batterydata/paper-abstracts huggingface dataset:
Flower-like hydrogenated TiO2(B) nanostructures have been synthesized via a facile solvothermal approach combined with hydrogenation treatment. The obtained TiO2(B) nanostructures show uniform and hierarchical flower-like morphology with a diameter of 124 ± 5 nm, which are further constructed by primary nanosheets with a thickness of 10 ± 1.2 nm. The Ti3+ species and/or oxygen vacancies are well introduced into the structures of TiO2(B) after hydrogen reduction, resulting in an enhancement in the electronic conductivity (up to 2.79 × 10−3 S cm−1) and the modified surface electrochemical activity. When evaluated for lithium storage capacity, the hydrogenated TiO2(B) nanostructures exhibit enhanced electrochemical energy storage performances compared to the pristine TiO2(B) nanostructures, including high capacity (292.3 mA h g−1 at 0.5C), excellent rate capability (179.6 mA h g−1 at 10C), and good cyclic stability (98.4% capacity retention after 200 cycles at 10C). The reasons for these improvements are explored in terms of the increased electronic conductivity and the facilitation of lithium ion transport arising from the introduction of oxygen vacancies and the unique flower-like morphologies.
Evidences support the view that central obesity is an independently cardiovascular risk. It is thought that leptin contributes to autonomic dysfunction and cardiovascular risks in type 1 and type 2 diabetes mellitus (T1DM and T2DM). This raises the possibility that leptin might mediate the relationship between central obesity and the severity of cardiovascular autonomic neuropathy (CAN) in patients with well-controlled T2DM and prediabetes.
Clark and Wells’ (1995) model of social phobia proposes that there are three types of maladaptive self-beliefs responsible for persistent social anxiety (high standard, conditional, and unconditional beliefs). Although these beliefs are theoretically important, there currently is not a validated measure of these beliefs in the social anxiety literature. Hence, the Self-Beliefs Related to Social Anxiety (SBSA) Scale was developed (Wong and Moulds 2009) and its psychometric properties were examined in the current study using a non-clinical sample (N = 600). Exploratory and confirmatory factor analyses ultimately indicated that a correlated three-factor solution optimally summarized the data with the three factors corresponding to the three belief types. The SBSA and its three subscales demonstrated good internal consistency and test-retest reliability, as well as convergent and divergent validity. The SBSA thus appears to have good psychometric properties and is appropriate for use in non-clinical samples. The potential applications of the SBSA and avenues for future research are discussed.
The carbon intensity of the electricity used to charge an electric vehicle (EV) is dependent on when in the day charging occurs. However, persuading EV owners to adopt incentives to charge during off-peak hours is challenging. Here we show that governments could exploit the ‘window of opportunity’ created when people purchase their first EV to promote time-of-use tariffs. Email recipients (n = 7,038 EV owners) were more likely to click-through to an information webpage when the email emphasized specific reductions in home-charging costs versus general bill savings. However, the ‘window of opportunity’ for maximizing potential adoption is short; email open rates declined from over 70% immediately after purchase to 40% for recipients owning their EV for over three months. These results demonstrate the potential of prompts to change behaviours for which opt-out enrolment (where enrolment is automatic unless people explicitly opt out) would be unethical or less effective.
The practical application of LithiumSulfur battery is limited due to its rapid capacity fading and early battery failure caused by the shuttling of soluble polysulfide. Thus, the key to improve the performance of a LithiumSulfur battery is to suppress the shuttling effect. Herein, we report a NbN modified PP separator with high performance for LithiumSulfur battery applications. The NbN functionalized layer of the separator can strongly interact with soluble polysulfide species, as demonstrated by both experimental investigation and theoretical verification. As a result of the high polysulfide affinity, the composite separator effectively prevents the shuttling of soluble polysulfide through the separator. Besides, the high electrolyte wettability of NbN modification layer lowers the resistance of Li+ transport through the separator. Due to these favorable features, LithiumSulfur battery assembled with the multifunctional NbN modified separator exhibits excellent cycling performance with a reversible capacity of 554.6 mAh g−1 after 200 cycles at 0.2C. The significantly improved rate performance of the battery based on the modified separator is also demonstrated. Our results show that NbN is a promising material for the modification of separators in LithiumSulfur battery and the strategy of separator engineering is effective for improving the performance of LithiumSulfur battery.
