batterydata/paper-abstracts huggingface dataset:
Lithium-sulfur (Li-S) batteries are regarded as a promising next-generation electrical-energy-storage technology due to their low cost and high theoretical energy density. Furthermore, flexible and wearable electronics urgently requires their power sources to be mechanically robust and flexible. However, the effective progress of high-performance, flexible Li-S batteries is still hindered by the poor conductivity of sulfur cathodes and the dissolution of lithium polysulfides as well as the weak mechanical properties of sulfur cathodes. Herein, a new type of flexible porous carbon nanofiber film modified with graphene and ultrafine polar TiO2 nanoparticles is designed as a sulfur host, in which the artful structure enabled the highly efficient dispersion of sulfur for a high capacity and a strong confinement capability of lithium polysulfides, resulting in prolonged cycle life. Thus, the cathode shows an extremely high initial specific discharge capacity of 1501 mA h g−1 at 0.1 C and an excellent rate capability of 668 mA h g−1 at 5 C as well as prolonged cycling stability. The artful design provides a facile method to fabricate high-performance, flexible sulfur cathodes for Li-S batteries.
The present work describes the development of a passive hydrogen-recirculating scheme for the anode of a proton exchange membrane (PEM) fuel cell system. A vacuum ejector is fluidly connected to the stack anode outlet to entrain the unused hydrogen into the main hydrogen supply. A combination of a continuous-flow mode and a pulse-flow mode is employed to cover a wide range of power consumption. The former deals with the normal and high stack power conditions, while the latter is active only at low stack power. Transient results showed that the hydrogen anode stoichiometry has been successfully stabilized in the range of 1.4–1.6 with an entrainment ratio of 40–50% under the constant system load of 1.45 kW. In addition, the reliable operation of the PEM fuel cell system without any failure during the approximate 1-h test indicates the stability and reliability of the present hydrogen recovery scheme.
The fluid dynamics of multi-component alloy systems subjected to high energy density sources of heat largely determines the local composition, microstructure, and material properties. In this work a multi-component thermal fluid dynamics framework is presented for the prediction of alloy system development due to melting, vaporisation, condensation and solidification phenomena. A volume dilation term is introduced into the continuity equation to account for the density jump between liquid and vapour species, conserving mass through vaporisation and condensation state changes. Mass diffusion, surface tension, the temperature dependence of surface tension, buoyancy terms and latent heat effects are incorporated. The framework is applied to describe binary vapour collapse into a heterogeneous binary liquid, and a high energy density power beam joining application; where a rigorous mathematical description of preferential element evaporation is presented.
Abstract The Hybrid Electric Vehicle (HEV) powertrain comprising Electric Motors, High Voltage Power Electronics, High Voltage Battery Pack and an on-board generator (Auxiliary Power Unit – APU) in case of Range Extended – Electric Vehicles (RE-EV) require appropriate cooling. Based on the cooling requirements, different cooling system architectures, heat exchanger arrangements, battery cooling and cabin cooling / heating methods have been evaluated using a holistic system modelling approach with 1D simulation software Flowmaster™(1). This paper will present the approach and process for evaluating different cooling architectures, the simulation methodology, and how the simulation can help to understand the thermal issues encountered on an HEV and related architectures.
An experimental relationship between local structure and electrochemical properties is established for lithium metal phosphates LiMePO4 (Me = Fe, Co, Mn), LiFeP2O7 and Li3Fe2(PO4)3 which crystallise with either the olivine-like or the Nasicon-like structure. Structural features of several lithium metal phosphates are investigated by a local probe such as the FTIR spectroscopy in order to explain the influence of either P O 4 3 − or P 2 O 7 4 − covalent bonds on redox energies. The local cationic arrangement is also discussed with the aid of a molecular vibration model to figure out the strong covalent bonds within a P O 4 3 − complex for glassy Nasicon compounds.
Specific design and optimization of the configuration of micro-scale materials can effectively enhance battery performance, including volumetric density. Herein, we employed commercially available low-cost bulk silicon powder to produce multi-dimensional silicon composed of porous nanowires and micro-sized cores, which can be used as anode materials in lithium-ion batteries, by combining a metal deposition and metal-assisted chemical etching process. Nanoporous silicon nanowires of 5–8 μm in length and with a pore size of ∼10 nm are formed in the bulk silicon particle. The silicon electrodes having multi-dimensional structures accommodate large volume changes of silicon during lithium insertion and extraction. These materials show a high reversible charge capacity of ∼2400 mAh g−1 with an initial coulombic efficiency of 91% and stable cycle performance. The synthetic route described herein is simple, low-cost, and mass producible (high yield of 40–50% in tens of gram scale), and thus, provides an effective method for producing high-performance anode materials.
