batterydata/paper-abstracts huggingface dataset:
A novel tin composite Sn/CaSiO3 for the anode of Li-ion batteries was prepared by solid-state reaction. The CaSiO3 matrix was synthesized by a sol-gel route. The crystalline structures and morphology were determined by X-ray diffraction (XRD) and 119Sn Mössbauer spectroscopy; the electrochemical properties were evaluated by galvanostatic charge and discharge. The results obtained show that the Sn/CaSiO3 composite presents very interesting electrochemical performances in terms of specific capacity in the first discharge (591 mAh/g) and a good reversibility due to both the formation of an interface between active and inactive materials and the reversible formation of LixSn alloys. We have also highlighted, by 119Sn Mössbauer spectroscopy, the various tin species constituting the material of the starting electrode, as well as the chemical evolutions occurring during the discharge and the charge of the electrode.
Organic electroactive materials derived from biomasses are promising candidates for next generation rechargeable batteries due to the low cost, sustainability and environmental benignity. Since organic materials have very low electronic conductivity, they are normally synthesized into nano-scale and mixed with conductive carbon before electrode fabrication. Herein, we first reported a unique role-to-role fabrication technology by taking advantage of the high solubility of organic materials in water. The synthetic process of nano-size organic materials is merged into the organic electrode fabrication process. 2,5-Dihydroxy-1,4-benzoquinone disodium salt (DHBQDS) is used as a model, and the DHBQDS nanorod electrode is in situ formed by precipitating DHBQDS nanorods from DHBQDS–sodium alginate–carbon black aqueous slurry film on a Cu current collector during electrode drying process. Due to the fast ionic and electronic conductivity of DHBQDS–carbon nanocomposite, the DHBQDS nanorod electrodes deliver a reversible capacity of 167mAhg−1 at a high current density of 200mAg−1 after 300 cycles, which is 87% of its initial capacity (capacity decay rate of 0.051% per cycle). To reduce the dissolution of DHBQDS in the electrolyte upon cycling, a thin layer of Al2O3 with thickness of 1nm or 2nm is coated on the DHBQDS nanorod electrodes using atomic layer deposition (ALD). The Al2O3 coating remarkably suppresses the dissolution of DHBQDS nanorods as evidenced by the increased Coulombic efficiency from 94% to ~100% at a low current density of 50mAg−1. The reversible capacity of Al2O3 coated DHBQDS nanorod electrodes remains at 212mAhg−1 after 300 cycles with a very low capacity decay rate of 0.049% per cycle. The ALD enhanced organic nanorods exhibit the best reversible capacity and cycle life among the organic electrodes reported for Na-ion batteries.
To analyze the independent relationship between the risk of eating disorders and bone health and to examine whether this relationship is mediated by body composition and cardiorespiratory fitness (CRF).
With the popularity of e-commerce, posting online product reviews expressing customer’s sentiment or opinion towards products has grown exponentially. Sentiment analysis is a computational method that plays an essential role in automating the extraction of subjective information i.e. customer’s sentiment or opinion from online product reviews. Two approaches commonly used in Sentiment analysis tasks are supervised approaches and lexicon-based approaches. In supervised approaches, Sentiment analysis is seen as a text classification task. The result depends not only on the robustness of the machine learning algorithm but also on the utilized features. Bag-of-word is a common utilized features. As a statistical feature, bag-of-word does not take into account semantic of words. Previous research has indicated the potential of semantic in supervised SA task. To augment the result of sentiment analysis, this paper proposes a method to extract text features named sentence level features (SLF) and domain sensitive features (DSF) which take into account semantic of words in both sentence level and domain level of product reviews. A word sense disambiguation based method was adapted to extract SLF. For every similarity employed in generating SLF, the SentiCircle-based method was enhanced to generate DSF. Results of the experiments indicated that our proposed semantic features i.e. SLF and SLF + DSF favorably increase the performance of supervised sentiment analysis on product reviews.
