batterydata/paper-abstracts huggingface dataset:
Accurate models of lithium-ion batteries are important for analyzing and predicting battery dynamics and aging. This paper presents an electrochemistry-based impedance model for lithium-ion batteries to better understand the relationship between battery internal dynamics and external measurement. The proposed impedance model is a modified single particle model which balances between simplicity and accuracy. The model includes electrochemical impedance due to charge-transfer reaction, diffusion dynamics in the electrodes, effects of ion concentration, capacitance dispersion in the double layer, and anode insulating film growth, etc. The impedance tests for model validation were performed on two lithium-ion cells at ambient temperature and at different SOC levels. A particle swarm optimization method is employed to identify model parameters. The model accuracy under different conditions is compared with that of conventional Randles model and the parameter variations at different stage of the aging process are studied.
We present herein a diagnostic method which provides insights into the interactions between parasitic reactions at battery electrodes and their consequences for battery performance degradation. We also provide a cautionary tale about misinterpreting or misrepresenting the significance of test data, as is sometimes found in the peer-reviewed literature or in developers' claims. Reversible cycling of the LiNi0.5Mn1.5O4 positive electrode in a full cell with an electrolyte solution containing no additives may appear achievable through tailoring of the operating potential window of the cell. Self-discharging of the negative stems from parasitic oxidation products formed on the positive. We show that either excess negative electrode capacity over the positive or initial pre-lithiation of the negative suppresses their detrimental effect on capacity retention. Simultaneous monitoring the potentials of the two electrodes vs. Li/Li+ during galvanostatic cycling of a full cell shows, however, that self-discharging of the negative still takes place. The latter process was tracked by the drift of the average potential of the cell towards higher values and leads to two characteristic patterns in the failure of full cells during their long-term cycling, depending on whether a cut-off voltage or a capacity limit is used as the control criterion during cycling.
As one of obvious electrolyte design technologies of Li ion batteries (LIBs) to meet durable high-rate capability at elevated temperatures for battery electric vehicles, this study assesses the superiority of gel polymer electrolyte (GPE) based on experimental results supporting its working mechanism. Our previous study indicated that degradation of cathode electrode under high-rate cycling at elevated temperature was a major cause of the decrease in performance of LIBs, and the single full cells (SFCs) with a GPE designed from dipentaerythritol hexaacrylate and methyl ether methacrylate was re-verified to have superior 3.0C cycling performance at 80°C. The superiority of the GPE is studied from comparing mid-voltages of discharge profiles of the SFCs, observing the cross-sectional morphology of the electrodes by field emission scanning electron microscopy, assessing the interacting force among the electrolyte components by thermogravimetric analysis, and examining each resistance component of the SFCs by electrochemical impedance spectroscopy. Gel polymerization of liquid electrolyte results in a significant increase of durable high-rate capability of LIBs due to the mechanisms of not only its buffering effect on solvating process of Li+ ions being extracted from the active materials during high rate operation, but also higher thermal stability of electrolyte components, lower susceptibility of the ionic conductivity of the electrolyte to a temperature change, and lower energy barrier to breakup of solvated structures during conducting of Li+ ions in gel polymer matrix.
Pulse rate is one of the major physiological parameters for monitoring of cardiovascular conditions or excise states during daily life. However it is difficult to precisely measure the exact pulse rates as photoplethysmography (PPG) is easy to be affected by motion artifacts. Instead of using accelerometers followed by algorithms such as least mean square (LMS), recursive least square (RLS) and independent component analysis (ICA) or other equipment such as complex laser systems to measure displacement directly, a novel motion artifact estimation method which had lower computational complexity and higher signal dynamic range was studied and implemented, where a differential channel following green and red light PPG channels was applied to reduce the motion artifact caused by displacement of light emitting diode (LED), photo diode (PD) and tissue deformation before the analog signal was converted to digital form. A miniaturized, battery powered wrist worn artifact-resistive pulse rates monitoring system (PRMS) was presented to verify the proposed method. Four kinds of motions were performed and the results showed that the differential channel improved the morphology of the PPG signal and appeared to be artifact resistive during motions through light intensity control and high gain-phase consistency circuit design here.
Two experiments tested predictions from a theory in which processing load depends on relational complexity (RC), the number of variables related in a single decision. Tasks from six domains (transitivity, hierarchical classification, class inclusion, cardinality, relative-clause sentence comprehension, and hypothesis testing) were administered to children aged 3–8 years. Complexity analyses indicated that the domains entailed ternary relations (three variables). Simpler binary-relation (two variables) items were included for each domain. Thus RC was manipulated with other factors tightly controlled. Results indicated that (i) ternary-relation items were more difficult than comparable binary-relation items, (ii) the RC manipulation was sensitive to age-related changes, (iii) ternary relations were processed at a median age of 5 years, (iv) cross-task correlations were positive, with all tasks loading on a single factor (RC), (v) RC factor scores accounted for 80% (88%) of age-related variance in fluid intelligence (compositionality of sets), (vi) binary- and ternary-relation items formed separate complexity classes, and (vii) the RC approach to defining cognitive complexity is applicable to different content domains.
