batterydata/paper-abstracts huggingface dataset:
In this work multi-scale homogenization approaches for porous electrodes are developed and compared. The results are used for the simulation of mass transport, and charge transfer processes at different active material loadings in various power sources, such as batteries, fuel cells and supercapacitors. A general pore-scale model is developed by mimicking the layer fabrication process. Electrode structures are virtually generated taking into account the interaction between the deposited particles during layer formation and surface relaxation. The effective transport and kinetic coefficients of the layers are calculated by different homogenization approaches and used in macro homogeneous models to predict macroscopic behaviour of fuel cells, supercapacitors and Li-ion batteries. The model predictions are compared with experimental kinetic and transport coefficients of fuel cells and supercapacitors and a good agreement was found. The results imply that porosity, tortuosity and specific surface area may follow a power law scaling with increasing deposited mass as a consequence of agglomeration during layer deposition. Consequently, effective transport and kinetic coefficients depend on the active material loading of the electrode.
In this work, α-Co(OH)2 is electrodeposited onto carbon nanofoam forming a composite electrode operating in a potential window of 2 V in aqueous medium. Prior to electrodeposition, the carbon nanofoam substrate is subjected to a functionalization process, which leads to an increase of about 40% in its specific capacitance value. Formation of cobalt hydroxide clusters onto the functionalized carbon nanofoam by pulse electrodeposition further enhances the specific capacitance of the electrode. The combination of these factors with an enlarged working potential window, results in a material with specific capacitance close to 300 F g−1 at current density of 1 A g−1, considering the total mass loading of the composite. This suggests the potential application of the prepared composites in high energy density electrochemical supercapacitors.
This paper deals with occurrence of lithium plating on the negative electrode of lithium-ion batteries, a significant ageing phenomenon known to damage lithium-ion battery performances. Charge transfer process, one of the two different steps of the process of Li insertion in the negative active material being the cause of this ageing, was considered here to be the limiting process. This transfer occurs at short-time scales. The second process, the diffusion of lithium in the solid insertion compound, occurring at relatively long-time scales, has not been fully examined here. The aim of this paper was to develop a new method to evaluate the maximal rate of a charge pulse solicitation to prevent this ageing phenomenon. The approach relies on the use of a fundamental model of lithium ion battery with coupled mass and charge transfer. To validate the method, 2 s microcycles have been performed on a commercial VL41M SAFT cell. Theoretical and experimental works led to the maximum current density to be applied without undesired Li deposition, depending on the state of charge (SOC). The abacus established for the cell of interest can orient further specifications for suitable use of the battery.
A series of polymer-clay nanocomposites have been synthesized, characterized, and electrochemically tested as possible candidates for polymer electrolytes in lithium ion cells. Only cations are mobile in these materials, rather than both cations and anions, leading to a higher conductivity. The nanocomposites are based on synthetic lithium hectorite (SLH) and different mass ratios of polyethylene oxide (PEO). Transparent films with excellent mechanical strength are obtained with conductivity that is comparable to more traditional polymer electrolytes made with added lithium salts.
A series of LiMgxMn2-xO4 (x ≤ 0.20) cathode materials were rapidly synthesized at a low temperature of 500°C for 1h by a solid-state combustion process. The morphologies and crystal structures of LiMgxMn2-xO4 were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. All LiMgxMn2-xO4 samples exhibited a single phase LiMn2O4 spinel structure with good crystallinity. The linear decrease of the lattice parameters with the increase of Mg-doping content could suggest that Mg2+ ions had put into the spinel LiMn2O4 lattice substituting for Mn3+. The effect of Mg2+ ions on the electrochemical performance of LiMgxMn2-xO4 was investigated by galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the Mg-doped LiMn2O4 possessed better cycling stability, for example, a capacity retention of 93.2% for LiMg0.08Mn1.92O4 after 150 cycles at 0.2C.
Cell inconsistency is inevitable due to manufacturing constraint. Therefore, cell equalization is essentially required. In this paper, we propose a novel active equalization method based on the remaining capacity of cells which is feasible for lithium-ion battery packs in electric vehicles (EVs). The cell models are established based on a combined electrochemical model of lithium-ion batteries. The remaining capacity and state-of-charge (SOC) of cells are observed at the beginning of equalization. The particle filter (PF) method is employed to estimate the cell SOCs during equalization in order to eliminate the drift noise of the current sensor. The first high-SOC cell discharge (FHCD) and first low-SOC cell charge (FLCC) equalization algorithms are proposed and compared with 1% and 3% SOC bounds, respectively. The validation experiment results have shown that the proposed algorithm is suitable for equalization of lithium-ion batteries in EVs.
