batterydata/paper-abstracts huggingface dataset:
The active lithium loss in cathode materials is responsible for the capacity fading of LiFePO4/graphite battery at ambient temperature and low C-rate. In this work, we investigate the changes of lithium amount in four components involving cathode, anode, separator and electrolyte at different capacity loss levels when the LiFePO4/graphite batteries are cycled at a rate of 2C. The results show that the lithium content in the cathode decreases from 4.2% to 1.8% as the capacity retention decreases to 23.4%, while that in the graphite anode increases from 1.1% to 4.9%. Internal and intrinsic fading causes are investigated by subsequent analysis of their structures and morphologies. Besides, electrochemical testing results show that the loss of lithium ions for the cycled LiFePO4 electrodes is restorable due to the well-maintained olivine structure, while the cycled graphite anodes exhibit quick fading of charging/discharging specific capacity after long-term cycling. The capacity fading mechanism can be mainly ascribed to the active lithium consumption on graphite anode for solid electrolyte interface breaking/repairing and side reactions induced by graphite's inner structural deterioration.
This work provides a study of mixtures of the azepanium-based ionic liquid (IL) N-methyl, N-butyl-azepanium bis[(trifluoromethane) sulfonyl]imide (Azp14TFSI) and propylene carbonate (PC) as electrolyte components in electrochemical double layer capacitors (EDLCs). The considered mixtures’ properties were then compared to the properties of mixtures of N-butyl, N-methylpyrrolidinium bis[(trifluoromethane) sulfonyl]imide (Pyr14TFSI) and PC in terms of viscosity, conductivity and electrochemical behavior. The mixtures’ operative potentials were found to be comparable to each other, leading to operative voltages as high as 3.5V, while retaining the low viscosities and high conductivities of PC based EDLC electrolytes.
Hybrid wireless sensor networks (WSNs) contain static and mobile sensors to support various applications. Static sensors monitor environment to find where events occur. Mobile sensors (MSs) move to event locations (ELs) to do advanced analysis. Since MSs are powered by batteries, how to dispatch them to visit ELs in an energy-efficient manner is critical. Moreover, as the technology of wireless chargers (WCs) is mature, it is feasible to use WCs to replenish energy of MSs during their working time. The paper addresses the multi-round sensor dispatch problem in a hybrid WSN with WCs, whose goal is to schedule the paths of MSs to visit ELs and WCs in each round, such that their lifetime is maximized. The problem is NP-hard and we propose a group-based mobile sensor dispatch (G-MSD) algorithm, which clusters ELs into groups by their positions. G-MSD dispatches MSs to visit each group of ELs to save and balance their moving energy costs. Besides, it schedules MSs to call at WCs to recharge batteries on demand. Simulation results verify that the G-MSD algorithm greatly extends lifetime of MSs, as comparing with other methods.
Based on the energy barrier theory, we proposed a kinetics investigation method to research the rate constants of the charging/discharging processes for the metal hydride electrodes. The Tafel polarization curves and galvanostatic intermittent titration technique (GITT) method were applied to characterize the electrochemical parameters of the electrode reactions. In this paper, the values of the standard Gibbs free energy and the rate constants obtained from different over-potentials and various depth of discharge (DOD) were compared. Both the rate constants of the charging/discharging reactions decreased with the increase of DOD, which were in agreement with the variations of the hydrogen diffusion coefficient. The proposed method is more visualized and accurate for studying the reaction rates of the metal hydride electrodes and can be used to quantitatively investigate the kinetics properties of the Ni/MH batteries.
Spinel LiMn1.925M0.075O4 (M=Cr, Co) powders with small and uniform particle size were successfully synthesized by microwave-induced combustion. The LiMn1.925M0.075O4 (M=Cr, Co) samples were used as cathode materials for lithium-ion battery, which their discharge capacity and electrochemical characteristic properties were investigated in this study. The results revealed that The Li/LiMn1.925M0.075O4 (M=Cr, Co) cells showed lower capacity loss than Li/LiMn2O4 cell after 30cycles. Moreover, Cr-substituted spinel exhibited a lower capacity loss than Co-substituted spinel. The initial capacity of LiMn2O4 and LiMn1.925M0.075O4 cells can be ranked as follows: LiMn2O4 >LiMn1.925Cr0.075O4 >LiMn1.925Co0.075O4.
