batterydata/paper-abstracts huggingface dataset:
This paper presents a contribution to implementation of hybrid power plants in rural areas without electricity in Senegal. Wind and photovoltaic generators coupling is used to benefit from renewable energy resources in this country. Lead acid storage batteries are coupled with the generators to ensure smoothness of the electricity generation. This work is focused in particular on the development of a low cost online impedance spectroscopy method to address the problem of limited lifetime of batteries and the difficulties of their maintenance in isolated areas. Control of static converter associated with the battery is adapted to integrate the functionality of characterization of batteries by impedance spectroscopy. An experimental platform developed in the laboratory has validated the method for online measurement of battery impedance spectrum and to initiate a phase of data monitoring.
Improving maternal health is one of the eight Millenium Development Goals developed by the United Nations. One of the targets under this goal is to reduce the maternal mortality ratio by three quarters, between 1990 and 2015. Overall, maternal mortality ratios are highest in sub-Saharan Africa and in South Asia. Medical devices could potentially prevent maternal morbidity and mortality especially due to hemorrhage, hypertension, and direct causes of maternal mortality. The objective of this research was to identify medical devices that can be used to address maternal health during pregnancy and childbirth in resource-poor settings. We searched databases such as Pubmed, maternova and the Maternal and Neonatal Directed Assessment of Technology database. We also researched the literature though the Google search engine. We included all devices that were developed for use in developing countries. The majority of the devices we identified were designed to prevent, diagnose or treat hemorrhage (n = 11, 17 %), assist with pre-term or difficult labor (n = 8, 13 %), and ultrasound technologies (n = 7, 11 %). It was encouraging to find that devices to prevent or treat hemorrhage were the most common, as this is the most important cause of maternal mortality. However, in terms of absolute numbers, devices to diagnose or treat hypertension were the 4th most common, while this is the second most common cause of maternal mortality. Maternal mortality remains a significant global health problem, with most deaths occurring in sub-Saharan Africa and in South Asia. Meeting the fifth Millennium Development Goal will require making significant investments in reducing maternal mortality in less than 5 years. This might involve innovations to develop technological solutions faster, commercialize the solutions and distribute them where they are most needed.
Sodium transition-metal phosphate NaMPO4 is known to mainly present two polymorphs: the thermodynamically metastable and electrochemically active olivine and the thermodynamically stable and electrochemically inactive maricite. The direct synthesis of the olivine and the activation of the maricite thus become the focuses of preparation of high-performance phosphate cathode materials for Na-ion batteries. To obtain better understanding of these two issues, the structural stabilities and the ionic transport properties of NaMPO4 polymorphs are investigated using atomistic simulation method. Free energy calculations predict pressure-induced structural phase transitions from maricite to olivine at low or negative pressures, and the critical pressures shift towards the negative pressure region as the applied temperature increases. It suggests that the introduction of negative pressure or lattice expansion will increase the structural stability and accordingly facilitate the direct synthesis of olivine NaMPO4. Migration energy calculations reveal a less direction-dependent ion migration for maricite lattice, which may contribute to the activation of nano-sized maricite NaMPO4. Interestingly, the calculated energy barriers decrease with the increase of the ionic radius of M2+ ion. Chemical substitution with larger divalent cations to increase the average ionic size of M2+ ions is thus expected to further improve the rate capability of maricite Na-phosphate.
Lithium iron pyrophosphate has drawn great attention because of its interesting physical and electrochemical properties, whereas its high rate capability is far from satisfactory. We synthesize nano-Li2FeP2O7/C with hierarchical pore via a low cost method which uses iron powder instead of Vitamin C as the reducing agent. The hierarchical pore is constructed through a “combustion” mechanism according to the thermogravimetric and morphological characterizations. The phase-pure nanoparticles of Li2FeP2O7 are embedded in the three-dimensional network of amorphous carbon. The hierarchical pore together with the two-dimensional diffusion channel of lithium in Li2FeP2O7 is beneficial to lithium diffusion capability which is evaluated by the lithium diffusion coefficients calculated from the results of GITT measurements. The fast lithium intercalation chemistry facilitates the reversible de/intercalation of lithium, resulting in the high cycling stability and rate-capability. After 100 cycles at the current density of 1C, 93.8% of the initial capacity is retained. The discharge capacity is 62.1 mAh g−1 at the current density of 4C. Therefore, the hierarchically porous nano-Li2FeP2O7/C is a promising cathode material for advanced rechargeable lithium ion battery.
