1,720,966 research outputs found
METODO PER LA RELITIAZIONE AD ELEVATA SOSTENIBILITA’ DELLA MATERIA ATTIVA DI UNA BATTERIA LFP ESAUSTA, NONCHE’ POLVERE RELITIATA CON TALE METODO E METODO PER LA REALIZZAZIONE DI UNA BATTERIA LFP A PARTIRE DALLA POLVERE RELITIATA
No full textLa presente invenzione si riferisce al campo tecnico delle batterie al litio, ed ha in particolare per oggetto un metodo per la relitiazione della materia attiva di una batteria LFP esausta ad elevata sostenibilità, nonchè una polvere relitiata con tale metodo e un metodo per la realizzazione di una batteria LFP a partire dalla polvere relitiata
Batteries
No full textA solid polymer electrolyte has been developed and employed in lithium-metal batteries of relevant interest. The material includes crystalline poly(ethylene glycol)dimethyl ether (PEGDME), LiTFSI and LiNO3 salts, and a SiO2 ceramic filler. The electrolyte shows ionic conductivity more than 10(-4) S cm(-1) at room temperature and approaching 10(-3) S cm(-1) at 60 & DEG;C, a Li+-transference number exceeding 0.3, electrochemical stability from 0 to 4.4 V vs. Li+/Li, lithium stripping/deposition overvoltage below 0.08 V, and electrode/electrolyte interphase resistance of 400 & omega;. Thermogravimetry indicates that the electrolyte stands up to 200 & DEG;C without significant weight loss, while FTIR spectroscopy suggests that the LiTFSI conducting salt dissolves in the polymer. The electrolyte is used in solid-state cells with various cathodes, including LiFePO4 olivine exploiting the Li-insertion, sulfur-carbon composite operating through Li conversion, and an oxygen electrode in which reduction and evolution reactions (i. e., ORR/OER) evolve on a carbon-coated gas diffusion layer (GDL). The cells operate reversibly at room temperature with a capacity of 140 mA h g(-1) at 3.4 V for LiFePO4, 400 mA h g(-1) at 2 V for sulfur electrode, and 500 mA h g(-1) at 2.5 V for oxygen. The results suggest that the electrolyte could be applied in room-temperature solid polymer cells
Evaluation of high-entropy (Cr, Mn, Fe, Co, Ni)-oxide nanofibers and nanoparticles as passive fillers for solid composite electrolytes
No full textSolid-state electrolytes (SSEs) could represent the key to solve safety issues of lithium-ion batteries (LIBs). Among them, those obtained by homogenously dispersing inorganic nanofillers into a polymer matrix combine advantages of all SSE typologies. In this work, high-entropy (Cr,Mn,Fe,Co,Ni) oxide (HEO) with different morphology
(nanoparticles or nanofibers) are evaluated as passive fillers for the preparation of composite polyethylene oxide (PEO)-based SSEs. By varying their preparation conditions (calcination at 400 or 800 ◦C for 0.5 or 2 h, followed by rapid cooling) different size and crystallization degree of the oxide grains are obtained. The results of the electrochemical testing of the PEO/HEO composites evidence the crucial role of the filler microstructure and morphology. The best results in terms of electrolyte resistance (22.5 Ω), electrochemical stability window (4.7 V), Li+transference number (0.37) and ionic conductivity (3.0⋅10− 4 S cm− 1 at 65 ◦C) are obtained by using well crystallized HEO nanofibers with highly defective surface. The suitability of the most promising composite for practical applications is validated by successfully using it in full cell with commercial high-voltage cathode materials
Assessing Manufacturing‐Performance Correlation On LiMn0.7Fe0.3PO4 Electrodes For Application In Upscaled Li‐ion Battery Cells
Full text linkOlivine LiMnxFe1−xPO4 (LMFP) cathodes are gaining attention as a promising alternative to LiFePO4 (LFP) for lithium-ion batteries (LIBs), offering higher energy density while maintaining lower costs and improved safety compared to traditional layered oxide cathodes. However, their low electronic conductivity remains a challenge. One effective strategy to enhance electrode kinetics is incorporating
carbon additives during fabrication. This study examines the role of conductive additives optimization in LiMn0.7Fe0.3PO4 (LMFP73) electrodes and evaluates the impact of refining the electrode manufacturing to improve performance under practical conditions. Electrodes with 0.5% single-walled carbon nanotubes (SWCNTs) dispersion demonstrated improved performance. Optimization of mixing
