batterydata/paper-abstracts huggingface dataset:
Present paper focuses on studies of the Co-free La2MgNi9 alloys as active materials of negative electrodes in nickel-metal hydride (NiMH) batteries. The effect of annealing treatment on the phase composition, microstructure, hydrogen absorption–desorption and electrochemical properties was investigated. The phase-structural composition, microstructures and morphologies of the phases were analyzed by X-ray diffraction and by scanning electron microscopy. Increase of the annealing temperature to 950°C leads to a higher abundance of the La2MgNi9 and La3MgNi14 phases and an elimination of the present at lower temperatures LaNi5−x and LaMgNi4 intermetallics. The hydrogen absorption–desorption behaviors, the electrochemical performance and electrochemical cycling stability significantly improve after the annealing. For pasted electrodes, the annealed alloys had a discharge capacity of 350–360mAhg−1 compared to 325mAhg−1 for the as-cast sample. The discharge capacity of the annealed samples remained high, almost 50% after 300 cycles with 100% depth of discharge (DOD) in half-cell tests. Pellet electrodes prepared from the annealed alloy and carbonyl nickel powder showed a discharge capacity of 396mAhg−1. In present work we also report the performance of a small prototype NiMH cell where the annealed alloy was used as the active material in the negative MH electrode and a sintered Ni electrode acted as the positive electrode. After 300 cycles at charge/discharge rates of 0.2C the cell showed a very good cycling stability with its capacity remaining on the level of 87%.
There has been little published research critically examining the mechanical integration of battery systems within either EVs or HEVs. Many of the existing Standards are designed to validate the fail safe function of the battery pack as opposed to assessing the mechanical durability of the complete system. If excessive vehicle warranty claims are to be avoided it is important that engineers tasked with the design of the battery installation properly understand the magnitude and frequency of the vibration inputs that the battery will be exposed too during the vehicle's predicted life. The vibration characteristics of three different commercially available EVs have been experimentally evaluated over a wide range of different road surface conditions. For each vehicle, a durability profile has been sequenced to emulate the vibration energy that the battery pack may be exposed too during a representative 100,000 miles service life. The primary conclusions from the results presented are that the battery packs may well be exposed to vibration loads outside the current evaluation range of existing Standards.
In this work, we introduce a new concept to fabricate on chip, all solid-state and flexible micro-supercapacitors based on MnOx/Au multilayers, which are compatible with current microelectronics. The micro-supercapacitor exhibits a maximum energy density of 1.75 mW h cm−3 and a maximum power density of 3.44 W cm−3, which are both much higher than the values obtained for other solid-state supercapacitors. At a scan rate of 1 V s−1, a volumetric capacitance of 32.8 F cm−3 is obtained for MnOx/Au multilayer electrodes, which is much higher than the bare MnOx electrode. Electrochemical impedance spectroscopy (EIS) and evolution complex capacitance confirm that the electrical conductivity of MnOx is improved due to the incorporation of gold, and a low relaxation time constant around 5 ms is observed. The MnOx/Au multilayer micro-supercapacitor also shows good long-term cycling stability, with a capacitance retention rate of 74.1% after a large cycling number of 15000 times. Compared with other supercapacitors, which are not portable and are relatively bulky, the device demonstrated here allows fast and reliable applications in a portable and smart fashion. Furthermore, the nature of the process allows the micro-supercapacitor to be integrated with other micro-devices, to meet the need for micro-scale energy storage.
The tools of weakly coupled phase oscillator theory have had a profound impact on the neuroscience community, providing insight into a variety of network behaviours ranging from central pattern generation to synchronisation, as well as predicting novel network states such as chimeras. However, there are many instances where this theory is expected to break down, say in the presence of strong coupling, or must be carefully interpreted, as in the presence of stochastic forcing. There are also surprises in the dynamical complexity of the attractors that can robustly appear—for example, heteroclinic network attractors. In this review we present a set of mathematical tools that are suitable for addressing the dynamics of oscillatory neural networks, broadening from a standard phase oscillator perspective to provide a practical framework for further successful applications of mathematics to understanding network dynamics in neuroscience.
