batterydata/paper-abstracts huggingface dataset:
Solid-state electrochemical double-layer capacitors (ELDCs) based on alkaline polyvinyl alcohol (PVA) solid polymer electrolytes (SPEs) are prepared. Electrochemical capacitance performance of these capacitors is studied by cyclic voltammetry, galvanostatic charge–discharge testing, and ac impedance spectroscopy. For comparison, two types of EDLC cells are constructed and tested. It is found that an EDLC with a PVA polymer electrolyte exhibits much higher capacitance and longer cycle-life than one with the PP/PE separator. The specific capacitance for the EDLC with the PVA-based SPE is in the range of 100–112Fg−1, and depends on the scan rate or the charge–discharge current rates. The results also indicate that the solid-state EDLC shows a relatively stable specific capacitance of 100Fg−1 after 1000 cycles. The findings suggest that the PVA-based SPE is a promising material for use in EDLCs.
Zeolitic imidazolate framework-derived carbon and metal oxide composites are promising for applications in lithium-ion batteries due to their morphology and porous structure. Herein, we report freestanding carbon nanofibers grafted with amorphous ZnO where the rhombic dodecahedral morphology of the parent (ZIF8) is maintained. The impacts of ZIF8 loading temperature on particle size after pyrolysis and on the electrochemical properties of these hybrid structures for LIBs are investigated. Polyacrylonitrile nanofiber loaded with ZIF8 at 45 °C exhibits a perfect sodalite topology and optimized particle size. The carbonized freestanding composite fibers have a high specific capacity of 818 mAh·g−1 at a current density of 100 mA·g−1 after 100 cycles. This remarkable performance of ZIF8-derived ZnO is due to its loading and coordination chemistry, which facilitates flexible volume changes and continuity in electrical conductivity through a continuous carbon nanofiber.
TiO2 nanofibers were prepared by improved electrospinning technique and subsequent thermal treatment. The as-prepared TiO2 nanofibers possess anatase-rutile mischcrystal structure. Sulfur was mixed with the TiO2 nanofibers to form S–TiO2 composite by a melt diffusion process. The S–TiO2 composite displays more excellent discharge capacity retention of 58% after 50 cycles compared to pure S, and the discharge capacity is 530mAhg−1 after 50 cycles, which is ascribed to the adsorption of lithium polysulfide by TiO2.
We review our recent work in the field of molecule-based magnets showing the structural and magnetic properties of a special class of hybrid organic–inorganic compounds, i.e. metal(II) organophosphonates. The synthesis, the crystal structures and, in particular, the magnetic studies of selected examples of compounds of formulas M(II)[(R–PO3)(H2O)], and M2[(O3P–R′–PO3)(2H2O)] M=Cr, Fe, Co; R=C n H2n+1, n =1, 2, 3… and C6H5, R′=(CH2)2 prepared in our laboratory are presented and discussed. Metal alkylphosphonates, except those of Co(II), are weak ferromagnets at low temperatures. The observed magnetic ordering temperature T N varies from 4.2 to 25K, depending on the transition metal ions and on crystal and molecular structure. Moreover, in the case of a bifunctional molecule like aminoethylphosphonic acid, NH2(CH2)2PO3H2, or the carboxyethylphosphonic acid, HO2C(CH2)2PO3H2, is used as a ligand, then a novel Cr(II) compound of formula Cr[NH3(CH2)2PO3(Cl)(H2O)] and a microporous Fe(III) salt (NH4)[Fe2(OH){O3P(CH2)2CO2}2] are isolated. The latter are both polar and, more interesting, Cr(II) ammoniumethylphosphonate chloride results to be a weak ferromagnet below T N =5.0K.
