batterydata/paper-abstracts huggingface dataset:
An optimal structural design model of residential power and heat supply devices (R-PHDs), including cogeneration and heat pump units, was developed by considering their operational and capital recovery constraints. The structure of R-PHDs with peripheral devices, sizes of energy storage devices, and their multi-period operation were determined so as to minimize annual primary energy consumption. In addition to various operational constraints for a cogeneration unit and a battery unit, an operable-hours constraint and daily selection of outlet water temperature were newly formulated for heat pump units. The capital recovery by reducing energy cost was also considered in order to select R-PHDs that have high energy-saving effects but are presently expensive. The developed model took the form of a mixed-integer linear programming problem. The model was applied to the structural design of R-PHDs, whose candidates are three types of cogeneration units (gas engine, polymer electrolyte fuel cell, and solid oxide fuel cell), heat pump unit, storage tank, battery unit, and peripheral devices. The result revealed a trade-off between energy savings and initial cost in the optimal structures. A sensitivity analysis of the initial costs of expensive devices was also carried out to clarify their initial cost targets.
Films of poly[(R)-(−)-3-(1-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] (polyDNBP) were deposited, using the galvanostatic method, onto indium tin oxide electrodes in the presence of the electrolytes tetrabutylammonium tetrafluoro-borate [(C4H9)4NBF4] or LiClO4. Atomic force microscopy revealed that polyDNBP/(C4H9)4NBF4 films exhibited a grainy morphology with higher roughness and greater superficial area than polyDNBP/LiClO4 films. Moreover, polyDNBP/(C4H9)4NBF4 films exhibited a higher capacitive electrochemical response when characterised in LiClO4 rather than in (C4H9)4NBF4. Since polyDNBP films exhibit both n- and p-doping, they may have considerable potential application as electrodes in type III capacitor assemblies.
Electrospinning is utilized to prepare composite fiber Li-ion battery anodes containing titania and carbon nanoparticles with a poly (acrylic acid) binder. The electrospun material exhibits a stable charge/discharge capacity with only 5% capacity fade over 450 cycles at 0.5 C. Compared to a conventional slurry cast electrode of the same composition, the electrospun anode demonstrates 4-fold higher capacity retention (31% vs. 7.9%) at a charge/discharge rate of 5 C. Electrospinning is also used to prepare ultrathick anodes (>1 mm) with areal capacities up to 3.9 mAh cm−2. Notably, the thick electrodes exhibit areal capacities of 2.5 and 1.3 mAh cm−2 at 1 C and 2 C, respectively. Electrospun anodes with densely packed fibers have a 2 C volumetric capacity which exceeds that of the slurry cast material (21.2 and 17.5 mAh cm−3, respectively). The excellent performance of the electrospun anodes is attributed to interfiber voids which provide complete electrolyte intrusion, a large electrode/electrolyte interface, and short Li+ transport pathways between the electrolyte and titania nanoparticles.
Mixed metal oxides in the nanoscale are of great interest for many aspects of energy related research topics as water splitting, fuel cells and battery technology. The development of scalable, cost-efficient and robust synthetic routes toward well-defined solid state structures is a major objective in this field. While monometallic oxides have been studied in much detail, reliable synthetic recipes targeting specific crystal structures of mixed metal oxide nanoparticles are largely missing. Yet, in order to meet the requirements for a broad range of technical implementation it is necessary to tailor the properties of mixed metal oxides to the particular purpose. Here, we present a study on the impact of the nature of the gas environment on the resulting crystal structure during a post-synthesis thermal heat treatment of manganese–cobalt oxide nanoparticles. We monitor the evolution of the crystal phase structure as the gas atmosphere is altered from pure nitrogen to synthetic air and pure oxygen. The particle size and homogeneity of the resulting nanoparticles increase with oxygen content, while the crystal structure gradually changes from rocksalt-like to pure spinel. We find the composition of the particles to be independent of the gas atmosphere. The manganese–cobalt oxide nanoparticles exhibited promising electrocatalytic activity regarding oxygen evolution in alkaline electrolyte. These findings offer new synthesis pathways for the direct preparation of versatile utilizable mixed metal oxides.