Germanium, as a semiconductor material, has a poor electrical conductivity, but the high theoretical capacity of 1600mAhg−1 makes it as a promising high-capacity anode material for lithium-ion batteries (LIBs). The huge volume variation during charge and discharge leads to a poor cycling stability. In this paper, Ge with reduced graphene oxide nanofibers (Ge@RGO NFs) are firstly prepared by electrospinning. The nanofibers with a uniform diameter of 50nm combined RGO delivered a high specific capacity of 1727.0mAhg−1 in the fist discharging and 1205.1mAhg−1 after 100 cycles at the constant current density of 200mAg−1. RGO in the composites has two important roles: (i) as a conductive agent to improve electrical conductivity; (ii) as a buffer to protect Ge nanostructure from pulverization during charge and discharge processes. Electrochemical testing results show that the Ge@RGO nanofibers anode has a high specific capacity of 661.6mAhg−1 at the current density of 5000mAg−1, suggesting the Ge@RGO electrodes can be used to high current and high-power electronic equipments.
Organic redox flow batteries receive increasing interest for large-scale electrical energy storage owing to the structural diversity and elemental abundance of organic compounds. However, their implementation is challenged by the cyclability, which is an order of magnitude lower than traditional redox flow batteries using inorganic redox couples. The unsatisfactory cyclability mainly arises from electrolyte contamination and irreversible losses of active material in the electrolyte. To address such issues, a highly water-soluble artificial bipolar molecule containing cathode-active ferrocene moiety and anode-active bipyridinium moiety is realized and used as the sole active material in a symmetric organic redox flow cell. Owing to the good reversibility, minimum electrolyte contamination, and stability of the synthesized molecule, the demonstrated cell boosts the cyclability to 4000 cycles with capacity retention of ca. 75% at 100% depth of discharge, which fills in the gap of cyclability between organic redox flow batteries and conventional redox flow batteries.
Tin hexachloroplatinate (SnPtCl6) films have been prepared by mixing Sn2+ and PtCl6 2− ions in an aqueous KCl solution. An electrochemical quartz crystal microbalance (EQCM), a rotating ring-disk electrode, UV–Vis absorption spectroscopy, and cyclic voltammetry were used to study the deposition and growth mechanism of the tin hexachloroplatinate films. The electrochemical properties of the films indicate that the redox processes were confined to the immobilized tin hexachloroplatinate films. Deposition of a tin hexachloroplatinate film occurs when PtIVCl6 2− is electrochemically reduced to PtIICl6 4−, or when Sn2+ reacts with PtIVCl6 2− and PtIICl6 4− ions in an aqueous KCl solution. The electrocatalytic reduction of NAD+ and of sulfur oxoanions (S4O6 2−, S2O8 2−, and SO5 2−) was studied using tin hexachloroplatinate films. The electrochemical reactions of NAD+ and NADH were investigated using cyclic voltammetry and the rotating ring-disk electrode method.
A facile method is developed to in situ one-step synthesize CoFe2O4/graphene (CFO/GN) nanocomposites as a promising high-performance anode for lithium-ion batteries. This method involves two processes occurring simultaneously: Co2+ and Fe2+ ions co-precipitate homogeneously on the surface of graphene oxides by using urea as the precipitant, while in situ reduction process reduces graphene oxides at the same time. As a consequence, the nanocomposites of CFO/GN self-assembled into a three-dimensional (3D) network architecture, in which CoFe2O4 nanoparticles with the diameter of 50-80nm uniformly dispersed on graphene sheets. The as-synthesized CFO/GN nanocomposites exhibit a high specific reversible capacity up to 937.73 mAh g−1 with high charge/discharge reversibility at high current densities of 1000mAg−1. In addition, it shows superior rate capability and good capacity retention of 69.5% after 50 cycles. The improved cyclic stability can be attributed to the synergistic interaction between uniformly dispersed CoFe2O4 nanoparticles and graphene, which offers the fast diffusion of Li ions (diffusion coefficient: 1.29×10−13 cm2 s−1) and low internal resistance (equivalent series resistance: 138.49Ωcm−2).
