batterydata/paper-abstracts huggingface dataset:
For high-voltage cycling of rechargeable Li batteries, a nano-scale amorphous Li-ion conductor, lithium phosphorus oxynitride (Lipon), has been coated on surfaces of LiCoO2 particles by combining a RF-magnetron sputtering technique and mechanical agitation of LiCoO2 powders. LiCoO2 particles coated with 0.36wt% (∼1nm thick) of the amorphous Lipon, retain 90% of their original capacity compared to non-coated cathode materials that retain only 65% of their original capacity after more than 40 cycles in the 3.0–4.4V range with a standard carbonate electrolyte. The reason for the better high-voltage cycling behavior is attributed to reduction in the side reactions that cause increase of the cell resistance during cycling. Further, Lipon coated particles are not damaged, whereas uncoated particles are badly cracked after cycling. Extending the charge of Lipon-coated LiCoO2 to higher voltage enhances the specific capacity, but more importantly the Lipon-coated material is also more stable and tolerant of high voltage excursions. A drawback of Lipon coating, particularly as thicker films are applied to cathode powders, is the increased electronic resistance that reduces the power performance.
On October 2004, a sampling survey was carried out in Florence to estimate urban fine particle exposure concentrations inside commuting vehicles during workdays characterized by heavy traffic. Portable samplers were positioned inside four regularly scheduled diesel-powered buses and four taxis during eight weekdays. Each sampler consisted of a 2.5μm size pre-separator cyclone, a direct-reading data logging photometer (pDR-1200), and a 4Lmin−1 filter sampler for the determination of PM2.5 mass concentration. Based on reflectance analysis measurements, a PM2.5 Black Smoke Index was determined for each filter, and the elemental composition of the PM2.5 was analyzed by Particle Induced X-ray Emission (PIXE). PM2.5 mass concentrations inside the vehicles correlated well with the urban ambient air PM2.5 concentrations measured at the fixed-site monitoring stations. The PM2.5 excess above the urban ambient level was on average 32μgm− 3 (range: 22–52μgm− 3) and 20μgm− 3 (range: 11–29μgm− 3) in buses and taxis, respectively. The PM2.5-bound sulfur concentration was also higher in the buses than in the taxis. Based on daily Time-Microenvironment-Activity-Diary (TMAD) data, the Florentines spend on average 9.7% of their day in traffic, and the corresponding average exposure is approximately 12% of their daily PM2.5 personal exposure. The obtained data could be used to plan interventions to minimize the PM2.5 citizen exposures in commuting.
Ordered nanoporous carbon (ONC) was comprehensively tested for the first time as electrode material in lithium-ion battery. Structure characterization shows the order nanoporous structure and tiny crystallite structure of as-synthesized ONC. The electrochemical properties of this carbon were studied by galvanostatic cycling and cyclic voltammetry. Of special interest is that ONC gave no peak on its positive sweep of the cyclic voltammetry, which was different from other known anode materials. Besides, X-ray photoelectron spectroscopy (XPS) and XRD were also used to investigate the electrochemical characteristics of ONC.
Composite polymer electrolyte (PE) films comprising of thermoplastic polyurethane (TPU) and polyacrylonitrile (PAN) (denoted as TPU–PAN) have been prepared by two different processes. Scanning electron microscope (SEM) of the films reveal the differences in morphology between them. The electrochemical properties of composite electrolyte films incorporating LiClO4–propylene carbonate (PC) were studied. TPU–PAN based gel PE shows high ionic conductivity at room temperature. Thermogravimetric analysis informs that the composite electrolyte possesses good thermal stability with a decomposition temperature higher than 300°C. Electrochemical stability in the working voltage range from 2.5 to 4.5V was evident from cyclic voltammetry. Cycling performances of Li/PE/LiCoO2 cells were also performed to test the suitability of the composite electrolyte in batteries.
