batterydata/paper-abstracts huggingface dataset:
Nickel hydroxide is widely utilized for the cathode material of asymmetric supercapacitors due to high electrochemical performance and low cost. However, considering its poor electrical conductivity as well as short cycle life, Ni(OH)2 is not capable of applying to high performance supercapacitors. An efficient solution is to fabricate the activated graphene nanosheets (AGNSs)/spinule-like Ni(OH)2 composite by controllable complex-precipitation method. The electrochemical measurement results demonstrate that AGNSs/spinule-like Ni(OH)2 composite as cathode material for supercapacitor has high specific capacitance of 2450 F g−1 at 1 A g−1 and excellence cycling capacity (1499 F g−1 after 5000 cycles at 10 A g−1). The asymmetric supercapacitor (ASC) displays a superior energy density of 55.6 Wh Kg−1 at power density of 1628 W kg−1, as well as rate capacity. These excellent electrochemical properties are attributed to the synergy effect of activated graphene and nickel hydroxide.
Obesity is characterized by chronic inflammation of low grade. The cholinergic anti-inflammatory pathway favors the reduction of the inflammatory response. In this work the effect of stimulation of the cholinergic anti-inflammatory pathway on SHIRPA behavioral test and mitochondrial respiratory chain activity in obese mice was evaluated. The animals were paired in four groups: saline + control diet; donepezil + control diet; saline + high-fat diet and donepezil + high-fat diet. 5 mg/kg/day orally of donepezil or saline were given 7 days before the beginning of the diet until completing 11 weeks of the experiment. Food intake and body weight were measured. At the end of the experiment the animals were submitted to the SHIRPA behavioral test, soon after they were killed by decapitation, the open abdominal cavity and the mesenteric fat were removed. The hypothalamus, hippocampus, prefrontal cortex, and striatum were removed for evaluation of the mitochondrial respiratory chain. It can be observed that donepezil prevented weight gain and food consumption, as well as a tendency to prevent the accumulation of mesenteric fat in obese animals. There was no behavioral change in obese animals, nor did the influence of donepezil on these parameters. On the other hand, donepezil did not prevent inhibition of complex I activity, prevented the inhibition of complex II, and showed a tendency to prevent IV complex activity inhibited in obesity. With these results it can be concluded that the activation of the cholinergic anti-inflammatory pathway is promising for the alterations found in obesity.
Previously, a highly efficient reduced order model (ROM) for Li(MnNiCo)O2/Graphite polymer battery based on electrochemical principles has been developed for real time applications. The execution time is significantly reduced compared to that of the electrochemical thermal full order model while beginning of life of the battery with the approximately same accuracy can be predicted. However, prediction of the end of life associated with degradation effects of battery was not included. Our investigations on aging mechanisms of the Li(MnNiCo)O2 (MNC) lithium ion batteries have revealed that side reaction is the main cause among others for capacity and power fade of the battery. The production of the side reaction forms thin unsolvable layers that adhere to the surface of the graphite particles and grow as cycled, which is called solid electrolyte interphase (SEI). Growth of the SEI leads to loss of the lithium ions, loss of the electrolytes and loss of the active volume fraction. These effects are described using the Butler-Volmer kinetics and aging parameters. Particularly, electrolyte solvent diffusion described by Fick's law is integrated into the degradation model, which results in quantifying the electrolyte solvent concentration in SEI. The exchange current density of the side reaction is formulated as a function of electrolyte solvent and lithium ion concentration, which justifies the reaction rate in the aspect of reactants. In addition, temperature dependency of the model parameters is also considered by adopting the energy equations. Finally, the degradation model is incorporated into the ROM. Performances of the integrated ROM are compared with the experimental data collected from a high power pouch type lithium ion polymer battery with Li [MnNiCo]O2/Graphite chemistry.
