batterydata/paper-abstracts huggingface dataset:
In the present work, we report high temperature performance of solid electrolyte supercapacitor based on activated carbon (AC) and phosphoric acid doped poly [2,5 benzimidazole] (ABPBI). Supercapacitors with varying concentrations of solid electrolyte in the electrode were fabricated and unit cells were analyzed over a wide temperature range of 27–120°C. Supercapacitor with AC/ABPBI wt ratio 1.0:0.25 exhibited a specific capacitance of 197Fg−1 at room temperature. To the best of our knowledge, the value reported here is one of the highest for electric double layer supercapacitor with a solid electrolyte. The specific capacitance of supercapacitors having various compositions increased with temperature. The specific capacitance for AC/ABPBI wt ratio 1.0:0.25, capacitance increased to 248Fg−1 at 120°C. The performance of supercapacitors was also analyzed by electrochemical impedance spectroscopy. The Nyquist plots at room temperature and 100°C were studied by fitting them using Randles equivalent circuit. Supercapacitor with AC/ABPBI wt ratio 1.0:0.25 showed phase angle of 86.8° at low frequency which indicated excellent capacitive behavior at room temperature. The supercapacitor was found to have good stability during galvanostatic charge–discharge cycling even after repeated heating and cooling.
MnO powder materials are investigated as anode active materials for Li-ion batteries. Lithium is stored reversibly in MnO through conversion reaction and interfacial charging mechanism, according to the results of ex situ XRD, TEM and galvanostatic intermittent titration technique. A layer of the solid electrolyte interphase with a thickness of 20–60nm is covered on MnO particles after full insertion. MnO powder materials show reversible capacity of 650mAhg−1 with average charging voltage of 1.2V. It can deliver 400mAhg−1 at a rate of 400mAg−1. The cyclic performance of MnO is improved significantly after decreasing particle size and coating with a layer of carbon. Among observed transition metal oxides, MnO shows relatively lower voltage hysteresis (<0.7V) between the discharging and the charging curves at 0.05C. In addition to its environmental benign feature and high density (5.43gcm−3), MnO seems a promising high capacity anode material for Li-ion batteries among transition metal oxides. However, the initial columbic efficiency is less than 65% and the voltage hysteresis is still too high. The origins of them are discussed.
Carbon–polymer-composite bipolar plates (BPP) are suitable for fuel cell and flow battery applications. The advantages of both components are combined in a product with high electrical conductivity and good processability in convenient polymer forming processes. In a comprehensive techno-economic analysis of materials and production processes cost factors are quantified. For the first time a technical cost model for BPP is set up with tight integration of material characterization measurements.
Structure building describes the process by which people mentally organize information while reading to comprehend and later recall text. We investigated how individual differences in structure building ability affect students' learning of complex, educational texts. College students studied a complex text with a mechanical theme, engaged in retrieval practice, made metamemory judgments, and then were given another study opportunity. Following a short delay, memory and comprehension of the text were assessed with a range of dependent measures, including performance on free recall, multiple-choice questions, and problem-solving questions. Participants with high structure building ability outperformed those with low structure building ability on information recalled, factual and inference multiple-choice questions, and problem solving questions. Although high and low structure builders demonstrated equivalent metamemory accuracy, high structure builders appear to better regulate their restudy time according to a discrepancy reduction strategy, which allowed them to acquire more new information that they were unable to retrieve initially during recitation. Our findings suggest that low structure builders may suffer from deficiencies at many levels of text representations as well as deficiencies in metacognitive control during restudy. Our study highlights structure building ability as an important individual difference for learning educational texts and furthers our understanding of exactly what aspects of learning are related to these differences.
