batterydata/paper-abstracts huggingface dataset:
Hierarchical porous graphitic carbon material is obtained by one-step vapor-assisted catalytic graphitization accompanied with chemical activation of phenolic resin. Water vapor is used to enhance the catalytic graphitization process by etching carbon layers coated on metal nanocatalysts to maintain their high catalytic activity, and the resultant hydrogen and carbon monoxide as strong reduction gases arising from water-gas shift reaction can promote the transformation of metal ions to metal catalysts. Thus, the resultant graphitic carbon exhibits hierarchical pore structure, large surface area and high graphitic degree, which is advantageous over conventional activated carbon materials in electrochemical energy storage. The applications of hierarchical porous graphitic carbon as electrode materials for supercapacitors, and host for sulfur in lithium-sulfur cells is demonstrated, which shows remarkably enhanced electrochemical performance due to the unique structure.
This paper presents a novel solar driven direct-expansion heat pump system employing micro-channel PV/T modules as the evaporator. The system can provide both the electrical power and thermal energy used for space heating for buildings. Experimental work was carried out to investigate the performance of the system under real-life condition and numerical simulation work was carried out for the same condition as the experimentation using a two-dimensional model developed by the authors. This specialist simulation model contains energy balance calculation of individual models of components, i.e., models of the micro-channel PV/T module (evaporator), compressor, heat storage tank (condenser), electric expansion valve and testing room. The experimental and simulation results showed a good agreement each other, with the maximum error of 7.2% which is the temperature of refrigerant at the outlet of PV/T modules. The experimental average electrical, thermal and overall efficiencies of the PV/T module are 13.1%, 56.6% and 69.7%, respectively. While the simulated results are 13.7%, 55.0% and 68.7%, respectively. The average experimental and simulated COP of the system is 4.7 and 5.0, respectively. With the solar heat pump system providing energy for the room of 150 m2 in the real-life testing condition, the temperature of the room can remain at 18.5 °C which was high enough for the space heating. Comparison among the simulation and testing results indicated that the simulation model was reasonable for predicting the performance of the system and provided feasibility for analyzing the annual energy performance in the future.
Isolated generation in micro hydroeletric power plant (MHPP) through the induction generator (IG) has been the subject of extensive research due to the fact that this type of electrical machine is easy to operate, requires simplified maintenance, and has also a lower cost when compared to the synchronous machine, mainly in the range from 0.5 to 50 kW. In this work a single voltage control loop of an squirrel cage induction generator in an isolated operation system was implemented in a 30 kW MHPP. The proposed system uses a ballast load (BL) controlled via a digital circuit board. The generated voltage and frequency are maintained around their nominal rated values for typical applications in rural areas. For this purpose a control system has been implemented via phase anti–parallel thyristors. Tests were made with varying loads to obtain the voltage waveforms in the main load (ML) and BL. The control allowed by the electronic board was also tested for performance under sudden connection and disconnection of loads. The proposed system proved to be robust and effective in controlling the voltage and frequency of the isolated system.
Fluorine-free lithium battery electrolytes have been prepared from lithium salts with nitrile based anions, LiB(CN)4 or LiDCTA, dissolved in PEGDME or PC. After soaked into electrospun PAN membranes the resulting electrolytes were tested for physical and electrochemical properties and compared with reference PAN electrolytes containing LiPF6 or LiTFSI. The fluorine-free electrolytes were successfully cycled in Li/LiFePO4 cells at room temperature with up to 98% Coulombic efficiency. Small and qualitatively different effects were observed with the addition of Al2O3 particles to the PAN membranes, which could be of importance for long-term performance. However, for fluorine-free electrolytes to be truly competitive, the relatively low anodic stability and elevated temperature performance must first of all be improved by a change of solvent – or addition of co-solvents. Further work in this direction is encouraged by the strong influence of the solvent (PC or PEGDME) on the properties of the LiDCTA electrolytes demonstrated in this work.
