batterydata/paper-abstracts huggingface dataset:
The search of advanced anodes has been an important way to satisfy the ever-growing demands on high rate performance lithium-ion batteries (LIBs). It was observed that the capacity of Fe3C as an anode is larger than its theoretical one, which might be attributed to the pseudocapacity on the interface between the carbide and electrolyte. In this work, a novel carbon sphere doped with Fe3C nanoparticles was fabricated and tested as the anode in LIBs. In the first place, iron precursors were embedded in the cross-link polymer resorcinol-formaldehyde (RF) spheres via a facile hydrothermal reaction, in which RF served as the carbon source and ethanol as a dispersant agent. Consequently, the hydrothermal products were carbonized successively at 700°C under inert atmosphere to obtain porous carbon spheres doped with Fe3C. When the composite severed as an anode in LIBs, its discharge capacity increased to the largest during the first 250-400 cycles, then dropped down to a similar level of that after 1000 cycles at different current rates. The discharge capacity of the composite increased from ∼300mAhg−1 to ∼540mAhg−1 at the current of 100mAg−1 during the initial hundreds cycles, and even a discharge capacity of ∼230mAhg−1 at the current of 2000mAg−1. Moreover, it was observed that a discharge plateau gradually appeared between 0.7∼1.1V during the first hundreds of cycles. The electrochemical behaviors of the anode before 1000 discharge/charge cycles were compared with that after 1000 discharge/charge cycles by cyclic voltammetry and electrochemical impedance spectroscopy to find out the differences between their features. The high rate performance of LIBs might result from the decomposition of electrolyte and the pseudocapacity behavior presented on the interfacial (surface) lithium storage of the active materials.
The effect of activation temperature on Li-ion batteries with flame-retarded electrolytes containing 5wt.% dimethyl methyl phosphonate (DMMP) and trimethyl phosphate (TMP) is investigated respectively. It is found that activation at elevated temperature promotes the formation of a stable solid electrolyte interface layer on the graphite electrode, which may significantly suppress the reductive decomposition of DMMP and TMP and avoid graphite exfoliation. But fierce oxidation of the electrolytes on the LiCoO2 electrode at elevated temperature is harmful to the cell performance. A procedure of so-called altered temperature activation (ATA) is adopted for LiCoO2/graphite full-cells. It can compromise the contradictive effects on the separate electrodes at the elevated temperature. High capacity and good rate capability are obtained for the cells with the flame-retarded electrolytes, especially for the TMP-containing electrolyte.
The study compared postoperative range of motion (ROM) and functional outcome of total knee arthroplasty (TKA) with a posterior cruciate ligament (PCL)–substituting knee prosthesis compared with an ultracongruent PCL–sacrificing design. Two hundred nine patients underwent primary TKA. Posterior stabilized design (121) and highly conforming, PCL-sacrificing, ultracongruent design (88) TKAs were reviewed. Surgeon, surgical approach, and a hyperflexion postoperative rehabilitation protocol were the same. Results showed significant improvement in knee flexion, ROM, Knee Score, and Function Score within each group. Postoperative mean total ROM was slightly higher with the posterior stabilized design. The 2 groups were the same postoperatively in the improvement in ROM, Knee Score, Function Score, satisfaction level, among other activity metrics. There was no clear evidence proving superiority and the need for posterior stabilization in PCL-sacrificing TKA.
LiFe0.2Mn0.8PO4 has been prepared by a solid state reaction process in combination with a ball-milling with carbon black and sucrose as carbon sources. The effects of the ratio of carbon precursors, the total carbon content, and ball-milling time on the physico-chemical and electrochemical properties of C-LiFe0.2Mn0.8PO4 are extensively studied. Under the optimal condition, the as-prepared Li Fe0.2Mn0.8PO4 gives a capacity of 150mAhg−1 at 1/20C and 110mAhg−1 at 1C. A novel lithium-ion battery consisting of LiFe0.2Mn0.8PO4 cathode, Li4Ti5O12 anode delivers a capacity of 70mAhg−1 and a specific energy of 170Whkg−1 with an output voltage of 2.45V based on the total weight of both active electrode materials. The cell also exhibits an excellent cycling stability with a capacity retention of 92% over 200 charge/discharge cycles.
