batterydata/paper-abstracts huggingface dataset:
A model elucidates two transport mechanisms associated with the volumes dissolved electrolytes occupy: the ‘excluded-volume effect’, which arises when concentration polarization induces solution-density gradients that drive volume redistribution; and ‘Faradaic convection’, which occurs when interfacial electrochemical reactions induce bulk flow. The excluded-volume effect can be accounted for in Newman's concentrated-solution theory by incorporating a thermodynamic state equation that describes the solution's local molar volume. Faradaic convection is introduced through boundary conditions that include volume-average velocity, which is distributed throughout a solution by a volume-balance governing equation. Two dimensionless parameters quantify the importances of these phenomena, which prove relevant when modeling nonaqueous electrolytes. Analytical formulas are derived to describe concentration polarization and diffusion potentials in parallel-electrode cells undergoing symmetric ion-deposition/stripping half-reactions. In moderately concentrated nonaqueous electrolytes, Faradaic convection elevates limiting currents by as much as ten percent above those predicted by a theory neglecting it. The excluded-volume effect similarly impacts diffusion potentials.
Porous nanostructure composites materials had attracted widely attention due to their potential application in energy storage (Lithium ion batteries (LIBs) and supercapacitor) and electrocatalyst of oxygen evolution reaction (OER). Co3O4@CoO@Co@C nanocomposites had been successfully synthesized using glucose as carbon source and cobalt nitrate as metalprecurs or of Co3O4@CoO@Co@C, which has excellent electrochemical performance for LIBs, supercapacitor and OER. Three kinds of morphology samples marked by Co3O4@CoO@Co@C-2/1, Co3O4@CoO@Co@C-1/1 and Co3O4@CoO@Co@C-1/2 are synthesized due to different atomic ratio of cobalt/carbon in precursors. Electrochemical and catalytic performance of Co3O4@CoO@Co@C-2/1 nanocomposites is more excellent than Co3O4@CoO@Co@C-1/1 and Co3O4@CoO@Co@C-1/2. Co3O4@CoO@Co@C-2/1 shows that discharge capacity can maintain 450mA h g−1 and coulombic efficiency is nearly 100% during 500 cycles for LIBs. It indicates the excellent cycling stability of Co3O4@CoO@Co@C-2/1 as electrode for supercapacitor that about 78.3% of initial specific capacitance can be retained after 10000 cycles at current density of 2Ag−1. Co3O4@CoO@Co@C-2/1 as catalyst of OER shows excellent electrochemical durability over 15hours continuous experiment.
Solid polymer electrolytes (SPEs) have been proposed as substitutes for conventional non-aqueous electrolytes in various electrochemical devices. These promising materials may be of interest in various practical devices including batteries, sensors and electrochromic displays as they can offer high performance in terms of specific energy and specific power (batteries), safe operation, form flexibility in device arquitecture and low manufacturing costs. Many different host polymers have been characterized over the last 30 years, however a relatively un-explored strategy involves the use of interpenetrating blends incorporating two or more polymers. Electrolyte systems based on interpenetrating blends of known host polymers, poly(ethylene oxide) and poly(trimethylene carbonate), doped with lithium perchlorate, were prepared by co-dissolution in acetonitrile. This combination of polymer components results in the formation of a material that may be applicable in batteries and electrochromic devices. The results of characterization of polymer electrolyte systems based on interpenetrating blends of amorphous poly(ethylene oxide) and poly(trimethylene carbonate) host matrices, with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as guest salt, are described in this study. Electrolytes with compositions of n between 5 and 15 (where n represents the total number of cation-coordinating units per lithium ion) were obtained as flexible, transparent and free-standing films that were characterized by measurements of conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry.
Self-assembled mesoporous LiFePO4 (LFP) with hierarchical spindle-like architectures has been successfully synthesized via the hydrothermal method. Time dependent X-ray diffraction, scanning electron microscopy, and cross section high resolution transmission electron microscopy are used to investigate the detailed growth mechanism of these unique architectures. Reaction time and pH value play multifold roles in controlling the microstructures of LFP. The LFP particles are uniform mesoporous spindles, which are comprised of numerous single-crystal LFP nanocrystals. As the cathode material for lithium batteries, LFP exhibits high initial discharge capacity (163mAhg−1, 0.1C), excellent high-rate discharge capability (111mAhg−1, 5C), and cycling stability. These enhanced electrochemical properties can be attributed to this unique microstructure, which will remain structural stability for long-term cycling. Furthermore, nanosizing of LFP nanocrystals can increase the electrochemical reaction surface, enhance the electronic conductivity, and promote lithium ion diffusion.