Values for reaction-kinetic parameters of electrophiles can be used to predict mutagenic potency. One approach employs the Swain–Scott relationship for comparative kinetic studies of electrophilic agents reacting with nucleophiles. In this way glycidamide (GA), the putatively mutagenic/carcinogenic metabolite of acrylamide, was assessed by determining the rates of reaction with different nucleophiles. The rate constants (k Nu) were determined using the “supernucleophile” cob(I)alamin [Cbl(I)] as an analytical tool. The Swain–Scott parameters for GA were compared with those of ethylene oxide (EO). The substrate constants, s values, for GA and for EO were found to be 1.0 and 0.93, respectively. The reaction rates at low values of nucleophilic strength (n =1–3), corresponding to oxygens in DNA, were determined to be 2–3.5 times higher for GA compared to EO. GA was also more reactive than EO towards other nucleophiles (n =0-6.4). The mutagenic potency of GA was determined in Chinese hamster ovary cells (hprt mutations in CHO-AA8 cells per dose unit with gamma-radiation as reference standard). The potency of GA was estimated to be about three mutations per 105 cells and mMh corresponding to about 400rad-equ./mMh. A preliminary comparison of the mutagenic potency (per mMh and as rad-equivalents) of GA and EO shows an approximately seven times higher potency for GA. A higher mutagenic potency of GA compared to EO is compatible with expectation from reaction-kinetic data of the two compounds. The data confirmed that GA is not a strong mutagen, which is in line with what is expected for simple oxiranes. The present study shows the value of cob(I)alamin for the determination of reaction-kinetic parameters and their use for prediction of mutagenic potency.
Calcium is an attractive electrode material for use in grid-scale electrochemical energy storage due to its low electronegativity, earth abundance, and low cost. The feasibility of combining a liquid Ca–Bi positive electrode with a molten salt electrolyte for use in liquid metal batteries at 500–700 °C was investigated. Exhibiting excellent reversibility up to current densities of 200 mA cm−2, the calcium–bismuth liquid alloy system is a promising positive electrode candidate for liquid metal batteries. The measurement of low self-discharge current suggests that the solubility of calcium metal in molten salt electrolytes can be sufficiently suppressed to yield high coulombic efficiencies >98%. The mechanisms giving rise to Ca–Bi electrode overpotentials were investigated in terms of associated charge transfer and mass transport resistances. The formation of low density Ca11Bi10 intermetallics at the electrode–electrolyte interface limited the calcium deposition rate capability of the electrodes; however, the co-deposition of barium into bismuth from barium-containing molten salts suppressed Ca–Bi intermetallic formation thereby improving the discharge capacity.
We report for the first time new Li+ ion conducting thin film solid electrolytes based on Li–B–O–N system. Substitution of oxygen in xLi2O–B2O3 (x =1, 3, 5) by nitrogen was successfully achieved by reactive sputtering under nitrogen plasma. FTIR and XPS analyses indicated that N atom was incorporated in the Li–B–O matrix film, and an increase in the composition of Li2O together with N-substitution caused the structural conversion from ring-type borate to open structured one, where more free space and ionic bonding characteristic are offered for higher mobility of Li+ ions. A high ionic conductivity of ca. 2.3×10−6 Scm−1 at room temperature was obtained from the thin film electrolyte of Li3.09BO2.53N0.52 glass that was prepared using 3Li2O–B2O3 target. Electrochemical analyses suggest the high Li+ ion conductivity is induced by the reduced activation energy through the control of the composition and the structure.