Current kinetic limitations of carbon anode materials in sodium-ion batteries can be effectively tackled by using tailor-made carbon materials with hierarchical porosity prepared via the nanocasting route. Capacities exceeding 100 mA h g−1 at C/5 are found while exhibiting excellent rate capability and reasonable cycle life.
Nano-sized LiMn2O4 particles were prepared at 1023K by electrospray pyrolysis in which they were directly deposited on a Pt substrate in gas phase. Cyclic voltammetry gave very sharp and symmetrical redox peaks at ca. 4.0 and 4.1V vs. Li/Li+ owing to the insertion and extraction of lithium-ion at LiMn2O4. However, the redox peaks broadened and their peak separation in an electrode potential increased when aggregated nano-sized LiMn2O4 particles were used. In Nyquist plots, a semi-circle due to lithium-ion transfer resistance appeared at potentials above 3.90V. The values of the lithium-ion transfer resistances were small for dispersed nano-sized LiMn2O4 particles. On the other hand, the lithium-ion transfer resistances increased and the Warburg impedance became obvious as the nano-sized LiMn2O4 particles aggregated. These results clearly indicate that the apparent rapid diffusion of lithium-ion can be attained using well-dispersed nano-sized particles of electroactive materials.
Needle-like TiO2(B) powder was obtained from K2Ti4O9 precursor by ion exchange to protons, followed by dehydration. The charge and discharge characteristics of the TiO2(B) powder were investigated as a high potential negative electrode in lithium-ion batteries. It had a high discharge capacity of 200–250mAhg−1 at around 1.6V vs. Li/Li+, which was comparable with that of TiO2(B) nanowires and nanotubes prepared via a hydrothermal reaction in alkaline solution. It showed very good cycleability, and gave a discharge capacity of 170mAhg−1 even in the 650th cycle. It also had a high rate capability, and gave a discharge capacity of 106mAhg−1 even at 10°C. In most of ethylene carbonate-based solutions, the TiO2(B) powder exhibited good charge and discharge characteristics. However, it showed a poor compatibility with LiBF4, propylene carbonate, and γ-butyrolactone. The TiO2(B) powder showed good cycle performance in the presence of a non-flammable additive, trimethyl phosphate, up to 20vol.%, and a high tolerance to water up to 1000ppm. It was also found that inexpensive Al foil can be used as a current collector of the TiO2(B) powder instead of Cu foil without sacrificing the performance.
Silicon, one of the most promising candidates to replace graphite anodes in lithium-ion batteries (LIB), suffers from large volume change, structural instability, pulverization, shedding, and low conductivity. Here we present a LIB anode made of graphene nanowall (GNW) - Si nanocomposite (GNWs@Si). The GNWs featuring stable structure, large specific surface area, flexibility and excellent conductivity are grown by plasma-enhanced deposition directly on a Ni foam current collector. A mixed-phase silicon nano-layer is conformally and uniformly coated over the three-dimensional nanowall network, forming the GNWs@Si nanocomposite. Compared with conventional anodes, the GNWs@Si shows higher specific capacity, and better rate performance and capacity retention. The discharge specific capacities of the anodes made of pure Si and the GNWs@Si nanocomposite are 704.2 and 1116.2 mAh g−1, respectively. The GNWs@Si outperforms pure Si in the corresponding capacity retention (relative to the discharge specific capacity in the 4th cycle) by showing 79.1% after 200 cycles as opposed to 50.4% for Si. The GNWs@Si anode features large electrochemical reaction areas, short and fast transport paths for Li+ and electrons, relieved internal stress caused by Si volume expansion, and excellent electrochemical performance.
