batterydata/paper-abstracts huggingface dataset:
Porosity effect of carbon materials on the electrochemical performances as cathode materials in non-aqueous Li-oxygen cells has been investigated. A carbon aerogel material is chosen to represent mesoporosity and a couple of activated carbon materials are selected to represent microporosity. Carbon aerogel shows at least ten times higher discharge capacity (4155 mAh g−1) than activated carbons. It is found that as much as 61% of pore volume of carbon aerogel is filled with discharge products (Li2O2) while less than 18% of pore volume is occupied with Li2O2 at the end of discharge in activated carbons, indicating that mesopore is more effective than micropore. In another experiments, the electrolyte impregnated electrode shows a capacitor-like discharge behavior, meaning it is necessary to have some open pore for the oxygen supply even though they are micropores.
Demolition wastes are generally disposed of in unlined landfills for inert waste. However, demolition wastes are not just inert wastes. Indeed, a small fraction of demolition waste contains components that are hazardous to human health and the environment, e.g., lead-based paint, mercury-contained in fluorescent lamps, treated wood, and asbestos. The objective of this study is to evaluate the release potential of pollutants contained in these hazardous components when they are mixed with inert wastes in unlined landfills. After identification of the different building products which can contain hazardous elements and which can be potentially pollutant in landfill scenario, we performed leaching tests using three different lysimeters: one lysimeter containing only inert wastes and two lysimeters containing inert wastes mixed with hazardous demolition wastes. The leachates from these lysimeters were analysed (heavy metals, chlorides, sulphates fluoride, DOC (Dissolved Organic Carbon), phenol index, and PAH). Finally, we compared concentrations and cumulative releases of elements in leachates with the limits values of European regulation for the acceptance of inert wastes at landfill. Results indicate that limit values are exceeded for some elements. We also performed a percolation column test with only demolition hazardous wastes to evaluate the specific contribution of these wastes in the observed releases.
An all-solid-state battery with a lithium metal anode is a strong candidate for surpassing conventional lithium-ion battery capabilities. However, undesirable Li dendrite growth and low Coulombic efficiency impede their practical application. Here we report that a high-performance all-solid-state lithium metal battery with a sulfide electrolyte is enabled by a Ag–C composite anode with no excess Li. We show that the thin Ag–C layer can effectively regulate Li deposition, which leads to a genuinely long electrochemical cyclability. In our full-cell demonstrations, we employed a high-Ni layered oxide cathode with a high specific capacity (>210 mAh g−1) and high areal capacity (>6.8 mAh cm−2) and an argyrodite-type sulfide electrolyte. A warm isostatic pressing technique was also introduced to improve the contact between the electrode and the electrolyte. A prototype pouch cell (0.6 Ah) thus prepared exhibited a high energy density (>900 Wh l−1), stable Coulombic efficiency over 99.8% and long cycle life (1,000 times).
Nickel hydroxide electrodeposition by cathodic reduction of nitrate ions follows an EC (electrochemical reaction followed by an irreversible chemical reaction) mechanism. On subsequent cycling, the electrodeposited nickel hydroxide undergoes a reversible redox reaction.
Energy trading markets are one of the most viable solutions to incentivize prosumers in Microgrids. They offer the utility a versatile access for flexible loads coordination without violating the consumer privacy. In the literature, several models and designs were presented to address different aspects of energy trading markets, yet there is a gap between these models and their application in real-life. This paper describes a novel discrete-timely double-sided auction model that facilitates energy trading between prosumers in near real-time and forward markets. Since the practical realization of the model represents a crucial criterion for this model, the market is designed with fast clearing mechanism and simple bidding rules that guarantee the benefits of the prosumers, their privacy, and consider their personal preferences. Additionally, a decentralized home energy management approach is followed at the prosumer level to maximize the system reliability and enable an easy integration of multiple devices from different manufacturers. Hence, a device-oriented bidding strategy is demonstrated that considers the physical characteristics and technical limitations of each device type such as electric vehicles (EV), micro-combined heat and power systems (micro-CHP) or heat pumps. Furthermore, an open-source day-ahead probabilistic forecast for the photovoltaic systems (PV) is integrated with a bidding scheme that maximizes the prosumers commitment in the forward market. In the results, field measurements and testbeds data are used to quantify the benefits of the market model to the utility and the prosumers based on different metrics such as self-sufficiency, self-consumption, peak load and CO2 emission reduction, and total costs. The results indicate that the market model can increase self-sufficiency and self-consumption of a microgrid while reducing the prosumer costs on average by 23%.
