batterydata/paper-abstracts huggingface dataset:
About 1.4 billion people around the world still do not have access to the regular electricity. It is estimated that roughly 85% of the people without electricity live in rural, semi-urban or remote rural areas of the sub-Saharan Africa and South Asia. Although grid expansion is a vital objective of several developing countries and could be a long-term solution, the remoteness, isolation, low electricity demand of many rural communities, high investment cost of grid expansion make them very unlikely to be reached by the extension of the power grid. Consequently, the off-grid generation systems seem to be the most suited alternative to provide the electricity services to these isolated rural communities. Solar home systems (SHSs) with Light Emitting Diode (LED) lamps are considered to be cost effective and robust decentralized option for rural electrification. Two financing schemes, fee for service and micro-credit system (ownership), are primarily important for acquiring the SHSs by the rural population. However, high upfront cost of SHSs and absence of payment flexibility is deterring the penetration into larger market of lower-income group rural population. Non-availability of facile finance to rural population at the grass-root level is the major barrier inhibiting the widespread adoption of solar-powered lighting systems. Micro-Finance Institutions (MFIs) can be useful to address the gap between the high initial upfront cost of SHS and low paying capacity of rural households by providing flexible and affordable credit. The One-Stop-Shop Model based on a single micro-energy provider who provides the services of finances, supply of standardized SHSs, and after sale energy services is crucial. The success of the SHS program depends on the satisfactory technical performance, an adequate financing infrastructure, responsive after sales support, and the extent to which it can fulfill the needs of the end users of having grid quality energy.
Thin LiCoO2 films, typically used as cathode layers in thin-film solid-state batteries were RF magnetron sputter-deposited using targets that were either freshly produced, or had seen over 100h of sputter erosion. The substrates, as received (100) silicon wafers, were either held stationary or were rocked back and forth under the target. Film texturing, grain size, composition, and thickness were examined using X-ray diffraction (synchrotron light source), inductively coupled plasma-mass spectroscopy (ICP-MS), Rutherfords backscattering spectrometry (RBS) and stylus profilometry. Films that were sputtered from the heavily used target were, on average, lithium-deficient, while films deposited using the fresh target were slightly lithium-rich. Film thickness, composition, and type of crystallographic texture varied radially, in the plane of the film in the stationary substrate case, in a pattern that reflected the sputter target erosion ring. For films deposited with substrate motion, an ovular area was defined on the film in which composition, and texturing were essentially uniform. The Li/Co ratio in the target and subsequent films was found to decrease over many hours of sputtering. Possible causes for the compositional and orientational variations observed are discussed.
We report the synthesis of TiNb2O7/Graphene (TNO-TG) hybrid nanomaterial by simple solvothermal process, with TiNb2O7 nanoparticles anchored on the reduced graphene oxide (rGO) sheets. TNO-TG hybrid nanomaterial showed excellent electrochemical performance when studied as anode for Lithium-ion battery, with an exceptionally high rate capability (capacity retention of 80% at 16C rate) along with high discharge capacity (∼230mAhg−1 after 50 cycles at 0.1C). A full cell Li-ion battery has been fabricated with TNO-TG as anode and LiNi1/3Mn1/3Co1/3O2:LiNi0.5Mn0.5O2 (wt% of 75:25) as cathode, which delivered an average cell voltage of ∼2.5V with an initial anode-specific discharge capacity of 211mAhg−1, when cycled in the voltage range of 1.5–3.5V at 0.1C. The obtained results are very promising and we believe the current findings will lead to new directions in the on-going search for safe and high performance anodes for rechargeable lithium-ion batteries.
