batterydata/paper-abstracts huggingface dataset:
In present work, we demonstrate a rapid and easy approach to fabricate three-dimensional (3D) reduced graphene hydrogels (RGHs) by using thiourea dioxide as reducing agents in an aqueous solution of graphene oxide (GO) with ammonia. The transformation of GO suspension to the hydrogels can be confirmed by X-ray powder diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy. The hierarchical porosity, structure and surface chemical properties can be demonstrated by N2 sorption experiments, scanning electron microscopy and X-ray photoelectron spectroscopy. With adding different amounts of thiourea dioxide, the obtained RGHs behave different degree of reduction, controlled specific surface area and pore size distribution, and unlike performances in supercapacitors. Benefiting from well-defined and cross-linked 3D porous network architectures, the supercapacitors based on the RGHs in KOH electrolyte exhibited a high specific capacitance of 258.6, 167.3 and 198.3 F g−1 at 0.1 A g−1 for RGHs-1, RGHs-2 and RGHs-5, respectively. Furthermore, this capacitance also showed good electrochemical stability and a high degree of reversibility in the repetitive charge/discharge cycling test.
Molybdenum disulfide (MoS2) has been intensively investigated for its high theoretical capacity as an advanced anode material for lithium storage. However, the low electronic conductivity and frail layered structure give rise to its poor cycling stability and low rate performance. Herein, by taking advantages of the porous structure and the high N content of metal-organic frameworks (MOFs) derivatives, a facile and scalable method combining electrospinning and following a hydrothermal process was developed to fabricate MoS2-based composite fibers, in which ultrathin MoS2 nanoplates were vertically assembled on the polyacrylonitrile-MOF-derived N-doped porous carbon nanofibers (PCNF). As expected, benefiting from the hierarchical structure of PCNF and the synergies between MoS2 and PCNF, the obtained PCNF@MoS2 exhibited high capacity and cycling performance in a lithium battery.
An electrochemical study of the bismuth oxide Bi2O3 with a cavity microelectrode coupled in situ to Raman microspectroscopy allowed species transformations during the redox behavior of this oxide to be identified. It was shown that the electroactive species are probably bismuth oxy-hydroxides rather than Bi2O3 when a potential is applied, whereas they are Bi2O3 on open circuit voltage.
Composites of rutile-type TiO2 and Si were synthesized by a facile sol–gel method for a high-performance anode of Li-ion battery. We have investigated anode performance of binder-free thick-film electrodes prepared by a gas-deposition method using the TiO2/Si composites obtained. The composite electrode exhibited a remarkably improved cyclability and a good high-rate performance: a discharge capacity at the 900th cycle was 710mAhg−1, and a specific capacity per Si weight was as large as 1870mAhg(Si)−1 even at a high current rate of 4.8C. It is suggested that a fast Li-ion diffusion in TiO2 provides smooth insertion/extraction of Li-ion into/from the composite electrodes. The results offer a utility of rutile TiO2 as a Li-ion conductor in Si-based electrodes for the next-generation Li-ion battery.
A novel phenol–formaldehyde carbon with ordered/disordered bimodal mesoporous structure is synthesized by the facile evaporation induced self-assembly strategy under a basic aqueous condition with SiO2 particles as template. The prepared bimodal mesoporous carbons (BMCs) are composed of ordered mesoporous and disordered mesoporous with diameter of about 3.5 nm and 7.0 nm, respectively. They can be employed as supercapacitor electrodes in H2SO4 aqueous electrolyte after the simple acid-treatment. BMC exhibits an exceptional specific capacitance of 344 F g−1 at the current density of 0.1 A g−1, although it has a relatively low surface area of 722 m2 g−1. And the BMC electrode displays an excellent cycling stability over 10,000 cycles.
