batterydata/paper-abstracts huggingface dataset:
Ruthenium (Ru)-catalyzed aprotic Li–O2 batteries have attracted a great deal of interests because of their excellent electrochemical performances including high specific energy and round-trip efficiency. However, it remains unclear how the incorporated Ru catalysts function to enhance the batteries’ performance. Herein, we report Ru nanocrystal-catalyzed carbon nanotube-based aprotic Li–O2 batteries with electrochemical performances that can match or even surpass some of the best literature results. The catalytic mechanism of Ru nanocrystals has been studied by a combination of Coulometry and in situ differential electrochemical mass spectrometry (DEMS). It has been found that through the synergy of water additive in electrolyte and Ru-based catalysts, the charging reaction overpotential can be brought down to 0.12V (usually η>1V). Moreover, an isotope-labeled DEMS study on the electrochemical oxidation of Li2 13CO3 indicated that Ru nanocrystals also have the capability to decompose Li2CO3, a detrimental by-product formed in almost all aprotic Li–O2 batteries, at a surprisingly low potential of ~3.5V vs. Li/Li+ (usually >4.0V). The capabilities of Ru nanocrystals to decompose Li2O2, LiOH, and Li2CO3 at low voltages, which drastically decreases the degradation of electrode and/or electrolyte, are crucial to achieve outstanding electrochemical performances for Li–O2 batteries.
The increasing concern over global warming has led to the rapid development of the electric vehicle industry. Electric vehicles (EVs) have the potential to reduce the greenhouse effect and facilitate more efficient use of energy resources. In this paper, we study several EV route planning problems that take into consideration possible battery charging or swapping operations. Given a road network, the objective is to determine the shortest (travel time) route that a vehicle with a given battery capacity can take to travel between a pair of vertices or to visit a set of vertices with several stops, if necessary, at battery switch stations. We present polynomial time algorithms for the EV shortest travel time path problem and the fixed tour EV touring problem, where the fixed tour problem requires visiting a set of vertices in a given order. Based on the result, we also propose constant factor approximation algorithms for the EV touring problem, which is a generalization of the traveling salesman problem.
The surface of LiMn2O4 was coated with a nano-layer of FePO4 by the co-precipitation method followed by heat treatment at different temperatures in air. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that the FePO4 coatings remained in the amorphous phase from 300°C to 400°C, whereas crystalline FePO4 was obtained above 500°C. In addition, the diffusion of Fe ions into the LiMn2O4 lattice was promoted at higher temperatures. The results of the cycle capacity test showed that 3wt% FePO4-coated LiMn2O4 heat treated at 400°C exhibited optimum cyclability, with cycle retention of 90.3% after 100 cycles at elevated temperature (55°C). The electrochemical impedance spectroscopy (EIS) results indicated that 3wt%–400°C FePO4-coated LiMn2O4 showed the lowest charge transfer resistance (R ct) value and the highest diffusion coefficient of the lithium ion of 9.85E−10cm2 s−1. These results indicated that heat treatment at the proper temperature could maintain FePO4 in the amorphous phase, thereby facilitating Li ion transport and prevent the detachment of FePO4 and LiMn2O4, which was caused by the diffusion of Fe ions into LiMn2O4 lattice.
Metallic interconnects have been becoming an increasingly interesting topic in the development in intermediate temperature solid oxide fuel cells (SOFC). High temperature oxidation resistant alloys are currently considered as candidate materials. Among these alloys however, different groups of alloys demonstrate different advantages and disadvantages, and few if any can completely satisfy the stringent requirements for the application. To integrate the advantages and avoid the disadvantages of different groups of alloys, clad metal has been proposed for SOFC interconnect applications and interconnect structures. This paper gives a brief overview of the cladding approach and its applications, and discuss the viability of this technology to fabricate the metallic layered-structure interconnects. To examine the feasibility of this approach, the austenitic Ni-base alloy Haynes 230 and the ferritic stainless steel AL 453 were selected as examples and manufactured into a clad metal. Its suitability as an interconnect construction material was investigated.