Mechanically milled graphite powder for different durations was used as anode in lithium-ion battery. Reversible capacity and coulombic efficiency of the milled and pristine powders were measured. It was found that the controlled milling increases the reversible capacity and coulombic efficiency of the first cycle from 356 to 368Ahkg−1 and from 83 to 86%, respectively. The milled powder was analyzed for particle size distribution, bulk and surface structure by particle size analyzer, powder X-ray diffractometer, and Raman spectroscopy and electron microscope, respectively, to understand the effect of mechanical milling of graphite powder on its physical properties. The mild milling lead to aggregation of graphite particles, that had significant influences on the electrode performance. Graphite–tin dioxide composite electrode has also been prepared by the mechanical milling and the preliminary result indicates that the mechanical milling would be used to prepare the high capacity composite electrodes.
This work provides kinetic and transport parameters of Li-ion during its extraction/insertion into thin film LiNi0.5Mn1.5O4 free of binder and conductive additive. Thin films of LiNi0.5Mn1.5O4 (0.2 μm thick) were prepared on electronically conductive gold substrate utilizing the electrostatic spray deposition technique. High purity LiNi0.5Mn1.5O4 thin film electrodes were observed with cyclic voltammetry, to exhibit very sharp peaks, high reversibility, and absence of the 4 V signal related to the Mn3+/Mn4+ redox couple. The electrode subjected to 100 CV cycles of charge/discharge delivered a capacity of 155 mAh g−1 on the first cycle and sustained a good cycling behavior while retaining 91% of the initial capacity after 50 cycles. Kinetics and mass-transport of Li-ion extraction at LiNi0.5Mn1.5O4 thin film electrode were investigated by means of electrochemical impedance spectroscopy. The apparent chemical diffusion coefficient (D app) value determined from EIS measurements changed depending on the electrode potential in the range of 10−10–10−12 cm2 s−1. The D app profile shows two minimums at the potential values close to the peak potentials of the corresponding cyclic voltammogram.
Surface and electrochemical properties of micrometric and nanometric tetragonal β-MnO2 of, respectively, 4 and 61m2 g−1 surface area were studied. The monodispersed nanocrystalline phase prepared by spray pyrolysis and characterized by transmission electron microscopy (TEM), is made of facetted crystals with 70nm×40nm edges. Three types of energy domains were identified by surface acid–base titration. Slow step linear voltammetry reduction (10mV/2h scan rate) showed one current peak at −0.6V (versus Hg–HgO 1M KOH) for the micrometric phase, but three current peaks at −0.18, −0.36 and −0.55V for the nanometric phase. They were assigned to the reduction of: (1) surface Mn atoms related to 〈111〉 and 〈311〉 faces; (2) more stable surface Mn atoms related to 〈100〉 and 〈110〉 faces; (3) bulk Mn atoms, respectively. The presence of new reduction peaks at higher potential is ascribed to the increase in Gibbs free energy caused by the surface energy of the nanometric particle.
Higher Education Institutions (HEIs) are often the size of small municipalities. Worldwide, the higher education (HE) sector has expanded phenomenally; for example, since the 1960s, the United Kingdom (UK) HE system has expanded sixfold to >2.4million students. As a consequence, the overall production of waste at HEIs throughout the world is very large and presents significant challenges as the associated legislative, economic and environmental pressures can be difficult to control and manage. This paper critically reviews why sustainable waste management has become a key issue for the worldwide HE sector to address and describes some of the benefits, barriers, practical and logistical problems. As a practical illustration of some of the issues and problems, the four-phase waste management strategy developed over 15years by one of the largest universities in Southern England – the University of Southampton (UoS) – is outlined as a case study. The UoS is committed to protecting the environment by developing practices that are safe, sustainable and environmentally friendly and has developed a practical, staged approach to manage waste in an increasingly sustainable fashion. At each stage, the approach taken to the development of infrastructure (I), service provision (S) and behavior change (B) is explained, taking into account the Political, Economic, Social, Technological, Legal and Environmental (PESTLE) factors. Signposts to lessons learned, good practice and useful resources that other institutions – both nationally and internationally – can access are provided. As a result of the strategy developed at the UoS, from 2004 to 2008 waste costs fell by around £125k and a recycling rate of 72% was achieved. The holistic approach taken – recognizing the PESTLE factors and the importance of a concerted ISB approach – provides a realistic, successful and practical example for other institutions wishing to effectively and sustainably manage their waste.