Electric two-wheeler is booming in China, and there are two kinds of electric two-wheelers. One is electric bike, another is over-standard electric bike. Nowadays, over-standard electric bikes that account for 60 percent of electric two-wheeler become the major part. However, they have caused a series of problems affecting the traffic efficiency and safety. In order to take effective and practicable measures to supervise over-standard electric bikes, it is necessary to research it. In this paper, RP survey is used to approach to travel characteristics of over-standard electric bikes. Conclusion shows that over-standard electric bicycles have strong competitiveness with public transport and bicycle. The users prefer to a longer travel distance commuter trip. If over-standard electric bikes will be unavailable, users may travel by motorized traffic.
Research carried out in the USA at Massachusetts Institute of Technology, and elsewhere, has demonstrated for the first time that when inserted into a pool of liquid, nanowires naturally draw the liquid upwards in a thin film which coats the surface of the wire. The finding could have applications in biomedical research and microfluidic devices.
We report the fast charge–discharge Li ion battery based on the nanostructural controlled Na0.44MnO2 wires with high aspect ratio. The good fast charge–discharge property is observed because the single crystalline Na0.44MnO2 nanowires have a high electronic conductivity as electrode active materials of lithium ion battery due to the one-dimensional single crystalline nanowire. Moreover, such nanosize structure could reduce the required lithium diffusion length in the active materials to the several tens of nanometer, also reduce the effective specific current density by high surface area, and increase the stability of cycle performance by the one-dimensional single crystalline structure.
Electrochemical oscillation (EO) system with many kinds of coupling processes is normally accompanied by rich nonlinear dynamic mechanism. The electrochemical potential oscillation on quaternary alloy anode in electrolytic metal manganese (EMM) with and without sodium oleate (NaOL) was studied to investigate electrode reaction process. It is observed that NaOL affected the amplitude and frequency of potential oscillation by chronoamperometry measurement and phase space reconstruction. Furthermore, the linear sweep voltammetry (LSV) results revealed a certain amount of NaOL could reduce the overpotential of oxygen evolution reaction (OER) on the anode. In electrochemical impedance spectroscopy (EIS) exploration, the electrode process presented different reaction mechanisms in the absence and presence of NaOL. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were utilized to characterize the obtained electrolytic product. The combination of OL− and Mn2+, to a certain extent, inhibited the side reaction on anode, responded with reduced potential oscillation frequency and decreased potential value in phase space portrait. Based on the gained results, the relationship between EO and electrode reaction mechanism regulated by NaOL in EMM was proposed. This makes it possible to regulate electrochemical reaction by adjusting the intuitive oscillating signals.
Most of the challenges facing dialogue editors are the result of decisions made on the set. Location mixers must make choices about sound, story, sample rates, timecode, and formats. These decisions will irrevocably affect the future of the production tracks and hence your way of working.
MoO3/multiwalled carbon nanotube (MWCNT) composites were prepared by Magnetron sputtering in Ar/O2 atmosphere. This will provide a greener alternative for the fabrication of binder free composite electrode for supercapacitor applications. MWCNT provides good support for the growth of MoO3 thin films. This integrated composite electrode exhibited specific capacitance of 93Fg−1 and a corresponding energy density of 7.28Whkg−1 in non-aqueous electrolyte, which is almost fourfold increase compared to the bare MWCNT. Also the electrode maintains high power density of 4930Wkg−1 at high current rates, suggesting a potential energy storage material for portable and consumer electronics.