Lithium-ion batteries with graphite as the anode consume ∼10% of the active lithium from the cathode to form a solid electrolyte interphase layer during the first cycle, resulting in a reduced reversible capacity. Here, we report using Li2S as a cathode pre-lithiation material to compensate for the loss of active lithium and, consequently, enhance the specific energy of lithium-ion batteries. A Li2S material with a core-shell structure is prepared by mixing Li2S, Ketjenblack (KB) and poly(vinylpyrrolidone) (PVP) in anhydrous ethanol, and the material shows a specific charge capacity of ∼1053mAhg−1 (631mAhg−1 based on the total weight of cathode pre-lithiation materials, binders and conductive additives). The ability of this material to compensate for active lithium is investigated by coating a typical cathode LiFePO4 as an example, with the core-shell Li2S/KB/PVP via a simple and non-toxic coating method. Our results show that the LiFePO4 (Li2S)/graphite full cell exhibits a specific discharge capacity of 146.7mAhg−1 in the first cycle, which is the same as the specific discharge capacity of the LiFePO4 half cell. XPS analysis reveals Li2S decomposes into lithium ions and sulfur with release of electrons in the first charge. Such a successful extraction of the active lithium from Li2S results in excellent cycling performance with increased specific energy.
Aluminum-ion batteries have emerged as a potential alternative to lithium-ion batteries by offering advantages such as abundant aluminum resources, low costs and good safety. Exploring suitable electrode materials lies at the heart of the development of aluminum-ion batteries. Relying on first-principles density functional theory, this study predicts the thermodynamics of aluminum intercalation in TiO2(B) as a promising aluminum storage material. Three sites are identified to be the preferential locations for aluminum within the TiO2(B) structure, and the stable intercalation site is found to prefer 5-fold coordinated to oxygen atoms with a slightly off-center position. The supercell volume change associated with aluminum intercalation is < 10%, and the thermodynamically maximum achievable Al/Ti ratios are respectively 0.6562 and 0.75 without and with considering this volume change. The corresponding specific capacities without and with volume change are calculated to be 660.62 mA h g−1 and 755.05 mA h g−1, doubling the theoretical value of lithium storage in TiO2(B). As expected, aluminum has a very poor mobility in bulk TiO2(B) due to its exceptionally high surface charge density, which would be addressable through the use of nanosized and defective materials. Our calculations suggest that TiO2(B) can offer new opportunities for developing electrode materials for aluminum-ion batteries.
The disposal of batteries is a problem that has grown in the last few years, due to the increase in the use of portable devices. Batteries may contain toxic metals such as cadmium, mercury and lead, so their disposal must be controlled. Brazil was the first country in Latin America to regulate the disposal and treatment of batteries. Limits were established on the concentration of heavy metals within batteries, so that they could be disposed along with domestic waste. Since batteries are products used broadly, it is very difficult to control their disposal. In order to have an efficient collection, the population must be engaged, and that can only happen if they are informed about the laws and regulations regarding the subject, as well as the importance of disposing of batteries with higher concentrations of heavy metals or toxic substances separately from domestic garbage. Around the world, there are some long-established recycling processes for batteries. In Brazil, automotive (lead–acid) batteries have been recycled for several years, whereas the recycling of other types of batteries is just starting. This work does an analysis of the Brazilian law for battery recycling and presents some suggestions and examples of the initiatives of other countries, in order to manage of this kind of dangerous waste.
Previous research has shown that communicative-pragmatic ability, as well as executive functions (EF) and Theory of Mind (ToM), may be impaired in individuals with traumatic brain injury (TBI). However, the role of such cognitive deficits in explaining communicative-pragmatic difficulty in TBI has still not been fully investigated. The study examined the relationship between EF (working memory, planning and flexibility) and ToM and communicative-pragmatic impairment in patients with TBI. 30 individuals with TBI and 30 healthy controls were assessed using the Assessment Battery of Communication (ABaCo), and a set of cognitive, EF and ToM, tasks. The results showed that TBI participants performed poorly in comprehension and production tasks in the ABaCo, using both linguistic and extralinguistic means of expression, and that they were impaired in EF and ToM abilities. Cognitive difficulties were able to predict the pragmatic performance of TBI individuals, with both executive functions and ToM contributing to explaining patients’ scores on the ABaCo.
