batterydata/paper-abstracts huggingface dataset:
A novel three-dimensional hierarchical ternary aerogel of TiO2 nanoparticles@porous carbon nanofibers-reduced graphene oxide (TiO2@PCNF-GA) was designed as an advanced anode for lithium-ion capacitors. TiO2@PCNFs were first fabricated by electrospinning assisted by carbonization and a post-etching process, and then assembled into reduced graphene oxide aerogels (GAs) to obtain the TiO2@PCNF-GAs. The uniform distribution of the ultrafine TiO2 nanoparticles in the PCNFs inhibits the aggregation of the TiO2 nanoparticles. Meanwhile, the interconnected three-dimensional network constructed from the TiO2@PCNFs and the GAs inhibits the aggregation of the TiO2@PCNFs. Moreover, the hierarchical porous structure of the TiO2@PCNF-GAs affords numerous Li-ion transport paths. Therefore, the lithium-ion capacitor composed of the TiO2@PCNF-GAs anode and an activated carbon cathode exhibits high energy density versus power density (79.7 Wh kg−1 versus 75 W kg−1, 15.0 Wh kg−1 versus 15 kW kg−1) with superior cycle stability (93.3% retention after 10000 cycles at 5.0 A g−1).
Graphene is ideally suited for implementation in electrochemical applications due to its reported large electrical conductivity, large surface area, unique heterogeneous electron transfer rate, and low production cost. This paper presents a method for the construction of graphene paste electrode (GPE) from reduced graphene oxide (RGO). Direct electrochemical detection of drug is of high importance in analytical chemistry. Here, the GPE was successfully used for the determination of acetazolamide (ACZ). So, the influence of some experimental variables such as working solution pH, supporting electrolyte, scan rate, pulse amplitude, and possible interferences were studied. The proposed sensor exhibited a high sensitivity and good selectivity, and it was applied for clinical evaluation of ACZ.
Lithium-ion cells (Li-ion) comprising lithium iron phosphate (LiFePO4) based cathode active material are a promising battery technology for future automotive applications and consumer electronics in terms of safety, cycle and calendar lifetime and cost. Those cells comprise flat open circuit voltage (OCV) characteristics and long-term load history dependent cell impedance. In this work the special electric characteristics of LiFePO4 based cells are elucidated, quantified and compared to Li-ion cells containing a competing cathode technology. Through pulse tests and partial cycle tests, performed with various olivine based cells, the cycling history dependency of the internal resistance and therefore on the power capability is shown. Hence, methods are illustrated to quantify this load history impact on the cells performance. Subsequently, methods to achieve a safe battery operation are elucidated. Furthermore strategies are given to obtain reliable information about the cells power capability, taking the mentioned properties into consideration.
Cobalt oxide-doped copper oxide composite nanofibers (CCNFs) were successfully achieved via electrospinning followed by thermal treatment processes and then exploited as active electrode material for direct enzyme-free fructose detection. The morphology and the structure of as-prepared samples were investigated by X-ray diffraction spectrum (XRD) and scanning electron microscopy (SEM). The electrocatalytic activity of CCNFs films towards fructose oxidation and sensing performances were evaluated by conventional electrochemical techniques. Cyclic voltammetry (CV) and chronoamperometry (I−t) revealed the distinctly enhanced sensing properties towards fructose compared to pure copper oxide nanofibers (CNFs), i.e., showing significantly lowered overpotential of 0.30V, ultrafast (1s) and ultrasensitive (18.988μAmM−1) current response in a wide linear range of 1.0×10−5 M to 6.0×10−3 M with satisfied reproducibility and stability, which could be ascribed to the synergic catalytic effect of the binary CuO/Co3O4 composite nanofibers and the highly porous three-dimensional network films structure of the CCNFs. In addition, a good selectivity for fructose detection was achieved. Results in this work demonstrated that CCNFs is one of the promising catalytic electrode materials for enzymeless fructose sensor fabrication.