Power management strategy is as significant as component sizing in achieving optimal fuel economy of a fuel cell hybrid vehicle (FCHV). We have formulated a combined power management/design optimization problem for the performance optimization of FCHVs. This includes subsystem-scaling models to predict the characteristics of components of different sizes. In addition, we designed a parameterizable and near-optimal controller for power management optimization. This controller, which is inspired by our stochastic dynamic programming results, can be included as design variables in system optimization problems. Simulation results demonstrate that combined optimization can efficiently provide excellent fuel economy.
Li7La3Zr2O12 (LLZ) solid electrolyte is one of the promising electrolytes for all-solid-state battery due to its high Li ion conductivity and stability against Li metal anode. However, high calcination temperature for LLZ preparation promotes formation of La2Zr2O7 impurity phase. In this paper, an effect of Al2O3 addition as sintering additive on LLZ solid electrolyte preparation and electrochemical properties of Al2O3-added LLZ were examined. By the Al2O3 addition, sintered LLZ pellet could be obtained after 1000°C calcination, which is 230°C lower than that without Al2O3 addition. Chemical and electrochemical properties of the Al2O3-added LLZ, such as stability against Li metal and ion conductivity, were comparable with the LLZ without Al2O3 addition, i.e. σ bulk and σ total were 2.4×10−4 and 1.4×10−4 Scm−1 at 30°C, respectively. All-solid-state battery with Li/Al2O3-added LLZ/LiCoO2 configuration was fabricated and its electrochemical properties were tested. In cyclic voltammogram, clear redox peaks were observed, indicating that the all-solid-state battery with Li metal anode was successfully operated. The redox peaks were still observed even after one year storage of the all-solid-state battery in the Ar-filled globe-box. It can be inferred that the Al2O3-added LLZ electrolyte would be a promising candidate for all-solid-state battery because of facile preparation by the Al2O3 addition, relatively high Li ion conductivity, and good stability against Li metal and LiCoO2 cathode.
The strong corrosion behavior at the Al current collector restricts the application range of lithium bis (trifluoromethanesulfonylimide) (LiTFSI), despite its high stability against water and thermal. SEM, LSV and Tafel curves proved that adding LiODFB into LiTFSI-based electrolytes could suppress aluminum corrosion caused by LiTFSI-based electrolytes. The cycling stability and rate capability of LiFePO4-based batteries using LiTFSI0.6–LiODFB0.4-based electrolytes is excellent as compared to LiFePO4-based batteries using LiPF6-based electrolytes.
Activated carbon aerogels (ACAs) with hierarchically porous structures and high specific surface area have been prepared via CO2 and KOH activation processes. The pore structures of ACAs are characterized by N2 adsorption/desorption and scanning electron microscopy. The experimental results show that the ACAs contain three types of pores: micropores with diameters below 2nm, small mesopores with diameters from 2 to 4nm and large pores or channels with diameters over 30nm. The typical sample ACAs-4, which possess pore volume of 2.73cm3 g−1 and specific surface area of 2119m2 g−1, exhibits high specific capacitances of 250Fg−1 and 198Fg−1 at the current densities of 0.5Ag−1 and 20Ag−1 respectively in 6M KOH aqueous solution. Furthermore, the resultant ACAs electrode materials also exhibit high power density, good cycling stability and long lifetime. With these features, ACAs are expected to be promising electrode materials for electrical double layer capacitors.
The electrochemical behavior of γ-MnO2 in lithium hydroxide (LiOH) and potassium hydroxide (KOH) aqueous media has been studied using slow-scan cyclic voltammetry (25μVs−1) in conjunction with X-ray analysis (XRD) and scanning electron microscopy (SEM). The reduction of γ-MnO2 in aqueous LiOH results in intercalation of Li+ forming a new phase of lithium intercalated MnO2 (Li x MnO2). The process is found to be reversible. In this regard, the reduction of γ-MnO2 in LiOH is quite different from that in aqueous KOH, which is irreversible and no lithium intercalation occurs. This difference in behavior is explained in terms of the relative ionic sizes of Li + and K+. The Li x MnO2 lattice is stable only for Li+ because Li+ and Mn4+ are of approximately the same size whereas K x MnO2 is not stable because K+ has almost double the size.