Ionic liquid gel polymer electrolyte (ILGPE) based on N-methyl-N-butylpiperidinium-bis(trifluoromethanesulfonyl)imide (PP14TFSI), bis(trifluoromethanesulfonyl)imide lithium salt (LiTFSI) and poly(vinylidene difluoride-co-hexafluoropropylene) (P(VdF-HFP)) is prepared for lithium ion batteries by solution casting. The ILGPE is characterized by scanning electron microscopy (SEM), thermogravimetry (TG) and electrochemical tests. The results indicate that the addition of PP14TFSI to the P(VdF-HFP)–LiTFSI polymer electrolyte leads to 3-dimensional network structures, and the ILGPE is stable below 150°C and will not decompose until 310°C without considering the volatilizing of the residual solvent. The ionic conductivity increases with the temperature rising, and the ionic conductivity is 0.23×10−3 Scm−1 and 2.1×10−3 Scm−1 at 20°C and 80°C, respectively. The electrochemical window is −0.15 to 4.85V vs. Li+/Li, which is wide enough to be used with common electrode materials. Battery tests show that the ILGPE is stable even at 80°C when operated in Li/LiFePO4 batteries, and Li/LiFePO4 batteries with the gel polymer electrolyte exhibit good cycling performance at 60°C at 1C current rate. The discharge capacity was 131.01mAhg−1 after 100 cycles with 90% capacity retention.
Light traps are one of the most common attractive method for the collection of nocturnal insects. Although light traps are generally referred to as “CDC light traps”, different models, equipped with incandescent or UV lamps, have been developed. A new light trap, named Laika trap 3.0, equipped with LED lamps and featured with a light and handy design, has been recently proposed into the market. In this study we tested and compared the capture performances of this new trap with those of a classical light trap model under field conditions. From May to November 2013, a Laika trap and a classical light trap were placed biweekly in an area endemic for sand flies. A total of 256 sand fly specimens, belonging to 3 species (Sergentomyia minuta, Phlebotomus perniciosus, Phlebotomus neglectus) were collected during the study period. The Laika trap captured 126 phlebotomine sand flies: P. perniciosus (n=38); S. minuta (n=88), a similar number of specimens (130) and the same species were captured by classical light trap which collected also 3 specimens of P. neglectus. No significant differences in the capture efficiency at each day of trapping, neither in the number of species or in the sex of sand flies were observed. According to results of this study, the Laika trap may be a valid alternative to classical light trap models especially when handy design and low power consumption are key factors in field studies.
XRD, SEM micrographs, BET analyses and typical electrochemical experiments (cyclic voltammetry, step voltammetry and Li insertion/deinsertion at constant current) have been carried out to characterize a new type of soft carbons obtained by pyrolysis of hexaphenylbenzene (HPB). By means of XRD and cyclic voltammetry at least three different type of sites for lithium storage were found. The first is graphite like type with d 002 graphene layer distance greater than pure graphite; the second is associated to disordered volumes among crystallities and the third is represented by Li sites at the hydrogen-terminated edges of hexagonal carbon fragments, characterized by higher energy in comparison with simple insertion sites. These last two types of sites are able to store some extra lithium, compared to pure graphite. BET analyses and cyclic voltammetries demonstrate the key role of the milling time on the characteristics and properties of this HPB pyrolysed carbon. Specific capacities shown by this pyrolysed material in Li coin-type cell have been also reported.
Novel PbO@C composite is synthesized through an optimized mechano-chemical method and used as negative active materials for enhanced performance of lead-carbon battery. Mechanical ball-milling of solid lead acetate, sodium hydroxide and carbon additives (Vulcan-72) would generate uniform composite of lead oxide and carbon (PbO@C) via chemical reactions and mechanical dispersion. The constant mechanical impact and friction during ball-milling leads to lattice distortion and enables intimate connection between Pb and C in the synthesized PbO@C composite, which is proved to be critical for the enhanced battery performance. The specific capacity is higher than battery with direct addition of carbon as additives (126.5 vs. 118.9 mAh g−1), and the cycle performance under high rate partial-state-of-charge duty is also improved. Batteries with the utilization of PbO@C composite accomplished 15119, 11296, 9882, 8336 and 7038 cycles within five consecutive cycle-sets of cycle test, with a decreasing rate of 19.12%, which was drastically lower than battery with direct addition of VC 72 (30.14%). The proposed research provides a promising strategy for feasible synthesis of negative active materials for lead-carbon batteries.