The introduction of hybrid electric vehicle (HEV) technology in the private car fleet of Mexico City is evaluated in terms of private costs, energy, public health and CO2 emission benefits. In addition to constructing plausible scenarios for urban expansion, emission, car fleet, and fuel consumption for year 2026 and comparing them with a 2004 base case, a time series is built to obtain accumulated economic benefits. Experimental techniques were used to build a vehicle library for a car simulator that included a Prius 2002, chosen as the HEV technology representative for this work. The simulator is used to estimate the emissions and fuel consumption of the car fleet scenarios. In the context of an urban scenario for year 2026, a complex air quality model obtains the concentrations of criterion pollutants corresponding to these scenarios. Using a technology penetration model, the hybridized fleet starts unfolding in year 2009 reaching to 20% in 2026. In this year, the hybridized fleet resulted in reductions of about 10% of CO2 emissions, and yielded reductions in daytime mean concentrations of up to 7% in ozone and 3.4% in PM2.5 compared to the 2004 base case. These reductions are concentrated in the densely populated areas of Mexico City. By building a time series of costs and benefits it is shown that, depending on fuel prices and using a 5% return rate, positive accumulated benefits (CO2 benefits+energy benefits+public health benefits−private costs) will start generating in year 2015 reaching between 2.8 and 4.5 billion US Dlls in 2026. Another modernized private fleet consisting exclusively of Tier I and II cars did not yield appreciable results, signaling that a change in private car technology towards HEV's is needed to obtain significant accumulated benefits.
Electrochemically formed thin film polyaniline (PANI) anode and lead dioxide (PbO2) cathode, obtained from sulfuric acid solution, for potential applications as electrode materials in PANI|H2SO4|PbO2 aqueous based rechargeable power sources, have been studied using cyclic voltammetry and galvanostatic techniques. Based on the investigations of half cell reactions, the simulation of the charge/discharge characteristic of the possible cell has been done.
The compatibility of polyphosphazene (PPZ) polymer electrolytes with MnO2/C/SPE intercalation cathodes (IC) was investigated. Three-layered laminates of a phosphazene-based solid polymer electrolyte (SPE) film sandwiched between two MnO2-based ICs (one preloaded with lithium) were constructed. The cathodes were fabricated by either solvent casting or compression techniques. Two different crystal forms of manganese(IV) oxide—λ-MnO2 and γ-MnO2—were employed, together with methoxy ethoxy ethoxy PPZ (MEEP) SPE binder material. Carbon black was employed as the electronically conductive phase. One cathode in each laminate was prepared in the ‘chemically intercalated’ form by using LiMn2O4 in place of MnO2. The podand polymer, SMEP, which has better thin film mechanical properties than does MEEP, was complexed with lithium trifluoromethane sulfonate (Li triflate) and used as the SPE. Li+ ions were cycled galvanostatically between the two-ICs, through the phosphazene-based SPE layer. The performance of the cell was continuously monitored by electrochemical impedance spectroscopy (EIS) and by measuring the laminate thickness and voltage drop. The method of cathode fabrication (casting vs. pressing) was found to be the primary factor influencing the cycle life.
A 3D structured composite of carbon nanofibers@MnO2 on copper foil is reported here as a binder free anode of lithium ion batteries, with high capacity, fast charge/discharge rate and good stability. Carbon nanofiber yarns were synthesized directly over copper foil through a floating catalyst method. The growth of carbon nanofiber yarns was significantly enhanced by mechanical polishing of the copper foils, which can be attributed to the increased surface roughness and surface area of the copper foils. MnO2 was then grown over carbon nanofibers through spontaneous reduction of potassium permanganate by the carbon nanofibers. The obtained composites of carbon nanofibers@MnO2 over copper foil were tested as an anode in lithium ion batteries and they show superior electrochemical performance. The initial reversible capacity of carbon nanofibers@MnO2 reaches up to around 998 mAh·g−1 at a rate of 60 mmA·g−1 based on the mass of carbon nanofibers and MnO2. The carbon nanofibers@MnO2 electrodes could deliver a capacity of 630 mAh·g−1 at the beginning and maintain a capacity of 440 mmAh·g−1 after 105 cycles at a rate of 600 mA·g−1. The high initial capacity can be attributed to the presence of porous carbon nanofiber yarns which have good electrical conductivity and the MnO2 thin film which makes the entire materials electrochemically active. The high cyclic stability of carbon nanofibers@MnO2 can be ascribed to the MnO2 thin film which can accommodate the volume expansion and shrinking during charge and discharge and the good contact of carbon nanofibers with MnO2 and copper foil.