The objective of this paper is to further improve the method of treating hemangioma with the copper needle and to standardize this method. The CHT-5302/MP copper needle therapeutic instrument has been used in a number of assorted cases. A review of 180 hemangioma cases treated by this instrument verifies that it can offer sufficient electricity for clinical use. This shows that the new treatment method offers a reliable, effective means for the treatment of high- or low-flow vascular malformations and hemangiomas. As there are no complications, it is better than previous treatments for hemangioma. It can offer an effective therapy for patients who previously could not be treated or who might require excision of limbs.
The use of technology in classrooms in Spanish universities has been following an upward path, and in many cases technological devices are substituting other materials that until now have been used, such as books, notebooks and so on. Step by step in higher education, more of these latest generationdevices are being used, and are providing significant improvements in training. Nowadays, there are Spanish universities that use tablets, a device with multiple applications for teaching as well as for students to study differently. They are definitely a notable innovation that will gradually become incorporated into university life. Tablet PCs make teaching more dynamic and available to students through the use of up to date digital materials, something which is key in training engineers. This paper presents their different functions employed in three Spanish universities to support teachingin engineering degrees and masters using the tablet PC, and their impact on the training process. Possible uses in specific programs like the Erasmus Masters Programmes are also assessed. The main objective of using tabletsis to improve the academic performance of students through the use of technology.
A total of twenty four binuclear metal azaphthalocyanine compounds in four series of M2(azaPc)2Me, M2(azaPc)2SO2, M2(azaPc)2, M2(azaPc)2CO (M=Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+) were synthesized by solid phase method, which were applied for Li/SOCl2 battery as electrocatalysts to enhance its capacity and discharge voltage. In all cases, the electrochemical performances of Li/SOCl2 batteries were improved compared with controls. It is worth mentioning that Mn2(azaPc)2SO2 increased the discharge voltage to 3.3485V, rising by 0.1570V compared with that of the blank. Co2(azaPc)2CO lengthened the discharge time to 1821s, rising by 75.80%. And Co2(azaPc)2 raised battery capacity to 35.24mAh, increasing by 79.56%. Based on cyclic voltammetry measurements, the reaction mechanism was found to involve an irreversible two-step electron transfer process and a hypothesis was conjectured. All the azaphthalocyanine compounds were characterized by element analysis, IR analysis, and UV-Vis absorption.
Recent technological advances have led to new light-weight battery-operated systems for electrophysiology. Such systems are head mounted, run for days without experimenter intervention, and can record and stimulate from single or multiple electrodes implanted in a freely behaving primate. Here we discuss existing systems, studies that use them, and how they can augment traditional, physically restrained, ‘in-rig’ electrophysiology. With existing technical capabilities, these systems can acquire multiple signal classes, such as spikes, local field potential, and electromyography signals, and can stimulate based on real-time processing of recorded signals. Moving forward, this class of technologies, along with advances in neural signal processing and behavioral monitoring, have the potential to dramatically expand the scope and scale of electrophysiological studies.