ABSTRACT Nanocomposites rationally designed in structure and component are highly desirable for the development of electrodes in lithium-ion battery application for that they can take full advantages of different structures and components to achieve superior electrochemical properties. A nanocomposite with the two-dimension (2D) NiO nanoplate of a hexagonal structure and zero-dimension (0D) Co3O4 nanoparticles was synthesized by the hydrothermal method. Scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to characterize the composition, morphology, microstructure and chemical state of the nanocomposite, respectively. As an anode material of lithium-ion battery, the nanocomposite exhibits greatly improved specific capacities and stable cyclability of 633mAhg−1 at a current density of 100mAg−1 up to 70 cycles, much higher than the corresponding building block alone. The outstanding performance of the NiO/Co3O4 nanocomposite is attributed to the hybrid structure and the synergistic effect of different components. This large-scale and cost-efficient synthesis can be extended for the design and synthesis of transition metal oxides composite for high-performance electrochemical energy storage.
Publisher Summary The consumption of thermoplastics and thermoplastic composites is controlled by user market demand and the capacity for innovation in terms of materials and processes. The purpose of this exploratory study is to provide some background information on these points. The use of thermoplastics and thermoplastic composites makes it possible to satisfy some of the requirements. To achieve greater market penetration, thermoplastics and thermoplastic composites must enhance prices, performances, characteristics, productivity, ease of processing and recycling. Intensive processing research is based on several routes to reduce costs: globalization of processing, from raw materials to finishing, automation, industrialization and simplification. Patents published in the year 2004 have been analysed by polymer type, reinforcement type, and material structure and process type. The study recalls some facts concerning the environmental impact of plastics. Sustainability, pollution minimization, recycling and safe elimination of wastes are basic principles of environment policy.
It has been hypothesized that nouns and verbs are processed within relatively separable semantic memory networks. Although abnormal semantic processing is a common feature of schizophrenia-spectrum disorders, no prior studies have specifically examined the comparability of noun and verb generation deficits in schizophrenia. In the current study, verb (action), noun (animal), and letter (f) fluency performance was evaluated in 22 inpatients with schizophrenia and 27 healthy comparison subjects. On average, individuals with schizophrenia performed approximately one standard deviation below the healthy comparison subjects on action, animal, and letter fluency. Action fluency—but not letter or animal fluency—was moderately correlated with tests of working memory, response inhibition, semantic memory, and cognitive flexibility. Findings suggest that verb- and noun-based fluency deficits are of comparable severity in schizophrenia, but that the impairment in verb generation may be driven by different underlying cognitive mechanisms. Further, hypothesis-driven research on the nature and extent of verb network disruption in schizophrenia appears warranted.
Objective Olfactory and trigeminal systems interact and contribute to the perception of odorants. This study was aimed at investigating the effect of local anesthesia on olfaction. Methods One percent of tetracaine on a cotton swab was applied intranasally at three different locations in 20 volunteers and 4% of lidocaine was applied to the olfactory cleft in a head-down position. Before and after anesthesia, self-assessment, psychometric testing and olfactory event-related potentials [OERPs, using H2S and phenyl ethyl alcohol (PEA)], and chemosomatosensory event-related potentials (CSSERPs, using CO2) were examined. Results Anesthesia at all four locations significantly lowered the perceived self-assessment of olfaction, while using the cotton swab only anesthesia in the middle meatus elevated threshold (P=0.020), lowered discrimination (P=0.015) and prolonged OERP (PEA, P=0.008; H2S, P=0.016), as well as CSSERPs latencies (CO2, P=0.020). However, complete temporary anosmia was only achieved after applying 4% lidocaine into the olfactory cleft. Conclusions Intranasal anesthesia applied with a swab reduced self-assessment of olfaction but was unable to produce anosmia. Psychometric test results were concordant with changes in chemosensory event-related potentials. Significance Temporary anosmia is technically difficult to achieve but could be demonstrated for the first time using local anesthesia. Even though anesthesia influences self-assessment, measurable olfactory function can remain unchanged.