Recycling and reusing recyclables is an important way to solve the municipal solid waste (MSW) problem. As the collection of solid waste takes up the largest percentage of MSW management budgets, improving the collection of recyclables is important. Since the decline of government-run waste buying depots in the late 1980s, the collection of recyclables from households and waste deposit sites in China is done by buyers with small informal bases and waste pickers, who are usually unskilled rural people who have come to the cities. Because of this, the current system is seen to have social problems. So, the recyclable collection system has both social as well as economic significance. China is in the process of rapid industrialization and urbanization, and a new mode of community collection system is emerging. It operates by market mechanisms, with waste collection companies that are supported by the municipal government, establishing recycle service sites, and employing workers to buy recyclables door-to-door. This paper is a case study of the new system in the Haidian District, Beijing. It summarizes the system, compares it to experiences in other countries and discusses whether the new approach contributes to resources recycling in China.
Addition of copper trifluoromethanesulphonate (CuTF) to propylene carbonate (PC)-based electrolyte effectively suppresses the cointercalation and decomposition of PC in the mesocarbon microbeads (MCMB) electrodes during the first lithiation process. During the first charging cycle, copper ions are reduced at a higher potential (2V versus Li/Li+) than the potential of PC cointercalation and decomposition (0.6–0.8V versus Li/Li+), and predominately form a porous copper layer over the MCMB surface, thereby obstructing PC to cointercalate. An increase in reversible capacity can be achieved by increasing the amount of CuTF. However, above a critical value, the copper layer inhibits the intercalation of lithium ions and lowers the capacity. The AC impedance data reveal that the passivation film and the charge-transfer resistance are both increased when the deposited copper is in excess. An optimum result may be obtained when the addition is approximately 5wt.%. CuTF is a possibility for PC-based electrolyte additive in lithium-ion batteries.
A higher capacity and better cyclability are apparent when magnesium is introduced into the structure of LiCoO2 (y = 0.15). XRD analysis of LiMg y Co1−y O2 (y = 0, 0.1, 0.15), synthesized at 800 °C using a microwave assisted method, shows that the material is in the R-3m space group and to have a slightly expanded unit cell that increases with greater magnesium doping. Structural analysis by X-ray absorption spectroscopy (XAS) at the Co K-edge, L-edge and O K-edge shows that the magnesium is located in the transition metal layer rather than in the lithium layer and the charge balance results from the formation of oxygen vacancies rather than Co4+, while cobalt remains in the 3+ oxidation state. Interestingly, oxygen is found to participate in the charge compensation. Both magnesium, in the transition metal layer, and the Co-defect structure are attributed to the contribution towards structural stabilization of LiCoO2, thereby resulting in its enhanced electrochemical performance.
Polymer blend electrolytes comprising of poly(vinyl acetate), poly(vinylidene fluoride-co-hexafluoropropylene), LiClO4, and EC-based plasticizer combinations (EC + PC, EC + GBL, EC + DMP, EC + DBP, EC + DEC) are prepared by solvent casting technique. Ionic conductivities of the electrolytes are determined by ac impedance studies in the temperature range 303–363 K. Among the various combinations of plasticizers, EC + PC added complex exhibits maximum ionic conductivity of the order of 10−4 S cm−1 and the temperature-dependent ionic conductivity plots seem to obey the VTF relation. The structural and complex formations of the prepared samples have been confirmed by X-ray diffraction analysis. DSC technique is used to study the thermal behaviour. The surface images of the sample having maximum ionic conductivity are analyzed with the help of SEM and AFM techniques.