Li[Ni0.8Co0.15Al0.05]O2 particles are modified with AlF3 as a new coating material. Even though the initial discharge capacity of the coated Li[Ni0.8Co0.15Al0.05]O2 is almost the same as that of the pristine material, the capacity retention and the thermal stability, in a highly oxidized state are both significantly improved. This effect is attributed to the thin AlF3 coating layer protecting the oxidized cathode particles from attack by hydrogen fluoride in the electrolyte.
The use of renewable forms of energy is important throughout the world, not just in countries where there are concerns over the availability of fossil fuels. In order to develop and promote suitable energy policies for the future it is necessary to gain an understanding of stakeholder views in all countries, including those with substantial fossil fuel reserves. The volume of construction work in the Gulf Cooperation Council (GCC) countries has recently been at unprecedented levels, with a huge environmental impact from construction and also from potential future energy demands. The aim of this paper is to assess the potential to exploit use of a particular, but valuable, renewable energy option: building-integrated photovoltaics (BIPV) in those countries. Such exploitation could offset, at least in some part, the future environmental burdens. A large-scale survey, followed by a number of in-depth interviews, has been undertaken in order to examine the use of BIPV. Empirical research findings are presented, and then analysed in order to determine the current viability of a large-scale expansion of BIPV in the GCC region. The research indicates that the main factors hindering expansion are high costs and the negative public perception of BIPV in the countries concerned. Proposals are therefore provided to assist the development of suitable policies and the wider introduction of viable BIPV in the GCC markets.
A numerical model for cylindrical wound lithium-ion cells, which resolves thermal, electrical and electrochemical coupled physics, is presented in this paper. Using the Multi-Scale Multi-Domain (MSMD) model framework, the wound potential-pair continuum (WPPC) model is developed as a cell domain submodel to solve heat and electron transfer across the length scale of cell dimension. By defining the cell composite as a wound continuum, the WPPC model can evaluate layer-to-layer differences in electrical potential along current collectors, and electric current in the winding direction to investigate the effects of thermal and electrical configurations of a cell design, such as number and location of tabs, on performance and life of a cylindrical cell. In this study, 20-Ah large-format cylindrical cell simulations are conducted using the WPPC model with the number of electrical tabs as a control parameter to investigate how macroscopic design for electrical current transport affects microscopic electrochemical processes and apparent electrical and thermal output.
Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants, but the mechanisms by which they influence behavior are only partially resolved. Using a combination of different approaches, the authors demonstrate that serotonin 1A receptors expressed in mature dentate gyrus granule cells are critical mediators of the response to SSRIs.
Lithium-air batteries show a great promise in electrochemical energy storage with their theoretical specific energy comparable to gasoline. Discharge products such as Li2O2 or Li2CO3 are insoluble in several major nonaqueous electrolytes, and consequently precipitate at the reaction sites. These materials are also low in electric conductivity. As a result, the reduced pore space and electrode passiviation increase the reaction resistance and consequently reduce discharge voltage and capability. This work presents a modeling study of discharge product precipitation and effects for lithium-air batteries. Theoretical analysis is also performed to evaluate the variations of important quantities including temperature, species concentrations, and electric potentials. Precipitation growth modes on planar, cylindrical and spherical surfaces are discussed. A new approach, following the study of ice formation in PEM fuel cells, is proposed. Validation is carried out against experimental data in terms of discharge voltage loss.
This study presents a new method of PEMFC characterisation carried out experimentally on a self-breathing fuel cell from PaxiTech® (25 cm2 electrode surface area). First, dc and ac measurements were performed on this cell on the basis of models originally dedicated to a Gas Diffusion Cathode. Electrochemical Impedance Spectroscopy (EIS) measurements were performed to characterise the general electrical behaviour of the cell. This technique is of particular interest for improving our understanding of mass transport limitations in PEMFCs. Second, current and temperature distributions over the fuel cell area were determined. Measurements of the locally induced magnetic field and the temperature then provided an indirect evaluation of the current densities in the fuel cell. Both methods were used to determine heterogeneous current density distributions and showed that the highest current densities were close to the current collectors.
In this paper, a six-cell microfluidic fuel cell (MFC) stack is demonstrated. Low-cost aluminum is fed directly to the stack, which produces hydrogen fuel on site, through the Al-H2O reaction. This design is not only cost-efficient, but also eliminates the need for hydrogen storage. Unlike the conventional MFC stacks which generally require complex electrolyte distribution and management, the present Al-feed MFC stack requires only a single electrolyte stream, flowing successively through individual cells, which is finally utilized for hydrogen generation. In this manner, the whole system is greatly simplified while the operational robustness is also improved. With 2 M sodium hydroxide solution as electrolyte and kitchen foil Al as fuel, the present six-cell stack (in series) exhibits an open circuit voltage of nearly 6 V and a peak power density of 180.6 mWcm−2 at room temperature. In addition, an energy density of 1 Whg−1(Al) is achieved, which is quite high and comparable with its proton exchange membrane-based counterparts. Finally, pumpless operation of the present stack, together with its practical applications are successfully demonstrated, including lightening LED lights, driving an electric fan, and cell phone charging.