Changes in the composition of embedded pyrite (FeS2) particle electrodes in 1 M LiClO4 propylene carbonate solutions as a function of the applied potential have been examined in situ by S K-edge fluorescence X-ray absorption near edge structure (XANES), using a specially designed cell that minimizes attenuation of low energy X-rays. Pyrite electrodes that had been scanned from 3.0 V versus Li/Li+, i.e. close to the open circuit voltage, down to 1.0 V (fully discharged state, i.e. 4e−-reduction) and then half recharged (2e−-reoxidation) by scanning the potential in the positive direction up to 2.2 V versus Li/Li+, revealed features consistent with the presence of Li2FeS2, in agreement with in situ Fe K-edge results reported earlier by this research group. Moreover, only subtle changes were discerned between the in situ S K-edge XANES of the half-, and fully-recharged electrodes. This close resemblance may reflect similarities between the spectral signatures of Li2FeS2 and Fe1−x S (pyrrhotite), which is the main product of the discharge reaction. Evidence for the formation of elemental sulfur and Li2S, which are believed to be minor products of the reaction, was obtained from analysis of the first differential S XANES and selected difference spectra. The compositional variations of the embedded pyrite particles throughout the course of the electrochemical processes occur in the presence of a persistent sulfate coating.
The hydrogen-bromine redox flow battery's (H2 Br2 RFB) advantages of high energy capacity, high round-trip conversion efficiency and low cost, make it an optimal candidate for large-scale energy storage systems. The crossover of bromide species through the membrane degrades the performance of the H2 Br2 RFB by poisoning the catalyst responsible for the hydrogen evolution and oxidation reactions. Herein we propose the new concept of a selective catalyst coating layer that mitigates the effect of bromide crossover. The polymerization of dopamine on the catalyst surface yields a nanoscale conformal polydopamine layer which acts as a semi-permeable barrier to block bromide species. The H2 Br2 RFB with the coated catalyst shows a low capacity fading of 6% at 300 mA cm−2 after exposure to 4.5 M charged electrolyte for 2 h. Even the beginning of life polarization curves show the benefit of catalyst coating with a high peak power of ∼550 mW cm−2. Hence, the catalyst coating opens a way to solve the crossover issue in H2 Br2 RFB technology.
We report here thermal behaviour and various components of heat loss of 18650-type LiFePO4/graphite cell at different testing conditions. In this regard, the total heat generated during charging and discharging processes at various current rates (C) has been quantified in an Accelerating Rate Calorimeter experiment. Irreversible heat generation, which depends on applied current and internal cell resistance, is measured under corresponding charge/discharge conditions using intermittent pulse techniques. On the other hand, reversible heat generation which depends on entropy changes of the electrode materials during the cell reaction is measured from the determination of entropic coefficient at various states of charge/discharge. The contributions of irreversible and reversible heat generation to the total heat generation at both high and low current rates are evaluated. At every state of charge/discharge, the nature of the cell reaction is found to be either exothermic or endothermic which is especially evident at low C rates. In addition, electrochemical impedance spectroscopy measurements are performed on above 18650 cells at various states of charge to determine the components of internal resistance. The findings from the impedance and thermal loss analysis are helpful for understanding the favourable states of charge/discharge for battery operation, and designing better thermal management systems.
Implicit memory is generally supposed to be preserved in Alzheimer’s disease (AD). Yet, some implicit priming effects are impaired and others are not. The preserved/impaired priming effects are often interpreted according to the perceptual/conceptual or identification/production distinctions. Perceptual–identification priming paradigms shall be preserved and conceptual–production priming paradigms impaired. A third interpretation is yet possible based on the disconnection syndrome hypothesis which states that patients with AD should fail tasks requiring relatively complex brain communications. In this case, patients with AD should not demonstrated a significant perceptual priming effect in an identification task if this one involved complex brain communications. The present study tests this latter hypothesis with two cross-modal priming experiments using a categorization task. A visual meaningless mask presented with half of the auditory primes tested the nature of the cross-modal priming effect. The control group exhibited significant priming effects for unmasked primes. The interference effect of the mask demonstrated that the priming effect was perceptually driven. Patients with AD did not present any priming effect nor mask interference. The present findings therefore showed that perceptual priming using an identification task could be impaired in AD supporting the disconnection syndrome hypothesis.