An electrochemical cell is a multidisciplinary system which involves complex chemical, electrical, and thermodynamical processes. The primary objective of this paper is to develop a linear graph-theoretical modeling for the dynamic description of electrochemical systems through the representation of the system topologies. After a brief introduction to the topic and a review of linear graphs, an approach to develop linear graphs for electrochemical systems using a circuitry representation is discussed, followed in turn by the use of the branch and chord transformation techniques to generate final dynamic equations governing the system. As an example, the application of linear graph theory to modeling a nickel metal hydride (NiMH) battery will be presented. Results show that not only the number of equations are reduced significantly, but also the linear graph model simulates faster compared to the original lumped parameter model. The approach presented in this paper can be extended to modeling complex systems such as an electric or hybrid electric vehicle where a battery pack is interconnected with other components in many different domains.
Battery thermal barriers are reviewed with regards to extreme fast charging. Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell, the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today's market. Thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.
Individuals with non-central nervous system (CNS) cancers can experience cancer-related cognitive dysfunction (CRCD), negatively impacting daily functioning and quality of life. This systematic review examined cognitive rehabilitation programs aimed at improving cognitive function.
The effect of phosphoric acid in lead acid batteries was studied with potential sweep techniques. Lead–tin (2%) and lead–calcium (0.1%) tin (0.35%) alloys were used as the grids. The influence of phosphoric acid in the presence of tin, calcium and calcium alone on the grid were examined. Phosphoric acid inhibits the formation of β-PbO2 in the alloys.
The cross-linked poly(ether) electrolytes were prepared by the polymerization of a macro-monomer (tri-acryroyl terminated ethyleneoxide–co-propyleneoxide (EO–PO)) containing LiN(CF3SO2)2 for the three different salt concentrations (O/Li=10/1, 20/1 and 30/1). The self-diffusion coefficients (D) of the anions ( 19 F NMR) measured by the pulsed gradient spin-echo (PGSE) NMR method showed the time dependency. The short-range anion diffusion is faster than the long-range diffusion. The accurate measurement of the diffusion for lithium ( 7 Li NMR) was difficult but the lithium diffusion seems slower than that of the anion. The fast hopping motion of lithium ions is correlated to the segment motion of the polymer. The ion conduction is closely related to the anion diffusion in the longer range. The transport number of the lithium ion can also be estimated from the electrochemical measurements.
Understanding ageing mechanisms of Li-ion batteries is essential for further optimizations. To determine performance loss causes, post-mortem analyses are commonly applied. For each type of post-mortem test, different sample preparation protocols are adopted. However, reports on the reliability of these protocols are rare. Herein, Li-ion pouch cells with LiNi1/3Mn1/3Co1/3O2 – polyvinylidene fluoride positive electrode, graphite–carboxymethyl cellulose–styrene rubber negative electrode and LiPF6 – carbonate solvents mixture electrolyte, are opened and electrodes are recovered following a specified protocol. Negative and positive symmetric cells are assembled and their impedances are recorded. A signal analysis is applied to reconstruct the Li-ion pouch cell impedance from the symmetric cells, then comparison against the pouch cell true impedance allows the evaluation of the sample preparation protocols. The results are endorsed by Transmission Electronic Microscopy (TEM) and Gas Chromatography – Mass Spectrometry (GC-MS) analyses. Carbonate solvents used to remove the salt impacts slightly the surface properties of both electrodes. Drying electrodes under vacuum at 25 °C produces an impedance increase, particularly very marked for the positive electrode. Drying at 50 °C under vacuum or/and exposition to the anhydrous room atmosphere is very detrimental.