Silica/polyacrylonitrile (SiO2/PAN) hybrid nanofiber membranes were fabricated by using sol-gel and electrospinning techniques and their electrochemical performance was evaluated for use as separators in lithium-ion batteries. The aim of this study was to design high-performance separator membranes with enhanced electrochemical performance and good thermal stability compared to microporous polyolefin membranes. In this study, SiO2 nanoparticle content up to 27 wt% was achieved in the membranes by using sol-gel technique. It was found that SiO2/PAN hybrid nanofiber membranes had superior electrochemical performance with good thermal stability due to their high SiO2 content and large porosity. Compared with commercial microporous polyolefin membranes, SiO2/PAN hybrid nanofiber membranes had larger liquid electrolyte uptake, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. SiO2/PAN hybrid nanofiber membranes with different SiO2 contents (0, 16, 19 and 27 wt%) were also assembled into lithium/lithium iron phosphate cells, and high cell capacities and good cycling performance were demonstrated at room temperature. In addition, cells using SiO2/PAN hybrid nanofiber membranes with high SiO2 contents showed superior C-rate performance compared to those with low SiO2 contents and commercial microporous polyolefin membrane.
The new zinc barium metaphosphate glasses (50−x)BaO–xZnO–50P2O5 with 0≤x≤50 were prepared and studied. An analysis of the infrared spectra, of molar volume and of the variation of glass transition temperature with the ZnO content is discussed in order to describe the structure effect of Zn2+ additions in these glasses. The density of (50−x)BaO–xZnO–50P2O5 glasses decreases continuously as the ZnO substitution increases, in accordance with the mass differences between BaO and ZnO. For x less than 30mol%, the glass transition temperature decreases by the decrease in phosphate chain length. For larger x (30≤x≤50mol%), the T g increase, due to the effect of the high field strength of the cations Zn2+ increased due to the increase in the amount of Zn2+ ions in the glasses, that results in tighter network formed by the shortened phosphate chain length.
Electrolytes are essential for the proper functioning of any battery technology and the emerging Na-ion technology is no exception. Hence, a major focus on battery research is to identify the most appropriate formulation so as to minimize interface reactions and enhance both cell performances and safety aspects. In order to identify suitable electrolyte formulations for Na-ion chemistry we benchmarked various electrolytes containing diverse solvent mixtures (cyclic, acyclic carbonates, glymes) and Na-based salts having either F-based or perchlorate anions and measured viscosity, ionic conductivity, and thermal and electrochemical stability. The binary EC:PC solvent mixture has emerged as the best solvent formulation and has been used to test the performance of Na/hard carbon cells with both NaClO4 and NaPF6 as dissolved salts. Hard carbon electrodes having reversible capacities of 200 mA h g−1 with decent rate capability and excellent capacity retention (>180 cycles) were demonstrated. Moreover, DSC heating curves demonstrated that fully sodiated hard carbon cycled in NaPF6–EC:PC exhibits the highest exothermic onset temperature and nearly the lowest enthalpy of reaction, thus making this electrolyte most attractive for the development of Na-ion batteries.
Cuprous oxide (Cu2O) has been acknowledged as a potential electrocatalyst for oxygen electrochemistry. However, it has been a challenge to study its oxygen reduction and evolution reactions in conventional aqueous systems as the instability of Cu2O in aqueous solution, especially in acid or alkaline solution. In the present study, self-supported Cu2O films are prepared by an electrochemical method, and used as cathode catalysts in Li–O2 batteries. The nonaqueous environment of Li–O2 batteries prevents decomposition of Cu2O and guarantees the cathode processes. Instead of traditional strategy of mixing active materials with carbons and binders, the carbon- and binder-free Cu2O films are used to prevent the interference of carbon electrocatalysis and side reactions from carbon or binders. Based on electrochemical measurements, the discharge and charge voltage of the battery on the Cu2O surface are 2.7 and 3.6V, respectively, behaving a lower charging overpotential than traditional carbon materials. Furthermore, the X-ray photoelectron spectra (XPS) of cathodes after cycle tests indicate Cu2O catalysts is stable in Li–O2 batteries, and the battery performs 100 cycles with no evident decay. Finally, cyclic voltammetry and electrochemical impedance spectra are measured in order to study the cathode processes and the mechanism of rechargeability.
