batterydata/paper-abstracts huggingface dataset:
Silicon nanowires (SiNWs) have the potential to perform as anodes for lithium-ion batteries with a much higher energy density than graphite. However, there has been little work in understanding the surface chemistry of the solid electrolyte interphase (SEI) formed on silicon due to the reduction of the electrolyte. Given that a good, passivating SEI layer plays such a crucial role in graphite anodes, we have characterized the surface composition and morphology of the SEI formed on the SiNWs using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). We have found that the SEI is composed of reduction products similar to that found on graphite electrodes, with Li2CO3 as an important component. Combined with electrochemical impedance spectroscopy, the results were used to determine the optimal cycling parameters for good cycling. The role of the native SiO2 as well as the effect of the surface area of the SiNWs on reactivity with the electrolyte were also addressed.
Activated carbon fiber (ACF) containing Sn nanoparticles were prepared by impregnation and were investigated as a negative electrode material in lithium batteries. The tin particle size was controlled by selecting an ACF with an adequate surface structure. This Sn/ACF composite cycled versus Li metal showed a first discharge capacity as high as 200mAhg−1 compared to the pristine ACF which showed only 87mAhg−1. Excellent cyclability with these composites was obtained with ACF BET SSA as large as 2000m2 g−1 and 30wt.% Sn.
Layered positive electrode materials for rechargeable lithium-ion batteries of the general formula Li[Mn0.5−x/2Ni0.5−x/2Co x ]1−y M y O2 (x ≤1/3, 0≤ y ≤0.05) were synthesized by a solid state route. The effect of doping elements M on the electrochemical performance was investigated. It was found that doping with niobium or tantalum has a positive effect on the cycling stability compared to the undoped parent compounds (y =0). High discharge capacities, excellent cycling stabilities and high rate capabilities were achieved.
Hedgehog-like mesoporous rutile TiO2 (HLR-TiO2) composed of well-defined nanoneedles is fabricated in a solvothermal system containing tetrabutyl titanate, hydrochloric acid aqueous solution and diethylene glycol with a proper volume ratio. A possible formation mechanism of the HLR-TiO2 is proposed on the basis of different experimental results and three different morphologies are obtained by changing the solvent with other conditions unchanged. Given its unique hierarchical mesoporous nanostructures, the HLR-TiO2 shows superior lithium storage properties with excellent discharge specific capacity of 243.3 mA h g−1 obtained after 100 cycles at a current rate of 1 C among the three samples, which is almost unparalleled to other rutile TiO2-based electrodes. In particular, a specific capacity of 80.2 mA h g−1 is still maintained after 2000 cycles even at a high current rate of 20 C, indicating that great potential of HLR-TiO2 as an electrode material for lithium-ion batteries (LIBs).
A micro-reformer was made by using silicon fabrication technology and a new catalyst loading method of ‘fill-and-dry coating’. The techniques of silicon wet etching, bonding and thin-film deposition were applied in the micro-reformer process, and a commercial Cu-ZnO-Al2O3 catalyst served as the reforming catalyst. The volume of the single micro-reactor was 0.55cm3 and the micro-reformer stack, which consists of one vaporizer and two reformers, occupied 15cm3. Methanol solution was used as the reactant and the composition and feed rate were varied. The operating temperature of the reformer was in the range of 280–320°C and was controlled by an electrical thin-film heater at a fixed vaporizer temperature of 150°C. The product gas was composed of 75% H2, 25% CO2 and 2100ppm CO. The maximum hydrogen production rate and conversion were about 200cm3 and 95% at 320°C, respectively.
In the European Waste List (2000/532/EC as amended) the ash of municipal waste incineration is defined as a so called mirror entry. This waste can be classified as hazardous or non-hazardous depending on the content of hazardous substances and other risk properties. For the assignment of waste in mirror entries, 14 criteria are defined. One of the criteria is H14 “ecotoxic”. In the presented study, the ecotoxicological potential of 12 ashes from different incineration plants has been assessed using biological test systems. The test battery included aquatic tests with eluates (algae, daphnids, and luminescent bacteria) and terrestrial tests with solid waste (plants, earthworms and bacteria). The test results revealed a clear ecotoxicological hazard potential for some of the MWI ashes. Despite the fact that fresh ashes were several times more toxic than aged ashes both groups did not differ consistently in terms of toxicity. The results show also that there is no correlation between the biological effects and the analyzed chemical compounds of the ash samples.