Objective Studies exploring neurophysiological correlates of main psychiatric disorders have commonly used event-related potentials (ERP) during a visual or an auditory oddball task. The main results concern modulations of the P3b amplitude and/or latency. The present study aims to increase the clinical sensitivity of these P3b modulations by using a more ecological oddball design, using synchronized pairs of audio-visual emotional stimuli. Method Two groups of healthy participants, one composed of controls and the other of students displaying anxious and depressive tendencies completed visual, auditory and audio-visual (cross-modal) oddball tasks, in which they had to detect deviant happy and sad stimuli among neutral ones as quickly as possible. Behavioral performance and P3b ERP data were analyzed. Results Subjects displaying anxious and depressive tendencies exhibited lower P3b amplitude than the controls, but only in the cross-modal oddball task. Conclusions Although the two groups of subjects differed in their levels of co-morbid anxiety and depression, unimodal visual and auditory oddball tasks did not allow us to detect this difference by P3b amplitude modulations, but the cross-modal task did. Significance These results suggest that a cross-modal oddball design should be used in future studies to increase the sensitivity of the P300 amplitude differences between healthy participants and those with clinical symptoms.
Alkaline batteries have been in use for about 100 years. They display excellent life cycle characteristics and are extremely reliable in many industrial applications. This paper gives an overview of new developments at Hoppecke based on fibre structure electrodes in the fields of nickel/cadmium (Ni/Cd) and nickel/metal hydride (Ni/MH) batteries for industrial applications.
Solid-state glass electrolyte, xLi2O–(1− x)(yB2O3–(1− y)P2O5) glasses were prepared with wide range of composition, i.e. x =0.35–0.5 and y =0.17–0.67. This material system is one of the parent compositions for chemically and electrochemically stable solid-state electrolyte applicable to thin film battery. The purpose of this study is to seek the best composition among the various compositions for the deposition of thin film electrolytes. Lithium ion conductivity of Li2O–B2O3–P2O5 glasses was characterized by ac impedance technique. The ionic conductivity of the electrolyte at room temperature increased with x and y. The maximum conductivity of this glass system was 1.6×10−7 Ω−1 cm−1 for 0.45Li2O–0.275B2O3–0.275P2O5 at room temperature. It was shown that the addition of P2O5 reduces the tendency of devitrification and increases the maximum amount of Li2O added into glass former without devitrification.
A membraneless microfluidic fuel cell stack architecture is presented that reuses reactants from one cell to a subsequent one, analogous to PEMFC stacks. On-chip reactant reuse improves fuel utilization and power densities relative to single cells. The reactants flow separately through porous electrodes and interface with a non-reacting and conductive electrolyte which maintains their separation. The reactants remain separated downstream of the interface and are used in subsequent downstream cells. This fuel cell uses porous carbon for electrocatalysts and vanadium redox species as reactants with a sulfuric acid supporting electrolyte. The overall power density of the fuel cell increases with reactant flow rate and decreasing the separating electrolyte flow rate. The peak power, maximum fuel utilization, and efficiency nearly double when electrically connecting the cells in parallel.
Electrochemically active Si0.66Sn0.34 (SiSn) composite alloys dispersed in a carbon (graphite) matrix were synthesized using both wet and dry high-energy mechanical milling (HEMM). The resultant composites are comprised of amorphous carbon (in the case of dry HEMM) or crystalline carbon (in the case of wet HEMM), and crystalline silicon and tin (for both cases) as verified by X-ray diffraction (XRD). The XRD results also indicate the presence of iron–tin intermetallic (FeSn2) arising as a contaminant during dry HEMM. The composite composition of 85C–15[Si0.66Sn0.34] (mol%) resulted in reversible discharge capacities as high as 800mAhg−1 with a reasonable capacity retention (1.36% loss/cycle). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses were further conducted to examine the surface of the electrode and to determine the presence/absence of organic species resulting from reactions between the electrode, lithium ions and electrolyte, respectively.
Phenotypic divergence of eggshells between D. melanogaster and D. simulans strains, was compared, using SEM, for analyzing fitness related eco-physiological traits of the eggshells in the two sibling species. The variations of eggshell traits between strains within species, between species and asymmetry in hybrids of two species have been calculated for understanding the demographic success of the two species. The present results revealed that variation of traits between strains within species was not always same which suggest that many traits are not strongly constrained within species. The main findings show that following eco-physiological traits of eggshells are mostly diverged between two species: (i) dorsal appendages (DA) length, (ii) insertion position of DA in main body of eggshell, (iii) the number and size of respiratory pores in dorsal and ventral side of DA, (iv) average length and volume of eggshells and (v) the thickness of chorionic hexagonal ridges. Examination of interspecific hybrids showed that the traits have undergone considerable genetic changes during evolutionary divergence of the two species. The authors propose that divergent ovipositional preference of the females of two species, may be the driving force in establishing species specific life history parameters for avoiding competition at pre-adult stages and demographic success.