A novel nitrogen and iodine co-doped porous graphene with well-defined hierarchical microstructure is synthesized via a hydrothermal self-assembly strategy followed by heat treatment at elevated temperature. Its electrochemical properties as the cathode catalyst for Li–O2 batteries are investigated. Compared to un-doped, nitrogen or iodine single doped porous graphene, nitrogen and iodine co-doped porous graphene shows much higher activity for oxygen reduction reaction and oxygen evolution reaction. As oxygen cathode for Li–O2 batteries, nitrogen and iodine co-doped porous graphene exhibits an outstanding specific reversible capacity up to 14000 mAh g−1 at 200 mA g−1, a superior high-rate capability (5000 mAh g−1 at 1000 mA g−1), and an excellent cycling stability enduring over 225 cycles with a limited capacity of 1000 mA h g−1 at a current density of 500 mA g−1. The fantastic cycling performance can be attributed to a combination of porous structure and dual-doping, which not only provides a large number of channels for oxygen diffusion and electrolyte infiltration, but also supplies abundant active catalytic sites to affect the formation and decomposition of the discharge products with various morphologies. This study provides an effective approach to develop highly-efficient carbon-based catalysts with optimized pore structure and tunable surface chemistry.
Aluminum battery offers a new possibility for low cost and large-scale stationary storage of electricity because it can be made with cheap materials and exhibits high theoretical mass specific capacity and power density. Among many cathodic materials, graphite/graphene may be one of the most promising cathode materials for aluminum-ion battery. A suitable three-dimensional structure of the cathode is an important factor for the high performance of battery. In this paper, a binder-free cathode is prepared by dropcasting small ultrasonicated graphite flakes (u-GF) on carbon fiber cloth (CFC) which provides a three-dimensional network skeleton for the new cathode. Al|EMImCl-1.3AlCl3|u-GF@CFC battery exhibits a high discharge specific capacity of ~140 mAh g−1 at 100 mA g−1. The battery has good rate performance and cycling stability: the capacity still exceeds 100 mAh g−1 at 600 mA g−1 with a high coulomb efficiency of 98% and maintains 60 mAh g−1 at 3000 mA g−1 over 300 cycles.
A novel composite with antimony (Sb) nanoparticles anchored in three-dimensional carbon network (denoted as SbNPs@3D-C) is successfully synthesized via a NaCl template-assisted self-assembly strategy, followed by freeze-drying and one-step in-situ carbonization. The three-dimensional interconnected macroporous carbon framework can not only stabilize the architecture and buffer the volume expansion for Sb nanoparticles, but also provide high electrical conductivity for the whole electrode. Consequently, as a sodium-ion battery anode, the SbNPs@3D-C delivers a high reversible capacity (456 mAh g−1 at 100 mA g−1), stable cycling performance (94.3% capacity retention after 500 cycles at 100 mA g−1) as well as superior rate capability (270 mAh g−1 at 2000 mA g−1). When compared with commercial Sb particles, the SbNPs@3D-C exhibits dramatically enhanced electrochemical performance. Free from expensive template sources and complex manipulation, this work might shed some light on the synthesis of low-cost and high-performance materials for the next “beyond lithium” battery generation.
In-situ and operando neutron diffraction are used to analyze the degradation of 18650-type Li-ion cells. Structural characterization of the electrode materials is performed by applying the Rietveld refinement technique to the in-situ data. The structural refinement of both electrodes in the degraded cells indicates that the amount of active Li-ions is reduced by 14.4% and 13.7% in the cathode and anode, respectively. This reduction is good in agreement with the capacity loss determined electrochemically. The results suggest that capacity loss might be mainly caused by loss of active Li-ions due to side reactions such as solid electrolyte interface (SEI) growth. Furthermore, operando measurements are performed to examine the deterioration of the electrode and active materials. Because the structural evolution depending on capacity is increased in the cathode of degraded cells, it is presumed that the cathode active material has deteriorated due to phase transitions.