Electrically rechargeable zinc-oxygen batteries are promising for sustainable and resource-uncritical energy storage with high energy density. Their commercialization is hindered by the limited cycling stability – especially due to the zinc anode. In this study, we present a zinc anode that stands out with two advantages: The use of an energy-saving and low temperature preparation method, and the mechanical stabilization of the pore system with a lightweight anion-exchange ionomer. Our approach increases cycling stability for both the zinc-nickel oxide hydroxide cell and the zinc-oxygen cell: Electrochemical analysis in combination with operando X-ray diffraction measurements prove that the novel zinc anode is electrically rechargeable and can be cycled up to five times more often than zinc sponge anodes without anion-exchange ionomer to a depth of discharge of 35%. Scanning electron microscopy is used to evidence that the anion-exchange ionomer stabilises the entire pore system during cycling. We furthermore analyse zinc-oxygen batteries with anion-exchange ionomer at all parts – inside the zinc sponge anode, as separator and at the cathode. These cells can be electrically recharged with unprecedented high utilization of active material, and thus highlight the benefit of introducing an ion-selective coating into alkaline batteries with zinc anode.
Corrosion in grid-scale energy storage devices adversely affects service lifetime and thus has a significant economic impact on their deployment. In this work, we investigate the corrosion of steel and stainless steels (SSs) as positive current collectors in the Li||Sb-Pb liquid metal battery. The erosion and formation of new phases on low-carbon steel, SS301, and SS430 were evaluated both in static conditions and under cell operating conditions. The cell performance is not adversely affected by the dissolution of iron or chromium but rather nickel. Furthermore, the in situ formation of a Fe-Cr-Sb layer helps mitigate the recession of SS430.
Mechanical activation followed by rotary heating has been successfully applied to the synthesis of Cr-doped lithium manganese oxide (LiMn2O4) powders. The precursor of LiCr x Mn2−x O4 for Li-ion batteries has been synthesized from LiOH·H2O, MnO2, and Cr2O3 as starting materials by mechanical activation, which ensured a high level of homogeneity in the chemical composition of the precursor and resulted in a reduction in the synthesis temperature and heating time. Highly crystallized LiCr x Mn2−x O4 (0.04≤x≤0.10) powders were obtained by subsequent rotary heating of the precursor at 550–750°C for 2h. Rotary heating enhanced the experimental control in chemical composition, particle size distribution and microstructure of the final products. The optimum mechanical activation condition was determined based on XRD analysis. The synthesized LiCr x Mn2−x O4 powder has a narrow particle size distribution, high discharge capacities and good cyclability. The method of mechanical activation combined with rotary heating should be an excellent technique of decreasing synthesis temperature and shortening heating time, and enhancing the uniformity of particle size of the product.
The operation of proton exchange membrane (PEMFC) and direct methanol fuel cells (DMFC) is connected with the flow of different gaseous and liquid components in the cell's membrane-electrode assembly (MEA). The structural and wetting properties of different components of the MEA influence the rate and direction of these flows and hence the fuel cell's efficiency. For a better understanding of the mechanism of all processes influencing the fuel cell efficiency, for a mathematical modelling of these processes, and for a possibility of their optimization, a detailed knowledge of the geometrical structure and wetting properties of all MEA components is necessary. This review describes the results of such investigations performed mainly by using the method of standard contact porosimetry (MSCP). This method gives the possibility to receive information on multicomponent porous and powdered materials hitherto not accessible, viz. their wetting and swelling properties, pore corrugation, and also isotherms of capillary pressure and bond energy. Measurements of MEA components by this method can be performed under exactly the same conditions (temperature, compression degree, contact with water, etc.) as those existing in real fuel cells.
A randomized crossover study of BPN14770 in adult males with fragile X syndrome shows significant cognitive improvement in domains related to language with corresponding improvement in caregiver scales rating language and daily functioning.
Since the discovery of many types of mesoporous silicas, such as SBA-15, KIT-6, FDU-12 and SBA-16, porous crystalline transition metal oxides, such as Cr2O3, Co3O4, In2O3, NiO, CeO2, WO3, Fe2O3 and MnO2, have been synthesized using the mesoporous silicas as hard templates. Several synthetic methods have been developed. These new porous materials have high potential applications in catalysis, Li-ion rechargeable batteries and gas sensors. This article gives a brief review of the research of porous crystals of metal oxides in the last four years.
