batterydata/paper-abstracts huggingface dataset:
Lithium titanate (Li4Ti5O12) is well known as a zero strain material inherently, which provides excellent long cycle stability as a negative electrode for lithium ion batteries. However, the low specific capacity (175mAhg−1) limits it to power batteries although the low electrical conductivity is another intrinsic issue need to be solved. In this work, we developed a facile hydrothermal and ion-exchange route to synthesize the self-supported dual-phase Li4Ti5O12–TiO2 nanowire arrays to further improve its capacity as well as rate capability. The ratio of Li4Ti5O12 to TiO2 in the dual phase Li4Ti5O12–TiO2 nanowire is around 2:1. The introduction of TiO2 into Li4Ti5O12 increases the specific capacity. More importantly, by interface design, it creates a dual-phase nanostructure with high grain boundary density that facilitates both electron and Li ion transport. Compared with phase-pure nanowire Li4Ti5O12 and TiO2 nanaowire arrays, the dual-phase nanowire electrode yielded superior rate capability (135.5 at 5C, 129.4 at 10C, 120.2 at 20C and 115.5mAhg−1 at 30C). In-situ transmission electron microscope clearly shows the near zero deformation of the dual phase structure, which explains its excellent cycle stability.
Lithium-sulfur (LiS) batteries have been considering as a very promising energy storage system since their high theoretical specific capacity and energy density. Nevertheless, the practical commercialization of LiS batteries is hindered by their poor cycle stability and fast capacity fading. Herein, a carbonized bacterial cellulose/titania (CBC/TiO2) modified separator is designed to restrain the shuttle effect of LiS cells with its strong physical and chemical adsorption of polysulfides. Cells with CBC/TiO2 modified separator show an initial discharge capacity of 1314mAhg−1 at 0.2C, and the capacity retention is 1048.5mAhg−1 after 50cycles. A discharge capacity of 475mAhg−1 is obtained after 250cycles at 2C. And during the rate test, LiS cells can deliver a discharge capacity of 537.1mAhg−1 at 2C. The outstanding electrochemical performance of LiS cells with CBC/TiO2 modified separator shows a new approach for the application of LiS batteries.
Nickel-based oxide cathode material taking out from lithium-ion cell after storage for 2 years at 45°C is analyzed by electron energy-loss spectroscopy in a scanning transmission electron microscope (STEM-EELS) and the result of STEM-EELS is compared with cobalt-based oxide cathode material which is treated as same manor as nickel-based oxide cathode material. The Ni-L2,3 energy-loss near-edge structure (ELNES) spectra of nickel-based oxide cathode material show peak positions similar to original material before storage. This result indicates that nickel-based oxide material has no significant change in the surface structure. On the other hand, a remarkable shift to low energy is observed in the Co-L2,3 ELNES spectra of the cobalt-based oxide cathode material after storage. The cycle test at 60°C under the conditions of aggressive driving cycle (US06) mode for the nickel-based oxide cathode/graphite cell is also carried out. It is clear that cycle performance of the nickel-based oxide cathode/graphite cell is dependent on the depth of discharge (DOD).
High-performance supercapacitors materials (a-GNS/NiAl-LDH) was fabricated via in situ growth of NiAl-layered double hydroxide (NiAl-LDH) nanoflakes on well-activated graphene nanosheets (a-GNS). Graphene oxide was exfoliated and reduced using the microwave irradiation, alkali corrosion and thermal annealing in sequence. The resulting a-GNS is of large BET surface area of up to 3026m2 g−1 and excellent conductivity. The as-prepared a-GNS/NiAl-LDH was characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction and infrared spectrum. The results indicated NiAl-LDH nanoflakes are well dispersed on the wrinkled graphene nanosheets. Further, the apparent electron transfer rate constant (k s) and electrochemical performance of a-GNS/NiAl-LDH as electrode material for supercapactiors were also investigated. The k s value was found to be 0.0885cms−1, which is more than 2.5-fold that of pure NiAl-LDH. The a-GNS/NiAl-LDH provides a maximum specific capacitance of 1730.2Fg−1 at current density of 0.1Ag−1. The specific capacitance can remain 790Ag−1 when the current density increase to 10Ag−1, which is more than 6- and 3-fold that of pure NiAl-LDH (116.3Fg−1) and common GNS/NiAL-LDH (260.6Fg−1) made from the graphene produced by the chemical reduction of graphene oxide, respectively. The capacitance can keep at least 99.2% at current density of 5Ag−1 after 500 cycles. These demonstrated that the use of a-GNS obviously improve the specific capacitance, high-current capacitive behavior and cycle stability.
