batterydata/paper-abstracts huggingface dataset:
Single-ion polymer electrolytes are expected to play an important role in the development of next-generation lithium metal batteries. In this paper, the synthesis and characterization of single-ion conducting polyurethanes (SIPUs) based on PEG and a specifically designed ionic liquid monomer (bis-MPTFSI) is presented. Exploiting the flexible chemistry of polyurethanes, it was possible to tailor the composition and chemical structure of SIPE, obtaining both segmented and crosslinked lithium ion-conductive (σ=10−8−10−4 Scm−1) and free-standing films with the lithium transference number close to unity. Finally, the performances of gel polymer electrolytes based on SIPUs for lithium metal batteries operating at room temperature were investigated (80 cycles at C/10 with nearly 100% efficiency). To the best of our knowledge, these SIPUs represent one of the first examples of polyurethane-based poly(ionic liquid)s for application in the field of battery science.
The present paper will discuss the nano-mechanics foundations and experimental methodologies that provide a foundation for the prognosis of the functional behavior of nano-structured heterogeneous materials for energy systems. The principle objective of this work at the fundamental level is the creation of conceptual foundations for prognosis of heterogeneous functional materials. Our approach is to focus on the mechanics associated with the nano-structural configurations and interfaces (function and geometry) of the active phases. The paper will discuss conceptual foundations, experimental methods, and computational and analysis methods that associate global functional response of interest to energy conversion and storage with the multiphysics of nano-structured heterogeneous materials. New experimental room-temperature, non-invasive interrogation methods for establishing internal integrity and for following material state changes in solid oxide fuel cells as a function of operation history will also be introduced and discussed as an example of the application of these concepts.
Graphite/Phosphorus composite anodes are prepared by mixing graphite and the phosphorus/carbon material, which prepared by heating the mixture of red phosphorus and porous carbon. Their electrochemical performances are evaluated as anodes for Li-ion batteries. A graphite/Phosphorus composite|LiFePO4 full-cell is also attempted. When the phosphorus/carbon content in the composite anode is 28.6 wt.%, the composite anode presents high reversible capacity of 500 mAh g−1 and considerable cycleability comparable to that of graphite anode, showing promising performance.
Lithium sulfide (Li2S) is regarded as a promising cathode material for lithium–sulfur (Li–S) batteries in terms of its high theoretical specific capacity of 1166 mAh g−1 and good compatibility with lithium metal-free anodes. However, Li2S suffers from poor cycling stability and rate capability resulted from the serious shuttle effect of lithium polysulfides and its low electronic and ionic conductivity. Here, we present a facile ball milling combined with carbon coating method to synthesize porous carbon-coated Li2S (Li2S@C) composites with a high Li2S content by using polystyrene (PS) as a carbon precursor. The Li2S@C composites show a high reversible specific capacity of 676 mAh g−1 (equal to 971 mAh g−1 sulfur) after 3 cycles at the current density of 0.1 A g−1, superior cycling stability with an average decay rate of 0.18% per cycle over 200 cycles, and improved rate capability of 416 mAh g−1 at the current density of 1.0 A g−1. The enhanced electrochemical properties of Li2S can be attributed to the porosity and core–shell structure of the Li2S@C composites, which increased the electronic and ionic conductivity of Li2S and alleviated the shuttle effect of intermediate lithium polysulfides in the discharge/charge process.
The structural changes and voltages of LiMn2O4 spinel as a function of lithium content were investigated with density functional theory (DFT) in the generalized gradient approximation (GGA) and in the GGA with Hubbard U correction (GGA+U). The GGA+U approximation can distinguish the charge separation between Mn3+ and Mn4+, which GGA fails to capture. Therefore with this method the effects of local environments on Li diffusion activation energy barriers in the Li-rich phase could be systematically investigated. Our results showed that the different valences states of Mn ions and their arrangement surrounding the lithium ions have a profound effect on the activation barrier of lithium diffusion in the spinel structure.