Thermal stability of carbon structure anode materials for Li-ion rechargeable batteries is studied with the consideration to carbon physical property and structure. Differential scanning calorimeter (DSC) thermal test shows that the thermal decomposition of fully delithiated carbon anode materials at an elevated temperature to about 230°C generate weak exothermic heat and the heat amount is in the linear relation to their carbon specific surface area. Meanwhile, the fully lithiated carbon anode materials generates much stronger exothermic heat in the same temperature range and the heat amount is largely differed with their carbon structure. X-ray diffraction (XRD) and DSC tests reveal that intercalated lithium inside the carbon structure is involved in thermal reactions with aqueous liquid electrolyte and the evolved specific heat per lithium mol is largely differed with the carbon structure.
Sustaining injury is a common consequence of playing sport. At least one in every three recreational athletes with anterior cruciate ligament (ACL) reconstruction do not return to their preinjury sport following treatment. Psychological factors including confidence and fear of new injury exert large effects on returning to sport. The primary aim of this trial is to test whether a custom smartphone application delivering cognitive-behavioural therapy is effective for improving the number of people who return to their preinjury sport and level following ACL reconstruction.
Electrothermal impedance spectroscopy (ETIS), is introduced as a new measurement method and thermal parameters derived from a pouch-type lithium-ion cell are presented. ETIS is a valuable tool for (i) the determination of the thermal impedance and (ii) the validation of thermal models. The excitation signal applied to the cell during measurement does not cause a change in entropy, thus facilitating the parameter identification of a thermal model for heat conduction and thermal capacity. ETIS can be applied to measurements in time domain and in frequency domain. Both approaches are presented and a combination further improves measurement time and accuracy.
This paper examined the initiation, funding, realisation and the current state of some renewable energy applications in the West Region of Cameroon. The findings from the study conducted showed that all of the renewable energy applications were initiated by indigenes living outside the beneficiary communities. The lack of fee-for-service tariffs was partly responsible for the failure of a wind electric installation for potable water pumping. Conflicts in a local management committee resulted in the inoperative state of a pico-hydro installation, while the lack of finances accounted for the failure of a PV system of rural Health Centre. Although, some successful results were noted in the activities of African Center for Renewable and Sustainable Technologies (ACREST) involving foreign technical expertise in small scale renewable energy applications, ACREST had difficulties with the implementation of 100kW micro hydro project. The stakeholders identified for successful renewable energy applications in Cameroon included local management committees, microfinance institutions, Non-Governmental Organisations (NGOs), Renewable Energy Enterprises (REEs) and universities. Local management committees must be in charge of the supervision, operation and maintenance of installed systems as well as revenue collection based on fee-for-service tariffs. Microfinance institutions should grant loans for the acquisition of financially and economically viable off-grid renewable energy systems to communities with monthly installments based on established monthly energy expenditures. NGOs are expected to provide technical assistance for the conception of community projects, the procurement of funding from cooperation partners and for the realisation of projects. REEs should have competence for sizing, installation and post-installation maintenance of renewable energy equipment. Universities must train the technicians and engineers that will be used by NGOs and REEs. This important role has been recognised by the government of Cameroon through the creation of the first Department of Renewable Energy at the University of Maroua in 2008.
For decades, valve regulated lead acid batteries with gel electrolyte have proved their excellent performance in deep cycling applications. However, their higher cost, when compared with flooded batteries, has limited their use in cost sensitive applications, such as automotive or PV installations. The use of flooded batteries in deep or partial state of charge working conditions leads to limited life due to premature capacity loss provoked by electrolyte stratification. Different electrolyte formulations have been tested, in order to achieve the best compromise between cost and life performance. Work carried out included electrochemical studies in order to determine the electrolyte stability and diffusional properties, and kinetic studies to check the processability of the electrolyte formulation. Finally, several 12V batteries have been assembled and tested according to different ageing profiles.
This paper presents a simplified model of a nickel hydrogen battery based on a first approximation. The battery is assumed uniform throughout. The reversible potential is considered primarily due to one-electron transfer redox reaction of nickel hydroxide and nickel oxyhydroxide. The non-ideality due to phase reactions is characterized by the two-parameter activity coefficients. The overcharge process is characterized by the oxygen reaction. The overpotentials are lumped to a tunable resistive drop to fit particular battery designs. The model is implemented in the Virtual Test Bed environment, and the characteristics of the battery are simulated and in good agreement with the experimental data within the normal operating regime. The model can be used for battery dynamic simulation and design in a satellite power system, an example of which is given.