Using electrodes or catalytic layers that are porous increases the reactive surface area but also the distance that ions and electrons have to travel. Thicker electrodes, through their larger surface area, reduce the activation overpotential but increase the ohmic losses. There will therefore be an electrode thickness for which the voltage losses are minimal, corresponding to a maximum energy efficiency. Simple approximate relations are derived here for the value of this optimal thickness, for both Tafel and linearised Butler-Volmer kinetics. We additionally optimise the power density of Galvanic cells, the capacity of battery electrodes, and the porosity of both particulate and foam-like electrodes. For this analysis we introduce an intuitive new definition of the electrode effectiveness factor. An accurate explicit current-voltage expression, including the transition from linear to Tafel kinetics and from a single to a doubled Tafel slope, is obtained. The present analysis is limited to a configuration where ions and electrons enter and leave at opposite sides of the electrode, as in most stacks, and applies only when mass transfer effects can be neglected. These results can nonetheless be useful for optimization of various electrochemical devices including fuel cells, batteries, flow batteries, electrochemical reactors, and electrolysers.
The core–shell carbon/sulfur material with high performance is prepared by a facile and fast deposit method in an aqueous solution. As sulfur ratio is 85% (w/w) in the composite, scanning electron microscope (SEM) and transmission electron microscope (TEM) observation show that the moniliform particles with 10nm sulfur shells preserve the morphology of carbon cores. Tested as the cathode material in a lithium cell with binary organic electrolyte at room temperature, the composite shows excellent electrochemical performance. It exhibits a specific capacity up to 1232.5mAhg−1 at the initial discharge and its specific capacity remained above 800mAhg−1 after 50 cycles. Meanwhile, the composite also exhibits the high-rate behavior at 800mAg−1 of current density. Assuming a complete reaction to the final product, Li2S, the utilization of the electrochemically active sulfur is about 85% at the initial cycle. Electrochemical impedance spectroscopy (EIS) is introduced to understand the impact of the microstructure of composite on electrochemistry. According to our study, a novel core–shell structural carbon/sulfur material is proposed and the key factors of the preparation are discussed.
Three dimensional graphene-based composites (3DGCs) have attracted significant attention for lithium ion battery applications due to their unique structures and attractive properties. A large number of 3DGCs with novel structures and functions have been developed in the past few years. This review summarizes the current progress of 3DGCs, including their preparation and application in lithium ion batteries, especially from the viewpoint of structural and interfacial engineering, which have attracted more and more attention for the development of high performance electrode systems.
The objective of this investigation was to examine how instructional practices in 107 first- and second-grade classrooms in 17 high poverty schools moderate the impact on literacy outcomes of literacy-related skills students bring to the classroom. Ratings of teaching effectiveness and time allocation to literacy activities were obtained. Twenty time allocation variables were reduced into seven patterns of literacy activities that were examined as predictors of reading and spelling outcomes. Students’ initial reading ability and interactions of teaching effectiveness ratings by time allocation components predicted reading and spelling outcomes. Discussion centers on immutable versus flexible views of reading development and analytic approaches to examining instructional practices.
Car dealership experiences may influence EV purchase decisions of the majority of consumers who do not have pre-existing knowledge of EVs. This study shows that car dealerships present barriers to EV adoption because of dealer sales strategies that reflect government and industry conditions.
In this work, a core-shell composite composed of MoS2 nanosheets grown on hollow carbon microspheres is synthesized by a hydrothermal and a subsequent annealing route. The result shows that well-graphitized hollow-carbon@highlycrystallineMoS2(HC@MoS2) was obtained after the four-step reaction. And it is found that the synthesized MoS2 is consist of 2H and 1T phases. The lithium storage property of the composite is investigated as an anode material for lithium-ion batteries. Benefited from the special morphology and structure, a stable capacity of 970mAhg−1 for over 100 cycles at a current density of 0.25Ag−1 is realized on the material. Even at a high current density of 4Ag−1, a reversible capacity as high as 560mAhg−1 is delivered. Moreover, the reasons for the excellent electrochemical performance of the material are explored and discussed in detail.