Electrochemical properties and Li deposition morphologies of several kinds of carbon with different surfaces were studied. The surface conditions and Li deposition morphologies were analyzed using Raman spectroscopy and scanning electron microscopy. It appeared that the disordered carbon surface suppressed the Li dendrite deposition. Grinding methods with different clearances were adopted to modify the graphite into a desirable surface. The R-value increased from 0.10 to 0.63 after grinding to 40μm, though a significant change in d 002 did not occur. These results suggest that disordered carbon was created on the surface without a significant change in bulk crystallinity. Thus, the reversible capacity, which is about 350mAhg−1, was the same before and after grinding. However, the Li deposition morphologies significantly changed before and after grinding. The pristine graphite had a dendritic morphology, but the ground graphite had a granular morphology. It is believed that the defects on the disordered carbon act as electrodeposition nuclei and prevent the formation of Li dendrites.
A novel method, ion diffusion method controlled by ion exchange membrane was reported for the synthesis of Ni(OH)2 nanomaterials in the absence of any template or organic surfactant. The structure and morphology of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), BET specific surface area and pore size distribution analyzer. It can be observed that β-Ni(OH)2 nanoflake-like structure was obtained, and the sheet size, thickness and pore size of as-prepared samples can be controlled by altering reaction time and reaction temperature. The BET specific surface area of Ni(OH)2 nanomaterials obtained by this method can be up to 280.5m2/g at 30°C. The electrochemical supercapacitive properties of Ni(OH)2 nanostructures have been investigated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy techniques. All these Ni(OH)2 samples exhibit good capacity for electrochemical supercapacitor in KOH electrolyte. The flake nanostructures synthesized at 50°C for 12h exhibit a highest specific capacitance of 2102Fg−1 at a current density of 20mAcm−2 within the potential range of 0.5V and the Ni(OH)2 sample retains 85.1% of the initial capacitance even after 1000 continuous charge–discharge cycles. The results indicate that ion diffusion method controlled by ion exchange membrane is a useful method for synthesizing inorganic nanomaterials.
Achieving both high energy and power densities for electrochemical capacitors is always one of the greatest scientific and societal challenges. Owing to the outstanding electrochemical performances of transition metal sulfides, especially high theoretical capacities and wide potential windows, they have drawn extensive attention as promising electrode materials for electrochemical capacitors recently. Herein, the Ni–S/MWCNT composite as positive electrode and the Ni–Fe–S/MWCNT composite as negative electrode have been prepared by a hydrothermal method. The Ni–S/MWCNT electrode shows a high specific capacity of 265.6 mAh g−1 at 1 A g−1 and an excellent rate performance, which are attributed to a larger BET surface area and faster charge transfer rate due to an introduction of MWCNTs compared to the pure Ni–S electrode. The Ni–Fe–S/MWCNT electrode also exhibits a good electrochemical performance due to its rich redox reaction and high total pore volume after the integration of MWCNTs. The fabricated Ni–S/MWCNT//Ni–Fe–S/MWCNT asymmetric electrochemical capacitor delivers a high cell potential of 1.7 V, a high energy density of 42.2 Wh kg−1 at a high power density of 3.7 kW kg−1 (even 19.1 Wh kg−1 at 11.9 kW kg−1), and a relatively good cycling stability. Our work may provide an alternative protocol for the fabrication of high-performance electrochemical capacitors.
Through the development of novel PKC biosensors, the authors describe how PKCα, but not other classical isozymes, facilitates plasticity in dendritic regions through the integration of recent synaptic plasticity with current, local synaptic input.