A calorimetric technique was developed for determining time-dependant heat profiles of electrochemical capacitors. The profiles were extracted from the temperature change of the capacitor during charge–discharge current cycles. The technique is described and its good performance is demonstrated. Experiments were carried out on symmetric and asymmetric aqueous capacitors prepared with activated carbon and manganese oxide as active materials. Heat in double-layer and hybrid capacitors, C–C and C–MnO2, varied with time, according to special profiles depending on storage processes. In carbon double-layer capacitors, the heat component was decomposed into a reversible and an irreversible term. Results suggested that irreversible heat was caused by the Joule loss through the porous structure and the reversible heat by the ion adsorption on the carbon surface. Moreover, endothermic and exothermic processes were observed on the MnO2 electrode of the asymmetric capacitor, over the charge and the discharge respectively, proportional to the charge rate. These results suggested that heat in the MnO2 electrode originated from the redox reactions and ion adsorption on the active material.
The oxygen redox reaction (ORR) in pyrrolidinium-based ionic liquids (ILs) without and with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is investigated at different temperatures for lithium/oxygen battery application. Results obtained by cyclic voltammetry, rotating disk electrode, and ultramicroelectrode potential steps at glassy carbon are reported and discussed in relation to the physical–chemical properties of the investigated ILs. Diffusion coefficients and solubility of oxygen in the ILs and tentative values of ORR heterogeneous rate constant in ILs without LiTFSI are reported. The effect of lithium salt on the ORR in IL is also discussed in view of lithium/oxygen battery application.
The human brain is a highly interconnected network. Recent studies have shown that the functional and anatomical features of this network are organized in an efficient small-world manner that confers high efficiency of information processing at relatively low connection cost. However, it has been unclear how the architecture of functional brain networks is related to performance in working memory (WM) tasks and if these networks can be modified by WM training. Therefore, we conducted a double-blind training study enrolling 66 young adults. Half of the subjects practiced three WM tasks and were compared to an active control group practicing three tasks with low WM demand. High-density resting-state electroencephalography (EEG) was recorded before and after training to analyze graph-theoretical functional network characteristics at an intracortical level. WM performance was uniquely correlated with power in the theta frequency, and theta power was increased by WM training. Moreover, the better a person's WM performance, the more their network exhibited small-world topology. WM training shifted network characteristics in the direction of high performers, showing increased small-worldness within a distributed fronto-parietal network. Taken together, this is the first longitudinal study that provides evidence for the plasticity of the functional brain network underlying WM.
Production in the pharmaceutical industry has increased and along with it, the amount of wastewater of various characteristics and contaminant concentrations. The main chemicals in these effluents are solvents, detergents, disinfectants—such as sodium hypochlorite (NaClO)—and pharmaceutical products, all of which are potentially ecotoxic. Therefore, this study aimed to evaluate the oxidative stress induced in the amphipod Hyalella azteca by the effluent from a nonsteroidal anti-inflammatory drug (NSAID)-manufacturing plant. The median lethal concentration (72 h-LC50) was determined and H. azteca were exposed to the lowest observed adverse effect level (0.0732 %) for 12, 24, 48 and 72 h, and biomarkers of oxidative stress were evaluated [hydroperoxide content (HPC), lipid peroxidation (LPX), protein carbonyl content (PCC), and the activity of the superoxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)]. Statistically significant increases with respect to the control group (P < 0.05) were observed in HPC, LPX and PCC in H. azteca at all exposure times. Antioxidant enzymes activity SOD, CAT and GPx activity also increased significantly (P < 0.05) with respect to the control group. In conclusion, the industrial effluent analyzed in the present study contains NSAIDs and NaClO, and induces oxidative stress in H. azteca.
The concentration of sulfate ions was continuously monitored by Raman spectroscopy during the preparation of cathode material precursors. The obtained spectra were used for the quantitative analysis of sulfate ions by comparison with a reference solution, and a gradual increase of sulfate ion concentration was detected. Using a mathematical approach, a time-dependent equation describing sulfate ion concentration was theoretically derived, and the calculated concentrations were compared with the measured ones, showing good agreement between these values. Due to the increased sulfate ion concentration, the metal hydroxide cathode precursor became more contaminated with elemental sulfur. Two as-obtained hydroxide powders with different sulfur impurity contents were calcined with a lithium source, producing cathode materials. Electrochemical analysis of the prepared cathode materials showed that morphological aspects (such as particle size) more highly affected the cathode performance more than the sulfur impurity content.