Cobalt-free AB5-type hydrogen storage alloys have been examined for the purpose of lowering metal hydride raw material costs. For this purpose, the electrochemical behaviour of cobalt-free LaNi3.55Mn0.4Al0.3Fe0.75 alloy was investigated using chronopotentiometry and electrochemical impedance spectroscopy. It was shown that the discharge capacity decreases by 50% after fifty cycles. To investigate the capacity decrease, the impedance measurements were conducted during charging at different stages of life cycle. The experimental impedance spectroscopy reveals that the metal hydride electrode exhibits a porous behaviour. The results were then analyzed on the basis of equivalent circuit model involving the porous electrode behaviour according to de Levie's model, i.e. equivalent cylindrical pores connected in parallel. The pore texture of electrode material was then estimated namely by the pore number, mean values of cylinder radius and effective length. The loss of discharge capacity is due to that of the reactivity of the electrode material and not the collapsing of pore texture.
The growing need for alternative sources to power Internet of Things and autonomous devices has led to many energy harvesting solutions from ambient energy sources. Use of batteries requires complementary energy source for extending the lifetime of the device. In recent times, triboelectric nanogenerators have gained significant attention in charging applications through ambient energy harvesting field due to their simplicity, efficiency and adaptability to many device configurations in nature. It is deemed to sustainably address power for autonomous smart applications in various environmental conditions. In this work, a state-of-the-art triboelectric nanogenerator based on wind actuated venturi design system is demonstrated in sync with the smart system evolution for powering various sensor nodal network. Using natural wind, the 3D printed wind actuated venturi triboelectric energy harvester converts ambient mechanical energy into electricity. This simple and compact device produces an optimum average power of 1.5 mW and produces a maximum output power density of 2850 mW m−2 (peak power output of 4.5 mW), which is much higher than the existing reports that use larger surface area at higher wind velocity. Extensive material testing and future implementation in an array of applications aid for environment friendly energy production and increase the role of triboelectric nanogenerator in autonomous applications.
Herein, we demonstrate a sustainable strategy for scalable production of α-Fe2O3 nanocrystals on flexible carbon textiles via controllable chemical bath deposition process. The assembly of α-Fe2O3 nanocrystals is densely anchored onto the carbon textiles, and the temperature-dependent mass loading and crystal size of α-Fe2O3 are systematically investigated. As an integrated electrode for lithium-ion batteries, the optimized Fe2O3@CTs with ultrathin three-dimensional interconnected porous architectures achieves significantly enhanced cycling performance and rate capability attributing to the improved stability, electronic interconnection, and shortened solid state diffusion pathway for Li+ ions/electrons. After the reactivation of the precursor, the Li-ion batteries based on the recycled Fe2O3@CTs exhibits electrochemical performance with no decay compared to that of the devices based on the fresh products. This sustainable methodology, considering material abundance, eco-efficiency, synthetic approach and scalability, is of crucial importance to both academy and industry for achieving high-performance lithium-ion batteries.
C-LiFePO4 positive electrode materials were prepared by hydrothermal synthesis in which the solution was stirred with a rotation frequency varying from 50 to 1150 revolutions per minute (rpm), before carbon coating. The different synthesized cathode materials are discussed and compared in terms of structural, surface-morphological and electrochemical properties. The best C-LiFePO4 electrodes have been obtained using rotation frequencies in the range 280–360 rpm, in which case the capacity retention reaches ∼137mAhg−1 at coulombic efficiency >99% at C/12, against 106mAhg−1 in the absence of agitation. Better cycling stability at high current rates (1C) were also obtained. The improved performance of the C-LiFePO4 material obtained by controlled rotating agitation-hydrothermal solution synthesis is attributed to the production of less aggregated particles with high surface area and smaller concentrations of impurities. The controlled rotating agitation of the solution during the synthesis provides a scalable and eco-friendly way of producing better performing electrode particles for use in Li-ion batteries.
In this work the electrochemical characterization of V2O5 electrodes, prepared using polyacrylic acid (PAA) as binder, is presented. The obtained electrodes display stable high capacity values (250 mAh g−1) when cycled at low rates (44 mA g−1), and a reversible capacity of 90 mAh g−1 is obtained at high specific current (3 A g−1). The PAA-based electrodes possess an excellent cycling ability with a capacity retention of 94% after 100 cycles. The present study demonstrate the possibility to overcome the dramatic capacity fading of V2O5 by a simple approach, permitting to obtain electrochemical performance similar to those of more complicated nano-architectures via the use of a greener electrode manufacturing process.