Hypergeometric series solutions are presented for the electrodynamic response of bare-wire tether systems, and are used to generate closed-form expressions for the sensitivity coefficients in the generator configuration. For the thruster configuration, the governing equations are in the form of three simultaneous differential equations, which do not allow closed-form solutions for the sensitivity coefficients to be generated, and therefore numerical solutions for the sensitivity coefficients are presented.
Sulfide electrolyte (SE)-based all-solid-state lithium batteries (ASSLBs) have gained worldwide attention because of their instrinsic safety and higher energy density over conventional lithium-ion batteries (LIBs). However, poor air stability of SEs, detrimental interfacial reactions, insufficient solid–solid ionic contact, and the large gap between fundamental study and practical engineering have impeded the commercialization of SE-based ASSLBs. This review aims to combine fundamental and engineering perspectives to rationally design practical SE-based ASSLBs with high energy density, covering SEs, interface, and practical all-solid-state pouch cells. First, the latest progress of typical pseudo-binary, pseudo-ternary, and pseudo-quaternary SEs is summarized, and effective strategies to improve ionic conductivity and chemical and electrochemical stability are highlighted. Moreover, challenges and strategies at the cathode and anode interfaces are reviewed separately. Furthermore, advanced in situ characterization techniques are examined to better understand the interface of ASSLBs. Encouraging demonstrations of SE-based all-solid-state lithium-ion and all-solid-state lithium–sulfur batteries are exemplified. Most importantly, energy-density-oriented all-solid-state pouch cells are designed using practical engineering parameters. The proposed design can serve as a quantitative framework to predict the practical energy density of SE-based all-solid-state pouch cells in future. Finally, future directions and our perspectives in SE-based ASSLBs are presented.
In this study an attempt is made to put into perspective the problem of a rotating disk, be it a single disk or a number of concentric disks forming a unit. An analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is summarized. Results of an extensive parametric study are presented to clearly define the key design variables and their associated influence. In general the important parameters were identified as misfit, mean radius, thickness, material property and/or load gradation, and speed; all of which must be simultaneously optimized to achieve the ‘best’ and most reliable design. Also, the important issue of defining proper performance/merit indices (based on the specific stored energy), in the presence of multiaxiality and material anisotropy is addressed. These merit indices are then utilized to discuss the difference between flywheels made from PMC and TMC materials with either an annular or solid geometry. Finally two major aspects of failure analysis, that is the static and cyclic limit (burst) speeds are addressed. In the case of static limit loads, a lower (first fracture) bound for disks with constant thickness is presented. The results (interaction diagrams) are displayed graphically in designer friendly format. For the case of fatigue, a representative fatigue/life master curve is illustrated in which the normalized limit speed versus number of applied cycles is given for a cladded TMC disk application.
The electrochemical cycling stability is one of the most important parameters for the practical application of supercapacitors and highly depends on the electrode material. Herein, we report the cycling stability of reduced graphene oxide with different morphologies such as curly and flat graphene nanosheets prepared by the chemical and thermal reduction of graphene oxide, respectively. The “curly” graphene nanosheets displayed moderate capacitance, good cycling stability, and satisfactory rate performance up to 2,500 cycles. In contrast, the “flat” graphene nanosheets displayed a very high initial capacitance, but poor cycling stability and rate performance. The pore structure of the “curly” graphene nanosheets was found to be more stable than that of the “flat” graphene nanosheets.
