batterydata/paper-abstracts huggingface dataset:
In this study, experimental and numerical investigation for melting of paraffin wax is carried out for a portable thermal energy accumulation system in a rectangular enclosure of size 200 mm × 160 mm × 20 mm. The studied paraffin wax is typically used for a wide variety of applications including thermal management of buildings and solar energy storage. The melting behaviour was also investigated numerically with the help of FVM (Finite Volume Method) approach based commercial code Ansys Fluent. The melting behavior is observed for 1500, 1930, 2500 and 3100 W/m2 of heat flux values that suits for thermal accumulation and thermal regulation of the buildings. The images of the PCM domain have been captured at regular intervals of 30 min and the temperature readings at fifteen different locations in the PCM domain have been recorded simultaneously. The differences between experimental and numerical results were observed to be in acceptable range. The investigation reveals the facts about the transient behaviour of melting interface, melted proportion and the stored energy for melting cycle of 5–5.5 .
The crystallographic structure as well as the thermodynamic and electrochemical properties of the hydrogen absorbing compounds La5Ni19 and La4MgNi19 have been determined. X-ray diffraction and microprobe analysis have shown the presence of a single hexagonal (P63/mmc) phase for the Mg-free binary compound whereas only one composition but two different crystallographic structures, hexagonal (P63/mmc) and rhombohedral (R-3m), are observed for La4MgNi19. Each phase can be described as the stacking along the c-axis of n[A2B4]/m[AB5] sub-units with n =1 and m =3 and A=La, Mg; B=Ni. Depending on the stacking sequence, either the hexagonal or the rhombohedral phase is obtained. Thermodynamic properties toward hydrogen uptake (capacity and equilibrium pressure) and electrochemical properties (cycling behavior) in alkaline medium have been measured and are compared for these compounds with and without magnesium. It is observed that the Mg-free compound exhibits a much lower reversible hydrogen capacity than the Mg-containing one. However, despite larger capacity, this latter compound remains to be optimized in term of cycle life.
A CVD process was developed for producing 63Ni-based atomic batteries by deposition of active 63Ni layers onto semiconductor silicon supports. Tetrakis(trifluorophosphine)nickel synthesized from 63Ni metal and phosphorus trifluoride was used as the volatile precursor. The influence of the support temperature and working pressure on the characteristics of the 63Ni coating was examined.
Real-time stress evolution in a graphite-based lithium-ion battery negative electrode during electrolyte wetting and electrochemical cycling is measured through wafer-curvature method. Upon electrolyte addition, the composite electrode develops compressive stress of 1–2 MPa due to binder swelling. During electrochemical intercalation, the compressive stress increases with the electrode's state-of-charge, reaching a maximum value of 10–12 MPa. There appears to be an approximate correlation between the rate of stress rise and the staging behavior of the lithiated graphite. De-intercalation results in a similar decrease in electrode stress. Although higher peak stresses are seen at high C-rates, the dependence appears to be relatively weak (up to 5C). These measurements reveal, for the first time, the nature of stress evolution in practical lithium ion- battery electrodes and provide useful data to quantify the driving force for mechanical damage that accrues in composite electrodes upon repeated cycling. While the reported results can serve as reference for calibrating theoretical and computational models to predict electrode stress and damage evolution, the methodology demonstrated can be used to measure stresses and characterize fatigue damage in any composite lithium-ion-battery electrode as well as optimize its microstructure to mitigate stress-related damage mechanisms.
The compounds [H3O(dibenzo-18-crown-6)][Ix] (x = 3,5,7) have been synthesised and investigated by X-ray diffraction as well as Raman and far-IR spectroscopy. The structure of the triiodide contains two independent, slightly asymmetric and bent I3− ions with I–I distances in the range 2.92–2.94 Å. The pentaiodide can be described as composed of (I3−)·I2, where the I–I distances in the asymmetric and slightly bent I3 unit are 2.894(2) and 2.942(2) Å and in the I2 unit 2.763(2) Å. The L-shaped I5− ions are linked together forming a chain of I10 rectangles through van der Waals interactions in the range 3.7–3.8 Å. The structure determination supports a pyramidal geometry of the H3O+ ion in the dibenzo-18-crown-6 moiety of both structures. Because of severe crystal twinning the crystal structure of the heptaiodide could not be determined. However, the results from the spectroscopic investigation are consistent with a heptaiodide of composition (I3−)·2I2.