To enhance the resistance of lithium-ion battery components to ignition and to reduce the flammability of the electrolyte with minimal effect on performance, we added flame-retardant additives to the electrolyte. The flame retardants were selected from a group of organic phosphate compounds, triphenylphosphate (TPP) and tributylphosphate (TBP), to provide superior thermal safety in lithium-ion cells at the fully charged state. The cycling characteristics of the lithium-ion cells containing flame-retardant additives were found to be similar or superior to the cells that contained no additives. Horizontal burning tests of electrolytes were carried out in a flame test chamber referenced by Underwriters Laboratories (UL) test standard 94 (UL 94) and ASTM D4986-98 to evaluate the electrolyes’ flammability characteristics. The thermal stability characteristics of the electrodes and electrolytes with and without flame-retardant additives were investigated by accelerating rate calorimetry (ARC). Negative electrode samples with electrolytes containing flame-retardant additives revealed less heat generation and higher-onset decomposition temperatures. The results disclose that the thermal safety of lithium-ion cells can be improved by incorporating small amounts of suitable additives such as triphenylphosphate and tributylphosphate to the electrolyte.
The charge–discharge performance of LiCoO2 positive electrode was observed in a mixed electrolyte system consisting of two ionic liquids: cyano-substituted quaternary ammonium bis(trifluoromethane)sulfoneimide (TFSI) and a same-anion salt of 1-ethyl-3-methyl imidazolium (EMI). The positive electrode exhibited a discharge capacity rather close to the theoretical one when N,N,N,N-cyanoethyl trimethyl ammonium salt was applied. Differential scanning calorimetry (DSC) studies revealed that these electrolytes exhibited exotherm only around 260°C, 50°C higher than conventional carbonate-based electrolytes. This is the first attempt to reveal the thermal stability of ionic liquid electrolyte under a practical situation.
The CuCo2S4/reduced graphene oxide (rGO) nanocomposites were synthesized by a simple one-step solvothermal method. The composition and structural features of the CuCo2S4/rGO were researched by XRD, SEM, TEM, BET, XPS and Raman spectroscopy. As an anode material for sodium ion batteries (SIBs), CuCo2S4/rGO shows the notably enhanced Na-storage performance compared to single CuCo2S4. The reversible specific capacity of CuCo2S4/rGO keeps 433 mAh g−1 at 100 mA g−1 after 50 cycles. Furthermore the CuCo2S4/rGO shows good rate capability with specific capacity of 336 mAh g−1 at 1000 mA g−1. The excellent electrochemical properties of CuCo2S4/rGO nanocomposites forecast that they will be promising anode materials for SIBs.
Mutations of the SCN2A gene encoding a voltage-gated sodium channel alpha-II subunit Nav1.2 are associated with neurological disorders such as epilepsy, autism spectrum disorders, intellectual disability, and schizophrenia. However, causal relationships and pathogenic mechanisms underlying these neurological defects, especially social and psychiatric features, remain to be elucidated.
Letter position dyslexia (LPD) is a deficit in the encoding of letter position within words. It is characterized by errors of letter migration within words, such as reading trail as trial and form as from. In order to examine whether LPD is domain-specific, and to assess the domain-specificity of the visual analysis system, this study explored whether LPD extends to number reading, by testing whether individuals who have letter migrations in word reading also show migrations while reading numbers. The reading of words and numbers of 12 Hebrew-speaking individuals with developmental LPD was assessed. Experiment 1 tested reading aloud of words and numbers, and Experiment 2 tested same–different decisions in words and numbers. The findings indicated that whereas the participants with developmental LPD showed a large number of migration errors in reading words, 10 of them read numbers well, without migration errors, and not differently from the control participants. A closer inspection of the pattern of errors in words and numbers of two individuals who had migrations in both numbers and words showed qualitative differences in the characteristics of migration errors in the two types of stimuli. In word reading, migration errors appeared predominantly in middle letters, whereas the errors in numbers occurred mainly in final (rightmost) digits. Migrations in numbers occurred almost exclusively in adjacent digits, but in words migrations occurred both in adjacent and in nonadjacent letters. The results thus indicate that words can be selectively impaired, without a parallel impairment in numbers, and that even when numbers are also impaired they show different error pattern. Thus, the visual analyzer is actually an orthographic visual analyzer, a module that is domain-specific for the analysis of words.