Balance tests are commonly used to screen for impairments that put older adults at risk for falls. The purpose of this study was to determine the attributes that were associated with balance performance as measured by the Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT) balance test. This study was a cross-sectional secondary analysis of baseline data from a longitudinal cohort study, the Boston Rehabilitative Impairment Study of the Elderly (Boston RISE). Boston RISE was performed in an outpatient rehabilitation research center and evaluated Boston area primary care patients aged 65 to 96 (N=364) with self-reported difficulty or task-modification climbing a flight of stairs or walking 1/2 of a mile. The outcome measure was standing balance as measured by the FICSIT-4 balance assessment. Other measures included: self-efficacy, pain, depression, executive function, vision, sensory loss, reaction time, kyphosis, leg range of motion, trunk extensor muscle endurance, leg strength and leg velocity at peak power. Participants were 67% female, had an average age of 76.5 (±7.0) years, an average of 4.1 (±2.0) chronic conditions, and an average FICSIT-4 score of 6.7 (±2.2) out of 9. After adjusting for age and gender, attributes significantly associated with balance performance were falls self-efficacy, trunk extensor muscle endurance, sensory loss, and leg velocity at peak power. FICSIT-4 balance performance is associated with a number of behavioral and physiologic attributes, many of which are amenable to rehabilitative treatment. Our findings support a consideration of balance as multidimensional activity as proposed by the current International Classification of Functioning, Disability, and Health (ICF) model.
We employ a MnCo2O4–graphene hybrid material as the cathode catalyst for Li–O2 batteries with a non-aqueous electrolyte. The hybrid is synthesized by direct nucleation and growth of MnCo2O4 nanoparticles on reduced graphene oxide, which controls the morphology, size and distribution of the oxide nanoparticles and renders strong covalent coupling between the oxide nanoparticles and the electrically conducting graphene substrate. The inherited excellent catalytic activity of the hybrid leads to lower overpotentials and longer cycle lives of Li–O2 cells than other catalysts including noble metals such as platinum. We also study the relationships between the charging–discharging performance of Li–O2 cells and the oxygen reduction and oxygen evolution activity of catalysts in both aqueous and non-aqueous solutions.
The compounds deposited on a lithium transition metal oxide charged in a siloxane-based electrolyte were analyzed by Fourier transformation infrared (FT-IR) spectroscopy and thermal analysis. The decomposition of the siloxane-based electrolyte occurred at voltages above 4.2V, and the compounds that deposited on the cathode surface consisted of species from both the decomposed siloxane molecule and the electrolyte salt. Differential scanning calorimetry (DSC) profiles of the charged cathode revealed an exothermic peak at 130°C. The exothermic temperature corresponded to the onset of weight loss of the siloxane-based electrolyte, as revealed in the thermal gravimetry-differential thermal analysis (TG-DTA) diagram. The results indicated that the deposited compounds on the cathode surface and the siloxane-based electrolyte were decomposed at this temperature. Finally, two major exothermic peaks in the DSC profile for the siloxane-based electrolyte occurred at higher temperatures than those for carbonate-based electrolyte, and showed reduced heat flow. The present research suggests that the siloxane-based electrolyte can improve safety of a lithium battery.
In order to improve the utilization rate of the electrolyte and further reduce the energy storage cost, the physicochemical properties, electrochemical characteristics and charge/discharging behaviors of VFB with different concentration of VOSO4 and H2SO4 were investigated systematically. The physicochemical characterizations show that the viscosity increases with the increasing concentration of VOSO4 and H2SO4, and the conductivity increases with the increasing concentration of H2SO4 while decreases with the increasing concentration of VOSO4. Both CV and EIS results demonstrate that the electrolyte with 1.6 mol L−1 VOSO4 and 2.8 mol L−1 H2SO4 presents the best electrochemical performance because of the coupling effect of the viscosity, conductivity and electrochemical activity. Different with the half-cell electrochemical tests, the battery performance of VFB is not only dependent on the electrochemical activity of electrode/electrolyte interface, but also closely related to the conductivity of electrolyte and diffusion rates of the active particles between anolyte and catholyte. Taking the battery efficiencies and capacity into consideration, VFB with 1.6 mol L−1 VOSO4 and 2.8 mol L−1 H2SO4 exhibits the optimal electrochemical performance. The accomplishment of this work not only gives data support to the fundamental research of VFB, but also provides theoretical direction to the engineering application of VFB.