Due to importantly beneficial effects on physical and mental health and strong association with many rehabilitation programs, Physical Activity Recognition and Measure (PARM) has been widely recognised as a key paradigm for a variety of smart healthcare applications. Traditional methods for PARM relies on designing and utilising Data fusion or machine learning techniques in processing ambient and wearable sensing data for classifying types of physical activity and removing their uncertainties. Yet they mostly focus on controlled environments with the aim of increasing types of identifiable activity subjects, improved recognition accuracy and measure robustness. The emergence of the Internet of Things (IoT) enabling technology is transferring PARM studies to an open and dynamic uncontrolled ecosystem by connecting heterogeneous cost-effective wearable devices and mobile apps and various groups of users [35]. Little is currently known about whether traditional Data fusion techniques can tackle new challenges of IoT environments and how to effectively harness and improve these technologies. In an effort to understand potential use and opportunities of Data fusion techniques in IoT enabled PARM applications, this paper will give a systematic review, critically examining PARM studies from a perspective of a novel 3D dynamic IoT based physical activity collection and validation model. It summarized traditional state-of-the-art data fusion techniques from three plane domains in the 3D dynamic IoT model: devices, persons and timeline. The paper goes on to identify some new research trends and challenges of data fusion techniques in the IoT enabled PARM studies, and discusses some key enabling techniques for tackling them.
Microporous polymer separators and corresponding gel electrolyte have been widely used in lithium ion batteries. This work aims to explore a safety microporous separator for lithium ion batteries by studying the distribution and stability mechanism of liquid electrolyte in this kind of separator. A comb polymer P(MMA-co-PEGMA) was synthesized and blended into poly(vinylidene ﬂuoride) (PVDF) matrix to prepare porous separators via immersion precipitation phase inversion process. The separators then were immersed in liquid electrolyte to form lithium ion conducting gel polymer electrolyte membranes (GPEs). The influence of P(MMA-co-PEGMA) on the morphology, crystallinity, and the liquid electrolyte uptake and distribution in the porous separators was investigated. The ion conductivity increased with copolymer content and the maximum conductivity value of 3.01×10−3 S cm−1 was found at 25°C in the prepared samples. The Graphite|GPE|LiFePO4 cells assembled with modified separators showed improved capacity retention at various C-rates and higher coulombic efficiency than pure PVDF separators
Although many strong claims are made for the power of computer games to promote academic learning, the narrative content of a game may reduce the learner's tendency to reflect on its academic content. The present study examines adding a low-cost instructional feature intended to promote appropriate cognitive processing of the academic content during play. College students played a computer adventure game in which they guided a character through a bunker in search of lost artwork, building electromechanical devices to open stuck doors along the way. In Experiment 1, students who filled out worksheets about wet-cell batteries before and during the game outperformed students who played the game without worksheets on a written explanation of how wet-cell batteries work (d = 0.92), multiple-choice comprehension questions about wet-cell batteries (d = 0.67), and open-ended transfer problems about wet-cell batteries (d = 0.74). In Experiment 2, participants who completed only the in-game worksheet outperformed the control group on a written explanation of wet-cell batteries (d = 0.59) and transfer problems (d = 0.67), whereas participants who completed only the pre-game worksheet did not outperform the control group on any measure. These findings point to the learning benefits of adding instructional features suggested by cognitive theories of learning.
Spontaneous osteonecrosis of the knee affects the medial femoral condyle in patients above 55 years of age. Many reports and studies are available from western countries. But there is a gross paucity of literature on spontaneous osteonecrosis of the knee (SPONK) in the Indian subcontinent, either it is under-reported or detected at a later stage. The aim of our study was to detect SPONK in Indian population and describe its characteristics, treatment, and outcome.
Research has suggested many with schizophrenia experience impairments in metacognition, or difficulties apprehending their own thoughts and the thoughts of others, and that those deficits are not reducible to a single symptom or cognitive impairment. While links between metacognition and more severe levels of symptoms have emerged, less clear is whether there are consistent associations between metacognition and other neurocognitive capacities. Accordingly the current study sought to examine whether different patterns of metacognition deficits have different neurocognitive correlates. Narratives were gathered from 69 adults with schizophrenia spectrum disorder using the Indiana Psychiatric Illness Interview along with a symptom interview and neurocognitive battery including subtests of the Wechsler Adult Intelligence Scale III, Wechsler Memory Scale III and the Wisconsin Card Sorting Test. Metacognitive capacity within the narrative interview was assessed using the Metacognition Assessment Scale and participants were divided based on those scores into three groups: minimal self-reflectivity/not decentered (n =25); basic self-reflectivity/not decentered (n =33); and basic self-reflectivity/decentered (n =11). Basic self-reflectivity refers to the ability to distinguish one's own thoughts and feelings while decentered refers to the ability to see others as having independent perspectives and relationships with one another. MANOVA and ANOVA comparing groups revealed that the participants lacking basic self-reflectivity had significantly poorer working memory and more symptoms of disorganization, while participants able to see others as having independent perspectives and relationships demonstrated better visual memory. Results suggest different deficits in metacognition may be linked to different neurocognitive capacities.