One of the most significant difficulty in Wireless Sensors Network (WSN) is the development of an effective topology control method that can support the quality of the network, respect the limited memory and at the same time increase the lifetime of the network. This paper introduces a new approach by mixing a non-cooperative Game Theory technique with a decentralized clustering algorithm to address the problem of maximizing the network lifetime. More precisely, this approach uses Game Theory techniques to control the activities of a sensor node and its neighbors to limit the number of the forwarding messages and to maximize the lifetime of the sensor's battery. In other words, the approach will decrease the energy consumed by the WSN by decreasing the number of forwarded packets and improve the network lifetime by harvesting energy from the environment. The simulations results show that the performances in terms of energy saving and increasing the number of data packets received by base station outperforms those with distributed based clustering algorithms without GT, such as low energy and location based clustering LELC and LEACH algorithms.
A novel method of synthesizing lithium nickelate has been proposed by chemical oxidation of nickel hydroxide in a aqueous LiOH solution at lower temperature than 100°C. In this new process “direct-oxidation method”, the oxidation of Ni(OH)2 and a subsequent ion-exchange reaction successively took place in the same medium. The conversion yield of the ion-exchange process has not been complete and the product has seemed to remain some amount of proton in its structure. In order to increase the reaction rate and its conversion ratio, it was preferable that the reaction was allowed to proceed at higher temperature range 80–100°C, however, electrochemical activity of the product was drastically deteriorated with a lapse of reaction time at those temperature. Co doping in Ni(OH)2 was found to be effective in depression of the capacity decrease in the long-time reaction. In addition, the product prepared by the direct-oxidation method has a possibility of a further high-capacity active material based on two-electron redox reaction in the range from Ni2+ to Ni4+. It has exhibited larger discharge capacity than 310 mA h g−1 with a smooth potential change between two plateaux corresponding to Ni2+/Ni3+ and Ni3+/Ni4+ redox couples. Its cycle performance has also been superior to that of LiNiO2 prepared by the other synthetic methods.
In this study, the direct methanol fuel cell performance of Nafion®/poly(vinyl alcohol) (PVA) blend membranes at 5, 10, and 20wt% PVA (annealed at 230°C) was investigated at various methanol feed concentrations (2, 4, 8, and 16M) and compared to the performance of Nafion® 117 at similar membrane thicknesses and fuel cell conditions. For Nafion® 117, the maximum power density decreased three-fold when the methanol feed concentration increased from 2 to 16M. The Nafion®/PVA (5wt% PVA) blend membrane reveals a similar trend, however the decrease in power is only 26% compared to 47% when methanol concentration is increased from 2 to 8M. Furthermore, the maximum power density of the blend membrane (5wt% PVA) is higher than Nafion® 117 at 2, 4, and 8M methanol feed concentrations, while the maximum power density at 16M is comparable between the two membranes. Specifically, at 8M methanol, the maximum power density of the blend at 5wt% PVA is 33% higher than Nafion® 117. Blend membranes at higher PVA concentrations are noticeably lower in performance compared to Nafion® 117. Overall, fuel cell performance trends match observed transport property (proton conductivity and methanol permeability) trends.
An empirical method to measure respiratory CO2 recycling using a fast growing agricultural cover crop as a model system was tested and compared with a theoretical method which uses a variation of the Keeling plot. Both methods gave values which were high and similar to each other. The theoretical method gave a value of respiratory based CO2 recycling of 0.41, while the empirical method gave a value of 0.49. Therefore close to half of the respired CO2 is refixed during daytime photosynthesis in this densely planted cover crop. Refixation of respired CO2 during the day should lead to an isotopic enrichment of the remaining respired CO2 leaving the canopy of the cover crop. Therefore, calculations of gross respiration and photosynthesis using isotopic mass balance equations that do not take this isotopic fractionation into account could be in error. We tested this premise by using isotopic mass balance equations to estimate average gross photosynthesis and respiration in this cover crop under two scenarios: (1) no recycling and (2) recycling of respired CO2. Values of gross photosynthesis and respiration were unrealistically low when it was assumed that no recycling occurs. On the other hand, realistic values similar to previous publications were observed when recycling was taken into account.