Supercapacitors have attracted great attention as advanced energy storage devices. However, the low energy density and high cost of electrode materials are the downsides for their practical applications. Here, we introduce a facile and low-cost strategy to develop honeycomb-like Ni3S2 nanosheet arrays (NSAs) as a redox-type electrode for aqueous hybrid supercapacitors (HSCs). Owing to the porous structure of NSAs, the Ni3S2 electrode can show excellent electrochemical performance in 2 M KOH aqueous electrolyte. A high specific capacity of 151.2 mAh g−1 has been achieved at the current density of 3 A g−1. To demonstrate their further applications, HSCs have been assembled with activated carbon (AC) as negative electrode and the assembled devices can successfully work within a large voltage range of 0–1.6 V and deliver a maximum energy density of 35.2 Wh kg−1 at the power density of 491 W kg−1.
We present here a novel simple method for the synthesis of highly pure TiO2(B). The fast microwave-assisted synthetic route allows facile scale-up of the process. Aiming at an application of the titania polymorph as negative electrode for Li-ion batteries, we have prepared a Fe-containing TiO2(B) and tested the electrochemical performances of both pure and Fe-containing materials. Fe insertion in TiO2(B) allows enhancing capacity and rate capability.
Wilm's tumor protein 1 (WT1), a protein implicated in various cancers and developmental disorders, consists of two major isoforms: WT1(−KTS), a transcription factor, and WT1(+KTS), a post-transcriptional regulator that binds to RNA and can interact with splicing components. Here we show that WT1 interacts with the novel splicing regulator RBM4. Each protein was found to colocalize in nuclear speckles and to cosediment with supraspliceosomes in glycerol gradients. RBM4 conferred dose-dependent and cell-specific regulation of alternative splicing of pre-mRNAs transcribed from several reporter genes. We found that overexpressed WT1(+KTS) abrogated this effect of RBM4 on splice-site selection, whereas WT1(−KTS) did not. We conclude that the (+KTS) form of WT1 is able to inhibit the effect of RBM4 on alternative splicing.
Nanostructured NiCo2O4 spinel was fabricated with a facile, low-cost coprecipitation process. The ethylene glycol was applied to serve as a stabilizer to govern over the nucleation, growth, and agglomeration processes. The influence of the calcination time was also studied on the coprecipitation reaction. Both the reaction conditions have statistically significant effects on the size distribution, crystallinity, electronic conductivity and the electrochemical performances of the products. The optimized, 5–10nm NiCo2O4 spinel, calcinated at 375°C for 8h, had excellent crystallinity and electric conductivity. It showed a superior-specific capacitance of 671Fg−1 at a current density of 1Ag−1. The delay in the specific capacitance was insignificant, after a 7000-cycle test, revealing the high stability of the product. The simplicity and practicability of the modified coprecipitation process may facilitate the successful commercial applications in electrochemical capacitors for nanostructured NiCo2O4 spinel.
Accurate knowledge of lithium content within the solid electrolyte interphase (SEI) layer and anode would significantly enhance the current understanding of the lithium ion battery (LIB) degradation mechanisms, enabling knowledge-based improvements in the technology. For the first time, we have demonstrated the capabilities of highly selective Lithium Nuclear Reaction Analysis (Li-NRA) as a non-destructive depth profiling technique for quantifying Li within the SEI and anode without accurate knowledge of the composition, which is unavailable with other depth profiling techniques. The Li-NRA technique detects the gamma radiation resulting from a nuclear reaction at characteristic resonance energy between an incident high-energy proton and Li. The intensity of γ-ray is directly proportional to the Li content, and the energy of the incident proton is increased stepwise to depth profile the sample. We performed Li-NRA on the carbonaceous negative electrodes of commercial LIB coin cells at varying states of charge (SOC) and states of health (SOH) conditions. We used three simple models for the composition of SEI and anode material to show concurrence between theoretical and experimental value for Li content at varying SOC conditions, estimated the average SEI layer thickness, and correlated the residual Li content within the SOH samples with electrochemical data.