Transition-metal sulfides have been generally identified as one of the promising anode candidates for sodium ion batteries yet still suffer from serious capacity decay. Herein, we carry out a simple and effective hydrothermal method for preparation of vertically aligned SnS2 nanosheets grown on carbon cloth as binder-free anode for sodium ion batteries. Specifically, the self-standing anode material displays excellent electrochemical properties including high specific capacity, outstanding rate capability, and long cycle stability. The large discharge capacity of 1039.9 mA h g−1 at 0.2 A g−1 is achieved. Even at much high current density of 2 A g−1, the reversible capacity can reach 673.4 mA h g−1 after 400 cycles. Meanwhile, this anode material can also withstand various current densities ranging from 0.1 to 2 A g−1 and exhibits good capacity recovery ability. Electrochemical kinetic analysis suggests that the mechanical flexibility between SnS2 nanosheets and carbon cloth conductive substrate could well maintain the structural integrality, thus providing favorable transport kinetics for both electrons and sodium ions during repeated battery operation.
Stroboscopic visual training (SVT) is a form of training aimed at improving visual and perceptual performance by having individuals perform activities under conditions of intermittent vision. The efficacy of SVT has never been examined in people with multiple sclerosis (PwMS), therefore, our aim was to examine the immediate effect of SVT on cognitive function, gait and static balance performance in PwMS. This assessor-blinded, randomized crossover study included 26 PwMS, 16 females, mean age 47.9 and median EDSS score 4.5. Participants attended two sessions: SVT and control training. Exercises for both the SVT and control sessions were based on ball-catching tasks. Training sessions were identical in length (40–50 min) and type of exercise drills. The difference between the two practice regimes was that the SVT session was performed wearing stroboscopic glasses and the control training was performed with similar glasses without lenses. Cognition was evaluated by a computerized software (Mindstreams®, NeuroTrax Corp., NY). Gait and balance were evaluated via wearable accelerometers (APDM, Oregon, USA). Outcome measures were collected twice during a single session, prior to training and immediately afterward. Information processing speed (p = 0.003) increased at the post-evaluation compared with baseline, solely in the SVT session. No differences between pre–post evaluations were observed for other cognitive scores following the SVT session. No differences between pre–post measurements were noted for gait and balance following the SVT session. The present study’s results justify performing future RCT studies to examine the effects of a longer SVT program on cognition in PwMS.
Carbon coating of natural graphite particles was performed by mechanical mixing of natural graphite with different carbon precursors in a scale of about 100g. Anode performance in lithium ion rechargeable batteries was studied on the resultant carbon-coated graphite. Carbon formed on graphite particles had amorphous structure and low density. By carbon coating, a decrease in irreversible capacity of the first charge/discharge cycle in an electrolyte solution of EC/PC=3/1 was observed, without noticeable change in discharge capacity. Carbon derived from different precursors did not give any marked difference in anode performance of carbon-coated graphite. Optimum conditions for carbon coating were determined as the coating of 4–13mass% at 700–1000°C. The present mechanical mixing of natural graphite and carbon precursor in powder is concluded to be a simple but sufficient process to produce carbon-coated graphite for anode material in lithium ion rechargeable batteries. As carbon precursor, PVA was shown to be one of the appreciable carbon precursors.
The development of Ni-rich layered lithium transition metal oxides is plagued by their voltage and capacity fading on battery cycling. Here, the authors demonstrate an effective approach to treat these problems by infusing a solid electrolyte into the grain boundaries of the secondary particles of these layered materials.
The geometric parameters of 1, 3-benzodioxol-2-one (BO) and propylene carbonate (PC) was optimized at the B3LYP/6-311++G (d, p) level of density functional theory (DFT) with the polarized continuum models (PCM). The obtained frontier molecular orbital energies and vertical electron affinities indicate that BO is reduced more easily than PC. The transition state (TS) of ring-opening reaction BO −1 →BO −1 was optimized and confirmed by vibrational frequency analysis and intrinsic reaction coordinate (IRC) method. The bond orders and atomic charge distribution of the stable points along the minimum energy path (MEP) were analyzed using the natural bond orbital (NBO) method at the B3LYP/6-311++G(d, p) level of DFT. With these calculated results, the reduction mechanism of BO for the formation of solid electrolyte interface (SEI) film on anode of lithium ion battery can be inferred as: BO+e→BO −1 →BO −1 →⋯→SEI Film.