In this paper, we report a flame deposition method to prepare carbon nanoparticles (CNPs) from coconut oil. The CNPs were further modified with a piranha solution to obtain surface-carboxylated carbon nanoparticles (c-CNPs). When used as an anode for sodium-ion batteries, the CNPs and c-CNPs respectively delivered discharge capacities of 277 and 278mAhg−1 in the second cycle at a current density of 100mAg−1. At the 20th cycle, the capacities of CNP and c-CNPs were 217 and 206mAhg−1 respectively. The results suggest that modification of the CNPs with the piranha solution improved neither the charge storage capacity nor the stability against cycling in a sodium-ion battery. When the CNP and c-CNP were used an anode in a lithium-ion battery, 2nd-cycle discharge capacities of 741 and 742mAhg−1 respectively at a current density of 100mAg−1 were obtained. After 20 cycles the capacities of CNP and c-CNP became 464 and 577mAhg−1 respectively, showing the cycling stability of the CNPs was improved after modification. The excellent cycling performance, high capacity and good rate capability make the present material as highly promising anodes for both sodium-ion and lithium-ion batteries.
NMR spectroscopy continues to evolve, and publications in 2007 provide an eclectic collection of applications, advances and incremental improvements, with solid-state MAS investigations of bio-systems making a significant contribution. Higher magnetic field spectrometers (or more accurately, some funding to enable the purchase of) have allowed “difficult-to-measure” nuclei such as 17O, for example, to become more mainstream. Fast 2D methods, covariance analysis and multiple acquisition methods allow chemists rapid access to detailed analyses. A 7D protein NMR data set can be recorded in 50 hours. The TROSY experiment has been used extensively to obtain dynamics information from large proteins. The accuracy of calculated and predicted NMR parameters (δ, J, D, CSA, Q) has improved and is becoming more accessible to the bench chemist, such that many solid-state NMR papers contain considerable computational and modelling data. I am indebted to the great and the good whose work has been reported here, all credit is theirs; errors, omissions and blame are all mine.
Ni3P–Ni films were deposited on nickel foam substrates by electrodeposition in an aqueous solution. The structure and morphology of the electrodeposited films were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The annealed electrodeposited films consisted of tetragonal structured Ni3P and cubic metal Ni. As anode for lithium ion batteries, the electrochemical properties of the Ni3P–Ni films were investigated by cyclic voltammetry (CV), electrochemical impedance spectrum (EIS) and galvanostatic charge–discharge tests. The electrodeposition time had a significant effect on the electrochemical performances of the films. The Ni3P–Ni film electrodeposited for 20min delivered the initial discharge capacity of 890mAhg−1. Although the irreversible capacity at the first cycle was relative large, the Ni3P–Ni film exhibited good cycling stability and its discharging capacity still maintained 340mAhg−1 after 40 cycles.
The rapid growth of lithium-ion batteries in many markets makes it increasingly urgent to address recycling of strategic materials from spent batteries.
Two kinds of different Co–S microspheres with novel structure are synthesized by liquid phase chemical method (hydrothermal method and solvothermal method), and their formation mechanisms are also constructed. The electrochemical properties as negative electrode for alkaline secondary batteries are first performed using LAND battery test instrument. Co–S nest-like spheres electrode displays high reversible discharge capacity of 250mAhg−1 and excellent cycle stability at current density 200mAg−1. The discharge curve and CV curve confirm that the reaction occurring on Co–S alloy electrode is a reversible redox reaction of Co. The higher specific surface areas of Co–S nest-like spheres may be responsible for the higher discharge capacity.
Enabling fast ion diffusion in thick electrodes (100–200 µm, ~ 10 mg cm−2) is critical for their practical application in state-of-the-art supercapacitors (SCs). We developed a three-dimensional (3D) boron, nitrogen, and phosphorus ternary-doped holey graphene hydrogel (BNP-HGH) film to achieve an optimized porous structure with a high electrical conductivity, large ion accessible surface area, efficient electron and ion transport pathways, as well as high ion adsorption capacity. The binder-free BNP-HGH electrode can deliver a specific capacitance of 350 F g−1 and a volumetric capacity of 234 F cm−3, which are the best performance reported so far for graphene-based SCs using an organic electrolyte. Fully packaged SCs using the BNP-HGH electrodes with a commercial level graphene mass loading (150 µm, ~ 10 mg cm−2) can deliver ultrahigh stack gravimetric and volumetric energy densities of 38.5 Wh kg−1 and 57.4 Wh L−1, respectively, which are comparable to those of lead-acid batteries (35–40 Wh kg−1 and 50–90 Wh L−1) while maintaining an ultrahigh power density of 83 kW kg−1 (~ 55 kW L−1) as well as a long cycle life (81.3% capacitance retention over 50,000 cycles). The high energy and power densities bridge the gap between traditional SCs and batteries, and should be very useful in practical applications.