Porous carbon-rich SiOC ceramic aerogels have been synthesized from a linear polysiloxane cross-linked with divinylbenzene (DVB) via hydrosilylation reaction in presence of a Pt catalyst and acetone as a solvent. The obtained wet gels are aged in solvent followed by drying under supercritical conditions using liquid carbon dioxide. The resulting pre-ceramic aerogels are subjected to pyrolysis at 1000°C under controlled argon atmosphere to form the desired SiOC aerogel. The synthesized SiOC ceramics contain 43wt% of free carbon, which is segregated within amorphous SiOC matrix. The high BET surface area up to 230m2g−1 of preceramic aerogels is only slightly diminished to 180m2g−1 after pyrolysis at 1000°C. The electrochemical characterization reveals a high specific capacity of more than 600mAhg−1 at a charging rate of C (360mAg−1) along with a good cycling stability. At a rate of 10C (3600mAg−1) the specific capacities as high as 200mAhg−1 are recovered. The excellent properties of the materials are discussed with respect to their structural features. The porous nature of the carbon rich ceramics allows for fast ionic transport and helps to accommodate the structural changes which in turn allow a stable performance during repeated lithiation/delithiation.
Treatment and disposal of sewage sludge is still a worldwide challenging problem. Improper sludge treatment results in severe environmental impact and endangering public health. Moreover, sewage sludge disposal is a cost-intensive process. Therefore, pathogen removal and solid reduction are indispensable for sludge disposal management. In this study, a novel electrochemical method in alkaline media was developed to break down the sludge structure at room temperature. A reduction of 24.85% in total solids and 46.42% in volatile solids was achieved, which represents approximately a 25% reduction in the sludge disposal cost when compared to conventional treatment methods. Also, a 90% reduction in energy consumption was demonstrated when compared to other electrochemical methods. The post-processed samples characterization showed that a large quantity of organic material was released from the sludge samples into the liquid phase, which indicates the potential to reduce the residence time in anaerobic digesters and to generate more biogas. The proposed treatment demonstrated the feasibility of pathogen removal and biosolid production for safe landfilling or agriculture applications such as fertilizers.
The availability of noise maps to assess exposure to noise is often limited, especially in North American cities. We developed land use regression (LUR) models for LAeq24h, Lnight, and Lden to assess the long-term spatial variability of environmental noise levels in Montreal, Canada, considering various transportation noise sources (road, rail, and air). To explore the effects of sampling duration, we compared our LAeq24h levels that were computed over at least five complete contiguous days of measurements to shorter sampling periods (20 min and 24 h). LUR models were built with General Additive Models using continuous 2-min noise measurements from 204 sites. Model performance (adjusted R2) was 0.68, 0.59, and 0.69 for LAeq24h, Lnight, and Lden, respectively. Main predictors of measured noise levels were road-traffic and vegetation variables. Twenty-minute non-rush hour measurements corresponded well with LAeq24h levels computed over 5 days at road-traffic sites (bias: −0.7 dB(A)), but not at rail (−2.1 dB(A)) nor at air (−2.2 dB(A)) sites. Our study provides important insights into the spatial variation of environmental noise levels in a Canadian city. To assess long-term noise levels, sampling strategies should be stratified by noise sources and preferably should include 1 week of measurements at locations exposed to rail and aircraft noise.
The Sn–O–C composite anode for the Li secondary battery was synthesized by electrodeposition using an organic carbonate solvent. The composite of Sn with organic/inorganic compounds was prepared by the simultaneous reaction of the reduction of Sn2+ ions and electrolysis of the mixture of ethylene carbonate and propylene carbonate. The galvanostatic potential transients for the electrodeposition of the Sn–O–C composite indicate that multiple steps of reactions corresponding to the electrochemical reduction of the tin precursor and the decomposition of organic solvents are involved. The morphology, crystalline structure and chemical composition of the as-deposited Sn–O–C composite anode were characterized to elucidate the mechanism of the synthesis of the buffering matrix enduring volume expansion. The electrochemical behavior of the Sn–O–C composite anode was investigated by cyclic voltammetry and galvanostatical charge/discharged tests. The discharge capacity of 465 mAh (g of Sn)−1 was obtained at the 100th cycle showing 80% of the capacity retention after the 100th cycle. The discharge capacity was stable after the 50th cycle, where the phase transformation of the Sn element from Sn to Li0.4Sn at the discharged state was found.