A very simple and rapid method for synthesizing LiFePO4-C composite has been developed by vibrant type ball-milling for 30min and microwave heating for 2–4min. X-ray diffraction and Mössbauer spectroscopy verify that well-crystallized LiFePO4 without Fe3+ impurities is obtained. From laser particle size analysis and transmission electron microscopy, it is confirmed that a LiFePO4-C composite with fine and uniform particle size (mean particle size ≤0.640μm, D75 in volume distribution ≤0.592μm) and with extremely uniform carbon distribution is prepared by vibrant type ball-milling and microwave heating. The LiFePO4-C delivers a high initial discharge capacity of 161mAhg−1 at C/10 and shows very stable cycling behaviour.
The layout of the current collecting tabs is an important design parameter due to their ability to affect current distribution and cell ohm resistance for 18650-type cell. In this work, a simplified 2D radial winding model of 18650 has been established to study the tabs’ layout designs based on the mainstream design where one positive tab is placed in the middle and one negative tab is placed at the outer end. Different layouts of positive and negative tabs have been investigated separately to seek the change of cells’ internal and extrinsic characteristics, so as to find a more applicable tab design to improve the high rate performance of 18650. The modeling results suggest that arranging multi-tabs on the negative electrode has better performance than the positive electrode with multi-tabs based on the mainstream tab design. More specifically, two negative tabs at the opposite ends with one positive tab at the center provide a significant benefit while further increases in the number of either positive or negative tabs contribute to a marginal improvement in voltage and temperature rise. Meanwhile, these modeling results have been well-validated by test results.
The aim of this research is to determine Science and Technology teacher candidate's use of integrated process skills to find a solution to a problem they faced through an example of a simple electrical circuit. Qualitative approach was preferred in this research. The sample of this study is Science and Technology teacher candidates who were attending Ondokuz Mayıs University Faculty of Education's first class in Turkey. The study was carried 78 students in the lesson General Physics II Laboratory as a group of two. The problem “What affects the brightness of the light bulb?” is given to students and they were asked to find solutions to this problem. They were asked to write hypothesis they established in the process of finding solution and variables they determined to the worksheet. The obtained data were analyzed by content analysis. As a result it is emerged that students have difficulty in the process of identifying variables (dependent, independent and controlled variable) which is one of experimental process skills. 4,8% of dependent, 5,6% of independent and 0,8% of controlled variables are correct. The students are more successful on establishing and testing the hypothesis than identifying variables. Established hypothese's 46,4% are correct, 23,2% are deficient and 30,4% are incorrect. 83,2% of designed and conducted experiments are in accordance with the hypothesis. As a result of this research it is concluded that the students do not know the epistemological meanings of variables they used on the experiment process.
This paper proposes a new probabilistic framework based on 2m Point Estimate Method (2m PEM) to consider the uncertainties in the optimal energy management of the Micro Girds (MGs) including different renewable power sources like Photovoltaics (PVs), Wind Turbine (WT), Micro Turbine (MT), Fuel Cell (FC) as well as storage devices. The proposed probabilistic framework requires 2m runs of the deterministic framework to consider the uncertainty of m uncertain variables in the terms of the first three moments of the relevant probability density functions. Therefore, the uncertainty regarding the load demand forecasting error, grid bid changes and WT and PV output power variations are considered concurrently. Investigating the MG problem with uncertainty in a 24 h time interval with several equality and inequality constraints requires a powerful optimization technique which could escape from the local optima as well as premature convergence. Consequently, a novel self adaptive optimization algorithm based on θ-Particle Swarm Optimization (θ-PSO) algorithm is proposed to explore the total search space globally. The θ-PSO algorithm uses the phase angle vectors to update the velocity/position of particles such that faster and more stable convergence is achieved. In addition, the proposed self adaptive modification method consists of three sub-modification methods which will let the particles choosel the modification method which best fits their current situation. The feasibility and satisfying performance of the proposed method is tested on a typical grid-connected MG as the case study.
This article presents a new approach to understanding and using cognitive styles to enhance individual language learning. Ehrman and Leaver (2002). Development of a profile approach to learning style diagnosis. Unpublished manuscript; Ehrman, M.E. (2001). Bringing learning strategies to the learner: the FSI language learning consultation service. In: Alatis, J.E., Tan, A. (Eds.), Language in Our Time: Bilingual Education and Official English, Ebonics and Standard English, Immigration and the Unz Initiative. Washington DC, Georgetown University, pp. 41–58] have established a learner profile schema usable for diagnosis and advising language learners with ten cognitive style dimensions, most of them well-known (e.g., field independence, leveling-sharpening, random-sequential), The model also includes a superordinate construct, called synopsis–ectasis to avoid confusion with earlier names and constructs like ‘global-analytic.’ The article introduces the Ehrman–Leaver Construct and illustrates it with two student cases.