Thermal models of Li-ion cells on various geometrical scales and with various complexity have been developed in the past to account for the temperature dependent behaviour of Li-ion cells. These models require accurate data on thermal material properties to offer reliable validation and interpretation of the results. In this context a thorough study on the specific heat capacities of Li-ion cells starting from raw materials and electrode coatings to representative unit cells of jelly rolls/electrode stacks with lumped values was conducted. The specific heat capacity is reported as a function of temperature and state of charge (SOC). Seven Li-ion cells from different manufactures with different cell chemistry, application and design were considered and generally applicable correlations were developed. A 2D thermal model of an automotive Li-ion cell for plug-in hybrid electric vehicle (PHEV) application illustrates the influence of specific heat capacity on the effectivity of cooling concepts and the temperature development of Li-ion cells.
Wireless signal transmission will play a critical role in developing reliable subdural spinal cord stimulation systems. We have developed an approach to inductively coupling signals across the epidural spacing between the pial and epidural surfaces. The major design constraints include tolerance of coil misalignments from spinal cord geometries in addition to reasonable power efficiencies within the expected range of movement. The design of the primary side as a driving circuit is simplified by several turns of commercial magnetic wire, whereas the implanted secondary side is implemented in a micro-planar spiral coil tuned to a resonant frequency of 1.6 MHz. We present the results of wireless inductive coupling experiments that demonstrate the ability to transmit and receive a frequency modulated 1.6 MHz carrier signal between primary and secondary coil antennae scaled to 10 mm. Power delivery is in the range of 400 mW at a link efficiency of 32 % for strong coupling (coil separations of 0.5 mm ) and in the range of 70 mW at 4 % efficiency for weak coupling (coil separations of 10 mm).
LiMnPO4/C nanocomposites could be prepared by a combination of spray pyrolysis and wet ball-milling followed by heat treatment in the range of spray pyrolysis temperature from 200 to 500°C. The ordered LiMnPO4 olivine structure without any impurity phase could be identified by X-ray diffraction analysis for all samples. It could be also confirmed from scanning electron microscopy and transmission electron microscopy observations that the final samples were the LiMnPO4/C nanocomposites with approximately 100nm in primary particles size. The LiMnPO4/C nanocomposite samples were used as cathode active materials for lithium batteries, and the electrochemical tests were carried out for the cell Li|1M LiPF6 in EC:DMC=1:1|LiMnPO4/C at various charge/discharge rates in three charge modes. As a result, the final sample which was synthesized at 300°C by spray pyrolysis showed the best electrochemical performance due to the largest specific surface area, the smallest primary particle size and a well distribution of carbon. At galvanostatic charge/discharge rates of 0.05C, the cell delivered first discharge capacities of 123 and 165mAhg−1 in correspondence to charge cutoff voltages of 4.4 and 5.0V, respectively. Furthermore, in a constant current–constant voltage charge mode at 4.4V, the cells also exhibited initial discharge capacities of 147mAhg−1 at 0.05C, 145mAhg−1 at 0.1C, 123mAhg−1 at 1C and 65mAhg−1 at 10C. Moreover, the cells showed fair good cycleability over 100 cycles.
This article summarizes the experience gained from the study, the siting, the design and the dimensioning of hybrid power plants in autonomous insular power systems in Greece. Wind parks and photovoltaic stations are employed as the RES units, while Pumped Storage Systems (PSS), electrochemical lead acid batteries and electrolysis units for hydrogen production are alternatively investigated as storage units. The examined hybrid power plants operation aims either at the maximization of the RES penetration or at the power demand peak shaving. The hybrid power plants’ dimensioning is optimized using as a criterion either the RES annual penetration maximization or the optimization of the required investments economic indices. The work is integrated with an economic feasibility study for each investigated hybrid power plant. The hybrid power plants presented in this article refer to insular autonomous systems of very small size (Agios Efstratios, Castellorizo), small size (Karpathos–Kasos, Astypalaia), medium size (Rhodes, Samos) and large size (Crete). The article designates how the size of the insular system affects the hybrid power plant’s synthesis and operating algorithm. The investigated hybrid power plants are proved to be technically and economically feasible, regardless of the size of the hosting insular system. The sensitivity analysis of the required investments’ economic indices indicated that the produced electricity selling prices can be lower than the specific electricity production costs in the existing systems. In small and very small power systems, the economic feasibility of the introduced hybrid power plants is achieved with annual RES penetration higher than 90% of the annual electricity consumption.