Depleted LiCoO2 cathode material in spent lithium ion rechargeable batteries was recovered and renovated in a single synthetic step using Etoile-Rebatt technology. The structural and compositional purities of the recovered and renovated LiCoO2 were confirmed by elemental analyses, X-ray diffraction pattern analyses, and Raman spectroscopy. In spite of the simple and economical recycling, the recovered and renovated LiCoO2 exhibits a prospective electrochemical activity; an initial discharge capacity of 134.8mAhg−1 and the discharge capacity retention of 95.9% after 50 cycles.
For the lithium super-ionic conductor Li10GeP2S12, the partial substitution of sulfur by oxygen is achieved via a solid-state reaction. The solid-solution range of oxygen is found to be 0 ≤ x < 0.9 in Li10GeP2S12−x O x . Structure refinements using synchrotron X-ray diffraction data confirm the preference for oxygen substitution in the PS4 tetrahedra. The local structural change in the P(S/O)4 tetrahedra upon substitution is also indicated by Raman spectroscopy. Ionic conduction properties are maintained even after the oxygen substitution in Li10GeP2S12; the ionic conductivity of Li10GeP2S12−x O x (0.3 ≤ x ≤ 0.6) ranges from 1.03 × 10−2 to 8.43 × 10−3 S cm−1 at 298 K. No redox current is observed by cyclic voltammetry from nearly 0 to 10 V versus Li/Li+ except for that due to the lithium deposition/dissolution reactions. All-solid-state batteries using Li10GeP2S12−x O x (x = 0.3 and 0.6) as solid electrolytes with Li metal anodes show discharge capacities exceeding 100 mAh g−1 and better cycling performance compared to batteries using the original Li10GeP2S12. The partial substitution of oxygen for sulfur in Li10GeP2S12 affords a novel solid electrolyte, Li10GeP2S12−x O x , with high conductive properties and electrochemical stability.
(1− x)Li[Ni0.20Li0.20Mn0.60]O2–xLi[Co0.50Li0.167Mn0.333]O2 solid solutions (x =0, 0.2, 0.4, 0.6, 0.8, and 1.0) have been prepared by a simple combustion method and investigated using X-ray diffraction (XRD), galvanostatic charge/discharge cycling, and cyclic voltammetry. The XRD analysis showed that single-phase compounds were obtained for all the compositions. Under the cycling condition of voltage range of 4.8–2.0V and a specific current of 100mAg−1 at 30°C, the first discharge capacity was found to exhibit the maximum value of 265mAhg−1 for Li[Ni0.16Co0.10Li0.193Mn0.547]O2 (x =0.2). Together with its excellent cycling property due to the structural stability, the observed capacity has potential for high capacity applications. It was also observed that the discharge capacity rapidly decreased during the cycling, when x is larger than 0.20. This implies that the charge/discharge mechanism of Ni-rich compounds is clearly different from that of Co-rich compounds, as being reflected in the evolution of cyclic voltammetry results.
Activated carbon is widely used for electrodes in supercapacitors. Fabrication of supercapacitors is currently based on hydraulic pressing method, which is a lengthy process (severalh) with challenges in controlling the layer thickness and mass. This work reports an electrophoresis method that can efficiently deposit activated biochar onto metal electrodes. The authors demonstrated that a suitable binder (ethyl cellulose) could ensure sufficient coating adhesion. Using commercial activated carbon (YP-50) as electrode material, supercapacitors were fabricated using electrophoretic deposition and the specific capacitance reached 158.6Fg−1. The electrophoretic deposition was highly efficient as it only took about 3min and enabled accurate control of the electrode mass by simply varying the deposition time. This work demonstrates that electrophoretic deposition has the potential to replace the conventional hydraulic press method in manufacturing supercapacitors that use sustainable and environmentally friendly biochar.