Hard carbon (non-graphitizable) and related materials, like tin, tin oxide, silicon, and silicon oxide, have a high theoretical lithium delivery capacity (>550 mAh/g depending on their structural and chemical properties) but unfortunately they also exhibit a large initial capacity loss (ICL) that overrides the true reversible capacity in a full cell. Overcoming the large ICL of hard carbon in a full-cell lithium-ion battery (LIB) necessitates a new strategy wherein a sacrificial lithium source additive, such as, Li5FeO4 (LFO), is inserted on the cathode side. Full batteries using hard carbon coupled with LFO-LiCoO2 (LCO) are currently under development at our laboratory. We find that the reversible capacity of a cathode containing LFO can be increased by 14%. Furthermore, the cycle performance of full cells with LFO additive is improved from <90% to >95%. We show that the LFO additive not only can address the irreversible capacity loss of the anode, but can also provide the additional lithium ion source required to mitigate the lithium loss caused by side reactions. In addition, we have explored the possibility to achieve higher capacity with hard carbon, whereby the energy density of full cells can be increased from ca. 300 Wh/kg to >400 Wh/kg.
Highly efficient bifunctional oxygen electrocatalysts are indispensable for the development of highly efficient regenerative fuel cells and rechargeable metal-air batteries, which could power future electric vehicles. Although perovskite oxides are known to have high intrinsic activity, large particle sizes rendered from traditional synthesis routes limit their practical use due to low mass activity. We report the synthesis of nano-sized perovskite particles with a nominal composition of Lax(Ba0.5Sr0.5)1−xCo0.8Fe0.2O3−δ (BSCF), where lanthanum concentration and calcination temperature were controlled to influence oxide defect chemistry and particle growth. This approach produced bifunctional perovskite electrocatalysts ∼50 nm in size with supreme activity and stability for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The electrocatalysts preferentially reduced oxygen to water (<5% peroxide yield), exhibited more than 20 times higher gravimetric activity (A g−1) than IrO2 in OER half-cell tests (0.1 M KOH), and surpassed the charge/discharge performance of Pt/C (20 wt%) in zinc-air full cell tests (6 M KOH). Our work provides a general strategy for designing perovskite oxides as inexpensive, stable and highly active bifunctional electrocatalysts for future electrochemical energy storage and conversion devices.
Li1.5V3O8 nanosheets as a cathode material for high-rate lithium-ion batteries are prepared by sol–gel method. SEM and TEM observations show that the prepared samples are nanosheet structure, with a typical width of 600 nm and length of 800 nm. Charge–discharge measurements demonstrate that Li1.5V3O8 nanosheets exhibit high initial discharge specific capacity of 260, 204 mAh g− 1 at current densities of 130 mA g− 1 and 175 mA g− 1, respectively. Even after 100 cycles, the discharge specific capacity still remains 170 mAh g− 1 and 100 mAh g− 1. The high discharge specific capacity and good cycling stability are attributed to nanosheets morphology of Li1.5V3O8 that can provide lithium ions with more sites, shorten diffusion distance, and maintain good contact between the active material and electrolyte. All these results indicate that Li1.5V3O8 nanosheets are promising cathode materials for lithium-ion batteries.
While Lithium-ion batteries have the potential to serve as an excellent means of energy storage, they suffer from several operational safety concerns. Temperature excursion beyond a specified limit for a Lithium-ion battery triggers a sequence of decomposition and release, which can preclude thermal runaway events and catastrophic failure. To optimize liquid or air-based convective cooling approaches, it is important to accurately model the thermal response of Lithium-ion cells to convective cooling, particularly in high-rate discharge applications where significant heat generation is expected. This paper presents closed-form analytical solutions for the steady-state temperature profile in a convectively cooled cylindrical Lithium-ion cell. These models account for the strongly anisotropic thermal conductivity of cylindrical Lithium-ion batteries due to the spirally wound electrode assembly. Model results are in excellent agreement with experimentally measured temperature rise in a thermal test cell. Results indicate that improvements in radial thermal conductivity and axial convective heat transfer coefficient may result in significant peak temperature reduction. Battery sizing optimization using the analytical model is discussed, indicating the dependence of thermal performance of the cell on its size and aspect ratio. Results presented in this paper may aid in accurate thermal design and thermal management of Lithium-ion batteries.