In this study, a promising cathode material in Na-ion batteries, Al-doped NASICON-type Na3V2-xAlx(PO4)3/C (0 ≤ × ≤ 0.03) samples are synthesized and characterized. The doping effects on the crystal structure are investigated by XRD and XPS, indicating that low dose of Al3+ doping generates no damage on the structure of the material, and aluminum is substituted for the vanadium site successfully. Electron microscopy and Raman data show that amorphous carbon coated on the matrix can enhance the electron conductivity. The electrochemical kinetic response of Al3+ doping are tested based on “slow-charge and rapid-discharge” electrochemical mode, results from before and after the cycles show that the doping samples have strong structure stability and excellent electrochemical performance because of low internal resistances and high ion conductivity. Thus, Na3V1.98Al0.02(PO4)3/C exhibits an initial reversible capacity of 102.7 mAh g−1 at 10 mA g−1 in the potential range between 2.3 and 3.8 V and delivers a discharge value of 95 mAh g−1 vs. 59.9 mAh g−1 of NVP/C at current density of 70 mA g−1 discharge after 50 cycles. The ionic conductivity of Na3V1.98Al0.02(PO4)3/C sample at 3.4 V after 50 cycles at 10 mA g−1 charge 200 mA g−1 discharge is 1.31 × 10−12 cm2s−1, four orders of magnitude higher than the undoped one(7.79 × 10−17 cm2s−1).
The chemical oxidative polymerization and electrochemical polymerization of 3-aminobenzenesulfonic acid with aromatic amines have been carried out in p-toluenesulfonic acid which acts as a supporting electrolyte as well as an external dopant. The presence of –SO3H groups in the ABSA co-monomer allows the copolymer to acquire intrinsic protonic doping ability. The electrochemically synthesized polymers and copolymers have been characterized by cyclic voltammetry for analyzing the growth of copolymers and chronoamperometry studies for their applications to the electrochromic devices. In addition to construction of electrochromic devices (ECDs), the electrochromic properties of the polymer films were further investigated. Electrochromic switching stability of the devices was estimated from switching times between their oxidized and reduced states, which indicates that the homopolymers and copolymer can be used for promising electrochromic devices. Chemically synthesized copolymers were also characterized using various techniques like Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy and electrical conductivity at room temperature.
Hydrous ruthenium oxide/carbon black nanocomposites were prepared by impregnation of the carbon blacks by differently aged inorganic RuO2 sols, i.e. of different particle size. Commercial Black Pearls 2000® (BP) and Vulcan® XC-72 R (XC) carbon blacks were used. Capacitive properties of BP/RuO2 and XC/RuO2 composites were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in H2SO4 solution. Capacitance values and capacitance distribution through the composite porous layer were found different if high- (BP) and low- (XC) surface-area carbons are used as supports. The aging time (particle size) of Ru oxide sol as well as the concentration of the oxide solid phase in the impregnating medium influenced the capacitive performance of prepared composites. While the capacitance of BP-supported oxide decreases with the aging time, the capacitive ability of XC-supported oxide is promoted with increasing oxide particle size. The increase in concentration of the oxide solid phase in the impregnating medium caused an improvement of charging/discharging characteristics due to pronounced pseudocapacitance contribution of the increasing amount of inserted oxide. The effects of these variables in the impregnation process on the energy storage capabilities of prepared nanocomposites are envisaged as a result of intrinsic way of population of the pores of carbon material by hydrous Ru oxide particle.
Road transportation using air as a fuel has attracted much attention over the past decade. The fuel (air) can be in two forms, compressed gas form and cryogenic liquid form and engines based on both forms of air have been investigated. Prototypes of air powered road vehicles are expected to emerge over the next few years. However, there have been debates over the advantages and disadvantages of the two technologies. This paper aims to compare the two technologies from the technological point of view. Engines for a typical small scale passenger car are used for the analyses and the comparison is based on the shaft work, coolth, efficiency and energy density. It is shown that the shaft work outputs and the coolth available to engines powered by both fuels increase with increasing working pressure and temperature. Given the working pressure and temperature, liquid air powered engines have a slightly lower specific work outputs than compressed air powered engines. The volumetric energy density of liquid air, however, is much higher than that of compressed air, and liquid air has much higher coolth than compressed air. On the other hand, the efficiency of the compressed air powered engines is higher than that of liquid air powered engines mainly because of the higher energy consumption of liquefaction plants. The analyses also suggest that an effective use of coolth be a key to improve the overall efficiency of liquid air powered engines.