This paper investigates the Proton Exchange Membrane Fuel Cell (PEMFC) Cold Startup problem within the specific context of the Plugin Hybrid Electric Vehicles (PHEV). A global strategy which aims at providing an efficient method to minimize the energy consumption during the startup of a PEMFC is proposed. The overall control system is based on a supervisory architecture in which the Energy Management System (EMS) plays the role of the power flow supervisor. The EMS estimates in advance, the time to start the fuel cell (FC) based upon the battery energy usage during the trip. Given this estimation and the amount of additional energy required, the fuel cell temperature management strategy computes the most appropriate time to start heating the stack in order to reduce heat loss through the natural convection. As the cell temperature rises, the PEMFC is started and the reaction heat is used as a self-heating power source to further increase the stack temperature. A time optimal self-heating approach based on the Pontryagin minimum principle is proposed and tested. The experimental results have shown that the proposed approach is efficient and can be implemented in real-time on FC-PHEVs.
A saprophytic, lignin-decomposing basidiomycete fungal isolate (BB1), identified as a member of the russuloid lineage closest to the genus Peniophora, plays a role in soil aggregation and stabilization. In liquid media this fungus secretes large amounts of extracellular materials or mucilage that act as soil binding agents. We investigated the nature of these materials using periodate treatment and lectin cytochemistry, and studied whether or not these materials are involved in soil aggregation. Water stability of artificial fungal amended soil aggregates was destroyed by periodate treatment suggesting that polysaccharides produced by the basidiomycete were involved in soil aggregation. Binding patterns of fluorescently labeled lectins were also investigated to determine specific carbohydrate moieties present in the fungal mucilage. Fluorescently conjugated lectins (Ulex europaeus Agglutinin I and Lotus tetragonolobus lectin) bound to extracellular mucilage indicating that this basidiomycete mucilage contains fucosyl sugar residues. We also demonstrated that water stability of artificial soil aggregates prepared with fungal mycelia pretreated with L(-)fucose lectins were significantly reduced. This study indicates that fungal-derived material containing fucosyl residues plays a role in soil adhesion.
The effects of surface fluorination on the electrochemical charge–discharge properties of a Mg2Ni electrode, prepared by mechanical alloying in Ni-MH batteries are investigated. After 20h milling, Mg and Ni powder form nanocrystalline Mg2Ni. The discharge capacity of this alloy increases greatly on the initial cycle but, due to the formation of a Mg(OH)2 passive layer, displays rapid degradation in alkaline solution within 10 cycles. In a 6M KOH+x M KF electrolyte (x=0.5, 1, and 2), a continuous and stable fluorinated layer is formed and the durability of the Mg2Ni electrode increases marketly and a high rate discharge capability is obtained (90–100mAh/g). Addition of 2M KF leads to the highest durability of all the electrodes tested. The improvement is due to a thin MgF2—flourinated layer, which reduces the charge-transfer resistance and protects the Mg2Ni electrode from forming a Mg(OH)2 layer.
Imaging-guided interventional procedures have become increasingly popular in the treatment of several pathologic conditions in the musculoskeletal system. Besides oncological treatments, musculoskeletal procedures can be performed to treat different degenerative or inflammatory conditions. This paper is aimed to review clinical indications and technical aspects of these kinds of procedures. In particular, we revise the general aspects common to most procedures and the different imaging-guided interventions which can be performed around joints, soft tissues, and spine.
Deficits for pitch structure processing in congenital amusia has been mostly reported for melodic stimuli and explicit judgments. The present study investigated congenital amusia with harmonic stimuli and a priming task. Amusic and control participants performed a speeded phoneme discrimination task on sung chord sequences. The target phoneme was sung either on a functionally important chord (tonic chord, referred to as “related target”) or a less important one (subdominant chord, referred to as “less-related target”). Correct response times were faster when the target phoneme was sung on tonic chords rather than on subdominant chords, and this effect was less pronounced, albeit significant, in amusic participants. These data report for the first time a deficit in congenital amusia for chord processing, but also provide evidence that, despite this deficit, amusic individuals have internalized sophisticated syntactic-like functions of chords in the Western tonal musical system. This finding suggests that thanks to this musical knowledge, amusic individuals could develop expectancies for musical events, and, presumably, follow the tension-relaxation schemas in Western tonal music, which also influence emotional responses to music.