With the successive advent of piezoelectric nanogenerator (PENG) and triboelectric nanogenerator (TENG), the harvest of ambient mechanical energy has become more high-efficient, low-lost and simpler for self-powered systems. Introducing lightweight alternative power source to bionic micro aerial vehicle (BMAV) which is widely used for military surveillance or monitoring air pollution and so on, is the forefront of the research hotspots. However, there is still no design applying the two kinds of nanogenerator (NG) together in BMAV to collect the flapping mechanical energy more efficiently. In this paper, we demonstrate a hybrid flexible nanogenerator (HFNG) based on the combination of triboelectric and piezoelectric devices in BMAV. It not only can solve the problem of power supply, but also make the BMAV intelligent to monitor the changes of specific environmental factors. The newly designed HFNG can produce a maximum open-circuit voltage of 80 V, short-circuit current of 3.0 μA with the instantaneous output power density of 34.1 mW/m2 when the flapping frequency of BMAV (f) is 14 Hz. The rectified output of HFNG has been applied to charge the commercial capacitor, rechargeable battery and drive light-emitting diodes. It was also demonstrated that HFNG can be used for testing the lift force (L) of BMAV. Moreover, the output performances of HFNG have been proved to be sensitive to temperature, humidity, alcohol concentration and PM2.5 in the environment.
Optical constituents as suspended particulate matter (SPM), chlorophyll (Chl-a), colored dissolved organic matter (CDOM), and grain sizes were obtained on a transect in the arctic fjord-type estuary Kangerlussuaq (66°) in August 2007 along with optical properties. These comprised diffuse attenuation coefficient of downwelling PAR (Kd(PAR)), upwelling PAR (Ku(PAR)), particle beam attenuation coefficient (cp), and irradiance reflectance R(−0, PAR). PAR is white light between 400 and 700 nm. The estuary receives melt water from the Greenland Inland Ice and stations covered a transect from the very high turbid melt water outlet to clear marine waters. Results showed a strong spatial variation with high values as for suspended matter concentrations, CDOM, diffuse attenuation coefficient Kd(PAR), particle beam attenuation coefficients (cp), and reflectance R(−0, PAR) at the melt water outlet. Values of optical constituents and properties decreased with distance from the melt water outlet to a more or less constant level in central and outer part of the estuary. There was a strong correlation between inorganic suspended matter (SPMI) and diffuse attenuation coefficient Kd(PAR) (r2 = 0.92) and also for particle beam attenuation coefficient (cp; r2 = 0.93). The obtained SPMI specific attenuation—Kd*(PAR) = 0.13 m2 g−1 SPMI—and the SPMI specific particle beam attenuation—cp* = 0.72 m2 g−1—coefficients were about two times higher than average literature values. Irradiance reflectance R(−0, PAR) was comparatively high (0.09−0.20) and showed a high (r2 = 0.80) correlation with Ku(PAR). Scattering dominated relative to absorption—b(PAR)/a(PAR) = 12.3. Results strongly indicated that the high values in the optical properties were related to the very fine particle sizes (mean = 2–6 μm) of the suspended sediment. Data and results are discussed and compared to similar studies from both temperate and tropical estuaries.