Ionic liquid gel polymer electrolytes (ILPEs) based on electrospun P(VdF-HFP) membrane were prepared by incorporating RTILs, BMImTFSI or BMImBF4. A suitable BMIm cation based ionic liquid with lithium salt and influence of temperature on electrochemical performance was investigated. The BMImTFSI-based polymer electrolyte with LiTFSI salt showed better electrochemical properties and the properties increase with increasing the operation temperature to 40 ˚C, to 140 mAh g−1 discharge capacity at 1 C-rate. However, after 40 ˚C the properties remained the same even when the temperature was increased at high current density.
Carbon-rich silicon oxycarbide ceramics (SiOC) prepared via thermal conversion of polyorganosiloxane demonstrate high lithiation capacity and reliable rate capability when used as anode material in Li-ion batteries. The electrochemical properties of carbon-rich SiOC are strongly related to microstructure and phase composition, dependent on final pyrolysis temperature. Both, the increasing organization of free carbon segregated within the microstructure and the gradual degradation of the amorphous Si–O–C network with increasing pyrolysis temperature (T pyr) lead to reduced capacities and changing voltage profiles. Within our study, the highest registered capacity of 660 mAh g−1 for T pyr = 900 °C dropped below 80 mAh g−1 for SiOC pyrolyzed at 2000 °C. A continuous decrease in capacity is observed, when increasing T pyr stepwise by 100 °C, which can be explained by major microstructural changes. First, the free carbon within the ceramic microstructure organizes toward higher ordered configurations, as determined by Raman spectroscopy. Second, X-ray powder diffraction demonstrates a decomposition of the amorphous Si–O–C network resulting in SiC crystallization and growth of SiC domains. Simultaneously, FTIR spectroscopy shows a strong increase of Si–C vibration with T pyr, while Si–O vibration diminishes and almost disappears after annealing at 1700–2000 °C. According to our study we find, that i) increasing carbon organization provides less Li-ion storing sites, ii) gradual Si–O–C network decomposition reduces the structural stability of the free carbon phase and iii) formation of electrochemically inactive SiC account for reduced capacities and changing voltage profiles with increasing T pyr.
As electrode materials for supercapacitors, nanostructured hybrids always show better performance compared to corresponding single material. In this work, Ni(OH)2 flakes/MnO2 nanosheets hybrid hierarchical architecture (Ni(OH)2/MnO2 HHA) was constructed on Ni foam (NF) through a two-step hydrothermal reaction. Interestingly, MnO2 nanosheets are vertically grown on the both sides of Ni(OH)2 flakes, forming a highly porous structure with large specific surface area and amounts of diffusion channels. As a binder-free electrode for supercapacitors, Ni(OH)2/MnO2 HHA/NF exhibits a high specific capacity of 253.6 mAh g−1 at 2 A g−1, which is much higher than the individual Ni(OH)2 and MnO2. The excellent electrochemical performance can be attributed to the highly porous architecture, two-dimensional (2D) feature and synergistic effect between Ni(OH)2 and MnO2. The asymmetric hybrid supercapacitor was assembled using Ni(OH)2/MnO2 HHA/NF (24 h) as positive electrode and activated carbon (AC) as negative electrode in 3 M KOH. The hybrid supercapacitor cell can be cycled in the voltage window of 0–1.9 V and exhibits a maximum specific energy of 29.9 Wh kg−1 at 1900 W kg−1. The results indicate that the Ni(OH)2/MnO2 HHA/NF electrode shows great potential in design of high-performance energy storage devices. The construction of this 2D branched hierarchical architecture provides an effective method to obtain excellent electrode materials for energy storage.