A three-dimensional amorphous SiO2@graphene aerogel (SiO2@GA) composites as anode material for lithium ion batteries was successfully synthesized via a one-pot process. The materials were characterized by nitrogen adsorption-desorption, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra and Fourier-Transform infrared spectra. The results demonstrate that the SiO2@GA composites are in meso-macoporous structures and present large surface area (SBET =396.9m2 g−1) and high pore volume (Vp =0.67cm3 g−1). Meanwhile, the incorporation of SiO2 does not make obvious effect at the reduction degree of GO to assemble GA. The results of their electrochemical performance reveal that in contrast with bare SiO2, the SiO2@GA anode exhibit higher reversible capacity (∼300mAhg−1 at a current density of 500mAg−1), more stable cycling performance, and excellent rate-capability. The significantly improves electrochemical performance may be ascribed to the 3D aerogel structure and the doping of GA.
A general method is reported for creating functional organic–inorganic hybrid materials by copolymerization of organic molecules and inorganic compounds. The approach is based on a miniemulsion polymerization technique followed by a thermal pyrolysis step, and yields nanostructured composites in which nanoparticles are uniformly embedded in a porous, partially graphitic carbon matrix. The method builds upon our previous report disclosing synthesis of organic–inorganic hybrids using miniemulsion polymerization and demonstrates that ex situ engineering of the inorganic phase leads to remarkably improved function. We specifically show that depending upon the chemistry of the starting materials, nanoscale organic–inorganic hybrid materials created using the approach are attractive as anodes and cathodes for next-generation lithium and other rechargeable battery systems. Additionally, we show that the platform is very versatile and through ex situ conversion or utilization of multiple precursors, can be applied to various classes of materials including metal oxides, metals, metal sulfides and alloys. The approach also lends itself to the development of scalable processes for production of nanostructured battery materials.
Ethnopharmacological relevance Achyranthes aspera (A. aspera) has been used as a brain tonic in folk medicine. Although, ethnic use of medicinal plant has been basis for drug discovery from medicinal plants, but the available in-silico tools can be useful to find novel pharmacological uses of medicinal plants beyond their ethnic use. Aim of the study To validate in-silico prediction for novel nootropic effect of A. aspera by employing battery of tests in mice. Material and methods Phytoconstituents of A. aspera reported in Dictionary of Natural Product were subjected to in-silico prediction using PASS and Pharmaexpert. The nootropic activity predicted for A. aspera was assessed using radial arm maze, passive shock avoidance and novel object recognition tests in mice. After behavioral evaluation animals were decapitated and their brains were collected and stored for estimation of glutamate levels and acetylcholinesterase activity. Results In-silico activity spectrum for majority of A. aspera phytoconstituents exhibited excellent prediction score for nootropic activity of this plant. A. aspera extract treatment significantly improved the learning and memory as evident by decreased working memory errors, reference memory errors and latency time in radial arm maze, step through latency in passive shock avoidance and increased recognition index in novel object recognition were observed, moreover significantly enhanced glutamate levels and reduced acetylcholinesterase activity in hippocampus and cortex were observed as compared to the saline treated group. Conclusion In-silico and in-vivo results suggest that A. aspera plant may improve the learning and memory by modulating the brain glutamatergic and cholinergic neurotransmission.
Lithium-ion battery constitutes one of the most popular energy sources which powers current electronic instruments. It is also a promising candidate to be used in future electric devices. To fulfil its potential in future battery market, the better properties of lithium-ion batteries, e.g., higher capacity, better rate performance, are undoubtedly required. The development of nanotechnology has greatly advanced the frontier of lithium-ion battery research. Recently, it was realized that the application of nanocable-like structure in the design of electrodes can significantly improve the properties of lithium-ion batteries. Here we give an overiew of the design, synthesis, and applications of such structures in lithium-ion batteries and highlight some of the latest achievements in this area. It is exciting that the future of lithium-ion batteries is quite bright in view of the high specific capacity, much improved rate performance, as well as superior cycling stability brought by the nanocable-like electrode materials.