In renewable power systems for remote islands, a significant amount of electricity is curtailed for power balance. This study examines the effect of reducing electricity curtailment on optimal renewable power system design for remote islands. A Mixed-Integer Linear Programming problem for obtaining the optimal design of remote renewable power systems is formulated with an additional constraint which limits the total electricity curtailment. For a parametric study, the problem is solved with various values of electricity curtailment limit, for four cases; two islands - one with a higher and the other with a lower capacity factor of wind turbines - in South Korea, and two renewable power penetrations - 60% and 90% - in the two islands. Variations in the optimal capacities of photovoltaic panels, wind turbines, and batteries for limited total electricity curtailment are examined for every case. Reasons of the variations are explained by an analysis on the temporal operation profiles of the remote renewable power systems. In addition, the appropriate upper limit of total electricity curtailment considering cost increment, normalized by the total electricity demand, is newly suggested as a function of renewable power penetration to guide policy design.
The rate performance of secondary batteries is one of the key factors to push these technologies towards large-scale applications such as hybrid- and all-electric vehicles. Common test procedures, to evaluate the rate capability of novel active materials, electrodes, cells and complete batteries, provide indispensable information but are very time consuming. In the present study, a straightforward and timesaving experimental approach to determine the rate capability of porous insertion electrodes for Li-ion batteries is proposed. The chronoamperometric response of various electrodes with different active materials and design parameters is compared with conventional rate capability tests using a straightforward mathematical conversion approach. The experimental results clearly show that the rate performance can be deduced accurately from the chronoamperometric measurements. The theoretical evaluation of a straightforward equivalent circuit model also indicates an equivalence of the information contained in the conventional rate capability tests and the chronoamperometric response, which supports the experimental findings. The presented approach provides similar information compared to conventional rate capability tests with the benefits of being much more straightforward and significantly faster.
The genotoxic potential of a high purity sample of single-wall carbon nanotubes (SWCNTs) was evaluated using a battery of in vitro and in vivo genotoxicity assays. These comprised a bacterial reverse mutation test (Ames test), an in vitro chromosomal aberration test, and an in vivo mouse bone marrow micronucleus test. The SWCNTs exerted no genotoxicity in Salmonella typhimurium TA97, TA98, TA100, and TA1535, or in Escherichia coli WP2 uvrA/pKM101, whether in the absence or presence of metabolic activation and at concentrations of 12.5–500μg/plate. In the chromosomal aberration test, at 300–1000μg/mL, the SWCNTs did not increase the number of structural or numerical chromosomal aberrations, whether the test was conducted with or without metabolic activation. In the in vivo bone marrow micronucleus test, doses of 60mg/kg and 200mg/kg SWCNTs did not affect the proportions of immature and total erythrocytes, nor did it increase the number of micronuclei in the immature erythrocytes of mice. The results of these studies show that the high purity and well-dispersed sample of SWCNTs are not genotoxic under the conditions of the in vitro bacterial reverse mutation assay, chromosomal aberration assay, or in vivo bone marrow micronucleus test, and thus appear not to pose a genotoxic risk to human health in vivo.
This is the property of earth that at a depth of about 1.5 to 2m, the temperature of ground remains almost constant throughout the year. This constant temperature is called earth’s undisturbed temperature which remains higher than surface temperature of earth in winter season and vice versa in summer. For effective utilization of heat capacity of earth, the earth–air heat exchanger (EAHE) has to be designed. The EAHEs are considered as an effective passive heating/cooling medium for buildings. This is basically a series of metallic, plastic or concrete pipes buried underground at a particular depth through which the fresh atmospheric air flows and gets heated in winter and supplied to the building if at sufficiently high temperature and vice versa in summer. Till date many researchers have carried out a number of studies in designing, modeling and testing of EAHEs systems. This paper reviews on the experimental and analytical studies of EAHE systems around the world but the studies are mainly focused on EAHE systems at the Indian universities as of the end June, 2012.
We report a highly promising electrolyte based on N-allyl-N-methylpiperidinium bis(trifluoromethanesulfonyl) imide (PP13*TFSI) and lithium difluoro(oxalato)borate (LiDFOB) to greatly improve the cycle performance of a Li/Li1.1Ni0.25Mn0.65O2 battery at 2.5 V–4.6 V and 55 °C, which shows an initial discharge capacity of 181.7 mAh g−1 and a capacity retention of 90.9% after 150 cycles. A multiphase bilayer membrane structure is observed, which inhibits the decomposition of carbonate components and structure destruction. Physical characterization demonstrates the chemical interaction between PP13*+ and DFOB−, which prevents the cathode particle from structure degradation at 55 °C under high voltage.