A model for expressing the differential capacity characteristics of the LiFePO4 (LFP)/graphite battery for the state-of-health (SOH) estimation was proposed. Our model was based on the deformed pseudo-Voigt peak function with several parameters which are directly associated with the phase transition behavior of the active LFP and graphite materials. Charge/discharge cycle tests for accelerated battery fading were performed under a constant high-temperature condition (40 and 45 °C). The SOH estimation was carried out at different fading point of the battery using a part of the responses for the differential capacity versus voltage (dQ/dV vs. V) against the charging process at the rate of C/5 under constant temperature of 25 °C. The changes in the variables of the model with cycling were correlated to the generally mentioned phenomena that the main factors determining the capacity fading of the LFP/graphite battery are the loss of Li+ by a side reaction and that of the active electrode materials. In addition, the robustness related to the charge/discharge history was confirmed, since the memory effect of the LFP/graphite battery, being induced by the previous condition for use, has an influence on the dQ/dV vs. V. The evaluated SOH errors were within ±3%.
An excellent CuO/Cu integrated anode with CuO nanoparticle-aggregated microsheets on Cu current collector showed higher capacity beyond the theoretical capacity of CuO. The reoxidation of Cu including converted Cu nanoparticles and Cu current collector into CuO guaranteed the highly reversible conversion reaction and high capacity. The combined current ex-situ methods of XRD, SEM and TEM were used to find the origin of the additional capacity by examining the structural evolution and phase transformation of CuO/Cu integrated anode during electrochemical cycling. After 110 cycles, the discharge capacity of CuO/Cu integrated anode retained a large value of 706 mAh g−1, which is beyond the theoretical capacity of CuO materials (674 mAh g−1). The specific electrode configuration and the release of Cu from integrated Cu current collector made these CuO/Cu electrodes maintain high capacity and cycling stability. The present research demonstrates a protocol for the design of high-performance anode structure: in situ chemical and electrochemical activating integrated electrode system.
One dimensional porous NiO-decorated Co3O4 composites were synthesized via a two-step solution-based method. The composites were detected by X-ray photoelectron spectroscopy (XPS), and it shows that the atomic ratio of nickle is about 1.74% in the composite. The obtained NiO-decorated Co3O4 composite yields a high specific capacitance of 1112Fg−1 at a current density of 2Ag−1, exhibits perfect rate and cycling stability. Furthermore, the specific capacitance of the composite can still keep a good retention of 97% after 1000 cycles at 2Ag−1, demonstrating the excellent long-term electrochemical stability of the composite.
Asymmetric supercapacitor (ASC) devices are emerging as effective high-performance energy storage systems. We report on the synthesis of novel and green electrode materials and their use to construct high performance ASCs. The assembled ASCs are based on 3D porous graphene-wrapped V2O5 nanospheres as the positive electrode and Fe3O4@graphene as the negative electrode. The optimal ratio of the V2O5 nanospheres intercalated graphene sheets in the composite electrodes was identified. Compared to all positive electrode formulations, the V2O5@3DGr (33%) hybrid electrode achieved the highest specific capacitance (612.5 Fg−1) at a current density of 1.0 A g−1. Based on the excellent electrochemical behavior of the fabricated electrodes, the assembled asymmetric supercapacitor devices of V2O5@3DGr//Fe3O4@3DGr exhibited a maximum energy density of 54.9 Wh kg−1 with a power density of 898 Wkg−1 with an extended voltage of 1.8 V in 1.0 M Na2SO4 aqueous electrolyte. Furthermore, the ASC device demonstrated excellent cycling stability with 89.6% capacitance retention over 10,000 cycles. The outstanding electrochemical performance of the fabricated electrodes can be attributed to the synergic effect between graphene sheets and metal oxides (V2O5, Fe3O4) sandwich network structures. Interestingly, the proposed asymmetric electrode materials provide a promising strategy for integrating low cost transition metal, green electrolyte, high energy, and power densities of supercapacitor devices and that can bridge the gap with commercial batteries.