Rate capability of Li/spinel LiMn2O4 or olivine LiFePO4 positive electrode cells containing mixed imidazolium ionic liquids electrolytes has been investigated under comparison with conventional organic solvent electrolyte and piperidinium ionic liquid. The LiMn2O4 electrode provides variation of rate capabilities among the ionic liquid electrolytes, while ionic liquid electrolytes provide similar extent of capacity degradation under high rate compared with organic solvent electrolyte for LiFePO4 electrode. Such differences in electrolyte dependences of the rate capabilities can be explained in relation to parameters in the high frequency resistances on AC impedance, assumed as interfacial resistances. The rate capability of LiMn2O4 is somewhat related to the activation energy of the high frequency resistance, while for LiFePO4 the resistance value appears to contribute to the rate capability.
In this study we have investigated the electrochemical properties of hollow silicon nanospheres encapsulated with a thin carbon shell, HSi@C, as a potential candidate for lithium-ion battery anodes. Hollow Si nanospheres are formed using a templating method which is followed by carbon coating via carbonization of a pyrrole precursor to form HSi@C. The synthesis conditions and the resulting structure of HSi@C have been studied in detail to obtain the target design of hollow Si nanospheres encapsulated with a carbon shell. The HSi@C obtained exhibits much better electrochemical cycle stability than both micro- and nano-size silicon anodes and deliver a stable specific capacity of 700mAhg−1 after 100 cycles at a current density of 2Ag−1 and 800mAhg−1 after 120 cycles at a current density of 1Ag−1. The superior performance of HSi@C is attributed to the synergistic combination of the nanostructured material, the enhanced conductivity, and the presence of the central void space for Si expansion with little or no change in the volume of the entire HSi@C particle. This study is the first detailed investigation of the synthesis conditions to attain the desired structure of a hollow Si core with a conductive carbon shell. This study also offers guidelines to further enhance the specific capacity of HSi@C anodes in the future.
In this work we demonstrate that biomass-derived proteins serve as an ideal precursor for synthesizing carbon materials for energy applications. The unique composition and structure of the carbons resulted in very promising electrochemical energy storage performance. We obtained a reversible lithium storage capacity of 1780 mA h g−1, which is among the highest ever reported for any carbon-based electrode. Tested as a supercapacitor, the carbons exhibited a capacitance of 390 F g−1, with an excellent cycle life (7% loss after 10000 cycles). Such exquisite properties may be attributed to a unique combination of a high specific surface area, partial graphitization and very high bulk nitrogen content. It is a major challenge to derive carbons possessing all three attributes. By templating the structure of mesoporous cellular foam with egg white-derived proteins, we were able to obtain hierarchically mesoporous (pores centered at ∼4 nm and at 20–30 nm) partially graphitized carbons with a surface area of 805.7 m2 g−1 and a bulk N-content of 10.1 wt%. When the best performing sample was heated in Ar to eliminate most of the nitrogen, the Li storage capacity and the specific capacitance dropped to 716 mA h g−1 and 80 F g−1, respectively.
It is necessary for VRLA batteries to be charged quickly in many applications. Four-step tapering current charging is utilized to study quick charging for small VRLA batteries in this paper. With the measurement of charging parameters, such as charging time, water loss, temperature rise, as well as charging efficiency, it is found that the best initial current for quick charging is within 1–1.5CA. Then a few group of batteries are taken to conduct cyclic life testing, also a recovery charging every 30 cycles is adopted since the charging regime is partial state of charging. The result shows that a better lasting life under quick charging regime is achieved compared to that under conventional charging. Thereafter failed batteries have been torndown and analyzed, it is found that favorable connectivity among positive particles and better activity of active material is formed under quick charging regime in comparison to that under conventional charging method through SEM, XRD and other electrochemical analysis. It is also found the failure mode under quick charging regime lies in the accumulation of passivation layer at the grid interface, which results in a higher impedance and eventually capacity deterioration.