Nitrogen-doped carbon nanofiber webs (N-CNFWs) are prepared by direct pyrolyzation of polypyrrole (PPy) nanofiber webs at 600°C. The structure and morphology of N-CNFWs are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), Raman spectra and elemental analysis. Both the doped N content and the N existing type in carbon, change with the pyrolysis time. As anode material for lithium-ion battery, the N-CNFWs show high capacity and good rate capability. The reversible capacity is up to 668mAhg−1 at a current density of 0.1Ag−1 and 238mAhg−1 at 5Ag−1, which can be ascribed to the nanofiber structure and high nitrogen content.
The aim of this article is focused on a comparative experimental study of the electrochemical feature of as-cast Pb–2.2wt.% Sb alloy with cellular/dendritic transition for applications in the manufacturing of lead-acid battery parts. A water-cooled unidirectional solidification system is used to obtain the alloy samples. Electrochemical impedance spectroscopy (EIS) plots, potentiodynamic polarization curves and equivalent circuit analysis are used to evaluate corrosion resistance in a 0.5M H2SO4 solution at 25°C. The cellular Pb–2.2wt.% Sb alloy is found to have a current density which is of about 3 times lower than that of the dendritic Pb–2.2wt.% Sb alloy. The Pb–2.2wt.% Sb alloy has lower current density than both the Pb–1wt.% Sb and the Pb–6.6wt.% Sb alloys evidencing its potential for application as positive grid material in lead-acid batteries. It is also verified that a conventional casting with low cooling rate of about 0.6°Cs−1 produces coarser cellular spacings which is more appropriate for the manufacturing of the Pb–2.2wt.% Sb alloys grids due to its corresponding electrochemical behavior.
This paper determines a least cost electricity solution for Sub-Saharan Africa (SSA). The power system discussed in this study is hourly resolved and based on 100% Renewable Energy (RE) technologies. Sub-Saharan Africa was subdivided into 16 sub-regions. Four different scenarios were considered involving the setup of a high voltage direct current (HVDC) transmission grid. An integrated scenario that considers water desalination and industrial gas production was also analyzed. This study reveals that RE is sufficient to cover 866.4 TWh estimated electricity demand for 2030 and additional electricity needed to fulfill 319 million m3 of water desalination and 268 TWhLHV of synthetic natural gas demand. Existing hydro dams can be used as virtual batteries for solar PV and wind electricity storage, diminishing the role of other storage technologies. The results for total levelised cost of electricity (LCOE) decreases from 57.8 €/MWh for a highly decentralized to 54.7 €/MWh for a more centralized grid scenario. For the integrated scenario, including water desalination and synthetic natural gas demand, the levelised cost of gas and the levelised cost of water are 113.7 €/MWhLHV and 1.39 €/m3, respectively. A reduction of 6% in total cost and 19% in electricity generation was realized as a result of integrating desalination and power-to-gas sectors into the system. A review of studies on the energy future of Sub-Saharan Africa provides the basis for a detailed discussion of the new results presented.
An accurate State of Charge (SoC) estimation method is one of the most significant and difficult techniques to promote the commercialization of electric vehicles. The paper attempts to make three contributions. (1) Through the recursive least square algorithm based identification method, the parameter of the lumped parameter battery model can be updated at each sampling interval with the real-time measurement of battery current and voltage, which is called the data-driven method. Note that the battery model has been improved with a simple electrochemical equation for describing the open circuit voltage against different aging levels and SoC. (2) Through the real-time updating technique of model parameter, a data-driven based adaptive SoC estimator is established with an adaptive extended Kalman filter. It has the potential to overcome the estimation error against battery degradation and varied operating environments. (3) The approach has been verified by different loading profiles of various health states of Lithium-ion polymer battery (LiPB) cells. The results indicate that the maximum estimation errors of voltage and SoC are less than 1% and 1.5% respectively.
A new design of a redox flow battery (RFB), which is composed of two subcells separated by a gas phase of hydrogen, is proposed to eliminate the crossover of ionic species between the anolyte and catholyte. This idea not only increases the possible combinations of the two electrolytes, but also opens up the prospect of a revival of the old idea of an indirect fuel cell, which is composed of an RFB and two chemical reactors to regenerate the electrolytes using a fuel and oxygen. This paper describes the operation of a subcell as a component of an indirect fuel cell system. In the cycling test, oxidation/reduction of the electroactive species in each electrolyte were repeated with a hydrogen electrode as the counter electrode. This result demonstrates the possibility of this newly proposed RFB without crossover. In the operation of the subcell with a chemical reactor, a molecular catalyst (a rhodium porphyrin) was dissolved in the anolyte, and then a fuel was bubbled in the anolyte reservoir. As the electroactive species was reduced by the fuel, a steady-state oxidation current was observed at the cell. This demonstrates the negative half of the newly proposed indirect fuel cell.