Li3V2(PO4)3/C was prepared as a pristine material by an improved sol-gel method. Then different amounts of CeO2 were employed to modify Li3V2(PO4)3/C cathode materials via a suspension mixing method assisted by polyvinyl alcohol. The 2 wt% CeO2 modified sample (Ce-2) exhibits the best initial charge-discharge performance at −20°C with a specific capacity of 70.4mAhg−1 and 103.3mAhg−1 at 1C in the potential range of 3.0-4.3V and 3.0-4.8V, respectively. The Ce-2 electrode still delivers a stable cycling performance with 95.6 % and 92.7 % capacity retention after 50 cycles even at 5C and at 0°C in the potential range of 3.0-4.3V and 3.0-4.8V, respectively. The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements indicate that the resistance and polarization of Ce-2 at low temperatures are lower than those of any other samples. In addition, the Ce-2 delivers the highest Li-ion diffusion coefficient derived from PSCA measurement, which further verifies that the electrochemical kinetics of Ce-2 is much more active than that of the pristine sample. The excellent low-temperature performances obtained in this work suggest that CeO2-modified Li3V2(PO4)3/C material is a promising cathode candidate for battery applications at low temperature conditions.
Stabilized Lithium Metal Powder (SLMP®) was applied in graphite anode and the effects of this prelithiation method to cell performance were investigated. Performance of prelithiated cells was compared with that of regular graphite based cells. The first cycle capacity loss of SLMP prelithiated cell was largely reduced and the corresponding first cycle Coulombic efficiency was significantly improved. The graphite/NMC cell with SLMP prelithiation but without any standard cell formation process showed better cycle performance than that of none SLMP containing cell with standard formation process. Prelithiation of graphite electrode with SLMP promote stable solid electrolyte interface (SEI) formation on the surface of graphite anode. Application of SLMP in lithium-ion battery thus provides an effective method to enhance capacity, and promises a low cost SEI formation process. This also implies the potential use of other promising anode materials, such as Si and Sn that have large first cycle capacity loss, in commercial lithium-ion batteries.
LiMn2O4 spinel cathode materials were coated with 0.5, 1.0, and 1.5wt.% CeO2 by a polymeric process, followed by calcination at 850°C for 6h in air. The surface-coated LiMn2O4 cathode materials were physically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron microscopy (XPS). XRD patterns of CeO2-coated LiMn2O4 revealed that the coating did not affect the crystal structure or the Fd3m space group of the cathode materials compared to uncoated LiMn2O4. The surface morphology and particle agglomeration were investigated using SEM, TEM image showed a compact coating layer on the surface of the core materials that had average thickness of about 20nm. The XPS data illustrated that the CeO2 completely coated the surface of the LiMn2O4 core cathode materials. The galvanostatic charge and discharge of the uncoated and CeO2-coated LiMn2O4 cathode materials were measured in the potential range of 3.0–4.5V (0.5C rate) at 30°C and 60°C. Among them, the 1.0wt.% of CeO2-coated spinel LiMn2O4 cathode satisfies the structural stability, high reversible capacity and excellent electrochemical performances of rechargeable lithium batteries.
Health service and health outcome data collection across many low- and middle-income countries (LMICs) is, to date largely paper-based. With the development and increased availability of reliable technology, electronic tablets could be used for electronic data collection in such settings. This paper describes our experiences with implementing electronic data collection methods, using electronic tablets, across different settings in four LMICs.