The sodiation and desodiation of sodium (Na) into the Super-P carbon anode material were investigated using electrochemical analyses, high-resolution transmission electron microscopy (HRTEM), and neutron powder diffraction (NPD). In the sodiated Super-P carbon, sodium is stored both in the graphite interlayer space of carbon nano-particles and pores between the particles. Sodium metal clusters found in micro-pores between the carbon particles are responsible for the large irreversible capacity of the Super-P electrode. The graphite interlayer distance increases on sodiation from 3.57 Å to two distinct values of ∼3.84 and 4.41 Å. The mechanism of the process is discussed.
An evaluation of currently optimization energy management strategies is done in this study. The load-following – based strategy for Proton Exchange Membrane Fuel Cell (FC) Hybrid Power Systems ensure the DC power flow balance using the FC system as main energy source. Thus, the battery will operate in charge-sustaining mode. So, the battery state-of-charge will vary in imposed window without need of monitoring the battery. Furthermore, the size and maintenance of the battery stack will decrease compared with rule-based strategies. So for the first time, the classification and evaluation of seven FC Hybrid Power Systems and their possible energy management strategies (including a new one) are performed using the performance indicators related to fuel economy and FC electrical efficiency of the FC system. Consequently, the optimization of the FC Hybrid Power Systems under variable load will mix these performance indicators through the weighting coefficients knet and kfuel into a new optimization function. A new switching strategy for the load-following control and real-time optimization loops is proposed to further increase the fuel economy based on the results obtained in this study. The objective of this study is to highlight how optimization function and switching strategy through choosing the weighting coefficients and the control references could improve the fuel economy. Thus, the design of the switching strategy based on available information about the current load demand and the distance to fuel stations is presented in this paper as well. This switching strategy will push hydrogen to become an energy carrier feasible for FC vehicles.
Nanostructured carbons with a number of redox-active sites play a key role as active electrode materials for supercapacitors and rechargeable batteries, owing to their pseudocapacitive charge storage behaviors. Nevertheless, there is currently no method to characterize the level of contribution of pseudocapacitance in overall capacitance values, hindering technological and scientific advancement of pseudocapacitive electrode materials. In this study, we can observe the voltage-dependent pseudocapacitive behaviors of heteroatom-enriched nanoporous carbons, which can be detected through a simple comparison of electrochemically obtained results in both aqueous and organic electrolyte systems. It is also confirmed that the voltage-dependent pseudocapacitive behaviors are so fast and stable that the heteroatom-enriched nanoporous carbons based on the voltage-dependent pseudocapacitive behaviors can deliver high specific energy and power as cathodes when they are assembled with a proper counterpart anode.
With the combination of Internet, information technology and energy, energy storage industry plays an important role in the adjustment of energy structure with its abundant resources and friendly environmental benefits. Firstly, this paper introduces the status of energy storage industry, and studies the relevant policy documents, which lays the foundation for the internal and external ecological research of energy storage industry. Then, this paper uses PEST-SWOT strategic analysis model, based on PEST analysis, analyzes the strengths, weakness, opportunities and threats of energy storage industry in China. Finally, based on the results of PEST-SWOT analysis, the strategic analysis matrix of energy storage industry is constructed. The research results of this paper provide a strategic idea for the development of energy storage industry in China.
Cognitive functions in community-dwelling adults at high risk of obstructive sleep apnea have not been described and nor are associations between cognitive functions and obstructive sleep apnea severity fully understood. The study aimed to describe verbal memory and executive function in community-dwelling adults identified by the Berlin Questionnaire and to investigate associations between these cognitive domains and different obstructive sleep apnea severity indicators.