As the next-generation high energy capacity cathode materials for Li-ion batteries, Ni-rich oxides face the problem of obtaining near-stoichiometric phases due to excessive Ni occupying Li sites. These extra-Ni-defects drastically affect the electrochemical performance. Despite of its importance, the fundamental correlation between such defects and the key electrochemical properties is still poorly understood. In this work, using density-functional-theory, we report a comprehensive study on the effects of non-stoichiometric phases on properties of Ni-rich layered oxides. For instance, extra-Ni-defects trigger charge disproportionation reaction within the system, alleviating the Jahn-Teller distortion of Ni3+ ions, which constitutes an important reason for their low formation energies. Kinetic studies of these defects reveal their immobile nature, creating a “pillar effect” that increases the structural stability. Ab initio molecular dynamics revealed Li depletion regions surrounding extra-Ni-defects, which are ultimate responsible for the arduous Li diffusion and re-intercalation, resulting in poor rate performance and initial capacity loss. Finally, the method with combination of high valence cation doping and ion-exchange synthesis is regarded as the most promising way to obtain stoichiometric oxides. Overall, this work not only deepens our understanding of non-stoichiometric Ni-rich layered oxides, but also enables further optimizations of high energy density cathode materials.
The ability of low-cost activated carbon prepared from Ceiba pentandra hulls, an agricultural waste material, for the removal of lead and zinc from aqueous solutions has been investigated. In the batch tests experimental parameters were studied, including solution pH, contact time, adsorbent dose and initial metal ions concentration. The adsorbent exhibited good sorption potential at pH 6.0. Maximum removal of lead (99.5%) and of zinc (99.1%) with 10g/l of sorbent was observed at 50mg/L sorbate concentration. Removals of about 60–70% occurred in 10min, and equilibrium was attained at around 50min for both metals. The functional groups (CO, SO,–OH) present on the carbon surface were responsible for the adsorption of metal ions. The adsorption parameters were analysed using both the Freundlich and Langmuir models. The data are better fitted by the Freundlich isotherm as compared to Langmuir model, and the adsorption capacities for lead and zinc were 25.5 and 24.1mg/g, respectively. Kinetics of adsorption obeyed a second order rate equation and the rate constant was found to be 2.71×10−2 and 2.08×10−2 g/mg/min for lead and zinc, respectively. The desorption studies were carried out using dilute HCl, and the effect of HCl concentration on desorption was studied. Maximum desorptions of 85% for lead and 78% for zinc were attained with 0.15 M HCl.
We can mass-produce metal/carbon nanotube (CNT) composites that show improved radiation tolerance. The 0.5wt% Al+CNT composite showed improved tensile strength without reduction of tensile ductility before radiation, and reduced void/pore generation and radiation embrittlement at high displacements per atom (DPA). Under helium ion irradiation up to 72DPA, the 1D carbon nanostructures survive, while sp2 bonded graphene transforms to sp3 tetrahedral amorphous carbon. Self-ion (Al) irradiation converts CNTs to a metastable form of Al4C3, but still as slender 1D nanorods with prolific internal interfaces that catalyze recombination of radiation defects, reducing radiation hardening and porosity generation. The 1D fillers may also form percolating paths of “nano-chimneys” that outgas the accumulated helium and other fission gases, providing an essential solution to the gas accumulation problem.
Surgeons strive to set patient expectations for recovery following total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, some patients report dissatisfaction after surgery due to unmet expectations.
Safety study regarding an exothermic reaction at elevated temperature of comb-shaped siloxane polymer and its interpenetrating network type solid polymer electrolyte (SPE) are investigated. Accelerating rate calorimetry (ARC) is used to examine exothermic reactions. The thermal stability of the polymer electrolyte in the presence of charged electrodes is also monitored. Resulting data were compared with those of 1.0 M LiPF6 in ethylene carbonate:ethyl methyl carbonate (3:7 by wt.) electrolyte. The self-heating exothermic reaction of mono comb-shaped siloxane polymer electrolyte starts at approximately 300°C. Comparison of the heat generation profiles from ARC tests indicates that SPE reduces the intensity of exothermic reactions resulting from charged electrodes and electrolyte.