A new acetamide based eutectic solvent is obtained via complexation with AlCl3. The electrodeposition of aluminum is successfully achieved from AlCl3/acetamide eutectic solvent. The cyclic voltammograms on tungsten electrode indicate that Al(III) are easier to be reduced from AlCl3/acetamide eutectic solvent at a molar ratio in a range of 1.1 to 1.5. Aluminum coatings were prepared at −0.25V (vs. Al/Al3+) and different temperatures at 313K and 333K in AlCl3/acetamide eutectic solvent at molar ratio=1.3 (r=1.3). The SEM images show that thick adherent aluminum films were deposited on the copper substrate. The EDS and XRD analysis confirm that the obtained deposits are pure aluminum. The present results allowed the new and cheap AlCl3/acetamide eutectic solvent to be a potential electrolyte for aluminum electrodeposition at room temperature.
This paper presents a thermal analysis of a semi-active battery/supercapacitor (SC) hybrid energy storage system (HESS), which is used in electric vehicles (EVs), at subzero temperatures. In subzero temperature environments, EVs suffer a dramatic driving range loss due to the energy and power capability reduction of LiFePO4 batteries, as well as severe battery degradation due to Li plating. This will increase the system operation cost because the battery pack needs to be changed frequently. Based on a novel degradation model of LiFePO4 batteries, which is validated over a wide temperature range, a near-optimal energy management strategy of the HESS for on-line use is proposed using the dynamic programming (DP) approach, which minimizes the operation cost (the electricity and the battery fade costs) over a typical China Bus Drive Cycle (CBDC). The convective heating method is integrated into the DP process. Finally, the required heating of the HESS at subzero temperatures over multi-CBDC is analyzed by evaluating the system operation cost. Simulation results show that the heating process becomes increasingly necessary with increased driving range, battery price, and heating efficiency, as well as decreasing environment temperature.
This study was primarily initiated to understand the consistently low levels of SO2 in cities in India in spite of rising SO2 emissions. A literature review suggested the possibility of chemical transformation of SO2 to SO4. Thus, the objective of research was to understand the formation of SO4 as a function of SO2, and other constituents of atmosphere such as PM10, water content, Ca (in aerosol) and pH (of aerosol). For this purpose, air quality monitoring was conducted at five locations in the city of Kanpur, India (during October 1999–April 2000) representing various land-use patterns. It was found that the SO4 levels were considerably high (2.8–43.6μgm−3) compared to levels in cities in the US (1.9–3.6μgm−3, Sandberg et al. (J. Air Pollut. Control Assoc. 26 (1976) 559; 15.7–18.4μgm−3, Altshuller (J. Air Pollut. Control Assoc. 26 (1976) 318; 4.0–14.0μgm−3 Dockery et al. (J. Med. 329 (1993) 1753), UK (3.2–9.0μgm−3, QUARG, 1996 http://www.environment.detr.gov.uk/airq/consult/naqs/index.htm), and 25 locations in Europe (0.34–1.68μgm−3 (1991–1999), EMEP website), but were comparable to the levels observed at Agra (14.67μgm−3, Kulshrestha et al. Indian J. Radio Space Phys. 24 (1995) 178) and at New Delhi (12.9−27.5μgm−3, Shandilya, M.E. Thesis, Malaviya National Institute of Technology, Jaipur, India, 2000). The high SO4 levels could provide a plausible explanation for low SO2 concentration levels in the city of Kanpur. It was concluded that high levels of PM10, Ca and high pH of aerosols in atmosphere provide a conducive environment for conversion of SO2 to SO4. It was also concluded that the important migration pathway in study area for the transformation of SO2 to SO4 appears to be oxidation of SO2 on the surfaces (of particulate) available in the ambient atmosphere.
A composite cathode material consisting of (010) facet-oriented LiFePO4 nanoplatelets wrapped in a nitrogen-doped graphene aerogel is reported. Such a composite possesses a 3D porous structure with a BET surface area as high as 199.3 m2 g−1. In this composite, the nitrogen-doped graphene aerogel combined with its interconnected porous networks provides pathways for rapid electron transfer and ion transport, while the thin LFP nanoplatelets with large (010) surface area enhance the active sites and shorten the Li+ diffusion distances. As a result, a high rate capability (78 mA h g−1 at 100 C) as well as a long life cycling stability (89% capacity retention over 1000 cycles at 10 C) are achieved.