Lithium metal–polymer electrolyte batteries with improved utilization of the active material at a moderate–low temperature (65°C) were realized. Low molecular weight poly(ethylene glycol) (PEG, MW=2000) was used as the lithium-ion conductive matrix in the composite cathode. The cathode active material was crystalline V2O5. A blend of poly(ethylene oxide) (PEO, MW=4×106) and PEG was used as a solid polymer electrolyte (SPE). The transport properties of the SPE were evaluated at various temperatures. A specific conductivity as high as 1.0×10−4 Scm−1 was calculated at 45°C. The temperature dependence of the interfacial resistances between lithium/SPE and cathode material/PEG was evaluated. The lithium/SPE interfacial resistance decreases linearly with the temperature. The charge transfer resistance between the cathode material and PEG reaches a minimum at 60°C and it does not decrease with a further temperature increase. The data clearly show that the battery is able to work at a temperature as low as 60°C. The operating temperature was set at 65°C and the battery performance was evaluated at different discharge rates. An energy density of about 500 Whkg−1 and a power density of about 150 Wkg−1 were achieved cycling the cell in about 3.3 h at 0.20 mAcm−2. Prolonged cycling showed a capacity fading of about 0.45% per cycle. This value does not differ very much from the value found cycling the cell in liquid electrolyte. The fade in capacity was associated with an increase of cell resistance. The evolution of the lithium/SPE and cathode material/PEG interfaces resistances was monitored. The interfacial resistance increases with time, but its value is not so high as to explain the increase of the total resistance of the cell. Anyhow, this additional resistance could be responsible for the difference in the capacity fading when cycling the cell in polymer electrolyte instead of in liquid electrolyte.
The Li1+x V3O8 material was successfully synthesized at 450°C in short sintering duration by microwave sol–gel route. X-ray diffraction suggests oxygen defects in the lattice. Based on Randles–Sevcik formula, cyclic voltammograms measurements were conducted to measure Li+ ion diffusion coefficient. The material exhibits high discharge capacity of 250mAg−1 at 0.2mA/cm2 after 30 cycles in the range of 2.0–4.0V. Alternating current impedance tests show that the growth of the charge transfer resistance at 0.4mA/cm2 is more rapid than that of at 0.2mA/cm2 as the galvanostatical charge–discharge continues.
The aim of this work is to study the effect of CO2 under pressure on hybrid inorganic–organic polymer electrolytes, by using broad band dielectric spectroscopy (BDS) in the frequency interval 40Hz–10MHz and in the temperature range of −80 to 120°C. Eleven inorganic–organic hybrid materials of the ORMOCERs type, with general formula {Al[O(CH2CH2O)8.7] ρ /(LiClO4) z } n were treated by applying CO2 at 293K and 5MPa. The results demonstrated that the CO2 treatment generally depressed the conductivity of about one order of magnitude. The decreased conductivity in treated complexes is explained in terms of a smaller anion-trapping ability of the Al centers. Residual CO2 molecules are likely to inhibit the interaction of the perchlorate anions with Al centers within the structure. Segmental motion of the polymer chains plays a crucial role in the conductivity of investigated samples, while the ion-hopping phenomenon is the most important charge transfer mechanism both in the pristine and CO2 treated materials. Equivalent conductivity studies have elucidated the different ionic species present at various salt concentrations and gave insight about the role of CO2 in modifying the transport properties of the samples.
In this work, a hydrothermal method has been exploited to synthesize porous δ-MnO2 nanosheets. The influence of hydrothermal temperature on the synthesis of δ-MnO2 has been investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM) and electrochemical methods. The results show that the pure δ-MnO2 appears at the hydrothermal temperature from 130 to 170°C, and the hydrothermal temperature has a great influence on the morphology and BET surface area of as-prepared samples. The δ-MnO2 prepared at 150°C delivers high specific capacitances of 411Fg−1 at a scan rate of 5mVs−1 and 332.7Fg−1 at a current density of 0.5A g−1. The excellent supercapacitor performance is attributed to the porous nanosheets structure, which brings a large specific surface area, increases the active sites, and shortens the ion diffusion distance in δ-MnO2 electrodes. It is suggested that the optimal synthesizing temperature is 150°C in order to obtain pure δ-MnO2 with good electrochemical performance by hydrothermal method.
