon economy, the demand for batteries is growing at an accelerating pace. Indeed, the development of batteries for transportation and stationary storage is one of the key strategies of the European Commission (EC) to enable the achievement of carbon neutrality by 2050.
This Special issue of Journal of Power Sources focuses on the current developments and future perspectives of various battery technologies, collecting 10 review articles from a wide range of European participants, i.e. 50 institutes from 12 countries, currently working together within Batteries Europe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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