ABSTRACT Background Light-emitting diode (LED) curing lights are becoming popular; however, questions about their efficiency remain. The authors performed a comprehensive analysis of the properties of resin-based composites cured with LED lights. Methods The authors evaluated seven LED lights and one quartz-tungsten-halogen light (control). They measured intensity, depth of cure (DOC), degree of conversion (DC), hardness and temperature rise. They used three shades of a hybrid resin-based composite and a microfill composite, as well as one shade of another hybrid composite. Results Two LED lights required additional cure time to reach a DOC similar to that of the control light. DC at the top of the samples was independent of the light used. At 2.0 millimeters, the DC for several LED lights was significantly lower than that for the control light and was correlated strongly to the light's intensity. The bottom-to-top ratio for hardness of resin-based composites cured by all but one light was greater than 0.80. All LED lights except one had smaller temperature rise than did the control light. Conclusions Six of the seven LED curing lights performed similarly to a quartz-tungsten-halogen curing light in curing resin-based composites. Clinical Implications While LED curing lights and a quartz-tungsten-halogen light could cure resin-based composites, some resin-based composites cured with LED lights may require additional curing time or smaller increments of thickness.
Publisher Summary This chapter reviews the usage of the numerical method of analysis that is used to model the concentration-time profiles of various reactions in a batch reactor. The chapter also provides sizing of the batch, semi-batch, continuous flow stirred tank, and the plug flow reactors for both isothermal and adiabatic conditions. Reactor design is primarily concerned with the type and size of the reactor and its method of operation for the required process. The design of any process where chemical reaction is required is given due consideration. The thermodynamics involving the equilibrium of a reaction are investigated before the chemical kinetics in relation to the reaction mechanisms. There are various advantages of using the liquid phase rather than the gas phase operation, if for the desired product the reactor is smaller. This is because the physical properties of liquids are greater than those for gases, for instance the heat capacities and the thermal conductivities, factors that increase the heat transfer. Also, the small equipment size results in lower power requirements and capital costs. The main disadvantages are corrosion and catalyst losses. In considering a liquid system, all operating conditions must fall within the two-phase region.
Microporous polymer membranes based on poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) with barium titanate (BaTiO3) ceramic nanoparticles at different concentration (4, 16 and 32%) and average sizes (10, 100 and 500nm) were prepared by thermally induced phase separation. The effects of fillers concentration and size on morphological, thermal, mechanical and electrochemical properties were evaluated. Pores remain homogeneously distributed after the addition of the fillers. In turn, the average pore size increases from ∼25μm for the pristine polymer to 90μm for the membrane with 32 wt% of BaTiO3. The porosity, on the other hand, remains nearly constant at ∼72%. The ionic conductivity increases in all temperature range with the addition of BaTiO3, being this increase larger for samples prepared with larger diameter filler particles. The stable operation window is at least 6.0V for all membranes. It was concluded that morphological, mechanical and electrochemical properties of the BaTiO3 filled P(VDF-TrFE) membranes actually depend on filler size and concentration the most adequate membrane for battery separator applications being the BaTiO3/P(VDF-TrFE) membrane with 16 wt% of 500nm diameter ceramic fillers.
Rechargeable Li-O2 batteries have aroused much attention for their high energy density. However, the poor rechargeability and low efficiency hinder their practical applications. To solve these issues, free-standing carbon films combined with high-activity NiFe2O4 catalysts are prepared by electrospinning method, and directly used as air cathodes for Li-O2 batteries. The obtained films have 3D networks formed by stacking and interlacing massive nanofibers with uniformly dispersed NiFe2O4 nanoparticles on them. The Li-O2 batteries with such binder-free air cathodes show low charging overpotential even comparable to precious metal cathodes, and can sustain excellent discharge/charge cyclic stability. The unique structure and binder-free superiority greatly facilitates the Li+ and O2 diffusion, accelerates the decomposition of Li2O2, and avoid the disturbance of polymer binders.