Li metal was galvanostatically electrodeposited on a horizontally positioned, downward-facing Li metal cathode in 0.5M LiClO4-PC electrolyte. The refractive index profile corresponding to the transient Li+ ion concentration profile formed in the electrolyte solution upon applying a current step was measured in-situ by holographic interferometry. The configuration of the electrolytic cell was such that mass transfer was governed only by transient diffusion and migration, in the absence of convection. Between the moment of closing the current circuit and the time at which the interference fringes started to shift, an incubation period was observed. Such an incubation period had earlier been observed in lithium electrodeposition at a vertical planar Li metal cathode. The incubation period for the horizontal Li cathode was roughly half that for a vertical one. To study the effect of the electrode material on the incubation period, interferometry measurements were also made at an electrodeposited Ni–Sn alloy electrode. The concentration profile formed near the Ni–Sn alloy electrode during lithiation (alloying or intercalation of Li+ into the electrode) agrees well with predictions made by means of the one-dimensional diffusion equation. Only very short incubation period was detected, but the magnitude was negligibly smaller than that of Li metal electrodeposition. The incubation period therefore appears to be characteristic for Li metal electrode only.
Although LiNO3 could effectively solve the polysulfide (PS) shuttle problem in Li-S battery, however, it causes explosive hazards with the cathode composition like gun powder (KNO3, Sulfur, and Carbon). Herein, a LiNO3-free electrolyte was designed to simultaneously inhibit the PS shuttle and lithium dendrite problem, with pure 1,3-dioxolane (DOL) as the solvent, due to the low Ksp of polysulfide as well as the stable SEI on lithium. As a synergistic effect, it enabled the Li-S batteries to achieve 95% coulombic efficiency, 3 times longer cycle life, and a slower self-discharging rate at 55°C compared to the DOL/DME blend solvent. Four kinds of batteries, from coins to soft packages, were carried out to confirm the superiority of this electrolyte. Li-S soft package batteries with 4000 mAh capacity were assembled, achieving the specific energy of 350Whkg−1 and specific power of 60Wkg−1, which could cycle over 30 times at 0.2C with high capacity retention of 80%. It is among the best comprehensive Li-S batteries performance reported using LiNO3-free electrolyte.
N,N′-Propyltriethoxysilane-bis-naphthalenediimide was used to obtain a thermo and photo-active bridged organo polysilsesquioxane gel in DMF. Photophysical and electrochemical measurements revealed a dense diimide π-stacked structure that favors electron-delocalized states and facilitates high yield inherent thermo and photo-generation of radical anions that may be used for photocatalytic purposes, or energy conversion.
Mg-doped composite, Li2.97Mg0.03VO4, with an orthorhombic structure was prepared by a sol-gel method. The effects of the Mg doping on the structure and electrochemical performance of Li3VO4 were investigated. The X-ray diffraction pattern shows that the Mg doping does not change the crystal structure of Li3VO4. The EDS mappings indicated the fairly uniform distribution of Mg throughout the grains of Li2.97Mg0.03VO4. Electronic conductivity of Mg-doped Li3VO4 increased by two orders of magnitude compared to that of pure Li3VO4. CV and EIS measurement confirms that the Li2.97Mg0.03VO4 sample exhibits a smaller polarization and transfer resistance and a higher lithium diffusion coefficient compared with the pure Li3VO4. Due to the better electrochemical kinetics properties, Mg-doped Li3VO4 showed a significant improved performance compared to the pure Li3VO4, especially for the high rate capability. At the higher discharge/charge rate (2C), the discharge and charge capacities of 415.5 and 406.1 mAh/g have been obtained for the Li2.97Mg0.03VO4 which is more than three times higher the discharge/charge capacities of Li3VO4. The discharge and charge capacities of pure Li3VO4 are only 126.4 and 125.8 mAh/g respectively. The excellent electrochemical performance of Li2.97Mg0.03VO4 enables it as a promising anode material for rechargeable lithium-ion batteries.