Tantalum oxide (TaO3) nanosheets coated on the surface of a LiCoO2 cathode decrease its interfacial resistance in a solid-state battery by two orders of magnitude. Since the interfacial resistance is rate-determining in the solid-state system, the interfacial structure of the nanosheet is anticipated to pave the way for realising high-performance solid-state lithium batteries. The reduction in the interfacial resistance also strongly suggests that the TaO3 nanosheet is a self-standing solid electrolyte layer with an ultimate thinness of 1 nm. It has a wide band gap and a mesh structure with openings that are almost the same in size as the lithium ion, which prevents electronic conduction and allows the penetration of lithium ions, respectively.
Endoscopic investigation of small bowel pathology in children has historically been difficult due to location, length and tortuosity of the small bowel. Recently, video capsule endoscopy and balloon-assisted enteroscopy techniques have evolved as new diagnostic tools and are increasingly used in the paediatric population. In this review the current literature is appraised to define the clinical indications and practical aspects of capsule endoscopy and balloon-assisted enteroscopy in children.
Herein, we demonstrate a novel amorphous composite layer-protected nanocrystalline NiO with superior long-term cyclability as an anode material for Li-ion batteries. Amorphous nickel and lithium carbon oxides form on nickel oxide (NiO nanoparticulate crystals with d < 15 nm) at room-temperature by mechanically milling a mixture of NiO and LiH under a CO2 atmosphere. The amorphous composite layer on the surface of NiO nanocrystal contains lithium carbonate (Li2CO3), nickel carbonate (NiCO3) and nickel acetate (NiC2O4). The NiO-0.4LiH sample milled under an atmosphere of 3 bar of CO2 delivers 770 mAh g−1 of specific capacity with nearly no capacity decrease from 2nd to 565th cycle at 100 mA g−1. Even operating at a high rate of 2 A g−1, the specific capacity remains at 530 mAh g−1, which is remarkably superior to that of pristine NiO (∼393 mAh g−1). The cycling stability is attributed to the amorphous carbon oxide layer effectively buffering the volume expansion of the anode during lithiation and stabilizing the solid electrolyte interphase (SEI) film during cycling of the NiO anode. The facile preparation process and favourable electrochemical performance of the composite NiO anode indicate this is a promising anode for a Li-ion battery.
The development of electrochemical processes for using captured CO2 in the production of valuable compounds appears as an attractive alternative to recycle CO2 and, at the same time, to store electricity from intermittent renewable sources. Among the different innovative attempts that are being investigated to improve these processes, the application of ionic liquids (ILs) has received growing attention in recent years. This paper presents a unified discussion of the significant work that involves the utilisation of ILs for the valorisation of CO2 by means of electrochemical routes. We discuss studies in which CO2 is used as one of the reactants to electrosynthesise value-added products, among which dimethyl carbonate has been the focus of particular attention in the literature. Approaches based on the electrochemical reduction of CO2 to convert it into products without the use of other carbon-based reactants are also reviewed, highlighting the remarkable improvements that the use of ILs has allowed in the CO2 electroreduction to CO. The review emphasises on different aspects related to process design, including the nature of IL anions and cations that have been used, the working conditions, the electrocatalytic materials, the electrode configurations, or the design of electrochemical cells, as well as discussing the most relevant observations, results and figures of merit that the participation of ILs has allowed to achieve in these processes. Several conclusions are finally proposed to highlight crucial challenges and recommendations for future research in this area.
Manganese dioxide (MnO2) nanostructures have been widely used as the supercapacitor electrode. However, their charge storage mechanism has not yet been fully understood. Herein, the charge storage mechanism of layered MnO2 nanosheets has been investigated. It was found that they store charges via three processes: electrochemical double layer capacitance (EDLC), surface redox reaction, and intercalation/de-intercalation. The EDLC of the layered MnO2 is equal to 71.6Fg−1 at all scan rates used (10–100mVs−1) without a diffusion limit. The surface redox contribution owing to the chemisorption of Na+ on the surface of MnO2 nanosheets is 30.8, 18.0, 20.0, 17.0, 13.5Fg−1 at 10, 25, 50, 75, and 100mVs−1, respectively. The intercalation contribution thanks to the solvated Na+ insertion into the crystalline bulk structure of layered MnO2 is 96.4, 57.1, 38.6, 30.5, and 25.3Fg−1 at 10, 25, 50, 75, 100mVs−1, respectively. The surface redox reaction and intercalation are still under diffusion limit. Understanding the charge storage mechanism/contribution of MnO2 nanosheets may lead to further development of these materials for practical applications.