Contrasting data on reading ability in Alzheimer's disease patients have been reported in the literature. Recently Patterson, Graham and Hodges (1994) found that irregular words were misread by demented subjects, while regular words were read correctly. The present study hypothesizes that reading latency may be a sensitive measure of Alzheimer's patients reading impairment. Fifteen Alzheimer's patients were compared with 17 elderly normal subjects on three tasks that used the same set of concrete, regular words: a picture naming task, a word-picture matching task and a word-nonword reading task. The results of the study indicate that reading latency is longer in Alzheimer's patients than in normal subjects, and that misnamed and mismatched words are read with the same mechanism as nonwords.
As a promising anode candidate for lithium-ion batteries (LIBs), SnO2-based material has been extensively investigated. However, its practical application is still hindered due to the inherent drawbacks of poor conductivity, severe volume expansion, and unavoidable agglomeration of active material during repeated discharge/charge process as well as formation of unstable solid electrolyte interface (SEI) layer. In this paper, the SnO2@carbon nanotube/reduced graphene oxide (SnO2@CNT/RGO) composite is rationally designed and fabricated, in which nano SnO2 nanoparticles (NPs, ~6 nm) are anchored onto three-dimensional (3D) conductive CNTs/RGO skeleton by first assembling SnO2 onto CNT and then entangling SnO2@CNT nanofibers in 3D graphene networks. The synergistic effect of CNT and RGO significantly increase the conductivity and prevent aggregation of active material. In addition, the mesopores structure constructed by CNT and RGO can accommodate the volume change of SnO2 NPs and form more stable SEI layer during repeated discharge/charge process. Therefore, the SnO2@CNT/RGO electrode exhibits not only more stable cycle performance but also more superior rate capacity. The discharge/charge specific capacity at 0.2 A g−1 is 1032/1022 mAh g−1 after 100 cycles. Even at high current density of 2.0 A g−1, it still maintains the discharge/charge capacity of 586/578 mAh g−1 after 200 cycles.
This paper proposes a support mechanism for energy storage devices for island power systems where intermittent renewable generation is rapidly growing. We base our proposal on the maturity level of storage devices (Chen et al., 2009 [7]) and on the linear model for the development of innovations [14]. We focus on storage technologies that can be technically developed in island power systems and that achieve the technical needs of these systems. We conclude and recommend the adoption of a feed-in tariff with a price varying with the time of day to push for the deployment of power storage avoiding the curtailment of massive intermittent renewable generation.
To find the best operating conditions and oxygen electrode catalyst of the PEM unitized regenerative fuel cell (URFC) system, we examined the effect of reaction conditions and the performance of several bifunctional electrocatalysts for oxygen electrode in a single cell PEM URFC system. When Pt black was employed for both electrodes, the URFC performance improved with increasing cell temperature up to 70 °C and catalyst loading up to 6.7mgcm−2. Among the catalysts prepared in the present study for oxygen electrode, fuel cell performance decreased in the order of Pt black > PtIr > PtRuO x > PtRu ∼ PtIr > PtIrO x , whereas, water electrolysis performance decreased in the order of PtIr ∼ PtIrO x > PtRu > PtRuIr > PtRuO x ∼ Pt black, showing significant performance improvement by addition of second metals such as Ir or IrO x to Pt black. Consequently, PtIr had the best URFC performance with high round-trip efficiency and stability during the cycling operation of the URFC system. Therefore, PtIr is promising as an oxygen electrode of the PEM URFC system.
Diesel particulate matter (DPM) is considered to be carcinogenic after prolonged exposure. With more diesel-powered equipment used in underground mines, miners’ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push–pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push–pull systems considered include: long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.
Nanorod-assembled spinel Li1.05Mn1.95O4 rods with a central tunnel along the rod-axis were synthesized using highly crystalline β-MnO2 rods as self-templates. The synthesized spinel Li1.05Mn1.95O4 is an assembly of several single crystal-like nanorods with an average diameter and length of 100 and 400nm, respectively, which was determined by microstructural Rietveld refinement using the synchrotron powder XRD data. Galvanostatic battery testing showed that central-tunneled and nanorod-assembled Li1.05Mn1.95O4 rods have a high charge storage capacity at high current densities in comparison with those of the spinel rods without a tunnel structure and commercial powders. Moreover, a capacity retention value of ∼81% was observed at the end of 100 cycles at a current of 250mAhg−1.