In spite of the strong relevance of electrochemical energy conversion and storage, the atomistic modeling of structures and processes in electrochemical systems from first principles is hampered by severe problems. Among others, these problems are associated with the theoretical description of the electrode potential, the characterization of interfaces, the proper treatment of liquid electrolytes, changes in the bulk structure of battery electrodes, and limitations of the functionals used in first-principles electronic structure calculations. We will illustrate these obstacles, but also indicate strategies to overcome them.
An experimental analysis was conducted on a 30kW fuel cell power train with the aim to elucidate specific concerns of dynamic behaviour of hydrogen fuel cells in automotive applications. The study was conducted on a dynamic test bench able to simulate the behaviour of the reference vehicle, a minibus for historical centres collective service, on predefined driving cycle. The transient performance of the fuel cell system was firstly investigated without electric drive, using as load electric resistances electronically controlled. Experimental data were collected during warmup phases characterized by two acceleration slopes (150W/s and 1500W/s) and during a sequence of dynamic test cycles characterized by a very high acceleration slope of about 6kW/s. The role of reactant feeding, humidification and cooling systems was investigated during all tests evaluating the performance during the transient steps in terms of cell voltage uniformity, expressed by the coefficient of variation C v, used as statistical indicator. A driving cycle characterized by stop-and-go pattern and acceleration slopes compatible with a real utilization of the reference vehicle was finally adopted for tests on the overall power train. The results demonstrated a very good dynamic performance of the fuel cell stack as evidenced by the analysis of C v, which resulted lower than 2.5% in all investigated working conditions, and by the overall power train efficiency which resulted about 30% with fuel cell system efficiency close to 50%.
A simple-to-fabricate, high-performance, wearable all-fiber triboelectric nanogenerator (TENG)-based insole composed of electrospun piezoelectric polyvinylidene fluoride (PVDF) nanofibers sandwiched between a pair of conducting fabric electrodes that effectively harvests energy during human walking is reported. The surface of the nanofibers is roughened with secondary nanostructure to enhance insole performance. The maximum output voltage, instantaneous power and output current from the insole reach 210V, 2.1mW and 45μA, respectively. The role of the piezoelectric effect in the electrospun PVDF nanofibers in this TENG-based insole is then systematically investigated. This device is shown to be a reliable power source that can be used to light up 214 serially connected light-emitting diodes directly. The soft fiber-based electric power generator demonstrated in this paper is capable of meeting the requirements of wearable devices because of its efficient energy-conversion performance, high durability, user comfort, and low cost.
The results of molecular dynamics simulations of ionic transport in nanostructured materials are presented. Two types of materials are considered, the single component nanostructured oxide, sodium β-alumina and the mixed phase composite LiI/Al2O3. In nanostructured β-alumina, the conductivity is observed to be considerably lower than in crystalline β-alumina. Blocking grain boundaries between the nanosized grains cause the reduction. In the case of the composite, a crystallite of LiI with (001) surface planes was sandwiched between α and γ-Al2O3, respectively. In both cases Li+-ions were observed to transfer from LiI to tetrahedral sites in the Al2O3 surface, α-alumina having the higher surface charge density. As a result, a defective region develops near the interface in the LiI and lithium transport along the surface can occur. The ions migrate through vacancy hopping in the defective regions in LiI. The defective region is only two Li+-layers thick. When the thickness of the LiI slab becomes comparable with the thickness of the defective region, the LiI becomes more disordered. The activation energy for Li+-diffusion decreases, but this is more than compensated for by a reduction in charge carriers.
Sulfur/nitrogen dual-doped graphene aerogels (SNGAs) with a unique porous network structure have been designed through a facile and versatile one-pot hydrothermal strategy. When employed as anode in LIBs, the SNGAs with nitrogen content of 1.50wt.% and sulfur content of 15.11wt.% exhibit superior cycle life and rate capability. For example, a high reversible capacity of 1109.8mAhg−1 can be obtained after 400 cycles even at a high current density of 800mAg−1. It was discreetly demonstrated that the prominent improved performance of SNGAs can be mainly ascribed to the effect of dual-doping heteroatoms in cooperation with each other in to the graphene lattice as well as the porous nanostructure facilitating the mass transfer for both ions and electrons. Our conclusions illustrate that the strategy of dual-doped graphene aerogel may promote the potential application of graphene for high performance lithium ion batteries.