Vascular plants have a network of vasculature in their leaves, which supplies water and nutrients and exports photoassimilates to other tissues. The vascular network is patterned during the development of leaf primordia through the induction of provascular differentiation by auxin. Arabidopsis thaliana Dof5.8, encoding a Dof-type transcription factor, is expressed early in provascular cells under the control of the MONOPTEROS transcription factor, also known as auxin response factor 5 (ARF5). Here, we report the effect of overexpressing Dof5.8 in provascular cells on the formation of the vascular network. Overexpression of Dof5.8 inhibited the formation of higher-order veins in cotyledons and leaves, probably through transcriptional repression by Dof5.8. The expression of auxin-associated transcription factor genes, DORNRöSCHEN and SHI-RELATED SEQUENCE 5, was downregulated in the Dof5.8 overexpressors, and overexpression of these genes partially rescued the impaired formation of higher-order veins in Dof5.8-overexpressing lines, suggesting that the overexpression of Dof5.8 modulates the auxin response and leads to impaired vein formation in A. thaliana.
We collected simultaneous dive Time Depth Recorder (TDR) data and video images from free swimming adult female leatherback turtles, Dermochelys coriacea, during the first 24 h after nesting on the beach, in order to determine relationships between dive parameters, activity, overall respiratory frequency and behaviour. We identified three different underwater locomotory activities (subsurface swimming, V-shaped dives and U-shaped dives) from video and TDR data that varied in their mean depth, duration and a number of other parameters. Overall respiratory frequency (overall f R) was significantly different between all locomotory activities, with turtles taking 1.7±0.1 breaths min−1 while subsurface swimming, 0.78 breaths min−1 after V-shaped dives and 0.57 breaths min−1 after U-shaped dives. Descent rates and ascent rates were significantly faster in U-shaped dives (descent 0.19±0.010 m s−1, ascent 0.28±0.015 m s−1) than in V-shaped dives (descent 0.10±0.008 m s−1, ascent 0.12±0.012 m s−1). Flipper stroke rates were significantly lower during the bottom component of U-shaped dives (0.18±0.02 strokes s−1) than during the descent (0.29±0.03 strokes s−1) or ascent (0.29±0.03 strokes s−1). From overall f R and flipper stroke rate data, we inferred that turtles used less energy during U-shaped dives than the other activity types. We recorded interactions between male turtles and the study females that lasted up to 11 min, during which male turtles displayed the characteristic courtship behaviour of sea turtles. It appeared that females attempted to avoid males by aborting ascent and extending dive duration to swim to the sea floor when males were present.
In this contribution, the novel 2D sandwich-like NiO/C arrays on Ti foil are successfully designed and fabricated for the first time via simple and controllable hydrothermal process. In this strategy, we use green glucose as carbon source and ultrathin Ni(OH)2 nanosheet arrays as precursor for NiO nanoparticles and sacrificial templates for coupled graphitized carbon layers. This advanced sandwiched composite can not only provide large surface area for numerous active sites and continuous contact between active materials and electrolyte, but also protect the active nanoparticles from aggregation, pulverization and peeling off from conductive substrates. Furthermore, the porous structure derived from lots of substances loss under high-temperature calcinations can effectively buffer possible volume expansion and facilitate ion transfer. In this article, sandwiched NiO/C arrays, utilized as anode for LIBs, demonstrated high specific capacity (∼1458 mAh g−1 at 500 mA g−1) and excellent rate performance and cyclablity (∼95.7% retention after 300 cycles).