Carbon nanofibers (CNFs)/MnO2 nanocomposites were prepared as freestanding electrodes using in situ redox deposition and electrospinning. The electrospun CNFs substrates with porosity and interconnectivity enabled the uniform incorporation of birnessite-type MnO2 deposits on each fiber, thus showing unique and conformal coaxial nanostructure. CNFs not only provided considerable specific surface area for high mass loading of MnO2 but also offered reliable electrical conductivity to ensure the full utilization of MnO2 coatings. The effect of MnO2 loading on the electrochemical performances was investigated by cyclic voltammetry (CV), impedance measurements and Galvonostatic charging/discharging technique. The results showed that an ultrathin MnO2 deposits were indispensable to achieve better electrochemical performance. The maximum specific capacitance (based on pristine MnO2) attained to 557F/g at a current density of 1A/g in 0.1M Na2SO4 electrolyte when the mass loading reached 0.33mg/cm2. This freestanding electrode also exhibited good rate capability (power density of 13.5kW/kg and energy density of 20.9Wh/kg at 30A/g) and long-term cycling stability (retaining 94% of its initial capacitance after 1500 cycles). These characteristics suggested that such freestanding CNFs/MnO2 nanocomposites are promising for high-performance supercapacitors.
Lithium ion batteries are a leading energy storage technology for electronic portable devices and hybrid electric vehicles. A long-standing challenge to understand Li ion transport is the fact that this light atom escapes direct detection by X-ray techniques (EDX, XRD and XAS) due to weak scattering and emission properties. Simultaneous characterisation of the structure, chemical composition (including Li) and elemental distribution in Li-ion battery materials can reveal the relationship between Li ion transport and structural effects (phase transformation, internal stress), and battery performance and degradation. Nanoscale mapping is achieved by multi-modal correlative microscopy combining focused ion beam and scanning electron microscopy (FIB-SEM) with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). Mapping Li, Mn and Co nanoscale distributions reveals the micro-structural consequences of the electrochemical reaction, and allows identifying Li “trapping” sites within the structure that control materials properties, and open the way towards designing better Li-ion cathode materials with superior performance.
A facile graphite assisted approach is proposed to synthesize high performance LiMn2O4 nanostructures. Graphite plates with different sizes and thicknesses are found to have different influences on the structure, morphology and performance of LiMn2O4. Larger and thicker graphite plates result in 2-D porous LiMn2O4 nanoplates whereas smaller and thinner ones lead to the formation of dispersed nanoparticles. Despite the smaller lattice constant, the shorter LiO and longer MnO bonds, and the lower BET surface area compared to dispersed LiMn2O4 nanoparticles, LiMn2O4 nanoplates formed by primary nanoparticles with similar sizes and morphologies exhibit the superior performance because of the better interparticle electronic conductivity. LiMn2O4 nanoplates show the discharge capacity of 104 mAh g−1 at 50 C and the capacity retention of 70.0% after 1000 cycles for 1 C at RT, better than the corresponding values, 95 mAh g−1 and 64.5% for dispersed LiMn2O4 nanoparticles, respectively. The more superior performance of LiMn2O4 nanoplates compared to dispersed LiMn2O4 nanoparticles is particularly manifested in the case of lower percentage conductive additive, which is very significant for practical application. This simple, cost effective, green and up scalable approach can also be employed to synthesize other 2–D nanostructured materials.
The current paper reviews existing literature that relates to how body worn cameras might influence an officer’s memory of their interactions with the public, namely those that involve the use of force. Notably, most of this research does not come from the policing field but focuses on the impact of camera technology in other settings. Much of the available research supports the commonly held view that body worn cameras could be used to enhance memory for these interactions, particularly interactions that are complex or stressful. However, contrary to what people might expect, research also exists that suggests body worn cameras may actually have a detrimental effect on officer memory. Three major potential detriments: cognitive offloading, retrieval-induced forgetting and misinformation-type effects are highlighted. Future studies examining the impact of body worn cameras on officers’ memory are necessary. Ways forward are discussed.