Utilizing an existing macro-homogeneous porous electrode model developed by John Newman, this paper aims to explore the potential energy density gains which can be realized in lithium-ion battery electrodes fabricated with co-extrusion printing technology. This paper conducts an analysis on two-dimensional electrode cross-sections and presents the electrochemical performance results, including calculated volumetric energy capacity for a general class of lithium cobalt oxide (LiCoO2) co-extruded cathodes, in the presence of a lithium metal anode, polymer separator and liquid ethylene carbonate, propylene carbonate, and dimethyl carbonate (EC:PC:DMC) electrolyte. The impact of structured electrodes on cell performance is investigated by varying the physical distribution of a fixed amount of cathode mass over a space of dimensions which can be fabricated by co-extrusion. By systematically varying the thickness and aspect ratio of the electrode structures, we present an optimal subset of geometries and design rules for co-extruded geometries. Modeling results demonstrate that ultra-thick LiCoO2 electrodes, on the order of 150–300 μm, can garner a substantial improvement in material utilization and in turn capacity through electrolyte channels and fine width electrode pillars which are 25–100 μm wide.
Engineered ultrafine porous Fe2SiO4/C composites (FS221/C, FS263/C and FS325/C) are successfully fabricated by solid state reactions from the mixture of ammonium citrate, ferrous oxalate dehydrate and nano porous SiO2 with different specific surface area (221, 263 and 325m2 g−1). XRD results proved that α-Fe2SiO4 phase are formed in the three samples. SEM and TEM results indicate that all the three samples are ultrafine composites and the particle size of FS325/C is the smallest. Pore structure analysis indicates that the external surface area of the ultrafine porous Fe2SiO4/C composites can be well controlled by tuning the surface area of nano porous SiO2 and the external surface area of FS325/C is the largest among the three samples. These unique features make FS325/C possess the highest reversible lithium storage capacity, best rate performance, longest cycling life, lowest charge transfer resistance and highest lithium ion diffusion coefficient among the three samples.
The potential reuse of lithium-ion batteries exhausted upon electric vehicle operation is a broadly discussed topic. However, a profound understanding of battery aging behavior is a prerequisite to assess overall system cost and economic benefit of battery reuse: Whereas the capacity fade under load is commonly reported to show a linear dependency on charge throughput, a turning point to nonlinear aging characteristics is observed at residual capacities of about 80% under different operational conditions. Based on a widespread aging matrix, results indicate an earlier appearance of nonlinear characteristics at high charging rates and operational voltage windows but low temperatures. Scanning electron microscopy images reveal areas of thick surface films at the anode while the cathode stays unmodified. Therefore, a thickening of the solid electrolyte interphase, catalyzed by oxidation products migrating to the anode, is believed to be the dominating aging mechanism before the turning point. Afterwards, lithium plating might even occur at moderate temperatures and charging rates due to deteriorated ionic kinetics and graphite active material loss. As all these mechanisms are dependent on the cell potential, an optimized operational strategy may avoid or retard nonlinear aging characteristics and extend the life of lithium-ion cells.
One new ether-functionalized ionic liquid (IL) composed of pyrazolium cation with one 2-ethoxyethyl group and bis(trifluoromethylsulfonyl)imide anion was synthesized and characterized. The IL showed the lowest viscosity among all the reported pyrazolium ILs, and the value was 38.9 mPa s at room temperature. The conductivity of the IL was 3.48 mS cm−1 at 25 °C, and its electrochemical window was 4.4 V. Cycling performance of symmetric lithium cell was investigated for the IL electrolyte with 0.6 mol kg−1 of LiTFSI. Li/LiMn2O4 cell using the IL electrolyte owned good cycling and rate performances, and it was found for the first time that LiMn2O4 cathode was compatible with electrolyte based on ether-functionalized IL. By the characterizations of X-ray diffraction and scanning electron microscopy for fresh and cycled LiMn2O4 electrodes, it was inferred that the slow dissolution of LiMn2O4 in the IL electrolyte might happen during the charge–discharge processes.