Hierarchical porous gold films with a well-defined bimodal architecture have been made by electrodepositing gold at a constant current around a close-packed assembly of raspberry-like latex spheres (1200/60nm) followed by template removal. Electrodeposition was stopped when the gold was either ½ layer or 1½ layer thick as evident from oscillations in the potential vs time traces. Scanning electron microscopy (SEM) images show the hierarchical pore structure with an ensemble of small ∼20nm openings located in a large ∼1200nm diameter macropore. Prior to electrochemical characterization, the electrodes were cleaned either chemically and/or via UV radiation and X-ray photoelectron spectroscopy (XPS) was used to evaluate the presence of residual polystyrene. Of the three cleaning methods investigated, sonication in chloroform–acetone followed by UV radiation proved best. The surface area of the hierarchical porous gold electrodes, determined by integrating the area under the gold oxide peak, was 4× larger than a bare gold electrode and 2× larger than a macroporous gold electrode prepared using unimodal, 1200nm diameter latex spheres as the template. The electrochemical performance of the electrodes relative to the macroporous gold and flat gold was undertaken using cyclic voltammetry. The results show that the non-Faradaic current scales linearly with electrode area while the Faradaic current of a diffusing electrochemically reversible redox probe (ferrocene methanol) does not. For an adsorbed redox couple (ferrocene hexanethiol), the voltammetric wave shapes and surface coverage were different for the different electrodes.
Production of hydrogen using aluminum and aluminum alloys with aqueous alkaline solutions is studied. This process is based on aluminum corrosion, consuming only water and aluminum which are cheaper raw materials than other compounds used for in situ hydrogen generation, such as chemical hydrides. In principle, this method does not consume alkali because the aluminate salts produced in the hydrogen generation undergo a decomposition reaction that regenerates the alkali. As a consequence, this process could be a feasible alternative for hydrogen production to supply fuel cells. Preliminary results showed that an increase of base concentration and working solution temperature produced an increase of hydrogen production rate using pure aluminum. Furthermore, an improvement of hydrogen production rates and yields was observed varying aluminum alloys composition and increasing their reactive surface, with interesting results for Al/Si and Al/Co alloys. The development of this idea could improve yields and reduce costs in power units based on fuel cells which use hydrides as raw material for hydrogen production.
The frontal lobes are critical for cognitive control over both abstract actions and motor plans. On the basis of the behavioral deficits of lesions patients, the authors report that there is a hierarchical organization of cognitive control, with rostral areas being required for decisions about more abstract actions and caudal areas being required for decisions about more concrete actions.
This study shows that excitatory neurons in the ventral hippocampus that express the serotonin receptor 2c gene control attention through direct innervation of the mouse equivalent of the Edinger–Westphal nucleus.
Safe and reliable operation of a Li-ion battery requires control and often management of the thermal envelope. In this context, a two-dimensional, transient mathematical model comprising conservation of charges, species, and energy together with electroneutrality, constitutive relations and relevant initial and boundary conditions for a spiral-wound cylindrical Li-ion battery is derived and solved numerically for passive thermal management with and without a phase change material (PCM) at various galvanostatic discharge rates. Two-way coupling of the electrochemical and thermal equations of change is attained through heat generation terms and temperature-dependent physical properties. Within this framework, the electrochemical and thermal behavior is discussed in terms of edge effects arising from the design of the spiral-wound structure and variations in heat generation in the functional layers. In addition, the cell performance with passive thermal management through a PCM is shown to lower the overall temperature of the cell at discharge rates around 5C-rates, provided the PCM layer is thick enough to provide cooling during the entire discharge. The model can be employed for wide-ranging parameter studies as well as multi-objective optimization of not only design parameters pertaining to the spirals but also, for example, for design of the thickness of the PCM layer.
Surface segregation in metal oxides can greatly influence the oxygen transport and surface oxygen exchange kinetics critical to the performance of solid-state devices such as oxygen permeation membranes and solid oxide fuel/electrolytic cell electrodes. Unfortunately detecting elemental distributions at the atomic scale near the surface remains challenging, which hampers the understanding of underpinning mechanisms and control of surface segregation for the design of high-performance materials. Using the coherent Bragg rod analysis (COBRA) method, we report the first direct 3D atomic imaging of a 4 nm-thick “La0.8Sr0.2CoO3–δ”/SrTiO3 epitaxial film. Of significance, energy differential COBRA revealed pronounced Sr segregation (La1−xSrxCoO3−δ, x ∼ 0.4) in the four unit cells from the top surface while complete Sr depletion was detected in the five unit cells from the “La0.8Sr0.2CoO3−δ”/SrTiO3 interface. The drastic strontium compositional changes in the film were associated with large changes in the atomic positions of apical oxygen sites in the perovskite structure. Such Sr segregation tendencies toward the surface were also found in nominal “La0.6Sr0.4CoO3−δ” thin films, which can greatly enhance the surface oxygen exchange properties of oxides. The results presented here show that COBRA and the differential COBRA methods can be used to investigate a variety of electrochemically active systems providing atomic scale structural and chemical information that can help understand the physical and chemical properties of these systems and serve as a basis for comparison with DFT calculations.