The electrodeposition of rhenium and rhenium oxides from an alkaline aqueous solution containing 0.125moldm−3 NH4ReO4 +0.01moldm−3 NaOH (pH 13.3±0.1) has been studied. Cyclic voltammetry studies were carried out using two electrodes, polycrystalline platinum and polycrystalline gold, and the galvanostatic electrodeposition was conducted on a pure copper electrode (99.9%). Information regarding rhenium electrodeposits has been obtained by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results in an alkaline aqueous electrolyte suggest that the electrocrystallization process follows a multi-step mechanism influenced by hydrogen adsorption. The main conclusion was that rhenium, rhenium (IV) oxide and rhenium (VI) oxide coexist in the electrodeposited material.
Phytases are widely used as feed additives for monogastric animals, which cannot easily utilise the phosphorus bound in phytate (myo-inositol hexakisphosphate). The current study presents a safety evaluation of a 6-phytase produced by an Aspergillus oryzae strain expressing two synthetic genes, both mimicking a phytase gene from a Citrobacter braakii strain. Oral administration of the phytase preparation to rats at a dose level of 0.86g total organic solids/kg body weight/day for 13weeks did not cause any adverse effect. The phytase preparation did not exhibit irritative potential when applied locally to the eyes of rabbits or when applied to the skin using the in vitro three-dimensional epidermis model of adult human-derived epidermal keratinocytes. Furthermore, the phytase preparation was found not to represent mutagenic or clastogenic potential in the bacterial reverse mutation assay and in the in vitro micronucleus assays. Based on the toxicological data, the large safety factors calculated under common recommended dose assumptions for broiler chickens and weaned piglets, and the fact that Aspergillus oryzae is considered a safe strain lineage, it is concluded that there are no reasons for safety concerns when using this phytase as a feed additive.
Researchers in Australia at the University of Adelaide have developed a process for turning waste plastic bags into a high-tech nano-material. This nanotechnology uses non-biodegradable plastic grocery bags to make carbon nanotube membranes that have a variety of applications, including filtration, sensing and energy storage.
Electrochemical reduction of oxygen (O2) in air electrode with manganese oxides (MnOx) as electrocatalysts was studied with MnOx/Nafion-modified gold (Au) electrodes using cyclic voltammetry, potential-controlled amperometry and rotating ring–disk electrode (RRDE) voltammetry in alkaline aqueous solution. At Nafion-modified (MnOx free) Au electrode, O2 reduction undergoes two successive two-electron processes with HO2 − as intermediate. The presence of MnOx, including Mn2O3, Mn3O4, Mn5O8 and MnOOH, on Nafion-modified Au electrodes obviously increases the first reduction peak current of O2 to hydrogen peroxide (HO2 − in this case) and decreases the second one of HO2 − to OH−, while does not shift the reduction potential. MnOx was found to show catalytic activity for the disproportionation reaction of HO2 − to O2 and OH− and thus, the O2 reduction in air electrode was considered to include an initial two-electron reduction of O2 to HO2 − followed by a disproportionation reaction of HO2 − into O2 and OH− catalyzed by MnOx. The excellent activity of MnOx for the follow-up disproportionation reaction substantially results in an overall four-electron reduction of O2 at MnOx/Nafion-modified Au electrodes in the first reduction step, depending on potential scan rate and the kind of MnOx. The present work provides a scientific significance of the mechanism of O2 reduction in air electrode using MnOx as electrocatalysts to effect a four-electron reduction of O2 to OH−.
A mathematical analysis of the diffusion process is carried out to examine the validity of the classical treatment when the diffusion coefficient depends on the concentration. Investigations concerning the analysis of intercalation processes by transient electrochemical techniques are examined. A digital simulation programme is used to obtain an accurate description of the transport mechanism. Examples of lithium intercalation in a Nb2O5 matrix are given.
Building integrated photovoltaic thermal (BIPVT) system has the potential to become a major source of renewable energy in the urban environment. In this paper, the system has been used as the roof top of a building to generate higher electrical energy per unit area and to produce necessary thermal energy required for space heating. One-dimensional transient model has been developed using basic heat transfer equations. On the basis of this model, an analysis has been carried in order to select an appropriate BIPVT system suitable for the cold climatic conditions of India. The PV performances, net energy gain and exergy of the building are determined. The results show that for a constant mass flow rate of air the system connected in series gives a better performance whereas for a constant velocity of air flow the system connected in parallel gives a better performance. The BIPVT system, fitted on the rooftop in an effective area of 65m2, is capable of annually producing the net electrical and thermal exergies of 16,209kWh and 1531kWh, respectively, at an overall thermal efficiency of 53.7%.
Pervasive computing’s historical driver applications include environmental monitoring, safety and security, home and office productivity and guided experience of cultural activities. It also suggests and offers the means to achieve new types of expression in art and entertainment, which has not been a significant area of research despite its cultural and socio-economic importance and unique requirements. This paper discusses motivations and requirements for a pervasive computing architecture for expression, and it presents a specific approach being developed at UCLA in collaboration among research groups in engineering, theater, film and television.