The new LiFeTiO4 polymorph with the CaFe2O4-type (CF) crystal structure was synthesized via ion exchange from NaFeTiO4. Due to the presence of tunnels sufficiently large to accommodate additional Li+ ions, CF-LiFeTiO4 was studied as a model compound for potential cathode material utilizing Fe2+/Fe3+ (on Li intercalation) as well as Fe3+/Fe4+ (on Li deintercalation) redox couples. Chemical and electrochemical Li intercalation preserves the structural motif of CF-LiFeTiO4 and results in Li2FeTiO4 compound. The electrochemical cycling of CF-LiFeTiO4 vs. Li occurs between 2 and 2.3 V with an initial specific capacity of 148 mAh g−1. High Li+ ionic conductivity in the compound is suggested based on the interconnection of Li+ bond valence sum isosurfaces at a bond valence sum value of 1.0. Chemical Li deintercalation from CF-LiFeTiO4 results in compound decomposition without Fe4+ formation, as confirmed by Mössbauer spectroscopy.
Abstract As the concept of informed consent to treatment has evolved, so has that of treatment without consent. Although the common law permits treatment without the patient’s explicit agreement in certain circumstances where they are incapacitated in keeping with the doctrine of necessity, the situation has become increasingly complex although statute based law has now made this more straightforward with the incapax. The framework to allow this to happen is considered and the manner in which the courts have been involved in such a scenario is described.
This paper reports on laboratory studies into the ac impedance spectra of nickel–metal hydride and nickel–cadmium batteries, aiming at finding out possible correlation between electrical parameters, extracted directly from the high frequency region, and the battery state-of-charge (SoC). Impedance diagrams were recorded immediately after interrupting the dc charge, or discharge, current. The study revealed that the series resonance frequency, at which the dynamic cell behavior switches from an inductive character (Z″>0) to a capacitive one (Z″<0), varied monotonously as a function of state-of-charge. This behavior was reproducible after intermittent charge and discharge. Half-cell measurements were also conducted to associate the cell impedance with either processes occurring at the positive or negative plates.
Rechargeable iron–air and nickel–iron batteries are attractive as sustainable and inexpensive solutions for large-scale electrical energy storage because of the global abundance and eco-friendliness of iron, and the robustness of iron-based batteries to extended cycling. Despite these advantages, the commercial use of iron-based batteries has been limited by their low charging efficiency. This limitation arises from the iron electrodes evolving hydrogen extensively during charging. The total suppression of hydrogen evolution has been a significant challenge. We have found that organo-sulfur compounds with various structural motifs (linear and cyclic thiols, dithiols, thioethers and aromatic thiols) when added in milli-molar concentration to the aqueous alkaline electrolyte, reduce the hydrogen evolution rate by 90%. These organo-sulfur compounds form strongly adsorbed layers on the iron electrode and block the electrochemical process of hydrogen evolution. The charge-transfer resistance and double-layer capacitance of the iron/electrolyte interface confirm that the extent of suppression of hydrogen evolution depends on the degree of surface coverage and the molecular structure of the organo-sulfur compound. An unanticipated electrochemical effect of the adsorption of organo-sulfur molecules is “de-passivation” that allows the iron electrode to be discharged at high current values. The strongly adsorbed organo-sulfur compounds were also found to resist electro-oxidation even at the positive electrode potentials at which oxygen evolution can occur. Through testing on practical rechargeable battery electrodes we have verified the substantial improvements to the efficiency during charging and the increased capability to discharge at high rates. We expect these performance advances to enable the design of efficient, inexpensive and eco-friendly iron-based batteries for large-scale electrical energy storage.