We demonstrate a novel Li-ion hybrid electrochemical capacitor (Li-HEC) assembled using 1D nanofibers of a high voltage spinel insertion electrode (LiNi0.5Mn1.5O4) and an activated carbon (AC) counter electrode in an organic electrolyte. A scalable electrospinning technique was employed to produce 1D nanofibers of the high voltage spinel electrode. Structural and morphological features of the nanofibers were studied using various characterization techniques. Performance of spinel and AC electrodes were evaluated in half-cell configurations with metallic Li. A Li-HEC assembly with optimized mass loading delivered a maximum energy density of ~19Whkg−1 while retaining ~81% of the initial value after 3000 cycles.
Lithium-ion batteries are now well known and widely available commercially. The vast majority use lithium cobalt oxide or variants as the cathode material. This has the advantage of good performance but the cost of the cobalt is high and it is slightly toxic. Iron would be preferable on grounds of cost and safety but unfortunately lithium iron oxides cannot be cycled. Iron compounds are cheap and iron sulphides can readily be obtained as minerals, without the need for chemical synthesis. However, to make a lithium-ion battery, the cathode material must contain lithium so the iron sulphide must be lithiated to use this as a cathode material. This can be synthesised by literature methods involving solid state syntheses at high temperature for long times. New syntheses have been developed which are much quicker and easier. Results on cycling of lithium-ion cells using lithiated iron sulphide prepared by the new method will be described using laboratory and envelope (pouch) cells. Because of the use of cheaper materials, these should be preferable to existing technology, particularly for larger size applications, such as electric vehicles.
Research exploring cognitive processing associated with Williams Syndrome (WS) has suggested that executive functioning deficits exist across the developmental spectrum. Such executive functions include problem solving, planning, dividing attention and inhibiting responses. Within a framework of executive functions, the aim of the current study was to explore attentional lapse and inhibition skills in older adults with WS (n =20; aged 36–61yr) and consider the implications of deficits within this group. Participants with WS were compared to typical adults of the same chronological age and typical older adults (aged 65+yr) to consider attentional changes seen in the ageing process. The study employed a sustained attention to response task known to assess inhibition and attentional lapse but which had not previously been used with this population. Compared to both groups of typical matches, the results indicated atypicalities of attention and inhibition in adults with WS. Specifically, compared to the typical matches, adults with WS failed to withhold a response (showing inhibition deficits), had problems re-engaging attentional control processes after making an error and showed a generalised deficit of concentration and task engagement. We conclude that further attention should be paid to the cognitive capacity of older individuals with WS in order to consider the everyday challenges faced by this group and to provide adequate intervention and support for daily living.
A silicon/disordered-carbon powder was applied as the negative electrode material in Li ion batteries. The thermal characteristics of the Si/C electrode mixed with or without the electrolyte were investigated by DSC. Both lithiated (with capacity of 1120mAhg−1) and delithiated Si/C electrode powder showed exothermic peaks in DSC curves due to the reactions between the Li in the electrode and the SEI. The lithiated electrode caused much larger exothermic heat than the delithiated one, especially when they were mixed with the electrolyte. By changing the ratio between the lithiated Si/C electrode and the coexisting electrolyte, the thermal behavior of the mixture could be studied in detail. At about 290°C, a mixture containing 0.5mg lithiated Si/C electrode and 0.5μl electrolyte showed the most drastic exothermic heat of 2.2J among all mixtures due to a direct reaction between the residual lithiated electrode and the solvent of the electrolyte after the thermal breakdown of the SEI. Under this condition, the heat value based on the electrode weight was 4.4Jmg−1, and that based on capacity was 5.1JmAh−1. These values of graphite were estimated to be 1.9Jmg−1 and 5.8JmAh−1, respectively. The generated heat was found to be very sensitive to the electrode/electrolyte ratio.