The entropy-variation of a battery is responsible for heat generation or consumption during operation and its prior measurement is mandatory for developing a thermal model. It is generally done through the potentiometric method which is considered as a reference. However, it requires several days or weeks to get a look-up table with a 5 or 10% SoC (State of Charge) resolution. In this study, a calorimetric method based on the inversion of a thermal model is proposed for the fast estimation of a nearly continuous curve of entropy-variation. This is achieved by separating the heats produced while charging and discharging the battery. The entropy-variation is then deduced from the extracted entropic heat. The proposed method is validated by comparing the results obtained with several current rates to measurements made with the potentiometric method.
Lithium sulfide (Li2S) provides a promising route for lithium storage due to high theoretical specific capacity (1166 mAh g−1). The electrochemical performance of Li2S can be significantly enhanced by forming Li2S–carbon composites with the introduction of carbon. However, the complex synthesis method of Li2S–carbon composites restrains the large-scale productivity. Herein, we propose a facile route to prepare carbon coated Li2S–carbon nanotube composites (Li2S@C-CNT) via spray drying and heat treatment, which is a low-cost and large-scale method for facile synthesis of Li2S–carbon composites. For the Li2S@C-CNT composites, Li2S nanoparticles are contacted with surrounding particles due to the 3D CNTs framework. The novel construction not only suppresses the diffusion of polysulfides during cycling, but also remarkably accelerates the transport of electron and ion, resulting in a high specific capacity (1100 mAh g−1) and good cycling performance. The rational designed architecture and good electrochemical performance of Li2S@C-CNT will pave the avenue for realizing high energy density of Li2S-based batteries.
The uniform and spherical LiNi0.5Co0.2Mn0.3O2 particles were successfully coated with AlF3. The structures and electrochemical properties of AlF3-coated LiNi0.5Co0.2Mn0.3O2 were characterized by various techniques. When the coating amount was 0.5mol%, the cathode showed enhanced cycling performance and rate capability compared to the pristine LiNi0.5Co0.2Mn0.3O2. The AlF3-coated LiNi0.5Co0.2Mn0.3O2/Li cell had capacity retention of 98% after 100 cycles even at 4C over 2.8–4.5V, while the pristine LiNi0.5Co0.2Mn0.3O2 exhibited capacity retention of only 89%. Moreover, the rate capability and cyclic performance at elevated temperature (55°C) were also improved. Electrochemical impedance spectroscopy testing revealed the improved electrochemical performance, which could be considered that the AlF3 coating layer can suppress the increase of impedance during the charging and discharging process by preventing directly contact of the highly delithiated active material with electrolyte.
Layered Li[Ni1/3Mn1/3Al1/3−x Co x ]O2 (0≤ x ≤1/3) cathode materials are synthesized by a solvent evaporation method. Although XRD shows that Li[Ni1/3Mn1/3Al1/3]O2 has no obvious impurity phase, it has poor electrochemical properties. To improve its capability, part of Al in Li[Ni1/3Mn1/3Al1/3]O2 compound is replaced by Co in this study. The samples are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and charge–discharge test. The results indicate that the introduction of Co has a large influence on the morphology, structure and electrochemical performances of the samples, which become more excellent with an increase of Co content in compounds. Meanwhile, the high-temperature behavior of the samples is also investigated.