Free-standing hybrid papers were fabricated by the vacuum-assisted filtration of graphene nanosheets (GNS) and carbon nanotubes (CNTs) both suspended in water, an approach that is environmentally benign. The CNTs are randomly dispersed between the GNS and hence, the hybrid papers exhibit high mechanical strength and flexibility even after being annealed at 800 °C. Electrochemical properties of the hybrid papers are strongly dependent on the CNT/GN ratios. Highest lithium ion storage capacities were obtained in the paper with a CNT/GN ratio of 2:1. The initial reversible specific capacities are ∼375 mAh g−1 at 100 mA g−1. The capacities remain above 330 mAh g−1 after 100 cycles, which are about 100 mAh g−1 higher than those of the graphene paper with nearly the same mass. The improved capacities were attributed to the contribution of the CNTs, which prevent restacking of the GNS, increase cross-plane electric conductivity of the paper and simultaneously, store Li ions. These results suggest that graphene–CNT hybrid paper has a high potential to be used as collector and binder free anodes for lithium ion batteries.
Monoclininc lithium vanadium phosphate, Li3V2(PO4)3, is regarded as a potential cathode material for the next generation of high-performance lithium ion batteries, since it exhibits a high discharge voltage (up to ∼4.1 V) and a large theoretical specific capacity (197 mAhg−1). However, the low intrinsic electronic conductivity of Li3V2(PO4)3, which is a prevailing challenge for olivine type compounds, inhibits its use in commercial applications. Although the substitution of V3+ by other cation species is a common procedure to increase the conductivity and electrochemical performance of Li3V2(PO4)3, the underlying mechanisms for the improved properties are not yet well understood. Therefore, a thermodynamic approach is used in this work to investigate the influence of dopant, i.e. Mg2+ as well as vacancies on the V3+ site on the stability of the resulting materials. On the basis of the measured partial molar Gibbs energies, entropies and enthalpies of the electrochemical reaction, a detailed discussion of the substitution mechanisms and their influence on the electrochemical performance is presented.
Transition metal oxysalts are evaluated as conversion electrode material. Anhydrous iron oxalate is investigated and a comparison with manganese carbonate is carried out to envisage the possible extension of these studies to a vast number of transition metal oxysalts. The dehydration process is studied by thermal analysis to prepare the anhydrous oxysalts. Both manganese carbonate and iron oxalate are interesting candidates for the active material of the negative electrode of lithium-ion batteries. A higher reversible capacity and lower irreversible capacity are observed for the oxalate compound. The reversible capacity cannot be exclusively ascribed to redox processes involving iron. The low temperature synthesis of these materials makes them an inexpensive option for this purpose.
This work explores low cost methods for the preparation of Si/nano-graphite sheets (NanoGs) composite materials for Li ion battery. The Si/NanoGs composites are prepared by magnesium thermal reduction of mechanical mixture of fumed SiO2 and NanoGs under Ar atmosphere. The structure of the samples is characterized by XRD, Raman spectroscope, SEM, and HRTEM. The results show that highly crystallized Si nanoparticles with a sheet-like morphology are uniformly distributed on the surface of NanoGs (both edge and a-b plane). The average diameter of Si nanoparticles is ∼20 nm. Electrochemical characterization shows that an electrode has an initial lithium storage capacity of 1702.9 mAh g−1 at a current of 100 mA g−1. The storage capacity decreases to 975.7 mAh g−1 after 100 cycles. Since cheap commercial fumed SiO2 and graphite are used and the process is simple and easy to scale up, with further improvement, the method has potential for use in large scale production of high energy density Si/NanoGs anode materials at low cost.