Lithium (Li) metal anodes have regained intensive interest in recent years due to the ever-increasing demand for next-generation high energy battery technologies. Li metal, unfortunately, suffers from poor cycling stability and low efficiency as well as from the formation of dangerous Li dendrites, raising safety concerns. Utilizing solid-state electrolytes (SSEs) to prevent Li dendrite growth provides a promising approach to tackle the challenge. However, recent studies indicate that Li dendrites easily form at high current densities, which calls for full investigation of the fundamental mechanisms of Li dendrite formation within SSEs. Herein, the origin and evolution of Li dendrite growth through SSEs have been studied and compared by using Li6.1Ga0.3La3Zr2O12 (LLZO) and NASICON-type Li2O–Al2O3–P2O5–TiO2–GeO2 (LATP) pellets as the separators. We discover that a solid electrolyte interphase (SEI)-like interfacial layer between Li and SSE plays a critical role in alleviating the growth of dendritic Li, providing new insights into the interface between SSE and Li metal to enable future all solid-state batteries.
Two graphene materials, TRGO-1 and TRGO-2, prepared by the thermal exfoliation/reduction at 1000 °C of two graphite oxides with different characteristics, are investigated as positive electrodes in a vanadium redox flow battery (VRFB). A detailed study of their electrochemical response toward the [VO2+]/[VO 2 +] redox system is carried out through cyclic voltammetry, electrochemical impedance spectroscopy and charge/discharge experiments. As a consequence of the differences in the structure of the parent graphite oxides, TRGO-1 and TRGO-2 exhibit different structural and physicochemical properties resulting in significantly different electrochemical performances toward the vanadium redox reactions. TRGO-1 exhibits a markedly enhanced electrochemical activity (higher peak current densities and lower overpotentials) and a better kinetic reversibility toward the oxidation/reduction vanadium processes than TRGO-2. Furthermore, charge/discharge tests performed on two VRB single cells, the only differing component being the positive electrode, present higher coulombic, voltage and energy efficiency values in that battery containing the TRGO-1 electrode. The better results achieved with this sample are attributed to the higher degree of restoration of the 2D graphitic structure, and to the consequently higher electrical conductivity which increases the heterogeneous electron transfer rate. Moreover, residual hydroxyl groups present may act as active reaction sites and contribute to enhance its electrochemical response.
Physical and electrochemical properties of the Na[FSA]–[C2C1im][FSA] (C2C1im+:1-ethyl-3-methylimidazolium and FSA−:bis(fluorosulfonyl)amide) ionic liquids have been investigated in view of their application as electrolytes for sodium secondary batteries operating in a wide temperature range. The Na[FSA]–[C2C1im][FSA] ionic liquids in the range of 0.0 ≤ x(Na[FSA]) ≤ 0.5 are in the liquid state at room temperature, where x(Na[FSA]) is the mole fraction of Na[FSA]. In the case of x(Na[FSA]) = 0.3, the ionic conductivity, viscosity, and electrochemical window at 298 K are 5.4 mS cm−1, 78 mPa s, and 5.1 V, respectively. Sodium metal deposition/dissolution test in the ionic liquid at x(Na[FSA]) = 0.3 resulted in average cycle efficiencies of 69% and 96% at 298 K and 363 K, respectively, at a current density of 1.0 mA cm−2.
It has recently been shown, in the case of the bis(fluorosulfonyl)amide (FSI) based ionic liquids, that as the concentration of the alkali metal salt (LiFSI or NaFSI) is increased, the alkali metal cation transference number increases, despite an increase in viscosity and decrease in conductivity. At the same time significant enhancements in electrochemical stability and rate performance of devices are also observed. Here we overview some of the recent findings already in the literature and in addition demonstrate the feasibility of stable, high rate room temperature lithium battery cycling in an electrolyte comprised of 60 mol% LiFSI in a trimethyl, isobutyl phosphonium FSI ionic liquid using a high voltage NMC cathode. We also demonstrate that the high rate cycling of lithium and sodium metal in these phosphonium FSI electrolytes leads to a nanostructured anode deposit and a lowering of the interfacial impedance, suggesting a stable SEI layer formation. Finally, we propose a hypothesis that may explain some of the observations thus made, by which the high alkali ion concentration in these mixed electrolyte systems leads to the effective elimination of the mass transport limitations that are chiefly responsible for the formation of dendrites in traditional electrolytes. This work suggests that a new type of ionic liquid consisting of a mixture of metal cations with organic cations can provide a solution to the instability of the reactive alkali metal anodes and hence enable higher energy density technologies.