A nitrogen and phosphorus co-doped hierarchical porous carbon (N, P-HPC) were fabricated by simply pyrolysis of polyaniline aerogels in the presence of phytic acid and subsequently activation treatment by KOH. The as-prepared N, P-HPC with a highly interconnected network structure and possesses a large surface area and pore volume is very favor in the impregnation of sulfur. Moreover, simultaneously introduced nitrogen and phosphorous into the carbon could create more active sites than the mono-doped carbons, the synergistic effects of dual activation of carbon atoms induced stronger chemical adsorption ability. Benefiting from the advantages of suitable hierarchical porosity, high conductivity, fast ion transportation, physical and chemical adsorption of the N, P-HPC, the Sulfur/N, P-HPC composite exhibits high initial discharge capacity of 1116 mAh g−1 at 0.1 C (1 C = 1675 mA g−1, based on sulfur content) and high rate capability of 550 mAh g−1 at 2C, as well as excellent long term cycling stability at a current rate of 1 C with only 0.058% capacity decay per cycle for over 500 cycles. Such a high capacity and stability suggests that the novel cathode have alluring prospect for Li-S batteries.
Most athletes who undergo anterior cruciate ligament (ACL) reconstruction surgery plan to return to some level of sporting activity. However, rates of return to pre-injury sport are often less than might be expected and many factors influence whether individuals return to sport after this surgery. They include surgical and rehabilitation factors as well as social, psychological and demographic characteristics. The fate of the younger athlete who sustains an ACL injury is a topic that has received recent attention due to accumulating evidence that younger athletes are at considerable risk for not only one, but multiple ACL injuries. Little is known about how to determine when it is safe to return to sport following ACL reconstruction or how to predict whether an athlete will be able to successfully return. The notion that a set of return to sport criteria can be applied to reduce the risk of further injury has become popular with many different criteria proposed. Another risk of returning to sport following ACL reconstruction is that of sustaining injury to the menisci or articular surfaces, which may in turn increase the risk of developing osteoarthritis. Although there is some evidence that ACL reconstruction reduces the risk of osteoarthritis there is stronger evidence that it does little to protect the knee from long term degeneration. Therefore, it should be recognized that return to sport following ACL reconstruction is associated with a risk of further injury and potential development of osteoarthritis.
Energy is the largest overhead cost in the production of agricultural greenhouse crops in temperate climates. Moreover, the initial cost of fossil fuels and traditional energy are dramatically increasing. The negative environmental impacts, limited sources of fossil fuels and a high consumption of energy and food have caused the increase in demand for solar energy as a green and sustainable choice. Therefore, this paper reviews the solar energy application technologies in the environmental control systems of greenhouses (cooling, heating and lighting) mainly the generated energy of photovoltaic (PV) and solar collectors, as well as the PV water pumping for irrigation. Furthermore, this paper briefly discusses the economic analyses and the challenges for this technology.
Li4Ti5O12/C composites were synthesized by one-step solid-state reaction method using four commonly used organic compounds or organic polymers as carbon source, i.e., polyacrylate acid (PAA), citric acid (CA), maleic acid (MA) and polyvinyl alcohol (PVA). The physical characteristics of Li4Ti5O12/C composites were investigated by X-ray diffraction, electron microscopy, Raman spectroscopy, particle size distribution and thermogravimetry-derivative thermogravimetry techniques. Their electrochemical properties were characterized by cyclic voltammograms, electrochemical impedance spectra, constant current charge–discharge and rate charge–discharge. These analyses indicated that the carbon source and carbon content have a great effect on the physical and electrochemical performances of Li4Ti5O12/C composites. An ideal carbon source and appropriate carbon content effectively improved the electrical contact between the Li4Ti5O12 particles, which enhanced the discharge capacity and rate capability of Li4Ti5O12/C composites. PAA was the best carbon source for the synthesis of Li4Ti5O12/C composites. When the carbon content was 3.49wt.% (LiOH·H2O/PAA molar ratio of 1), as-prepared Li4Ti5O12/C showed the maximum discharge capacity. At 0.2C, initial capacity of the optimized sample was 168.6mAhg−1 with capacity loss of 2.8% after 50 cycles. At 8 and 10C, it showed discharge capacities of 143.5 and 132.7mAhg−1, with capacity loss of 8.7 and 9.9% after 50 cycles, respectively.