This article addresses the fading mechanisms observed in carbon-coated and disproportionated Si/SiO x /C negative electrode for Li-ion secondary batteries. A combined characterization revealed that Si/SiO x consisted of multiple nano-sized domains of amorphous Si and SiO x , with some crystalline Si. The initial discharge capacity of Si/SiO x /C was 1380mAhg−1, however, it decreased to 578mAhg−1 at the 90th cycle. The electrode exhibited two different fading modes: local fading and global fading. Through intensive TEM analysis, it was concluded that both fading modes were closely related to the structural change in Si/SiO x /C during alloying/de-alloying. Local fading was induced by the contact loss between active material and conducting carbon, and the limited buffering effect of lithium silicates. Global fading was attributed to the crumbling of Si/SiO x , which limited further alloying, leading to ever decreasing discharge capacity. Both fading modes were thoroughly investigated and monitored by qualitative and quantitative STEM-EDX analysis.
Batteries will play critical roles in modernizing energy grids, as they will allow a greater penetration of renewable energy and perform applications that better match supply with demand. Applying storage technology is a business decision that requires potential revenues to be accurately estimated to determine the economic viability, which requires models that consider market rules and prices, along with battery and application-specific constraints. Here we use models of storage connected to the California energy grid and show how the application-governed duty cycles (power profiles) of different applications affect different battery chemistries. We reveal critical trade-offs between battery chemistries and the applicability of energy content in the battery and show that accurate revenue measurement can only be achieved if a realistic battery operation in each application is considered. The findings in this work could call for a paradigm shift in how the true economic values of energy storage devices could be assessed.
Two shapes of Co3O4 nanoarrays (i.e., nanosheets, nanowires) with different densities of exposed catalytic active sites were synthesized through a facile hydrothermal method on Ni foam substrates and tested as the binder/carbon free and free-standing cathodes for Li–O2 batteries. Particularly, the single crystalline feature of Co3O4 nanosheets with a predominant high reactivity {112} exposed crystal plane and hierarchical porous nanostructure displayed better catalytic performance for both oxygen reduction reaction (during discharge process) and oxygen evolution reaction (during charge process). Li–O2 battery with Co3O4 nanosheets cathode exhibited a higher discharge specific capacity (965 mAh g−1), lower discharge/charge over-potential and better cycling performance over 63 cycles at 100 mA g−1 with the specific capacity limited at 300 mAh g−1. The superior catalytic performance of Co3O4 nanosheets cathode is ascribed to the enlarging specific area and increasing the exposed Co3+catalytic active sites within predominant {112} crystal plane which plays the key role in determining the adsorption energy for the reactants, enabling high round-trip efficiency and cyclic life.
The interest in solid state electrochemical devices including sensors, fuel cells, batteries, oxygen permeation membranes, etc. has grown rapidly in recent years. Many of the same figures of merit apply to these different applications, the key ones being ionic conduction in solid electrolytes, mixed ionic-electronic conduction (MIEC) in electrodes and permeation membranes, and gas-solid reaction kinetics in sensors and fuel cells. Optimization of device performance often relies on the careful understanding and control of both ionic and electronic defects in the materials that make up the key device components. To date, most materials in use have been discovered serendipitously. A key focus of this paper is on the tools available to scientists and engineers to practice ‘defect engineering’ for the purpose of optimizing the performance of such materials. Dopants, controlled structural disorder, and interfaces are examined in relation to increasing the conductivity of solid electrolytes. The creation of defect bands is demonstrated as a means for introducing high levels of electronic conductivity into a solid electrolyte for the purpose of creating a mixed conductor and thereby a monolithic fuel cell structure. Dopants are also examined as a means of reducing losses in a high temperature resonant sensor platform. The control of microstructure, down to the nano-scale, is shown capable of inverting the predominant ionic to an electronic charge carrier and thereby markedly modifying electrical properties. Electrochemical bias and light are also discussed in terms of creating defects locally thereby providing means for micromachining a broad range of materials with precise dimensional control, low residual stress and controlled etch rates.