protocol, solid content, and coating speed, significantly enhanced the electrode’s microstructure, mechanical integrity, and electrochemical response, producing thick electrodes suitable for industrial use. Upscaling to Graphite|LMFP73 single-layer pouch (SLP) cells with 200 GSM cathode loading resulted in 110 mAh g−1 at C/2, retaining 93% of the initial capacity after 100 cycles. This work provides
practical process parameters to reduce the gap between academic and industrial perspectives in electrode performance assessment under realistic conditions, tackling challenges in performance improvement while taking into account high areal loadings, mechanical properties of the coatings, practical electrode balancing, and electrolyte amount in the cell fabrication process
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Triglyme-based electrolyte for sodium-ion and sodium-sulfur batteries
Full text linkHerein, we investigate a lowly flammable electrolyte formed by dissolving sodium trifluoromethanesulfonate (NaCF₃SO₃) salt in triethylene glycol dimethyl ether (TREGDME) solvent as suitable medium for application in Na-ion and Na/S cells. The study, performed by using various electrochemical techniques, including impedance spectroscopy, voltammetry, and galvanostatic cycling, indicates for the solution high ionic conductivity and sodium transference number (t⁺), suitable stability window, very low electrode/electrolyte interphase resistance and sodium stripping/deposition overvoltage. Direct exposition to flame reveals the remarkable safety of the solution due to missing fire evolution under the adopted experimental setup. The solution is further investigated in sodium cells using various electrodes, i.e., mesocarbon microbeads (MCMBs), tin-carbon (Sn–C), and sulfur-multiwalled carbon nanotubes (S-MWCNTs). The results show suitable cycling performances, with stable reversible capacity ranging from 90 mAh g⁻¹ for MCMB to 130 mAh g⁻¹ or Sn–C, and to 250 mAh g⁻¹ for S-MWCNTs, thus suggesting the electrolyte as promising candidate for application in sustainable sodium-ion and sodium-sulfur batteries
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A sustainable anode for Na-ion batteries based on holm oak waste-derived hard carbon and lignin binder
Full text linkSodium-ion batteries (SIBs) represent one of the key-enabling technologies for the ongoing energy transition. However, the economic success of SIBs relies on sustainable and low-cost electrode materials, such as the bio-derived ones. Particularly, it is important to find an environmentally friendly alternative to the commercial binder polyvinylidene fluoride, which currently poses several concerns in terms of environmental impact together with the other perfluorinated alkylated substances (PFAS). In this context, a holm oak waste biomass was used both for the production of hard carbon and as a source of lignin (a natural binder that is currently poorly valorized). A one-step pyrolysis of holm-oak waste followed by acid leaching was performed to obtain a hard carbon with low amount of impurities, good interlayer spacing and well-developed microporosity and surface area. On the other hand, lignin was extracted from holm oak waste feedstock through an organosolv process with a binary mixture of gamma-valerolactone and water, obtaining a lignin with a high level of purity. The obtained materials were combined to prepare bio-based anode materials for SIBs, exhibiting a reversible capacity of around 200 mA h g-1 in Na half-cells cycled at 300 mA g-1, with promising rate capability and long cycling stability even at high current rates. The electrochemical results combined with the interfacial and post-mortem SEM analysis demonstrated the ability of lignin binder to ensure longstanding adhesion with the hard carbon substrate, reflecting in electrodes with long cycle life and capacity retention
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