Mechanical breakdown of graphite materials due to diffusion-induced stress (DIS) is a key aging mechanism of lithium-ion batteries. In this work, electrochemical-thermal coupled model along with a DIS model is developed to study the DIS distribution across the anode thickness. Special attention is paid to the evolution behavior of surface tangential stress (STS) in the discharge process for graphite at different locations of the anode. For the first time, we report that the evolution of STS, as well as local current, at all locations of the anode, evolve like sinusoidal waves in the discharge process with several crests and troughs. The staging behavior of graphite active material, in particular the sharp change of open-circuit potential (OCP) of graphite in the region between two plateaus, is found to be the root cause for the sinusoidal patterns of current and stress evolution. Furthermore, the effects of various parameters, such as starting state of charge, discharge C-rate and electrode thickness on the current and stress evolutions are investigated.
Microporous bio carbon derived from coir pith has been evaluated for the first time for its suitability as anode material in lithium-ion batteries. Coir pith, used generally to fire bricks is well known for its carbon rich composition arising from three different carbon sources, viz., cellulose, lignin and organic carbon. As a result, preparation of bio carbon containing amorphous and disordered carbon along with the co-existing graphitic characteristics from coir pith appears to be a potential approach and deserves to be explored further. Coir pith derived carbon (CPC) generated through an eco benign and economically viable carbonization process was activated with KOH at temperatures such as 800, 850 and 900° C to obtain the desired microporous nature, especially due to the dissolution of lignin in alkaline solution. Pristine CPC, activated at 850°C in particular, upon investigation as anode in LIB applications exhibits a steady state progressive capacity of 837mAhg−1 at 100mAg−1 condition upon extended cycles. The study demonstrates the suitability of pristine CPC anode up to 5.4C rate with an acceptable capacity behavior and appreciable retention capability. The currently discussed waste-to-wealth attempt involves a cheap and scalable process, besides qualifying pristine CPC-850 as an energy efficient anode for LIB applications.
A homogeneous, composite polymer electrolyte (PE) containing poly(ethylene oxide) (PEO), CF3SO3Li and 33wt.% of aluminum carboxylate [RC(O)OAlEt2]2 with an oligooxyethylene group R=CH2CH2C(O)O(CH2CH2O) n CH3 (n =7) (AlCarb7), characterized by low glass transition temperature T g =−51.4°C was prepared. The interaction of aluminum carboxylate with various lithium salts was characterized on the basis of 27Al NMR spectroscopy in CDCl3 solutions. The bulk conductivity of solid PE with AlCarb7 is of the order of 10−5 Scm−1 at 60°C and 10−4 Scm−1 at 90°C. Electrochemical tests of Li|PE|Li cells showed a decrease in the R SEI with temperature, stabilizing at about 10Ωcm−2. The lithium ion transference numbers determined by ac–dc polarization experiments range from 0.7 to 0.9. 7Li, 19F and 1H NMR spectra, the relaxation time and diffusion data were obtained. The calculated lithium transference number t + at 50°C is equal to 0.995, which suggests practically complete immobilization of the triflate salt anions. In the range of high temperatures (130–180°C) t + is equal 0.35–0.39. The dependence of t + on temperature should probably be connected with the partial dissociation of the aluminum carboxylate and lithium salt complex.
One conventional electrolyte (“Gen 2”) for lithium-ion batteries consists of 1.2 M LiPF6 dissolved in ethylene carbonate and ethyl methyl carbonate. A comprehensive investigation of this electrolyte in a high-voltage graphite/LiNi0.5Mn1.5O4 (LNMO) cell was carried out to evaluate its voltage stability under various charging conditions. Although the carbonate-based electrolyte was relatively stable when the graphite/LNMO cell was charged to 4.8 V at room temperature, the introduction of a constant-voltage charging step aggravated the oxidative decomposition of the electrolyte. Further increase in the cell charging voltage to 4.9 V or above and further increase in the temperature to 55 °C caused cell performance to deteriorate dramatically.