Potassium hexafluorophosphate and tris (trimethylsilyl) phosphite are applied as electrolyte additives to enhance electrochemical performance of an anode-free lithium metal battery (AFLMB) based on a Cu‖NMC cell configuration. The synergistic effect of the dual additives has been investigated using a commercial carbonate electrolyte (1 M LiPF6-EC/DEC (1:1 vol%)). Herein, we report that an electrolyte with dual additive of 2 wt% KPF6 - 2 vol% TMSP significantly improves the charge/discharge capacity, average coulombic efficiency and retention capacity of a Cu‖NMC cell configuration. An AFLMB cell with 2 wt% KPF6 - 2 vol% TMSP additives retained 48% of its initial capacity at the 20th cycle, while the reference cell with the commercial electrolyte in the absence of additives reached only 14%. The enhanced performance using the prepared electrolyte is attributed to the self-healing electrostatic shielding (SHES) effect of KPF6 to prevent dendrite growth and the removal of hydrofluoric acid (HF) produced from the commercial LiPF6 carbonate electrolytes by the reaction of phosphorus pentafluoride (PF5) with water using TMSP. This study provides a broader vision in developing functional electrolyte additives for an anode-free lithium metal battery.
The current generation of high-power lithium-ion cells for transportation applications, being developed and studied at Argonne National Laboratory, contain LiNi0.8Co0.15Al0.05O2-based cathodes, graphite-based anodes, and LiPF6-based electrolytes. These cells show loss of capacity and power during accelerated testing at elevated temperatures. X-ray photoelectron spectroscopy (XPS) examination of negative electrode samples harvested from some cells that showed varying degrees of power and capacity fade revealed a surface film on the graphite. Samples from cells that showed higher fade exhibited a thicker film. Furthermore, solvent-based compounds were dominant on samples from low power fade cells, whereas LiPF6-based products were dominant on samples from high-power fade cells. The effects of sample rinsing and air exposure are explored. Mechanisms are proposed to explain the formation of compounds suggested by the XPS data.
Fine-structure (centimeters to meters) in vertical profiles of acoustic volume scattering strength is a common and ecologically significant characteristic of the coastal marine water column. The processes that create these structures modify the availability of food and exposure to predation for secondary producers at and below spatial and temporal scales that characterize their daily ambits. Thin acoustic scattering layers may persist for weeks at a particular coastal location, but they may also appear and disappear in only a few hours. These layers are usually evidence of mesozooplankton and micronekton having aggregated at peaks, gradients, or boundaries in the vertical distribution of various water column properties that characterize a marine ecosystem. The behaviors of both predators and prey are implicated in the generation of complex, time-dependent patterns of fine-structure. Specifically, diel vertical migration to layers of prey, isolumes, isotherms, isopycnals, or chemoclines can be responsible for the nighttime formation of thin acoustic layers. Physical processes such as horizontal shear, internal waves, water mass intrusions, tidal forcing, wind mixing of the upper water column, and horizontal advection modify acoustic scattering patterns by changing the vertical distributions of organisms that scatter sound.
The advent of self-powered functional garments has given rise to a demand for stretchable energy storage devices that are amendable to integration into textile structures. The electromaterials (anode, cathode and separator) are expected to sustain a deformation of 3% to 55% associated with body movement. Here, we report a stretchable fabric supercapacitor electrode using commonly available nylon lycra fabric as the substrate and graphene oxide (GO) as a dyestuff. It was prepared via a facile dyeing approach followed by a mild chemical reduction. This reduced graphene oxide (rGO) coated fabric electrode retains conductivity at an applied strain of up to 200%. It delivers a specific capacitance of 12.3Fg−1 at a scan rate of 5mVs−1 in 1.0M lithium sulfate aqueous solution. The capacitance is significantly increased to 114Fg−1 with the addition of a chemically synthesized polypyrrole (PPy) coating. This PPy-rGO-fabric electrode demonstrates an improved cycling stability and a higher capacitance at 50% strain when compared to the performance observed with no strain.