MnO-carbon hybrid nanofiber composites are fabricated by electrospinning polyimide/manganese acetylacetonate precursor and a subsequent carbonization process. The composition, phase structure and morphology of the composites are characterized by scanning and transmission electron microscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that the composites exhibit good nanofibrous morphology with MnO nanoparticles uniformly encapsulated by carbon nanofibers. The hybrid nanofiber composites are used directly as freestanding anodes for lithium-ion batteries to evaluate their electrochemical properties. It is found that the optimized MnO-carbon nanofiber composite can deliver a high reversible capacity of 663mAhg−1, along with excellent cycling stability and good rate capability. The superior performance enables the composites to be promising candidates as an anode alternative for high-performance lithium-ion batteries.
With plenty of unique porous structure at micro-/nano scale, hierarchically porous carbons (HPCs) are promising for usage in advanced electric double layer supercapacitors (EDLCs) as the electrode materials. However, wide-range adoption of HPC for practical application is largely shadowed by its extremely complex synthesis process with considerably low production efficiency. Herein we reported a simple template-free, one-step sintering method, to massively produce the HPCs for high-performance EDLCs. Resorting to the 3D structure modification of the wide pore size distribution, high surface area of HPCs (up to 3000 m2 g−1) was achieved. By using 1 M Na2SO4 as electrolyte, the as-fabricated HPCs based EDLCs can be operated reversibly over a wide voltage window of 1.6 V with superior specific capacitance of 240 F g−1 under a current density of 0.5 A g−1. In the meanwhile, the EDLCs exhibit excellent rate capability (high power density of 16 kW kg−1 at 10.2 Wh kg−1) and long-term cycling stability with 9% loss of its initial capacitance after 2000 cycles. This output performance distinguished itself among most of the carbon-based EDLCs with neutral aqueous electrolyte. Thus, the template-free one-step sintering method produced HPCs for EDLCs represents a new approach for high-performance energy storage.
Spherically shaped Ni-substituted LiNixMn2-xO4 (x=0, 0.1, 0.2) spinel cathode materials for lithium ion battery with high first cycle discharge capacity and remarkable cycling performance were synthesized using the solution-combustion technique. XRD confirmed the successful synthesis of the various spinel structures, with the Bragg diffraction peaks shifting to higher 2θ angles accompanied with lattice shrinking as the Ni concentration increased. The SEM images of the spinels revealed essentially spherical morphology. Galvanostatic charge-discharge experiments showed that by substituting the pristine spinel with a low amount of nickel enhanced the cell potential (hence the energy storage capability) and greatly improved the capacity retention (ca. 99%) even after 100 cycles. Electrochemical impedance spectroscopy experiments corroborated the enhanced capacity retention as lithium ion intercalation/de-intercalation resistance for the Ni substituted spinels was significantly improved (more than a magnitude higher) compared to the pristine spinel.
Local structural changes in a porous NiSi2/Si composite anode material are investigated by X-ray absorption spectroscopy. It is observed that the NiSi2 phase shows a strong metal-metal bond character and no clear changes can be observed in XANES during lithiation and de-lithiation. The variation of the number of nearest neighbors of the Ni atom for the 1st coordinate Ni-Si shell and σ 2 in the 1st cycle, both determined by refinement, demonstrates that NiSi2 can partially react with lithium during discharge and charge. A partially reversible non-stoichiometric compound NiSi2−y is formed during cell operation, the crystal structure of which is the same as that of the NiSi2 phase. It can be concluded that NiSi2 in the composite not only accommodates the pronounced volume changes caused by the lithium uptake into silicon, but also contributes to the reversible capacity of the cell.