Though many neuronal cell fate decisions result in reproducible outcomes, stochastic choices often lead to spatial randomization of cell subtypes. This is often the case in sensory systems where expression of a specific sensory receptor gene is selected randomly from a set of possible outcomes. Here, we describe recent findings elucidating the mechanisms controlling color photoreceptor subtypes in flies and olfactory receptor subtypes in worms and mice. Although well-known biological concepts such as lateral signaling and promoter selection play roles in these cases, fundamental questions concerning these choice mechanisms remain.
This paper reports the results from a randomized clinical trial evaluating an adaptation of the Promoting Alternative Thinking Strategies curriculum (PATHS) for preschool-age children in Head Start. PATHS is a universal, teacher-taught social-emotional curriculum that is designed to improve children’s social competence and reduce problem behavior. Twenty classrooms in two Pennsylvania communities participated in the study. Teachers in the 10 intervention classrooms implemented weekly lessons and extension activities across a 9-month period. Child assessments and teacher and parent reports of child behavior assessments were collected at the beginning and end of the school year. Analysis of covariance was used to control for baseline differences between the groups and pretest scores on each of the outcome measures. The results suggest that after exposure to PATHS, intervention children had higher emotion knowledge skills and were rated by parents and teachers as more socially competent compared to peers. Further, teachers rated intervention children as less socially withdrawn at the end of the school year compared to controls.
This article discusses the structural and dynamic properties of a model polymer electrolyte system suitable for Li-ion batteries, investigated by Molecular Dynamics simulations at 293K. It consists of a non-polar polyethylene backbone, onto which polar oligomeric polyethylene oxide side-chains of length 4–15 EO units are attached. LiPF6 salt is dissolved into the matrix to a concentration corresponding to a Li:EO ratio of 1:12. It is found that the system display significantly higher mobility values that linear PEO using the same concentration, which is attributed to the high side-chain dynamics and the polar/non-polar topology of the system. An optimum side-chain length of 10 EO units is found for many properties, such as the dissolution of salt, although the Li+ ion diffusion was found to be the highest for side-chain lengths of 15 EO units: 1.54×10−13 m2 s−1.
Storage equipment, such as batteries and thermal energy storage (TES), has become increasingly important recently for peak-load shifting in energy systems. Mathematical programming methods, used frequently in previous studies to optimize operating schedules, can always be used to derive a theoretically optimal solution, but are computationally time consuming. Consequently, we use metaheuristics, such as genetic algorithms (GAs), particle swarm optimization (PSO), and cuckoo search (CS), to optimize operating schedules of energy systems that include a battery, TES, and an air-source heat pump. In this paper, we used a GA, differential evolution (DE), our own proposed mutation-PSO (m-PSO), CS, and the self-adaptive learning bat algorithm (SLBA), of which m-PSO was the fastest, and CS was the most accurate. CS obtained the semi-optimal solution 135 times as fast as dynamic programming (DP), a mathematical programming method with 0.22% tolerance. Thus, we showed that metaheuristics, especially m-PSO and CS, have advantages over DP for optimization of the operating schedules of energy systems that include a battery and TES.
Thermal management is critical to improving battery performance and suppressing thermal runaway. Besides developing external cooling technologies, it is important to understand and control thermal transport inside batteries. In this paper, heat transfer inside batteries is first analyzed and the thermal conductivity of each component is measured. The results show that low thermal conductivity of the separator is one major barrier for heat transfer in Li-ion batteries. To improve thermal conductivity of the separator, a hierarchical nano/micro-Al2O3/polymer separator is prepared with thermal conductivity of ~1Wm−1 K−1, representing an enhancement of 5× compared to commercial polyethylene-based separators. Modeling has been performed to understand mechanism behind the enhancement of thermal conductivity, which suggests that addition of nanoparticles significantly reduces thickness of polymer coating on micron-sized Al2O3 particles and thus increase the thermal conductivity of the composite separator. This Al2O3-based separator also has similar ionic conductivity with commercial polymer separators. Such composite separator may have potential applications in developing batteries with better performance and safety.