The increasingly demanding requirements of a number of military applications mean that there is a need for more energy dense power sources that is unlikely to be satisfied with conventional battery chemistries. A high temperature electrochemical power source employing carbon as a fuel has been identified as a technology offering a step change in available energy density. Direct carbon conversion is an approach being pursued by several groups in the US. This paper discusses the state-of-the-art in this technology, and describes work carried out at Dstl and St. Andrews University to establish a new carbon–air semi fuel cell concept. This forms part of a four-year programme to develop a 50W, 500Wh demonstration unit.
Perovskite-type LaCrO3 used as negative electrode for Ni/MH batteries was prepared by Pechini method and characterized by XRD and SEM. The electrochemical properties under various temperatures and electrolyte concentrations were investigated. The results showed that the discharge capacity of LaCrO3 electrodes increased with the increase of temperature and electrolyte concentration. Meanwhile, the electrochemical properties of LaCrO3 electrodes were found to be greatly influenced by the dimension of Ni powders, which served as catalyst in electrodes. EIS was employed to study the phenomena above.
The development of cost-effective, highly efficient and robust multi-functional electrode materials can dramatically reduce the overall cost of electrochemical devices. We here report the controlled synthesis of NiS2/FeS2 nanoparticles encapsulated in N-doped carbon nanorods (NiS2/FeS2/NC) through carbonization and sulfurization of Fe/Ni-based bimetallic metal-organic frameworks. Benefiting from both structural and compositional characteristics, the resulting NiS2/FeS2/NC nanorods possess abundant active sites, high electrical conductivity and rapid mass transfer, thereby delivering 10 and 20 mA cm−2 at overpotential of 172 mV and 231 mV towards the hydrogen evolution reaction and oxygen evolution reaction with robust stability in 1.0 M KOH solution, respectively. When employed as a bifunctional electrocatalyst for overall water splitting, it requires only 1.58 V to deliver a current density of 10 mA cm−2 in 1.0 M KOH, outperforming that of the commercial Pt/C || RuO2. Additionally, lithium-ion batteries tests also show high reversible capacity (718 mA h g−1 at 100 mA g−1) and excellent cycling stability and rate performance. The work in this paper not only provides a promising strategy for designing efficient multi-functional electrode materials with similar morphology and structure, but also can be extended to the synthesis of other mixed metal sulfides for energy conversion and storage.
Background High prevalence of abnormal cerebral MRI findings as well as major and minor motor, perceptual and cognitive impairments has been reported in very low birth weight (VLBW) children. Aim To investigate whether cerebral MRI pathology relates to different types of neuroimpairments in adolescents with VLBW. Methods At age 15, 55 adolescents with birth weight ⩽1500g (VLBW) were examined. Motor function was evaluated by Movement Assessment Battery for Children (ABC) and the Grooved Pegboard (GP) test, cognitive function by Wechsler Intelligence Scales, and visuo-motor and visual perceptual function by The Developmental Test of Visual-Motor Integration (VMI) with the supplementary tests of Visual Perception (VP), and Motor Coordination (MC). Executive functions were assessed by Wisconsin Card Sorting Test (WCST) and the Stroop test. Cerebral MRI was assessed semi-quantitatively for ventricular, white and grey matter pathology. Results There was a rather weak relationship between MRI pathology and neuroimpairments. Poor performance on the WCST was related with ventricular dilatation (VD), white matter reduction and corpus callosum thinning. There was a correlation between results on the VMI test and the Movement ABC test and MRI pathology, but the correlation became much weaker when children with cerebral palsy were excluded. There was no relationship between MRI findings and estimated intelligence quotient (IQ) scores. Normal MRI predicted normal or near normal neuropsychological functioning. Conclusion Cerebral MRI pathology suggestive of perinatal white matter injury was related to disadvantages in performances on executive functions, to a lesser degree to motor and visual perceptual problems, but not to cognitive impairments in VLBW adolescents.