Rigid substrate e.g. glassy carbon is typically used in biofuel cells (BFCs). Compared with the substrates, paper-based materials are low cost, lightweight, flexible design and easy to manufacture. In this work, flexible BFCs have been constructed on filter papers coated with a composite material of cellulose and carbon nanotube as binder. For mediator-less electrode reactions, biliribin oxidase and fructose dehydrogenese were employed as cathodic and anodic biocatalysts respectively. The power of a BFC unit reached 4.3μW while the cathode was the main limitation based on discharge experiments. The BFCs can be designed and constructed to various shapes on paper substrates in series and parallel configuration, a maximum power output of 7.9μW was produced. The voltage reversal behavior of individual cell in stack has also been investigated for the first time, which was caused by the unit with lowest ability in power generation in stack. This unique BFC obtained here is promising to be used as a kind of flexible power resources for wearable or rolling-up devices in practice.
To develop an efficient and cost-effective cathodic electrocatalyst for microbial fuel cells (MFCs), carbon nanotubes (CNTs) coated with manganese dioxide using an in situ hydrothermal method (in situ MnO2/CNTs) have been investigated for electrochemical oxygen reduction reaction (ORR). Examination by transmission electron microscopy shows that MnO2 is sufficiently and uniformly dispersed over the surfaces of the CNTs. Using linear sweep voltammetry, we determine that the in situ MnO2/CNTs are a better catalyst for the ORR than CNTs that are simply mechanically mixed with MnO2 powder, suggesting that the surface coating of MnO2 onto CNTs enhances their catalytic activity. Additionally, a maximum power density of 210mWm−2 produced from the MFC with in situ MnO2/CNTs cathode is 2.3 times of that produced from the MFC using mechanically mixed MnO2/CNTs (93mWm−2), and comparable to that of the MFC with a conventional Pt/C cathode (229mWm−2). Electrochemical impedance spectroscopy analysis indicates that the uniform surface dispersion of MnO2 on the CNTs enhanced electron transfer of the ORR, resulting in higher MFC power output. The results of this study demonstrate that CNTs are an ideal catalyst support for MnO2 and that in situ MnO2/CNTs offer a good alternative to Pt/C for practical MFC applications.
The use of hydrogen produced from renewable energy sources is often reported as an attractive strategy to address the issue of urban environmental sustainability in automotive sector, and a potential alternative to fossil fuel-fed vehicles. The project ‘Filiera Idrogeno’ (Hydrogen Chain) has investigated the potential realisation of hydrogen production chains from renewables and its use as automotive fuel in Tuscany Region (Italy). In this context, life cycle assessment was used for evaluating the environmental sustainability of such chains, applied to a fleet of hydrogen vehicles for urban commercial delivery. From the energy supply side, renewable wind and biomass energy sources were considered for hydrogen production either by electrolysis or direct separation from biomass gasification syngas, according to specific simulations. Benchmarking with hydrogen produced by using Italian electricity mix was carried out. From the transport side, vehicles equipped with either fuel cell or internal combustion engine were evaluated. A benchmarking analysis with standard electric vehicles supplied with electricity produced from the same renewable energy sources was also carried out. The results give some indications on the environmental aspects of the different alternatives and on the contribution of the chain phases to the overall impacts.
A simple solvent method is proposed for the recovery of waste Li x CoO2 from lithium-ion batteries, which employs inexpensive DMF to remove the binder of PVDF. This method is convenient to manipulate and low-cost to apply. Electrochemical investigations indicate that recovered Li x CoO2 materials with a small amount of S-doping exhibit excellent properties as negative materials for alkaline rechargeable Ni/Co batteries. At the discharge current density of 100 mA g−1, the Li x CoO2 + 1% S electrode displays the max discharge capacity of 357 mAh g−1 and outstanding capacity retention rate of 85.5% after 100 cycles. It could overcome not only the sophisticated, energy-intensive shortcomings of conventional recycling methods, but also the high-cost restriction on alkaline rechargeable Ni/Co batteries.