To understand the thermal behavior of lithium-ion secondary batteries, distributed information related to local heat generation across the entire electrode plane, which is caused by the electrochemical reaction that results from lithium-ion intercalation or deintercalation, is required. To accomplish this, we first developed an enhanced single particle (ESP) model for lithium-ion batteries that provides a cost effective, timely, and accurate method for estimating the local heat generation rates without excessive computation costs. This model accounts for all the physical processes, including the solution phase limitation. Next, a two-way electrochemical-thermal coupled simulation method was established. In this method, the three dimensional (3D) thermal solver is coupled with the quasi-3D porous electrode solver that is applied to the unrolled plane of spirally wound electrodes, which allows both thermal and electrochemical behaviors to be reproduced simultaneously at every computational time-step. The quasi-3D porous electrode solver implements the ESP model. This two-way coupled simulation method was applied to a thermal behavior analysis of 18650-type lithium-ion cells where it was found that temperature estimates of the electrode interior and on the cell can wall obtained via the ESP model were in good agreement with actual experimental measurements.
A novel solvothermal method has been used for the synthesis of porous ellipsoidal GeO2 particles with oleic acid and oleylamine as solvent and co-surfactant, respectively and its performance has been studied as an anode material for Li ion battery applications. The presence of highly hydrophobic oleic acid and oleylamine on the surface of the as synthesized sample imparts a detrimental effect on its performance. Although removal of the capping agents with glacial acetic acid improves the performance to some extent, a drastic enhancement in both the specific capacity and cycling stability is observed when the nanoparticles are wrapped with rGO/PANI composites at low temperature.
A 1 kW phosphoric acid fuel-cell (PAFC) stack with 30 cells, was designed, fabricated, assembled with “in-house” developed components at ERI, KACST, and successfully operated for 250 h. The stack was operated at 180°C, 1 bar, using commercial H2/CO2 gas and air. The electrical output power generated by the stack was ∼1 kW (20.5×50 A), with a current density of 125 mA/cm2 at an average cell voltage of 0.7 V. From the results of the successful operation of the stack, it was found that the stack was stable during the operation and the heat generated in the stack was sufficient to retain the temperature at 175 to 180°C without any external heating. To cool the stack, three cooling plates were used in the stack. Insulation was applied to the stack to get a more uniform temperature. The water formed in the stack was collected through the H2 gas outlets and air manifolds during the operation of the stack. As the temperature of the stack at the centre was slightly high, it is recommended introducing two more cooling-plates to achieve a more uniform temperature and better stack performance.
We report graphene nanoplatelets (GNPs), which exhibit the advantages of both single-layer graphene and highly graphitic carbon, as a durable alternative support material for Pt nanoparticles for oxygen reduction in fuel cells. Pt nanoparticles are deposited on poly(diallyldimethylammonium chloride) (PDDA)-coated GNP, and characterized with transmission electron microscopy, X-ray diffraction, Raman spectra, and electrochemical tests. Pt/GNP exhibits greatly enhanced electrochemical durability (2–3 times that of Pt/CNT and commercial Etek Pt/C). These are attributed to the intrinsic high graphitization degree of GNP and the enhanced Pt-carbon interaction in Pt/GNP. If considering that GNP can be easily mass produced from graphite, GNP is a promising, low-cost, and durable electrocatalyst support for oxygen reduction in fuel cells.
In the communication, we firstly introduced a novel fiber-type zinc–carbon battery with high performance. The fiber battery comprises two carbon fiber based electrodes, one insulated wire as the separator, and electrolyte, which is sealed in a flexible plastic tube. The fiber battery does not exhibit any loss in the capacity during the bending tests, illustrating good flexibility. Two fiber batteries connected in series could light up a commercial green LED when bent around human finger. Furthermore, the fiber battery using carbon fiber as current collector, we believe, is a new light weight, low cost portable power source, showing great potential application in the field of flexible/wearable electronic devices.