Graphene and biomass-derived porous carbon materials are the basic materials for designing of many electrochemical energy storage devices. In this regard, we presented an environment-friendly, simple and scalable method for combining the porous carbon, derived from Typha domingensis, as an almost freely available biomass source, and graphene to produce a hierarchical carbon composite with high porosity and conductivity. The physical characteristics of composite were studied by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, thermogravimetric analysis (TGA), Raman spectroscopy, field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM). The electrochemical behaviors of the composite were investigated with two and three electrode systems. The composite used as a positive electrode, in two-electrode assembly, against a Vulcan XC-72R as the negative electrode in 6 M KOH as electrolyte. The specific capacitance of electrode was 277.5 F g−1 and it retained more than 94% of the initial specific capacitance after 5000 cycles of successive charge/discharge. The two-electrode capacitor had a specific capacitance of 45.8 F g−1 while it retained 93% of the initial specific capacitance after 5000 cycles of successive charge/discharge. Two cells in series lighted up LED lamps brightly.
Functionalized TiO2 (f-TiO2) was synthesized by the atom transfer radical polymerization process and then three types of composite nanofiber membranes including PI/PVdF-HFP (PI/PH, with no nanoparticles contained in PI), TiO2@PI/PVdF-HFP (T@PI/PH, with TiO2 mixed in PI) and f-TiO2@PI/PVdF-HFP (f-T@PI/PH, with f-TiO2 blended in PI) were prepared by bicomponent co-electrospinning technique which could separately maintain the original properties of both PVdF-HFP and PI nanofibers. UV–vis characterization manifested that the modified nanoparticles can provide significant improvements in reducing the particle agglomeration. Morphology, porosity, electrolyte uptake and liquid electrolyte contact angle of all the electrospun separators were investigated, and results showed that the composite separator with 2% f-TiO2 nanoparticle had smaller fiber diameter, higher porosity, larger electrolyte uptake, smaller contact angle and more excellent thermal dimensional stability. More importantly, the tensile strength of all the composite membranes increased by more than three times after thermal calendering process, which resulted from the several bonded points caused by the fusion of PVdF-HFP component with low melting temperature. Additionally, electrochemical properties of PI/PH, 2% T@PI/PH and 2% f-T@PI/PH composite separators and cycling performances of corresponding batteries were evaluated and 2% f-T@PI/PH composite separator showed better properties than the other two.
The soft polydopmine (PDA) layer with polar functional group was coated onto the ultralight graphene sheets (HRG) using a simple approach in a mixture of ethanol and water solution. Sulfur was further dispersed onto the surface of PDA-HRG sheets by S/CS2 solution impregnation method to obtain PDA-HRG/S composite as the cathode material for lithium sulfur batteries. The resulting composites are characterized by SEM, TEM, XRD and so on. The ultralight graphene matrix could improve the conductivity of the electrode and offer a large surface for deposition of sulfur, while the coating of hydrophilic soft PDA layer can adsorb polar polysulfides on-site and accommodate the volume change of S during the discharging processes, resulting in an excellent electrochemical performance.
This study aimed to investigate the ability of the diode and Nd:YAG lasers to decrease postoperative pain/discomfort after intracanal application in vital and devital endodontic cases.
The structure of amphiphilic low-dimensional copolymer electrolytes I of similar overall composition but prepared by different synthetic procedures X and Y are described. I are copolymers of poly[2,5,8,11,14-pentaoxapentadecamethylene(5-alkyloxy-1,3-phenylene)] (CmO5) and poly[2,-oxatrimethylene(5-alkyloxy-1,3-phenylene)] (CmO1) where the alkyl side chains having m carbons are hexadecyl or mixed dodecyl/octadecyl (50/50). 1H NMR shows that the copolymers have 50% (m =16) or only 18 and 13% of CmO5 units and DSC indicates that the copolymers have ‘block’ sequencing of CmO1 and CmO5 segments. Molecular dynamics modelling indicates that in CmO5 Li+ and BF4 − ions are separated by Li+ encapsulation in tetraethoxy segments but in ionophobic CmO1 units the salt is mostly present as neutral aggregates decoupled from the polymer. Conductivities of these microphase-separated mixtures with salt-bridge amphiphilic polyethers II and III of each system are similar. They have low temperature dependence over the range 20°C to 110°C at ∼10−3 Scm−1. 7Li NMR linewidth measurements confirm high lithium mobilities at −20°C. A conduction mechanism is proposed whereby Li+ hopping takes place along rows of decoupled aggregates (dimers/quadrupoles) within an essentially block copolymer structure. Subambient measurements to −10°C gave a conductivity of 4×10−5 Scm−1.