The Stand-alone Photovoltaic System (SAPS) should be sized optimally since there no steady backup supply connected to it. An optimally sized SAPS should have a low overall cost without compromising the reliability of the system. This paper presents the review of the microgrid and the sizing of the SAPS. The review includes seven type of sizing methods for the microgrid. The sizing of the SAPS combines the Loss of Power Supply Probability (LPSP) and Life Cycle Cost (LCC) using the Iterative Method to determine the optimal size for the SAPS. The reliability of the SAPS is further improved using the Reliability Improvement Method (RIM). The location for the SAPS is at FKE Building, UTM, Johor. The results obtained using the RIM are compared with the results obtained from the LCC Method and the GCM. The GCM does not consider the overall cost of the SAPS throughout the lifetime of the system. The LCC Method consider the overall cost for the SAPS but the LPSP is fixed at 0.812%. While the proposed RIM improves the reliability of the SAPS up to 77.8% from 0.812% LPSP with only 4.9% cost increases.
Polymer gel electrolytes (PGE) based on polyvinylidene fluoride (PVDF), lithium salts and appropriate solvent systems, developed at Leeds University, have been shown to form tough rigid films with conductivities approaching 10−2 Scm−1. A continuous process has now been developed for the construction of rechargeable lithium cells by extruding the PGE as a melt and directly laminating between the anode and cathode electrodes. On cooling, the solid PGE acts as electrolyte and separator and binds the cell laminate together from within requiring no external case. This process has been successfully applied for the fabrication of cells with electrodes developed by SpectraPower Inc. in a commercial process enabling cell laminates with PGE thickness less than 0.1mm and with energy densities approaching 170Whkg−1. A prototype manufacturing facility has been set up to produce rechargeable cells of high specific capacity and high energy density. Future developments will enable rechargeable lithium ion cells to be produced on a continuous process as flat sheets opening the way for novel battery geometries.
The electrochemical activity of the Ce 3+/4+ reaction in the presence of various mixed acid electrolytes containing methanesulfonic acid (MSA) as the base electrolyte along with hydrochloric, nitric and sulfuric acid was investigated as a function of acid concentration and reaction temperature on a Pt disk electrode. Cyclic voltammetry in 0.6 molL−1 cerium and 4molL−1 MSA with 0.5 - 1 molL−1 hydrochloric acid showed that the reversibility and kinetics of the Ce 3+/4+ reaction were significantly enhanced compared to that containing MSA only. Higher diffusion coefficients ( D ) and exchange current densities ( j o ) were also obtained for the mixed acid media containing sulfuric and nitric acid, but in this case the reversibility of the reaction was not that improved. Higher concentrations of hydrochloric, nitric and sulfuric acid (>1molL−1) made the oxidation of Ce3+ very hard to delineate from the cyclic voltammograms because of the side reactions occurring at such high potentials. The exchange current density (jo), obtained through polarization resistance and electrochemical impedance spectroscopy measurements (EIS), increased with temperature over the range 25 to 55°C. The EIS results showed that the solution resistance of the mixed electrolytes is considerably lower than that of the unmixed electrolyte facilitating the charge transfer reaction. Nonetheless, solubility issues arose at high Ce4+ concentrations (state of charge>60%) and elevated temperatures (>40°C).
Despite knowledge of subsequent melanoma risk and the benefit of sun protection in risk reduction, melanoma survivors often do not engage in adequate sun protection and continue to sunburn at rates similar to individuals without a history of skin cancer. This novel intensive intervention provided a wearable UV sensor delivering real-time UV exposure with a smartphone and daily text messages. On days 1–10 (period 1), behavioral facilitation and outcome expectancies messages were provided. On day 10, participants reviewed and reflected on their daily UV exposure on the previous 10 days and set goals for improving sun protection. Then on days 11–21 (period 2) self-efficacy and self-regulation messages were provided. Sixty melanoma survivors were randomized (1:1) to receive structured or unstructured goal setting queries on day 10. Controlling for cloudy/rain conditions with less UV due to weather, there was a time effect with a significant decrease in UV exposure from periods 1–2 [period 1–2, F (59) = 22.60, p < 0.0001]. In this short-term study, melanoma survivors managed their daily UV exposure to stay below their maximum tolerated UV dose. ClinicalTrials.gov Protocol Record NCT0334796, date of registration Nov 15, 2017.