This paper investigates the dynamical response of a nonlinear piezoelectric energy harvester under a hard harmonic excitation and assesses its output power. The system is composed of a unimorph cantilever beam with a tip mass and exposed to an harmonic tip excitation with a hard forcing amplitude. First, the governing dimensionless nonlinear electromechanical ordinary differential equations (ODEs) are obtained. Next, the multiple scales method (MSM) is exploited to provide an approximate-analytical solution for the ODEs in hard and soft forcing scenarios. It is observed that, the hard force results in sub- and super-harmonic resonances. The MSM-based solutions are then validated by a numerical integration method and a good agreement is observed between the approximate-analytical and numerical results. Furthermore, utilizing the MSM-based solutions for the subharmonic, superharmonic, and soft primary resonances cases, the associated frequency and force response curves are constructed. It is revealed that the hard excitation leads to a remarkable voltage generation in the secondary resonances; this leads to a broadband energy harvesting. In addition, the time-domain electrical responses of the secondary resonances are also obtained and compared with each other. Finally, the three-dimensional graphs of the electrical power versus detuning parameter and time constant ratio in the cases of the secondary resonances are plotted. The results show that the optimum output power of the superharmonic resonance is considerably larger than the maximum power of the subharmonic resonance case.
Nanostructure Sn–Co–C composites with different compositions are synthesized by a simple solution polymerization using inexpensive raw materials followed by pyrolysis in nitrogen atmosphere. The nanostructure Sn–Co–C composites are characterized using various analytic techniques. The results show that the electrochemical performances of the composites are strongly dependent on their structure and composition. Among these composites the Sn–Co–C-1 with a weight composition of Sn0.31Co0.09C0.6 exhibits high reversible capacity and excellent cycleability when used as an anode for rechargeable lithium ion batteries. This composite is composed of SnCo2, SnCo, Sn and amorphous carbon, and the nanoparticles of SnCo2, SnCo and Sn are uniformly dispersed into the amorphous carbon matrix, the average diameter of these metal nanoparticles is 8.44nm.
A surface cladding of nano-sized Li2SnO3 powder on Ni-rich layered LiNi0.5Co0.2Mn0.3O2 compounds for lithium ion batteries have been successfully achieved through a two-step synthesis process. The structures and morphologies of as-prepared samples have been analyzed. A cladding layer of Li2SnO3 can be distinguished on the surface of host material and the thickness is about 15nm with uniform distribution. The optimized Li2SnO3-coated sample displays better rate performance and higher capacity retentions of 94.9% at 10C after 100 cycles than that of the bare one (68.3%) at 3.0–4.5V. In addition, Li2SnO3 as an effective coating layer can enhance the cycle stability and rate property of electrodes.
Seven partially fluorinated ethers (PFE) were studied as co-solvents for lithium-sulfur battery with the goal to understand the interplay between the molecular structure and the electrochemical properties, including capacity, Coulombic efficiency and SEI formation on the Li anode. Electrochemical cycling indicates a loose correlation between the Coulombic efficiency observed over 200 cycles and the fluorination degree of the PFE, which correlates with the computed pKa of the C–H bond of the ethers. PFE with lower pKa (<36) tends to chemically react with lithium anode forming a solid-electrolyte-interphase (SEI) layer thus preventing the shuttling effect of the lithium polysulfides. The cycled lithium anodes with DOL/PFE electrolyte was found to produce a protective SEI analyzed by FT-IR and SEM/EDS. Computations of the interactions between the PFEs of interest and a lithium surface suggest the generation of LiF and unsaturated PFE derivatives which are easily reduced and polymerized on the Li surface. The PFE decomposition is more thermodynamically likely with increasing fluorination degree. This research sheds light on the role that fluorine substitution and structure play in the high Coulombic efficiencies observed for Li–S cells.
There is some evidence that insufficient effort may be common in schizophrenia, posing significant threats to the validity of neuropsychological test results. Low effort may account for a significant proportion of variance in neuropsychological test scores and the generalized cognitive deficit that characterizes the disorder. The current study evaluated clinical predictors of insufficient effort in schizophrenia using an embedded effort measure, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Effort Index (EI). Participants were 330 patients meeting DSM-IV-TR criteria for schizophrenia, schizoaffective disorder, or another psychotic disorder who received a battery of neuropsychological tests, including: Wechsler Test of Adult Reading (WTAR), Wechsler Abbreviated Scale of Intelligence (WASI), and RBANS. Clinical assessments designed to measure functional outcome and symptoms were also obtained. Results indicated that 9.4% of patients failed the EI. Patients who failed had lower full-scale, verbal, and performance IQ, as well as poorer performance on RBANS domains not included in the EI (immediate memory, language, and visuospatial/construction). Patients who failed the EI also displayed poorer community-based vocational outcome, greater likelihood of having “deficit schizophrenia” (i.e., primary and enduring negative symptoms), and increased severity of positive symptoms. Regression analyses revealed that insufficient effort was most significantly predicted by a combination of low IQ, negative symptoms, and positive symptoms. Findings suggest that although insufficient effort may be relatively uncommon in schizophrenia, it is associated with important clinical outcomes. The RBANS EI may be a useful tool in evaluating insufficient effort in schizophrenia.