During the operation of proton exchange membrane (PEM) fuel cell, water is easy to accumulate in the anode side, particularly if the fuel cell system is being controlled in ‘dead ended’ mode. The hydrogen purge operation prevents the anode being jammed by excessive water. It is observed that the voltage experiences a recovery and linear degradation after the hydrogen purge operation. In this paper an empirical dynamic voltage model for PEM fuel cell stack is introduced based on the result of experimental investigation. Compared with previous model, the suggested model indicates a better agreement between test and simulation, especially when the effect of hydrogen purge operation is obvious.
In situ high energy X-ray diffraction (HEXRD) and in situ X-ray absorption near edge spectroscopy (XANES) were carried out to understand the solid state synthesis of NaxMnO2, with particular interest on the synthesis of P2 type Na2/3MnO2. It was found that there were multi intermediate phases formed before NaMnO2 appeared at about 600 °C. And the final product after cooling process is a combination of O′3 NaMnO2 with P2 Na2/3MnO2. A P2 type Na2/3MnO2 was synthesized at reduced temperature (600 °C). The influence of Na2CO3 impurity on the electrochemical performance of P2 Na2/3MnO2 was thoroughly investigated in our work. It was found that the content of Na2CO3 can be reduced by optimizing Na2CO3/MnCO3 ratio during the solid state reaction or other post treatment such as washing with water. We expected our results could provide a good guide for future development of high performance cathode materials for sodium-ion batteries.
A discotic liquid crystal triblock copolymer consisting of a central main chain triphenylene-based liquid crystal block capped at both ends by blocks of poly(ethylene oxide) (PEO) (M W =2000gmol−1) has been doped with lithium perchlorate in an EO:Li 6:1 ratio. The polymer electrolyte exhibits a phase separated morphology consisting of a columnar hexagonal liquid crystal phase and PEO-rich regions. The polymer electrolyte forms self-supporting, solid-like films. The ionic conductivity on initial heating of the sample is very low below ca. 60°C but increases rapidly above this temperature. This is attributed to the melting of crystalline PEO-rich regions. Crystallisation is suppressed on cooling, and subsequent heating cycles exhibit higher conductivities but still less than those measured for the corresponding lithium perchlorate complex in poly(ethylene glycol) (M W =2000gmol−1). Instead the triblock copolymer mimics the behaviour of high molecular weight poly(ethylene oxide) (M W =300,000gmol−1). This is attributed, in part, to the anchoring of the short PEG chains to the liquid crystal block which prevents their diffusion through the sample. Temperature and pressure variations in ion mobility indicate that the ion transport mechanism in the new material is closely related to that in the conventional PEO-based electrolyte, opening up the possibility of engineering enhanced conductivities in future.
Objective The Screen for Cognitive Impairment in Psychiatry (SCIP) is a brief scale designed for detecting cognitive deficits in several psychotic and affective disorders. This study examined the psychometric properties of the Spanish version of the SCIP in a sample of outpatients suffering schizophrenia-spectrum disorders. Methods Psychometric properties were evaluated in a sample of 126 stable patients with schizophrenia. Men and women 18 to 55 years of age were recruited from consecutive admissions to 40 psychiatric outpatient clinics in Spain and asked to complete a series of cognitive measures at baseline, as well as three versions of the SCIP separated by one week intervals. A matched sample of 39 healthy controls was also subjected to the baseline examination. The feasibility, reliability and validity of the SCIP was examined; concurrent validity was assessed by means of a complete neuropsychological battery. Results Average time for SCIP administration was 16.02 (SD=5.01) minutes. Test–retest reliability intra-class correlation coefficients ranged from 0.74 to 0.90, with an internal consistency Cronbach's alpha value of 0.73. The three parallel forms of SCIP were shown to be equivalent. The SCIP scales were correlated with corresponding neuropsychological instruments, with Pearson's r between 0.38 and 0.60, p <0.01. The SCIP effectively discriminated between the patient and control samples. Factor analysis revealed one significant dimension, cognitive performance, that accounted for 49.8% of the total variance. Conclusions The Spanish version of the SCIP is a simple, brief, valid and reliable tool for detection of cognitive impairment in patients with schizophrenia by minimally trained healthcare personnel.