The reliability of automotive batteries is an important factor, especially for the OEM market. To ensure consistent reliability all automotive batteries are subjected to electrical load tests prior to shipment. These tests are performed in accordance with industry accepted standards. It is essential that the energy discharged from the battery during test be minimized to avoid the cost and delay associated with recharge. When defining the ideal high rate discharge test process one must consider these basic requirements. Immediately after formation, and preferably, after post cleaning, batteries are discharged at high current for a few seconds. The voltage under load at the end of test is determined and compared to nominal values resulting in a pass/fail decision. This paper discusses the effectiveness of the present high rate discharge test evaluation criteria in terms of it’s ability to accurately discriminate between acceptable and unacceptable batteries. Variations in materials and manufacturing processes affect open-circuit voltage (OCV) and constant current voltage (CCV) measurements leading to erroneous pass/fail determinations. The paper will illustrate how these variations can be recognized and statistically evaluated. A supplemental evaluation criterion is presented which significantly improves the reliability of test results. This criterion is the gradient ΔV of the discharge curve. Evaluation of test data using this criterion yields information that directly correlates to the failure mode of the rejected battery, including irregularities in pasting and assembly. This paper concludes that the implementation of ΔV criterion significantly improves the failure detection of batteries subjected to production line high-rate discharge tests. Using the ΔV criterion to evaluate the test results is a more accurate determinant of an acceptable battery than the traditional criteria and results in fewer customer returns.
We reported an asymmetric supercapacitor technology where RuO2/TiO2 nanotube composite was used as positive electrode and the activated carbon as negative electrode in 1mol/L KOH electrolyte solution. The electrochemical capacitance performance of the asymmetric supercapacitor was tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge tests. The results show that the asymmetric supercapacitor has electrochemical capacitance performance within potential range 0–1.4V. A power density 1207W/kg was obtained with an energy density of 5.7Wh/kg at a charge–discharge current density of 120mA/cm2. The supercapacitor also exhibits a good cycling performance and keep 90% of initial capacity over 1000 cycles.
Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb2O3 from carbon coated Sb2O3 nanoparticles can accommodate the Sb swelling upon sodiation and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~ 554mAhg−1, good rate capability (315mhAg−1 at 10C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na0.9[Cu0.22Fe0.30Mn0.48]O2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~ 130Whkg−1 (based on the total mass of cathode and anode) in the voltage range of 2.0–4.0V, ~ 1.5 times energy of full-cells with similar design using hard carbon anodes.
Semi-liquid configuration of sulfur cell is proposed as simple strategy to develop high-energy lithium battery. Two solutions of Li2S8 in diethylene glycol dimethyl ether (DEGDME), containing either lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or lithium trifluoromethansulfonate (LiCF3SO3) and lithium nitrate (LiNO3), are studied as catholytes for Li/S cells exploiting the polysulfides electrochemical reaction at about 2.2 V vs. Li+/Li. X-ray photoelectron spectroscopy (XPS) and thermal analyses, respectively, reveal composition and high-temperature stability of the catholyte solutions. Ad hoc study conducted by impedance spectroscopy, voltammetry, and galvanostatic techniques suggests well suitable characteristics in terms of Li+-transport ability, electrochemical stability window, and electrode/electrolyte interphase features. Cells with sulfur loading ranging from about 3 to 6 mg cm−2 into the solution are successfully studied with remarkable performances in terms of current rates, efficiency and cycle life. Hence, the lithium cells based on the catholyte deliver maximum capacity of the order of 1100 mAh gS −1 at C/10 rate and stable capacity of about 800 mAh gS −1 at C/3 rate with Coulombic efficiency exceeding 99%. Therefore, the catholyte solutions studied herein are considered as a very promising candidates for high-energy storage in next generation systems, such as the intriguing hybrid and electric vehicles.
A hybrid anode based on SnS x composited with reduced graphene oxide (RGO) is the most promising alternative material for the next generation lithium-ion batteries. In this work, we synthesized a novel amorphous SnS x /RGO (a-SnS x /RGO) by a facile hydrothermal method. A-SnS x /RGO exhibits an excellent lithium-ion storage capacity. After 100 cycles the discharge and charge capacity are 562.5 and 546.6 mAhg−1 at a current density of 100 mAg−1. It also exhibits a superior rate performance. When the current density increased to 1000 mAg−1 the reversible capacity was 357.8 mAhg−1. This superior lithium-ion storage performance is attributed to the amorphous structure and the existence of RGO. The amorphous structure could reduce the volume change effect during the discharge and charge process. Graphene with high specific surface area acted as the frame in composite material and can reduce lithium ions’ diffusion length and time. What is the most interesting is the existence of strong coupling effect in A-SnS x /RGO which make the interface reaction more faster and more easier. This amorphous material provide a new way for optimizing the cycling stability and improving the rate performance, which is important for the development of high performance electrode materials [1].