Electrodes prepared by electrospinning often exhibit an activation behavior, i. e. they are reaching their full capacity only after numerous charge and discharge cycles. The activation mechanism can be explained by the improvement of the accessibility of Li+ ions to the active particles of the cathode, which increases with the number of cycles. It is assumed that, as an effect of cycling, the dense, impermeable carbon layer which covers the active material due to the carbonization step during processing cracks and delaminates, allowing this way the Li+ ions to access the active material and to intercalate into it. This has been confirmed by scanning and transmission electron microscopy performed in correlation with the electrochemical performance of electrospun electrodes. However, with even further cycling a decrease in capacity is observed. The microscopic results suggest that this is partly caused by cracks at the carbon-LiFePO4 interfaces. Thus, the cracking responsible for the activation of the electrospun electrodes at the beginning of cycling seems also to cause a part of their degradation at the end of their life. Another slow degradation mechanism confirmed by scanning electron microscopy and by X-ray photoelectron spectroscopy is the ongoing formation of a cathode electrolyte interphase.
Lithium-ion capacitors (LICs) are novel advanced electrochemical energy storage (EES) systems integrating both battery and capacitor functions. Most efforts for developing high-power LICs are currently dedicated to nanostructure design of battery-type anodes, which in general results in low packing densities and cannot fundamentally improve the slow Faradaic reaction. Up to now, little attention has been focused on the effects of porous carbon cathodes and the reasonable matching of cathode/anode on the power performance of LICs. Herein, a novel nitrogen-enriched mesoporous carbon nanospheres/graphene (N-GMCS) nanocomposite is demonstrated, which shows simultaneously hierarchical porous structure, 3D conductive network, as well as very high mass density. When such N-GMCS cathode is coupled with prelithiated microcrystalline graphite (PLMG) anode, the integrated device shows quite high packing density which is highly desirable in EES systems. In particular, the PLMG anode in N-GMCS//PLMG system breaks the limitation of slow Faradaic reaction and lithium-ion bulk diffusion, providing an ultrafast capacitor-like electrochemical response. Quite attractive maximum energy density (80Whkg−1, 68.6WhL−1) and state-of-the-art maximum power density (352kWkg−1, 292kWL−1) can be achieved in N-GMCS//PLMG, which are 5 and 2.8 times as large as those of the supercapacitor counterpart, respectively.
The home energy management is an efficient tool to manage energy in the buildings that organizes different technologies and mathematical techniques to minimize energy cost. Home energy management often utilizes renewable energy resources to supply load demand in the building. Current home energy management systems utilize one or several of the available hardware-software capacity resources to deal with energy consumption in the buildings. However, a comprehensive model including various hardware and software capacity resources may increase the flexibility of the model. In this regard, this paper studies an efficient paradigm for home energy management in the building connected to electric grid. The proposed model forms an energy hub including the hardware resources (i.e., vehicle-to-home, wind turbine, and diesel generator) and software tools (i.e., demand response program). All the capacity resources and grid power are optimally adjusted to minimize the daily operational cost of the building as well as improvement of resiliency and self-healing. Wind energy and load uncertainty are modeled through stochastic programming. The seasonal pattern is considered for loads, prices, and wind energy. Simulation results demonstrate that operating all capacity resources minimizes the daily operational cost. When the wind energy, demand response program, vehicle-to-home, and diesel generator are not utilized, the cost is increased by 900, 230, 84, and 322%, respectively. It is also confirmed that the building not only can operate when one of the components is not connected, but also it is able to supply the demand under off-grid operation.
Non-flammable polymer gel electrolytes (NPGE) consisting of 1.0moldm−3 (=M) LiBF4/EC+DEC+TEP (55:25:20 volume ratio)+PVdF-HFP (EC: ethylene carbonate, DEC: diethyl carbonate, TEP: triethylphosphate, PVdF-HFP: poly(vinyledenefluoride-co-hexafluoropropylene)) have been developed for rechargeable lithium batteries. The effects of addition of Lewis-acid polymer (LAP) with different mole ratio in NPGE have been studied. The addition of LAP improved physico-chemical properties of NPGE, viz ionic conductivity and lithium ion transport number, as well as mechanical and thermal properties. The ionic conductivity of the gel electrolyte containing LAP reached that of the base solution electrolyte (1.0M LiBF4/EC+DEC+TEP (55:25:20)) along with better mechanical properties. Interfacial resistance at Li-metal electrode/NPGE was also improved by introducing LAP in the gel.