To meet the requirements of electronic vehicles (EVs) and hybrid electric vehicles (HEVs), the high energy density LiNi0.8Co0.15Al0.05O2 (NCA) cathode and Si–C anode have attracted more attention. Here we report the thermal behaviors of NCA/Si–C pouch cell during the charge/discharge processes at different current densities. The total heat generations are derived from the surface temperature change during electrochemical Li+ insertion/extraction in adiabatic surrounding. The reversible heat is determined by the entropic coefficients, which are related with open-circuit voltage at different temperatures; while the irreversible heat is determined by the internal resistance, which can be obtained via V–I characteristic, electrochemical impedance spectroscopy and hybrid pulse power characterization (HPPC). During the electrochemical process, the reversible heat contributes less than 10% to total heat generation; and the heat generated in charge process is less than that in discharge process. The results of thermal behaviors analyses are conducive to understanding the safety management and paving the way for building a reliable thermal model of high energy density lithium ion battery.
Flow based electrochemical energy conversion devices have the potential to become a prominent energy storage technology in a world driven by renewable energy sources. The optimal design of these devices depends strongly on the tradeoffs between the losses associated with multiple transport processes: convection and diffusion of reactants and products, migration of ionic species, and electrical charge transport. In this article we provide a balanced assessment of the compromise between these losses and demonstrate that for a broad range of electrochemical reactors, the use of microfluidics can enhance the energy conversion efficiency. Moreover, we propose proven scale-up strategies of microelectrochemical reactors which could pave the way to the large scale implementation of energy microfluidic systems.
Electrochemically active carbon (EAC), Gallium (III) oxide (Ga2O3) and Bismuth (III) oxide (Bi2O3) are used as the negative additives of valve-regulated lead-acid (VRLA) batteries to prolong the cycle life of VRLA batteries under high-rate partial-state-of-charge (HRPSoC) conditions, and their effects on the cycle life of VRLA batteries are investigated. It is found that the addition of EAC in negative active material can restrain the sulfation of the negative plates and prolong the cycle performance of VRLA batteries under HRPSoC conditions. It is also observed that the addition of Ga2O3 or Bi2O3 in EAC can effectively increase the overpotential of hydrogen evolution on EAC electrodes, and decrease the evolution rate of hydrogen. An appropriate addition amount of Ga2O3 or Bi2O3 in the negative plates of VRLA batteries can decrease the cut-off charging voltage, increase the cut-off discharging voltage, and prolong the cycle life of VRLA batteries under HRPSoC conditions. The battery added with 0.5% EAC and 0.01% Ga2O3 in negative active material shows a lowest cut-off charging voltage and a highest cut-off discharging voltage under HRPSoC conditions, and its' cycle life reaches about 8100 cycles which is at least three times longer than that without Ga2O3.
Manual perineal protection (MPP) is an intrapartum intervention suggested to protect perineal integrity during childbirth. Proper execution of MPP is complex and evaluation of its true contribution is difficult in the clinical setting because of the large number of obstetric variables, some of which are hardly quantifiable. In this study we aimed to gather initial data on the forces executed by the accoucheur’s thumb, index and middle fingers during MPP at the time of fetal head expulsion, quantify the duration of the intervention and investigate the timely interaction of the different components of MPP.