An organic–inorganic hybrid mesoporous silica was synthesized via post-grafting of KIT-6 with 4-(triethoxysilyl)butyronitrile. All samples were characterized using their N2 adsorption–desorption isotherms, XRD, FT–IR, TEM, SEM, and PT. The adsorption potential of this material for removing Pb(II) from aqueous solutions was investigated via the batch technique, and the effects of pH and contact time were studied. Experimental data showed that the maximum Pb(II) adsorption, 76%, occurred in the pH range around 6. The adsorption equilibrium was reached within 40min for 10wt.%COOH/KIT-6. The adsorption data were fitted using the Langmuir and Freundlich isotherms, and the obtained modeling equilibrium adsorption data suggested that the 10wt.%COOH/KIT-6 sample contained homogeneous adsorption sites that fit the Langmuir adsorption model well. The pseudo-second-order model described well the 10wt.%COOH/KIT-6 adsorption process. The desorption and regeneration experiments indicated that ≈95% of the metal desorbed and the adsorbent could be regenerated via an acid treatment without altering its properties.
Adding immiscible perfluorocarbons (PFCs), possessing superior oxygen solubility and diffusivity, to a free-standing (metal-free and binder-free) CNTs air-electrode tissues with a meso-pore structure, fully maximized the advantages of PFCs as oxygenated-species' channels-providers. The discharge behavior of hybrid PFCs-CNT Li-O2 systems demonstrated a drastic increase in cell capacity at high current density (0.2 mA cm−2), where oxygen transport limitations are best illustrated. The results of this research revealed several key factors affecting PFCs-Li-O2 systems. The incorporation of PFCs with higher superoxide solubility and oxygen diffusivity, but more importantly higher PFCs/electrolyte miscibility, in a meso-pore air-electrode enabled better exploitation of PFCs potential. Consequently, the utilization of the air-electrode' surface area was enhanced via the formation of artificial three phase reaction zones with additional oxygen transportation routes, leading to uniform and intimate Li2O2 deposit at areas further away from the oxygen reservoir. Associated mechanisms are discussed along with insights into an improved Li-O2 battery system.
It is well known that all high-capacity Li-alloy anodes for use in Li-ion battery (LIB) applications suffer from significant specific volume changes during Li-ion insertion/extraction. If the microstructure of the electrode materials can be designed properly, the volume change problems encountered during discharge (lithiation) and charge (delithiation) could be alleviated to some extent. We report on a novel route for the encapsulation of Sn nanoparticles (Sn-NPs) within graphene nanostructures via the microwave plasma irradiation of SnO2 for the fabrication of LIB anode materials. Here, the Sn@graphene nanostructure is synthesized in situ into a vertically aligned graphene host that sandwiches the nanostructures between rapid ion and electron transport pathways and demonstrates a structure that is highly suitable for solving the critical volume change problem. Binding of the Sn@graphene on the vertically aligned graphene product exhibits larger-than-theoretical reversible capacities of 1037mAhg−1 even after prolonged cycling, in addition to a Coulombic efficiency in excess of 97%, which reflects the ability of the Sn@graphene nanostructure to prevent the volume change and agglomeration of the Sn-NPs. The cycling ability exceeds 5000 times in half-cells at a 6C rate while retaining 400mAhg−1 reversible capacities (where a 1C rate represents complete charge or discharge after 1h). We successfully increased the charging and discharging rates by nearly 30-fold over the highest rate reported to date while attaining high power and energy densities, which represent the best performance values attained for a long-cycle Sn anode to date. The excellent electrochemical performance observed is mainly attributed to the confined volume change of the Sn within the graphene, ensuring the permanent electrical connectivity of the immobilized Sn@graphene anodes.