A relationship between electrical conductivity (σ) and local structure of 15Li2O·10Fe2O3·xSnO2·(70–x)V2O5·5P2O5 glass (x = 0–20 mol%), abbreviated as xLFSVP glass, was investigated by 57Fe- and 119Sn-Mössbauer spectroscopies, differential thermal analysis (DTA) and dc-four probe method. A small increase in quadrupole splitting (Δ) for FeIII was observed from 0.70 to 0.74± 0.02 mm s − 1 with an increase of “x”, whereas isomer shift (Δ) values of 0.40±0.01 mm s − 1 were independent of “x”. This result suggests that local distortion of FeIIIO4 tetrahedra was slightly increased in SnO2-containing vanadate glasses, which was reflected as an increase in glass transition temperature (Tg) from 266 to 285±5 °C. A slope of 675 K / (mm s − 1) obtained in ‘Tg vs. Δ plot’ proved that FeIII occupied the site of network former (NWF). An isothermal annealing of 10LFSVP glass at 500 °C for 100 min resulted in a marked decrease of Δ from 0.72 to 0.56±0.02 mm s − 1, indicating that local distortion of FeO4 tetrahedra was reduced by the structural relaxation of 3D-network. In contrast, identical δ and Δ values of 0.07±0.01 and 0.53±0.02 mms − 1, respectively, were observed in 119Sn-Mössbauer spectra of 10LFSVP glass before and after the annealing. These results indicate that SnIVO6 octahedra are loosely bound in the glass matrix as a network modifier (NWM). A marked increase in σ from 7.4 × 10 − 7 to 9.1 × 10 − 3 S cm − 1 was observed in 20LFSVP glass after the isothermal annealing, indicating that structural relaxation of 3D-network evidently causes a marked increase in σ.
Na-doped Li3−x Na x V2(PO4)3/C (x =0.00, 0.01, 0.03, and 0.05) compounds have been prepared by using sol–gel method. The Rietveld refinement results indicate that single-phase Li3−x Na x V2(PO4)3/C with monoclinic structure can be obtained. Among three Na-doped samples and the undoped one, Li2.97Na0.03V2(PO4)3/C sample has the highest electronic conductivity of 6.74×10−3 Scm−1. Although the initial specific capacities for all Na-doped samples have no much enhancement at the current rate of 0.2C, both cycle performance and rate capability have been improved. At the 2.0C rate, Li2.97Na0.03V2(PO4)3/C presents the highest initial capacity of 118.9mAhg−1 and 12% capacity loss after 80 cycles. The partial substitution of Li with Na (x =0.03) is favorable for electrochemical rate and cyclic ability due to the enlargement of Li3V2(PO4)3 unit cells, optimizing the particle size and morphology, as well as resulting in a higher electronic conductivity.
LiNi1/3Co1/3Mn1/3O2 was applied as a promising material to the all-solid-state lithium cells using the 80Li2S·19P2S5·1P2O5 (mol%) solid electrolyte. The cell showed the first discharge capacity of 115mAhg−1 at the current density of 0.064mAcm−2 and retained the reversible capacity of 110mAhg−1 after 10 cycles. The interfacial resistance was observed in the impedance spectrum of the all-solid-state cell charged to 4.4V (vs. Li) and the transition metal elements were detected on the solid electrolyte in the vicinity of LiNi1/3Co1/3Mn1/3O2 by the TEM observations with EDX analyses. The electrochemical performance was improved by the coating of LiNi1/3Co1/3Mn1/3O2 particles with Li4Ti5O12 film. The interfacial resistance was decreased and the discharge capacity was increased from 63 to 83mAhg−1 at 1.3mAcm−2 by the coating. The electrochemical performance of LiNi1/3Co1/3Mn1/3O2 was compared with that of LiCoO2, LiMn2O4 and LiNiO2 in the all-solid-state cells. The rate capability of LiNi1/3Co1/3Mn1/3O2 was lower than that of LiCoO2. However, the reversible capacity of LiNi1/3Co1/3Mn1/3O2 at 0.064mAcm−2 was larger than that of LiCoO2, LiMn2O4 and LiNiO2.