Rapid fabrication of layer-by-layer (LbL) electrodes is essential to expand their utility in energy storage applications. Herein, we address challenges in developing thick LbL electrodes of multi-wall carbon nanotubes (MWNTs) using conventional dip- and spray-LbL processes, and present a solution to overcome these challenges. The vacuum-assisted spray-LbL process using porous carbon substrates enabled a linear growth of LbL-MWNT electrodes with a 600 time decrease in their fabrication time. This result was attributed to the enhanced surface interactions between MWNTs and substrate via increased surface areas, enhanced capillary forces, physical entrapment in pores, and changes in hydrodynamic drag forces. Scanning electron microscopy (SEM) revealed high surface area carbon nanotube networks comprised of individual MWNT's. The spray MWNT electrodes delivered a high gravimetric energy of 100 W h kg−1 at high gravimetric power of 50 kW kg−1, which is higher than those of most carbon nanotube electrodes reported. Moreover, the spray MWNT electrodes delivered the highest energy capacity per unit area (up to 300 μW h cm−2 at 0.4 mW cm−2 among the LbL electrodes reported, and showed excellent retention of energy capacity up to 100 μW h cm−2 at high power capacity of 200 mW cm−2. These performance values are higher or comparable to the most advanced battery electrodes for high energy capacity per unit area.
The Pulse Power Current (PPC) profile is often the signal of choice for obtaining the parameters of a Lithium-ion (Li-ion) battery Equivalent Circuit Model (ECM). Subsequently, a drive-cycle current profile is used as a validation signal. Such a profile, in contrast to a PPC, is more dynamic in both the amplitude and frequency bandwidth. Modelling errors can occur when using PPC data for parametrisation since the model is optimised over a narrower bandwidth than the validation profile. A signal more representative of a drive-cycle, while maintaining a degree of generality, is needed to reduce such modelling errors. In Part 1 of this 2-part paper a signal design technique defined as a pulse-multisine is presented. This superimposes a signal known as a multisine to a discharge, rest and charge base signal to achieve a profile more dynamic in amplitude and frequency bandwidth, and thus more similar to a drive-cycle. The signal improves modelling accuracy and reduces the experimentation time, per state-of-charge (SoC) and temperature, to several minutes compared to several hours for an PPC experiment.
The authors regret that an error occurred in Figure 1 of the published article indicated above. The key in image (a) should state data instead of date, as shown in the corrected figure below.Image 1 The authors would like to apologise for any inconvenience caused.
Layered Li0.7[M1/6Mn5/6]O2 (M=Li, Ni) was synthesized using a sol–gel method. P2-Na0.7[M1/6Mn5/6]O2 precursor was first synthesized by a sol–gel method, and then O2-Li0.7[M1/6Mn5/6]O2 was prepared by an ion exchange of Li for Na in P2-Na0.7[M1/6Mn5/6]O2 precursor. From charge/discharge curves, it was seen that Li0.7[Li1/6Mn5/6]O2 has two plateaus similar to those observed from a spinel structure, but Li0.7[Ni1/6Mn5/6]O2 holds a single plateau as observed from a typical layered structure. It was considered that Li0.7[Li1/6Mn5/6]O2 undergoes a phase transformation from layered to spinel structure during the charge/discharge cycle, but Li0.7[Ni1/6Mn5/6]O2 maintains O2-layered structure after the cycles. Li0.7[Ni1/6Mn5/6]O2 was higher in discharge capacity and retention rate than Li0.7[Li1/6Mn5/6]O2.
A new type of semi-interpenetrating polymer network (Semi-IPN) gel polymer electrolyte (GPE) membrane based on the cross-linked poly(ethylene glycol) diacrylate-co-poly(vinylene carbonate) P(EGDA-co-VC) and PVDF-HFP linear polymer is successfully synthesized by UV-cured technology. The cross-linked P(EGDA-co-VC) can accommodate a large amount of liquid electrolyte inside the non-porous membrane via its strong interaction with Li+ and solvents, which avoids the liquid electrolyte leakage. The ionic conductivity of the Semi-IPN GPE reaches 1.49×10−3 Scm−1 at 25°C and the electrochemical stability window up to 4.2V (versus Li/Li+). It demonstrates excellent interface stability to lithium metal electrode, superior thermal stability and good mechanical properties. A symmetric Li/Li cell with the above electrolyte displays a lower voltage polarization and longer valid cycle life than that based on conventional liquid electrolyte. Moreover, the Li/LiFePO4 cells using the Semi-IPN GPE show superior cycling stability and rate performance comparable to the cell based on conventional liquid electrolyte. This Semi-IPN GPE is promising for rechargeable lithium batteries with high safety and energy density.