As the threat of global water scarcity continues to grow, a myriad of scientific effort is directed towards advancing water desalination technologies. Reverse osmosis (RO), solar thermal desalination (STD), and capacitive deionization (CDI), have dominated recent pressure-, thermal-, and electro-driven desalination research efforts, respectively. Despite being based on distinctive driving forces and separation mechanisms, research of these three processes has primarily shared the same fundamental goal and approach: the minimization of energy consumption for desalination through the development of novel materials. A variety of materials have been studied and proposed to enhance RO membrane permeability, STD solar absorptivity, and CDI electrode capacitance. Here, we critically discuss the advanced materials investigated and assess their efficacy in augmenting the energy efficiency of desalination. Through our systematic analysis, we show that materials have relatively insignificant impact on further increasing energy efficiency, regardless of the process applied. We provide insights into the inherent limitations of advanced materials for improving the energy efficiency of each of the evaluated technologies and propose more effective materials-based research directions. We conclude by highlighting the opportunity for considerable improvement in energy efficiency via system design, reinforcing the critical need for a paradigm shift in desalination research.
We tested three lithium-ion cells to evaluate capacity and power fade during cycle life testing of a hybrid electric vehicle (HEV) cell with varying state of charge (ΔSOC). Test results showed that the cells had sufficient power and energy capability to meet the Partnership for a New Generation of Vehicles (PNGV), now called FreedomCAR, goals for Power Assist at the beginning of life and after 120,000 life cycles using 48 cells. The initial static capacity tests showed that the capacity of the cells stabilized after three discharges at an average of 14.67Ah. Capacity faded as expected over the course of 120,000 life cycles. However, capacity fade did not vary with ΔSOC. The hybrid pulse power characterization (HPPC) tests indicated that the cells were able to meet the power and energy goals at the beginning of testing and after 120,000 life cycles. The rate of power fade of the lithium-ion cells during cycle life testing increased with increasing ΔSOC. Capacity fade is believed to be due to lithium corrosion at the anode, and power fade suggested a buildup of the SEI layer or a decrepitation of the active material.
Abstract The authors have been associated with the Instrumentation Systems of Power Plants for more than two decades and are still in touch with modern technology. This book is the outcome of their experiences to benefit practicing engineers and students associated with power plants. Power plant concepts are based on the laws of thermodynamics depicting the relations among heat, work, properties of a system, specific weight/volume, path, process, etc. The definitions of different types of energy, work, Boyle's Law and Charles Law with general and combined equations, Avogadro's Law/Hypothesis, the universal gas constant, enthalpy, entropy, and Rankine and other cycles are touched upon in this chapter along with pressure-volume and temperature-entropy diagrams for steam as well as different types of boilers, turbines, condensers, and regenerative cycles. These recapitulations have been done at the beginning to enable the readers to refresh their basic knowledge on power plants.
Li-excess layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 (LMNCO) nanoparticles are facilely synthesized using a surfactant-assisted dispersion method. Ultrathin and conformal oxide coatings are deposited on the surface of individual LMNCO nanoparticle via atomic layer deposition (ALD). The effect of oxide ALD coatings on improving electrochemical performance of LMNCO electrodes is evaluated and optimized via tuning the coating thickness and composition. In addition, we synthesize a novel core–shell structure cathode consisting of Li-excess LMNCO as core and Li-stoichiometric material as shell, and its electrochemical property is optimized by tailoring weight content and composition of shell materials. Finally, electrochemical performance of Li-excess cathode material can be maximized by surface modification with hierarch functional layers composed of 10 wt.% LiCoO2 shell (∼10 nm thick) and 6ZrO2 ALD layers (∼1 nm thick), which delivers very high initial discharge capacities of 296.4, 259.8, 156.6 and 104.2 mAh g−1 at 0.1C, 1C, 5C and 10C, and can retain 184.0 mAh g−1 at 1C after 100 electrochemical cycles. Such remarkably improved cycleabilitiy and rate capability of nanoarchitected Li-excess layered cathode material can be attributed to the synergic effect from hierarchical functional coatings to reduce electrochemical polarization, structural degradation and side reactions during electrochemical cycling.