Lithium batteries with Si, Al or Bi microsized (>10 µm) particle anodes promise a high capacity, ease of production, low cost and low environmental impact, yet they suffer from fast degradation and a low Coulombic efficiency. Here we demonstrate that a rationally designed electrolyte (2.0 M LiPF6 in 1:1 v/v mixture of tetrahydrofuran and 2-methyltetrahydrofuran) enables 100 cycles of full cells that contain microsized Si, Al and Bi anodes with commercial LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes. Alloy anodes with areal capacities of more than 2.5 mAh cm−2 achieved >300 cycles with a high initial Coulombic efficiency of >90% and average Coulombic efficiency of >99.9%. These improvements are facilitated by the formation of a high-modulus LiF–organic bilayer interphase, in which LiF possesses a high interfacial energy with the alloy anode to accommodate plastic deformation of the lithiated alloy during cycling. This work provides a simple yet practical solution to current battery technology without any binder modification or special fabrication methods.
This paper proposes a perfect energy source supplied by a polymer electrolyte membrane fuel cell (PEMFC) as a main power source and storage devices: battery and supercapacitor, for modern distributed generation system, particularly for future fuel cell vehicle applications. The energy in hybrid system is balanced by the dc bus voltage regulation. A supercapacitor module, as a high dynamic and high power density device, functions for supplying energy to regulate a dc bus voltage. A battery module, as a high energy density device, operates for supplying energy to a supercapacitor bank to keep it charged. A FC, as a slowest dynamic source in this system, functions to supply energy to a battery bank in order to keep it charged. Therefore, there are three voltage control loops: dc bus voltage regulated by a supercapacitor bank, supercapacitor voltage regulated by a battery bank, and battery voltage regulated by a FC. To authenticate the proposed control algorithm, a hardware system in our laboratory is realized by analog circuits and numerical calculation by dSPACE. Experimental results with small-scale devices (a PEMFC: 500-W, 50-A; a battery bank: 68-Ah, 24-V; and a supercapacitor bank: 292-F, 30-V, 500-A) corroborate the excellent control principle during motor drive cycle.
The performance of a Prussian blue cathode is affected by its structure and stability. Through the inhibitor and temperature control, the border-rich structure was obtained, which provides a good contact between electrode-electrolyte interfaces and increases the transmission path for Na+ ions. In addition, the as-prepared sample with rhombohedral phase demonstrated lower band gap and lower energy barrier for Na+ ions insertion. Benefiting from the kinetics optimization, the as-prepared electrode exhibited initial capacity of 120mAhg−1 and maintained nearly 80% after 280 cycles at current density of 100mAg−1. This electrode also exhibited good rate performance about 60mAhg−1 at rate of 10C. The structural stability is also related to the formation of the passivation layer during the charge-discharge process. The optimized passivation layer not only protects the electrode form the adverse side reactions at high voltage but also delivers low interface impedance. It can be inferred that the passivation layer plays a positive role in long cycling performance. When the as-prepared electrode was measured in an electrolyte with FEC additive, it exhibited a high capacity retention rate of 79% after 500 cycles.
Sodium ruthenium oxides (Na2RuO3 and Na1.33Ru0.67O2) belong to a special Na-rich type of cathode material which show high specific capacities and structural stability. Even though these Na-rich materials possess attractive electrochemical properties, owing to the low abundance of ruthenium (Ru) within the Earth’s crust, commercialization of sodium ruthenium oxide (NRO) cathodes is extremely difficult. To mitigate this disadvantage, we have substituted Ru in NRO using Fe, which is electrochemically active in many cathode materials for sodium-ion batteries (SIBs), Earth-abundant and cheap. Herein, a series of Fe-substituted (Fe% = 5 mol. %, 10 mol. %, 20 mol. %, and 30 mol. %) sodium ruthenium iron oxide (NRFOx) phases were synthesized using a conventional solid-state synthesis method. When used as a cathode material, among these novel Fe substituted phases, the composition with the lowest Fe mol. % displays the highest specific discharge capacities of 115 mAh g−1 and 61 mAh g−1, at 0.2C and 2C rate respectively, within a 2.0–3.7 V potential range. It was seen that the Fe substitution level significantly influences structural stability and discharge capacities. Cyclic voltammetry displays that Fe3+ is surprisingly electrochemically inert inside the NRO matrix and only plays a structural role.