Electrochemical double-layer capacitors (EDLCs) are emerging energy storage devices that provide high power density and rapid charging rates, with higher energy density than conventional capacitors. Extensive research efforts have been devoted to develop novel, high performing electrode materials to improve device performance, particularly to increase energy density. A number of methods have been used to characterize and report the performance of EDLCs in literature. The lack of a consistent and representative normalization parameter and the absence of consistent electrochemical testing procedures make the comparison of performance data challenging. In this work, key factors that affect EDLC performance data are discussed. Consideration is given to potential normalization parameters: mass, volume, and specific surface area (SSA). As well, an investigation into the effects of charging rate, maximum operating voltage window, and electrochemical analysis technique is performed. This work demonstrates the dependence of measured capacitance on maximum voltage window and the variation in performance between two different electrode materials. Moreover, an inherent discrepancy between cyclic voltammetry (CV) and galvanostatic cycling (GC) capacitance values at fast charging rates has been observed. We hope this effort will assist in the development of a much needed international protocol for accurate measurement and characterization of EDLC performance.
Ternary graphene/sulfur/polyaniline (graphene/S/PANI) composites have been successfully prepared via a facile two-step synthesis method. S nanoparticle is uniformly decorated on the graphene surface, and PANI nanowires cover the graphene/S surface. When used as cathode material for lithium-sulfur batteries, the specific ternary composite achieves excellent electrochemical performance with high capacity and improved cycling stability. The graphene/S/PANI sample delivers a specific capacity of up to 837mAhg−1 after a few cycles at 0.1C, which is considerably higher than that delivered by the graphene/S sample. In addition, the graphene/S/PANI sample and the graphene/S sample show improved cycling stability with improved Coulombic efficiency compared with pure S sample. This observation indicates the successful prevention of the polysulfide species diffusion owing to graphene introduction. Furthermore, the activation mechanism of graphene/S is studied through morphology change during cycling, which demonstrates that activation is ascribed to the gradual spread of S on the graphene surface during cycling.
The electrochemical behavior of a series of composites synthesized by a combination of incipient wetness impregnation and hydrothermal method for the first time is systematically compared (using cyclic voltammetric and electrochemical impedance spectroscopic analyses). Structural and morphological characterizations of the composites were undertaken using power X-ray diffraction (XRD), N2 adsorption/desorption isotherms and transmission electron microscopy (TEM). The results indicated that the binary nickel/manganese compounds of the Ni–Mn/ordered mesoporous carbon (OMC) composite had a synergistic effect of both components.
Worldwide, approximately two billion people are chronically infected with Toxoplasma gondii with largely unknown consequences.
This review describes the polymer electrolyte membranes (PEM) that are both under development and commercialized for direct methanol fuel cells (DMFC). Unlike the membranes for hydrogen fuelled PEM fuel cells, among which perfluorosulfonic acid based membranes show complete domination, the membranes for DMFC have numerous variations, each has its advantages and disadvantages. No single membrane is emerging as absolutely superior to others. This review outlines the prospects of the currently known membranes for DMFC. The membranes are evaluated according to various properties, including: methanol crossover, proton conductivity, durability, thermal stability and maximum power density. Hydrocarbon and composite fluorinated membranes currently show the most potential for low cost membranes with low methanol permeability and high durability. Some of these membranes are already beginning to impact the portable fuel cell market.
Depth profile of constituent elements of positive electrodes in lithium-ion batteries was analyzed by using glow discharge optical emission spectroscopy (GD-OES) from the surface to the interface with the current collector. Not only in pristine electrode but also in degraded electrode after 50,000 cycles of high rate charge and discharge, almost homogeneous concentration profile of lithium was observed, suggesting that particles of active electrode material in the deep region inside the electrode layer also concerned in the electrochemical reaction as well as the particles in the surface area. From observation of particles shape by scanning electron microscope (SEM), remarkable cracks were not observed in particles inside the electrode even in the degraded electrodes.