Introduction The user experience and clinical effectiveness with wearable global positioning system (GPS) devices for persons with dementia (PwDs) and caregivers (CGs) remain unclear although many are available. Methods Using a crossover design, 20 dyads tested two similar commercial GPS watches (products A and B) at home for 4 weeks each. Usability, product functions, design features and product satisfaction at home and the clinic were investigated. Caregiver burden and quality of life assessed clinical effectiveness. Results The final 17 dyads rated the usability, telephone function, overall design features, font, buttons, and battery life of B significantly better than A. PwDs rated the overall design features and buttons of A significantly better than CGs. Product satisfaction with both products was significantly lower at home. Clinical effectiveness was not found. Discussion User experience can be improved by optimizing specific product details. This might translate to clinical effectiveness. Social desirability bias may explain different product satisfaction ratings.
A high performance surface modified Li1.2Mn0.534Ni0.133Co0.133O2 cathode with graphene and CNTs (GNL-modified LMNCO) has been synthesized via a simple ultrasonic dispersion approach. Its morphology and electrochemical performance are investigated thoroughly in this work. Typically, the GNL-modified LMNCO demonstrates an initial discharge capacity of 285.8mAhg−1, showing initial coulombic efficiency of 83.3%. In addition, impressive discharge capacity of 162.3 and 123.5mAhg−1 are obtained at 5 and 10C, respectively. More satisfactorily, it reveals high capacity retention of 217.9mAhg−1 even after the 180th cycle. The extraordinary electrochemical performance of the GNL-modified LMNCO can be ascribed to the unique conducting network of graphene and CNTs coating on the particles, which greatly improves the conductivity of the electrode and enhances the diffusion coefficient of the Li+. Most significantly, a high-voltage and high-power electrochemical energy storage devices of lithium-ion battery (LIB) full cell has been simultaneously assembled with the GNL-modified LMNCO as cathode and silicon/graphite/amorphous carbon (Si/C) composite as anode, whose properties outclass many other systems of LIB full cells. Therefore, the acquaintance of the compatibility of the Li-rich cathode and Si/C composite anode for high-voltage and high-energy LIB full cells should attract more research efforts in the future.
An electrical equivalent circuit model of the proton exchange membrane (PEM) fuel cell system with parameters extracted through optimization is presented in this paper. The analytical formulation of the fuel cell behavior is based on a set of equations which enables to estimate his overall performance in terms of operation conditions without extensive calculations. The approach uses a set of parametrical equations and related parameters in order to characterize and predict the voltage–current characteristics of the fuel cell operation without examining in depth all physical/chemical phenomena, but including within the model different components and forms of energy actuating in the generation process. Although many models have been reported in the literature, the parameter extraction issue has been neglected. However, model parameters must be precisely identified in order to obtain accurate simulation results. The main contribution of this work is the application of Simulated Annealing (SA) as optimization method focused on the extraction of the PEM model parameters. Model validation is carried out comparing experimental and simulated results. The good agreement between the simulation and experimental results shows that the proposed model provides an accurate representation of the static and dynamic behavior for the PEM fuel cell. Therefore, the approach allows at getting the set of parameters within analytical formulation of any fuel cell. In consequence, fuel cell performance characteristics are well described as they are carried out through a methodology that simultaneously calibrates the model.
Inflammatory processes play a pivotal role in the degenerative process of Alzheimer’s disease. In humans, a biallelic (C/T) polymorphism in the promoter region (position-511) (rs16944) of the interleukin-1 beta gene has been significantly associated with differences in the secretory capacity of interleukin-1 beta. In this study, we investigated whether this functional polymorphism mediates the brain networks in patients with Alzheimer’s disease.
The role of technology - its economics and factors that influence technological choice decisions have been a concern in development policy. Logit and probit functional forms have been largely used in modelling technology choice (adoption). We employed two other functional forms; loglog and cloglog, applied to adoption of Fairtrade and organic cocoa producers in the Eastern Region of Ghana. Using fractional regression modelling, we demonstrate the need to explore alternative functional forms other than logit and probit, in binary choice related problems. Interestingly, the battery of tests employed rejected the logit and probit functional forms. Alternative assessment criteria such as size, statistical significance of parameters and differences in parameter estimates produced more interesting results.