Silver oxide nano layers were prepared by RF magnetron sputtering on amorphous SiO2 substrates. O2 pressure in chamber was varied from 1 to 4 and 7 mTorr during growth process. The effects of different O2 pressure on structural, morphological and optical properties of the films were investigated by means of X-ray diffraction, scanning electron microscopy, atomic force microscopy and UV–Vis spectroscopy analyses. Optical reflectance measured in the wavelength of 350–950 nm by spectroscopy. Other optical properties and optical band gaps were calculated using Kramers–Kronig relations. The X-ray diffraction measurements showed change in crystalline structure with increasing O2 pressure. Preferred orientation has been changed to another growth orientation at 4 mTorr O2 pressure. The Atomic force microscope images showed increasing in roughness consistently by increasing oxygen pressure. The thickness of the thin films decreases (from 217 to 180 nm) with increasing O2 pressure. Optical results revealed that the highest optical band gap of 3.1 eV and the highest transmittance of ~ 80% were achieved at lower O2 pressure (1 mTorr).
Due to the large radius of K-ion, K-ion batteries (KIBs) involving K-ion insertion and extraction processes generally exhibit an insufficient cycle life and poor rate performance. In this work, sulphur-doped reduced graphene oxide (S-RGO) sponges, which are used as free-standing anodes for KIBs, are obtained via simple freeze-drying of graphene oxide solution and subsequent thermal treatment in sulphur steam. After sulphur doping, our S-RGO sponges deliver preeminent electrochemical performance. Such free-standing electrodes exhibit high K-ion storage capacity of 361 mAh g−1 at 50 mA g−1 over 50 cycles. Furthermore, even at a high current density of 1 A g−1, they also display a highly stabile K-ion storage with a capacity of 229 mAh g−1 over 500 cycles, which outperforms all previously reported carbon-based materials for KIBs. Such preeminent performance is attributed to the S-RGO sponges’ unique conductive structure and the sulphur doping, which effectively enhance the insertion of large K ions. We also utilize ex-situ XPS to illuminate the reaction process of our sample during potassiation/depotassiation and highlight the role of sulphur doping in improving K-ion storage performance.
Transparent lithium-ion conducting films were prepared by adding lithium perchlorate to a mixture of chitosane (CHI) and poly(aminopropylsiloxane) (pAPS) in a molar ratio 0.6:1 by sol–gel methods. The morphological and molecular properties, determined by scanning electron microscopy and FT-IR, respectively, depend on the lithium salt concentration. The same techniques were also used for performing a “titration” of the capacity of the film for incorporating lithium salt. Results show that about 0.8 mol lithium salt per mol chitosane can be added before the product losses the transparence and molecular compatibility characteristic of the pristine CHI/pAPS polymer complex. When lithium salt addition reaches the tolerance limit, anisotropically oriented patterns are observed in the hybrid films. Both transparence and ionic conductivity of the product appear to be related to the layered nature of formed nanocomposites. The properties of obtained films may be furthermore rationalized considering the chemical functionality and the Lewis donor–acceptor affinity of the components.
Charging a battery beyond its maximum capacity can lead both to cell overheating and to the venting of gasses. A fundamental understanding of cell heating could lead to the development of real-time sensors that anticipate and avert catastrophic battery failure. Joule heating (also called ohmic or resistive heating) from cell internal resistance (R int ) dominates the overall thermal energy (ΔQ) generated during charging. Contrary to prior hypotheses, though, Joule heating does not appear to contribute to venting observed during overcharging. In this manuscript, we examine an alternate hypothesis, that heat released by the entropy change in the anode (ΔS anode ) and the concomitant increase in the anode temperature (T anode ) triggers the venting. Using our recently developed non-invasive battery internal temperature (BIT) sensor to monitor T anode , we separated the contributions of ΔS anode , R int and the anode resistance (R anode ) to ΔQ. These quantities were tracked during constant current charging of a 18650 Lithium-ion cell, from zero state of charge (SoC) to overcharge. The resulting analysis suggests that anode entropy change is more important than resistive heating resulting from R anode to the overall thermal energy. Anode entropy measurements, enabled by the BIT sensor, might serve as an alternative or adjunct method for anticipating and avoiding cell venting events.