Lithium sulfur (Li-S) batteries are promising candidates to replace lithium ion batteries as the next-generation energy storage devices. However, the operation of conventional Li-S batteries at low electrolyte/sulfur ratios is rather challenging with many obstacles to be addressed. In this work we use solid-state Li2S4 as the cathode active material to construct a new type of Li-Li2S4 battery. With the aid of electrochemical impedance spectrum, we find that the use of Li2S4(S) in the cathode alleviates the issue of surface coverage encountered under the lean electrolyte condition. We also find that the discharge capacity is not determined by the solubility of Li2S4 on the lower plateau of discharge. Consequently, the Li-Li2S4 cell with a high sulfur content of 84% and a low E/S ratio of 4.4 ml g−1 delivered a much higher discharge capacity compared to a conventional Li-S cell. In addition, improved cycle retention was achieved when controlling the Li-Li2S4 cell cycling between Li2S4 and Li2S. We believe that the reported results open a new direction of cathode development for high energy density Li-S batteries.
It is well known that phase separation could severely intensify mechanical degradation and expedite capacity fading in lithium-ion battery electrodes during electrochemical cycling. Experiments have frequently revealed that such degradation effects could be substantially mitigated via reducing the electrode feature size to the nanoscale. The purpose of this work is to present a fracture mechanics study of the phase separating planar electrodes. To this end, a phase field model is utilized to predict how phase separation affects evolution of the solute distribution and stress profile in a planar electrode. Behavior of the preexisting flaws in the electrode in response to the diffusion induced stresses is then examined via computing the time dependent stress intensity factor arising at the tip of flaws during both the insertion and extraction half-cycles. Further, adopting a sharp-interphase approximation of the system, a critical electrode thickness is derived below which the phase separating electrode becomes flaw tolerant. Numerical results of the phase field model are also compared against analytical predictions of the sharp-interphase model. The results are further discussed with reference to the available experiments in the literature. Finally, some of the limitations of the model are cautioned.
The differential discharge curve analysis that separates the discharge curve of battery cells into those of the positive and negative electrodes is useful for investigating deterioration mechanisms. We applied it to LiCoO2/graphite cells and investigated the capacity fading mechanisms during charge/discharge cycles. In the initial state, the discharge curves of the cells were reconstructed very well by the discharge curves of the positive and negative electrodes measured in advance. The discharge curve analysis revealed that the initial cell capacities were controlled by the negative electrodes. On the other hand, the capacity of the positive electrode decreased faster than that of the negative electrode during the course of the cycle test. With repeated charge/discharge cycles, the positive electrodes came to control the cell capacities. After that, deep charge/discharge cycles of the positive electrode accelerated the loss of capacity and the increase of the internal resistance. Furthermore, the rapid increase of the internal resistance lowered the accuracy of the discharge curve analysis. Although the discharge curve analysis was still applicable to the cells that were controlled by the positive electrodes, there were some discrepancies around the endpoints of the discharge curves.
Anatase TiO2 nanoparticles with a specific surface area of 100 m2 g−1 and 300 m2 g−1 have been investigated as negative insertion electrode material for lithium-ion batteries. Galvanostatic intermittent titration (GITT) and electrochemical impedance spectroscopy (EIS) were used to investigate the effect of the specific surface area on the performance of the material. GITT was performed at C/10 rate, followed by an EIS measurement after each relaxation step. Separation of kinetic and thermodynamic contributions to the overpotential of the phase transformation on Li+ (de-)insertion allowed revealing a dependency of both terms on the specific surface area. The material with higher surface area undergoes intrinsic transformation during the initial cycles affecting the thermodynamics of (de-)insertion while the sample with lower surface area shows large and asymmetric kinetic hindrances. For the material with 15 nm particles, Li+ de-insertion appears to have a higher resistance than lithium insertion.
For valve regulated lead acid (VRLA) applications involving deep cycling, significant cycle life improvement can be achieved by applying pressure to the plates via the compressible recombinant battery separator mat (RBSM). However, the latest work is showing that the plate-group pressure needs to be much higher than previously assumed, in order to inhibit positive active material expansion and capacity loss. This will require changes not only to the separator, but also to the battery design and assembly techniques. Techniques to apply very high pressures to the cell group during battery assembly need to be developed. Changes to the container design and materials may also be needed, and the overall battery design may need to include an internal or external means to maintain the applied pressure throughout battery life. Less compressible separators may also enable higher plate-group pressures to be maintained. This paper will review possible strategies to achieve these objectives of maintaining plate-group pressure and extending VRLA battery cycle life.