An enhancement in the secondary battery safety demands the optimum synthesis of glass-ceramics electrolytes with modified ionic conductivity. To achieve improved ionic conductivity and safer operation of the battery, we synthesized Li2O included zinc-tellurite glass-ceramics based electrolytes of chemical composition (85-x)TeO2·xLi2O·15ZnO, where x =0, 5, 10, 15mol%. Samples were prepared using the melt quenching method at 800°C followed by thermal annealing at 320°C for 3h and characterized. The effects of varying temperature, alternating current (AC) frequency and Li2O concentration on the structure and ionic conductivity of such glass-ceramics were determined. The SEM images of the annealed glass-ceramic electrolytes displayed rough surface with a uniform distribution of nucleated crystal flakes with sizes less than 1μm. X-ray diffraction analysis confirmed the well crystalline nature of achieved electrolytes. Incorporation of Li2O in the electrolytes was found to generate some new crystalline phases including hexagonal Li6(TeO6), monoclinic Zn2Te3O8 and monoclinic Li2Te2O5. The estimated crystallite size of the electrolyte was ranged from ≈40 to 80nm. AC impedance measurement revealed that the variation in the temperatures, Li2O contents, and high AC frequencies have a significant influence on the ionic conductivity of the electrolytes. Furthermore, electrolyte doped with 15mol% of Li2O exhibited the optimum performance with an ionic conductivity ≈2.4×10−7 Scm−1 at the frequency of 54Hz and in the temperature range of 323–473K. This enhancement in the conductivity was attributed to the sizable alteration in the ions vibration and ruptures of covalent bonds in the electrolytes network structures.
We demonstrate that the addition of 1-butyl-1-methylpyrrolidinium hexafluorophosphate ([Py14]PF6) to 1.0 M LiPF6 in ethylene carbonate-dimethyl carbonate (LP30) widens the temperature range, in which the electrolyte mixtures are ion conductive and safe. Specifically, at the concentrations of [Py14]PF6 above 50 wt%, the electrolyte mixtures exhibit a flash point higher than room temperature and fulfill the requirements of liquids having controlled flammability. In this concentration range, also crystallization of the mixtures is completely suppressed, and low temperature ionic conductivity is improved. With respect to the electrochemical properties at room temperature, electrochemical stability window is widened by the addition of [Py14]PF6 to LP30. However, it comes at the cost of slightly increased overall impedance and overpotential in Li | Li symmetric cells. We utilize these mixed electrolytes in high voltage Li | LiNi0.5Mn1.5O4 cells. In the presence of 30 wt% and 50 wt% of [Py14]PF6 in LP30, the cells exhibit high specific capacity of about 110 mAh g−1 over 200 cycles and improved coulombic efficiency, suggesting [Py14]PF6 is a promising additive for the electrolyte in high-voltage, stable and safe lithium batteries.
We investigated vegetation structure, seasonal water use and leaf deciduousness in a seasonally dry forest of Dzibilchaltún, Mexico. Legumes, species which tend to dominate these forests, have an array of water-saving traits. We explored whether legume species had reduced water use under similar growth conditions as other non-legume species of this seasonally dry forest. Sap flux and conductive sapwood area were measured for eight legume and 12 non-legume species. Species abundance, diameter at breast height (DBH), wood density and seasonal leaf cover were characterized in 16, 10 × 10 m2 plots. Seasonal stand water use was calculated using the sap flux and ecological data. As predicted, legumes presented lower whole-tree water use compared with sympatric non-legume species. This difference, however, was related to a higher allocation to non-conductive heartwood in legumes and not to differences in sap flux density. Differences in allocation were higher in wider stems (>10 cm DBH); legumes above 25 cm DBH presented nearly half the daily water use of non-legumes of similar size. Wet (July) and dry (March) season stand water use was 629,000 and 156,000 kg ha−1 month−1, respectively. During the wet season three non-legume species with high basal area dominated the stand water use, but due to early leaf fall in these species, dry season stand water use was dominated by the legumes.