The efficiency of perovskite solar cells is approaching that of single-crystalline silicon solar cells despite the presence of a large grain boundary (GB) area in the polycrystalline thin films. Here, by using a combination of nanoscopic and macroscopic level measurements, we show that ion migration in polycrystalline perovskites dominates through GBs. Atomic force microscopy measurements reveal much stronger hysteresis both for photocurrent and dark-current at the GBs than on the grain interiors, which can be explained by faster ion migration at the GBs. The dramatically enhanced ion migration results in the redistribution of ions along the GBs after electric poling, in contrast to the intact grain area. The perovskite single-crystal devices without GBs show negligible current hysteresis and no ion-migration signal. The discovery of dominating ion migration through GBs in perovskites can lead to broad applications in many types of devices including photovoltaics, memristors, and ion batteries.
Spinel nano-sized Li4Ti5O12 anode material of secondary lithium-ion battery has been successfully prepared by solid state reaction using axiolitic TiO2 assembled by 10–20nm nanoparticles and Li2CO3 as precursors. The synthesis condition, grain size effect and corresponding electrochemical performance of the special Li4Ti5O12 have been studied in comparison with those of the normal Li4Ti5O12 originated from commercial TiO2. We also propose the mechanism that using the nano-scaled TiO2 with special structure and unexcess Li2CO3 as precursors can synthesize pure phase nano-sized Li4Ti5O12 at 800°C through solid state reaction. The prepared nano-sized Li4Ti5O12 anode material for Li-ion batteries shows excellent capacity performance with rate capacity of 174.2, 164.0, 157.4, 146.4 and 129.6mAhg−1 at 0.5, 1, 2, 5 and 10C, respectively, and capacity retention of 95.1% after 100 cycles at 1C. In addition, the specific capacity fade for the cell with the different Li4Ti5O12 active materials resulted from the increase of internal resistance after 100 cycles is compared.
A recent Greenpeace US publication, ‘Losing the clean energy race: how the US can retake the lead and solve global warming’ by Janet Sawin, presents an intriguing picture of energy sources in which America may be a major player, but is amazingly, not actually dominant. Similar findings in the past, in high technology niche industries, such as compound semiconductor raw materials, authored by bodies such as the US Department of Defense, and combined with some hefty million dollar contracts, would in the space of a few years, suddenly find US companies overtaking the specialist sector leaders. But here, unless such an authority as the Department of Defense can be persuaded to fling its considerable financial muscle behind renewables, solar for one will be an open market for Asian and European companies to play in and dominate.
A block copolymer polyacrylonitrile-b-polyethylene glycol was synthesized by the macroinitiator method. The copolymer mixed with a plasticizer—propylene carbonate (PC) and LiClO4 to form plasticized polymer electrolytes. FT-IR spectra show that the lithium ion interacts with the groups that contain the un-bonded electrons. The results of FT-IR also indicate that the EO segment can improve the dissociation of lithium salt. The differential scanning calorimeter (DSC) used to study the thermal behaviors of different compositions. In this study, the conductivity increases with the content of PEG. Additionally, the plasticized polymer electrolyte based on the block copolymer has a good conductivity and can retain good mechanical strength.
Shadows are everywhere. Not much engineering use has been found for shadows, and this ubiquitous effect is strenuously avoided in optoelectronic applications. In this work, we present a shadow-effect energy generator (SEG) that scavenges the illumination contrast that arises on the device from shadow castings, and generates a direct current, simply by placing a part of the generator in shadow. The shadow-effect mechanism is experimentally validated by Kelvin Probe Force Microscopy (KPFM). The SEG is capable of harvesting energy from illumination contrasts arising under weak ambient light. Without any optimization, our generator has a power density of 0.14 μW cm−2 under indoor conditions 0.001 sun, where shadows are persistent. Our SEG performs 200% better than that of commercial silicon solar cells under the effects of shadows. The harvested energy from our generator in the presence of shadows arising at a very low intensity (0.0025 sun) can drive an electronic watch (1.2 V). In addition, the SEG can serve as a self-powered sensor for monitoring moving objects by tracking the movement of shadows. With its cost-efficiency, simplicity and stability, our SEG offers a promising architecture to generate green energy from ambient conditions to power electronics, and as a part of a smart sensor systems, especially in buildings.