Publisher Summary This chapter discusses a variety of methods proposed and used to reduce and in some cases to remove reconfiguration overhead, including various configuration architecture designs, scheduling, and caching techniques, and ways to reduce the configuration data size. The difficulty of clock speed increases and power consumption concerns motivate reconfigurable computing as an important technique to advance digital design, implementing compute-intensive application tasks in reconfigurable hardware. However, the performance and power penalty of reconfiguration has the real potential to overwhelm its benefits. In many cases, several approaches can be combined to further reduce the overhead. For example, relocation and defragmentation architectural features facilitate advanced configuration scheduling mechanisms that load configurations in advance of their use to minimize processor stall time during reconfiguration. Likewise, a configuration cache can be combined with a relocation- and defragmentation-enabled design that uses a staging area, providing a wide path to configuration memory to decrease transfer time. This in turn can be combined with wildcarding to allow multiple identical rows or columns to be configured simultaneously. Such combined methods allow reconfigurable computing system designers to effectively minimize reconfiguration overhead and to provide the full benefit of reconfigurable computing in future computing systems.
Using Plasma Enhanced Chemical Vapor Deposition, one can prepare methylated amorphous silicon thin-layer anodes for Li-ion batteries exhibiting good cyclability. The properties of that material are investigated here in view of this target application. In comparison with pure amorphous silicon prepared in the same conditions, the improvement is twofold: longer lifetime, and capability of working with thicker electrodes. For example, capacity retention after 100 cycles of 150 nm thick layers with 10% carbon content is almost 70% larger than that of pure a-Si layers. The observed improvement is attributed to mechanical softening of amorphous Si by incorporation of CH3 groups.
The compression of carbon felt electrodes for redox flow batteries leads to changes in the electrochemical performance and has a large effect on the pressure drop of electrolyte flow through the system. In this investigation, the authors have characterised the electrochemical performance of all-vanadium redox flow batteries by studying the effect of compression on the contact resistance, polarisation behaviour and efficiency. Contact resistance was seen to reduce from ca. 2.0Ωcm2 to 1.2Ωcm2 and an energy efficiency of 85% was obtained from a felt compressed to 75%. Moreover, X-ray computed tomography (CT) has been employed to study the microstructure of felt electrodes at compressions up to 70%, showing a linear decrease in porosity and a constant fibre surface area-to-volume ratio. The pressure drop was modelled using computational fluid dynamics and employing the 3D structure of the felts obtained from CT, revealing that a 60% increase in compression related to a 44.5% increase in pressure drop.
The inherent limited capacity of current battery technology is not sufficient for covering the increasing power requirements of widely extended portable devices. Among other promising alternatives, recent advances in the field of micro-Solid Oxide Fuel Cells (μ-SOFCs) converted this disruptive technology into a serious candidate to power next generations of portable devices. However, the implementation of single cells in real devices, i.e. μ-SOFC stacks coupled to the required balance-of-plant elements like fuel reformers or post combustors, still remains unexplored. This work aims addressing this system-level research by proposing a new compact design of a vertically stacked device fuelled with ethanol. The feasibility and design optimization for achieving a thermally self-sustained regime and a rapid and low-power consuming start-up is studied by finite volume analysis. An optimal thermal insulation strategy is defined to maintain the steady-state operation temperature of the μ-SOFC at 973 K and an external temperature lower than 323 K. A hybrid start-up procedure, based on heaters embedded in the μ-SOFCs and heat released by chemical reactions in the post-combustion unit, is analyzed allowing start-up times below 1 min and energy consumption under 500 J. These results clearly demonstrate the feasibility of high temperature μ-SOFC power systems fuelled with hydrocarbons for portable applications, therefore, anticipating a new family of mobile and uninterrupted power generators.