The paper explores state of charge (SoC) determination of lead-acid battery cell by electrochemical impedance spectroscopy (EIS) method. Lead-acid cell was explored during intermittent discharge and intermittent charge. Nyquist diagram, open circuit voltage, Z-modulus and the phase angle of the cell for frequencies 853 Hz, 5.37 Hz and 351 mHz were used for the state of charge determination.
Objective This pilot study investigated whether our previous findings of disrupted normal sexual brain dimorphisms in language-associated regions in schizophrenia were linked with our previously reported sex differences in language dysfunction in schizophrenia. Method Nineteen adults with schizophrenia and 15 normal comparisons were tested on phonology, semantics and grammar and underwent structural MRI. Results Among males, left hippocampal and left planum temporale (PT) abnormalities were associated with phonological, semantic and grammar deficits, accounting for 17–52% and 27–33%, respectively, of variance in diagnostic group differences. Anterior cingulate gyrus was significantly associated with semantics. Among females, right Heschl's Gyrus (HG) and left PT were significantly associated with phonology, right HG with semantics and grammar and right hippocampus with semantics. Conclusions These preliminary findings suggest disrupted sexual brain dimorphisms in schizophrenia are associated with sex-specific language deficits, and left hippocampal abnormalities, in particular, contribute to language dysfunction among men. Abnormalities in right cortical temporal regions showed stronger associations with language dysfunction among females.
The (1-x)LiMnPO4·LixTix(PO4)δ (x=0, 0.01, 0.05, 0.10, 0.15, 0.20) cathode materials are successfully synthesized through a solid-state method. The structures and electrochemical properties of the prepared samples have been characterized comprehensively. It is found minority phases containing LiTi2(PO4)3 and TiP2O7 were formed. The addition of Ti has obviously reduced the size of grains. Electrochemical tests indicate that the discharge capacities of LiMnPO4 samples can be significantly improved with the addition of Ti. Especially, the (1-x)LiMnPO4·LixTix(PO4)δ sample with x=0.1 has the largest discharge specific capacity, which is more than 131 mAh g−1 at 0.05C. And EIS tests1demonstrate that the 0.9LiMnPO4·Li0.1Ti0.1(PO4)δ sample has lower charge transfer resistance and higher diffusion coefficient than the pristine LiMnPO4 sample.
The drive for commercializing high energy density lithium-sulfur batteries is leading to the development of various material architectures for suppressing the notorious “shuttle effect” of intermediate polysulfides and improve cycle life. Inspired by the structural features of plant roots protecting soil erosion, herein, we report a novel strategy to use poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-sulfur@polyacrylonitrile electrospun nanofibers as flexible additives in the cathode of lithium-sulfur batteries to trap lithium polysulfides and suppress their dissolution into liquid electrolyte. The nanofibers consist of in-situ grown sulfur particles, embedded inside porous polyacrylonitrile shell and coated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate. The electrochemical performance of lithium-sulfur batteries using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-sulfur@polyacrylonitrile nanofiber incorporated sulfur hybrid cathode shows a significantly better cycle stability and excellent rate capability compared to the bare sulfur cathode owing to the adsorption effect of the nanofibers. Even after 500 cycles at a high rate of 0.5 C, the capacity retention is approximately 41% of the initial capacity with average columbic efficiency above 94%. This work offers a novel approach to fabricate viable lithium-sulfur batteries and possibly pave the way to further develop innovative flexible additives for practically applicable lithium-sulfur batteries.