Background Cognitive dysfunction is a key predictor of functional disability in schizophrenia. Davunetide (AL-108, NAP) is an intranasally administered peptide currently being developed for treatment of Alzheimer's disease and related disorders. This study investigates effects of davunetide on cognition in schizophrenia. Method Sixty-three subjects with schizophrenia received davunetide at one of two different doses (5, 30mg) or placebo for 12weeks in a multicenter, double-blind, parallel-group randomized clinical trial. The MATRICS Consensus Cognitive Battery (MCCB) assessed cognitive effects. The UCSD Performance-based Skills Assessment (UPSA) and the Schizophrenia Cognition Rating Scale (SCoRS) assessed functional capacity. Subjects continued their current antipsychotic treatment during the trial. Results There were no significant differences in MCCB change between davunetide and placebo over the three treatment arms (p=.45). Estimated effect-size (d) values were .34 and .21 favoring the 5 and 30mg doses vs. placebo, respectively. For UPSA, there was a significant main effect of treatment across study arms (p=.048). Between-group effect size (d) values were.74 and .48, favoring the 5 and 30mg doses, respectively. No significant effects were observed on the SCoRS or on symptom ratings. No significant side effects or adverse events were observed. Conclusion Davunetide was well tolerated. Effects of davunetide on MCCB-rated cognition were not significant relative to placebo. In contrast, a significant beneficial effect was detected for the UPSA. Based upon effect-size considerations, sample sizes of at least 45–50 subjects/group would be required to obtain significant effects on both MCCB and UPSA, providing guidance for continued clinical development in schizophrenia.
Reduced graphene oxide (rGO) was used to support Cu nanoparticles. As electro-active electrodes for supercapacitors composites of reduced graphene oxide/Cu nanoparticles (rGO/CuNPs) and polytyramine (PT) with good uniformity are prepared by electropolymerization. Composite of rGO/CuNPs–PT was synthesized by cyclic voltammetry (CV) methods and electrochemical properties of film were investigated by using electrochemical techniques. The results show that, the rGO/CuNPs–PT/G has better capacitance performance. This is mainly because of the really large surface area and the better electronic and ionic conductivity of rGO/CuNPs–PT/G, which lead to greater double-layer capacitance and faradic pseudo capacitance. Modified graphite electrodes (rGO/CuNPs–PT/G) were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) were employed. In comparison with a Cu–PT/G (Graphite), rGO/CuNPs–PT/G modified electrode shows a significantly higher response for methanol oxidation. A mechanism based on the electro-chemical generation of Cu(III) active sites and their subsequent consumptions by methanol have been discussed.
Most of the biomaterials used nowadays for the reconstruction of the spinal cord (SC) tissue after an injury, tested in animals, have obtained modest results. This work presents a study about the compatibility of two novel, non-biodegradable, semi-conductive materials, obtained by plasma polymerization: iodine-doped pyrrole (PPy/I) and pyrrole-polyethylene glycol (PPy/PEG). Both polymers, separately, were implanted in the SC tissue of rats after a transection. Prior to implantation, the elemental composition and the physico-chemical properties of polymers were studied by electron scanning microscopy, IR Spectroscopy and thermogravimetric analysis. We used adult female Long Evans rats, subjected to SC transection. Animals were randomized to be allocated in one of the treatment groups and were killed four weeks after the lesion for histology study. Results showed that both implants were integrated to the SC tissue, as inflammatory and gliotic responses, similar to those observed in the control group, and rejection of the implant, were not evident. Moreover, the immediate effect of PPy/I or PPy/PEG in the injured SC prevented secondary tissue destruction, as compared to non-implanted control animals. In conclusion, implants of semi-conductive polymers were well-tolerated and integrated favorably to SC tissue after transection
Under partial charge–discharge cycling conditions at a state of charge (SoC) of 50–70%, a greater effect on the suppression of the memory effect, which occurs in rechargeable alkaline batteries containing a Ni-electrode, was observed using conductive materials such as nano-sized Co(OH)2 and CoO powders in the Ni-electrode. The nano-sized Co(OH)2 powder, prepared by the reverse micelle method, consisted of approximately 15–60nm spherical-shaped particles. The Ni–Cd cells containing approximately 15- or 20-nm-sized Co(OH)2 powder and 18nm CoO powder in the Ni-electrode did not show any memory effect after a 150-cycle partial charge–discharge cycling test, and γ-NiOOH, which is mainly the origin of the memory effect, was not detected in the Ni-electrode, whereas the Ni–Cd cell containing the same content of 500nm Co(OH)2 powder and 18nm CoO in the Ni-electrode showed the memory effect. The nano-sized Co(OH)2 powder could be more homogeneously dispersed in the Ni-electrode when compared to the 500nm powders and might develop a superior electro-conductive network between the Ni(OH)2 particles.