As a lithium-ion battery (LIB) anode, transition metal oxide nanostructures usually exhibit an initially decreasing and subsequently increasing trend of specific discharge capacity, owing to the gradually enhanced interfacial storage capability. In this paper, a novel base-catalyzed reaction of nickel acetate is used to synthesize flowerlike hollow architectures of basic carbonate based precursor and then to obtain NiO flowerlike porous hollow nanostructures with a high surface-to-volume ratio. As a LIB anode at 200mAg−1, the observed discharge capacity of the working electrode decreases from an initial value of 1584.7mAhg−1 to the minimum value of 867.5mAhg−1 in the 76th cycle and then increases to the maximum value of 2142.8mAhg−1 in the 350th cycle. In each cycle, an interfacial fraction of the discharge capacity can be clearly distinguished and quantitatively estimated according to the discharging behaviors. These prove that the seemingly battery-to-pseudocapacitor transition relates both to bulk capacity loss and to interfacial capacity gain, depending upon the applied C-rate. Furthermore, the ordered arrangement of gradually crystallized Li2CO3, a main component of solid-electrolyte interface (SEI) layer, and its non-faradaic (double-layer capacitive) and faradaic (further reverse lithiation-delithiation) contributions may explain the over-compensating ability of interfacial storage.
An effective and practical method for producing Si/C composites with 10–15wt% of silicon nanoparticles embedded in a carbon matrix is developed. The procedure consists of mechanically mixing Si with pitch followed by dispersing in toluene and final heat-treatment between 1000 and 1100°C. The homogeneity of the materials was confirmed by optical microscopy and HRTEM. X-ray photoelectron spectroscopy, X-ray diffraction and N2 adsorption at 77K were applied for determining the structural and textural characteristics. The lithium insertion/deinsertion performance was monitored from the galvanostatic charge–discharge characteristics using a Si/C–lithium two-electrode cell, and varying the electrochemical parameters. Silicon essentially enhances the electrode capacity (C rev up to 600mAh/g for 15% Si), the effect being proportional to the component content, but it affects the cycle life. The first cycle reversible capacity increases with the decrease of current density and discharge cut-off potential. However, using such conditions during cycling leads to rapid saturation of the silicon particles, from which the decay of the electrochemical performance starts. It is demonstrated that the evolution of reversible and irreversible capacity is strongly dependent on the kinetics of lithium diffusion in silicon particles and on the discharge potential cut-off.
Li3VO4 nanoparticles with mean size about 100nm are uniformly deposited on the surface of natural graphite via a quasi sol gel method. The electrochemical performance of the Li3VO4/natural graphite composite as anode for lithium ion batteries is studied via galvanostatic battery testing, which shows excellent cycle stability and rate capability. At a specific current of 156mAg−1, it delivers discharge and charge capacity of 579 and 427 mAhg−1 in the initial cycle, which maintain of 469 and 468 mAh g−1 after 100 cycles. After 60 cycles at various specific currents from 234 to 11,719mAg−1, the discharge capacity can restore to 450 mAhg−1 when reverting the discharge/charge current to 234mAg−1. It is demonstrated that natural graphite has important effect on the electrochemcial performance of the composite electrode, and an appropriate amount of natural graphite is beneficial to reduce the charge transfer resistance and maintain stable charge transfer process in cycling.
The electrochemical behavior of vanadium oxide V2O5 and bismuth doped manganese oxide Bi–MnO2 as battery materials was studied with a cavity microelectrode (CME). This technique, which allows working on a very few amount of material, appears to be suitable when high scan rates are used. Thus, it is possible to perform many hundreds cycles in a short time. The performances of pure vanadium oxide as lithium insertion material in inorganic media, examined with a CME appear to be excellent whereas poor results were obtained with Bi doped MnO2, for which the electrochemical mechanism proceeds via dissolution.
There is an intensive effort in developing multi-shelled metal oxide nanostructures for lithium-ion battery applications. Now, a metal anion-adsorption mechanism, as opposed to the conventional cation adsorption on carbonaceous templates, is demonstrated in the synthesis of vanadium oxide hollow microspheres, which exhibit excellent battery performance.
FII is an uncommon form of child abuse which challenges the very core of the doctor-patient relationship. The unspoken contract of “You tell me what's wrong and I'll do my best to help you.” is breached by a parent who fabricates their child's symptoms and sometimes even their physical signs. Anecdotally these diagnoses tend to be very delayed and children often suffer extreme harm in the process. In 2002 RCPCH produced the first definitive guidance on FII. In 2008 the Government produced updated guidance for all professionals which led to RCPCH producing a new Practical Guide in 2009. This paper incorporates much of the 2009 RCPCH guidance and is intended to be a brief guide for the busy Paediatrician who may come across one of these most difficult and time consuming cases.