batterydata/paper-abstracts huggingface dataset:
Quadriceps femoris muscle (QFM) weakness is a feature of knee osteoarthritis (OA) and exercise programs that strengthen this muscle group can improve function, disability and pain. Traditional supervised resistance exercise is however resource intensive and dependent on good adherence which can be challenging to achieve in patients with significant knee OA. Because of the limitations of traditional exercise programs, interest has been shown in the use of neuromuscular electrical stimulation (NMES) to strengthen the QFM. We conducted a single-blind, prospective randomized controlled study to compare the effects of home-based resistance training (RT) and NMES on patients with moderate to severe knee OA.
Background This study compares the mental and physical workload of laparoscopic and robotic technique while performing simulated surgical tasks in a laboratory setting. Materials and methods Ten volunteer surgeons performed two tasks in a laparoscopic trainer using laparoscopic (LAP) and robotic (ROB) techniques. Outcome measures included: Task time, task-error, vertical/horizontal arm displacement, percent maximum electromyographic signal from the thenar, forearm flexor, and deltoid muscle compartments, skin conductance, and perceived difficulty and discomfort levels. A two-way repeated-measures ANOVA compared surgical technique and laparoscopic experience level (E = expert, N = novice). Results For the simple task, ROB technique was slower and had higher errors, and the surgeon’s arm was more elevated. For the complex task, ROB electromyographic signal was lower. Stress was lower in both tasks for ROB, but the decrease was not statistically significant. Conclusions Robotic technique appears slower and less precise than laparoscopic technique for simple tasks, but equally fast and possibly less stressful for complex tasks. Previous laparoscopic experience has a complex influence on the physical and mental adaptation to robotic surgery.
Extensive research has revealed that the ventral visual stream hierarchically builds a robust representation for supporting visual object categorization tasks. We systematically explored the ability of multiple ventral visual areas to support a variety of 'category-orthogonal' object properties such as position, size and pose. For complex naturalistic stimuli, we found that the inferior temporal (IT) population encodes all measured category-orthogonal object properties, including those properties often considered to be low-level features (for example, position), more explicitly than earlier ventral stream areas. We also found that the IT population better predicts human performance patterns across properties. A hierarchical neural network model based on simple computational principles generates these same cross-area patterns of information. Taken together, our empirical results support the hypothesis that all behaviorally relevant object properties are extracted in concert up the ventral visual hierarchy, and our computational model explains how that hierarchy might be built.
Chemical delithiation is used to prepare bulk quantities of amorphous silicon powder from lithium-silicon compounds. The amorphous silicon materials formed are air and water stable and are found to have layered structures. When cycled in Li-ion half cells, coatings containing layered amorphous silicon are found to have significantly lower volume expansion during lithiation and improved cycling characteristics compared to that of bulk crystalline Si. We suggest chemical delithiation as a convenient method to synthesize bulk quantities of Si powders containing self-organized void spaces that can accommodate volume expansion during lithiation.
A new type of Prussian blue analog, sodium titanium hexacyanoferrate, has been synthesized with good electrochemical performance using an environmentally friendly, solution precipitation method. Because of the hydrolysis reaction of titanium, it has been proved that the synthetic reaction is sensitive to heat, and the best reaction temperature is 60 °C. The resulting particles belong to a well-defined open framework with cubic structure. Because of the two sodium storage sites provided by the low-spin [Fe(CN)6]4−/3− couple and high-spin Ti3+/4+ couple, sodium titanium hexacyanoferrate exhibits a high specific capacity over 90 mAh g−1, and two pairs of clear charge/discharge platforms at 3.0 V/2.6 V and 3.4 V/3.2 V, respectively. The results show that this material can be applied as a low-cost cathode electrode with good electrochemical performance for sodium ion batteries.
The bimetallic nanoparticles of Ni and Fe co-modified reduced graphene oxide (rGO) aerogel were prepared by a fishnet-like one-step hydrothermal method, and the nitrogen atoms were successfully doped to the carbon layers with heat treatment of ammonia. By SEM and TEM, it could be observed that the rGO aerogel is a porous structure with particles of metal uniformly distributed on carbon sheets, and the sizes of nanoparticles were approximately 20–100 nm. The Raman results indicated that the GO was successfully reduced by ethylene glycol in the hydrothermal process. XPS results showed that nitrogen was introduced to rGO nanosheets, and Ni–Fe–NrGO possessed the higher contents of pyridinic N and graphitic N. XRD results suggested the Ni3Fe phase exists in the Ni–Fe–NrGO, which was consistent with EDX results. The electro-catalyzed oxygen reduction reaction (ORR) properties were evaluated by a rotating disk electrode (RDE). The Ni–Fe–NrGO sample showed synergistic effect with a relatively higher onset potential and diffusion-limiting current density of approximately 4.01 mA cm−2, with an electron transfer number close to 4, and exhibited an excellent ORR performance compared with the commercial Pt/C electro-catalyst.
This paper presents the use of nanometer scale resolution X-ray computed tomography (nano-CT) in the three-dimensional (3D) imaging of a Li-ion battery cathode, including the separate volumes of active material, binder plus conductive additive, and pore. The different high and low atomic number (Z) materials are distinguished by sequentially imaging the lithium cobalt oxide electrode in absorption and then Zernike phase contrast modes. Morphological parameters of the active material and the additives are extracted from the 3D reconstructions, including the distribution of contact areas between the additives and the active material. This method could provide a better understanding of the electric current distribution and structural integrity of battery electrodes, as well as provide detailed geometries for computational models.
Silicon as a promising candidate for the next-generation high-capacity lithium-ion battery anode is characterized by outstanding capacity, high abundance, low operational voltage, and environmental benignity. However, large volume changes during Si lithiation and de-lithiation can seriously impair its long-term cyclability. Although extensive research efforts have been made to improve the electrochemical performance of Si-based anodes, there is a lack of efficient fabrication methods that are low cost, scalable, and self-assembled. In this report, co-axial fibrous silicon asymmetric membrane has been synthesized using a scalable and straightforward phase inversion method combined with dip coating as inspired by the hollow fiber membrane technology that has been successfully commercialized over the last decades to provide billions of gallons of purified drinking water worldwide. We demonstrate that ~ 90% initial capacity of co-axial fibrous Si asymmetric membrane electrode can be maintained after 300 cycles applying a current density of 400 mA g−1. The diameter of fibers, size of silicon particles, type of polymers, and exterior coating have been identified as critical factors that can influence the electrode stability, initial capacity, and rate performance. Much enhanced electrochemical performance can be harvested from a sample that has thinner fiber diameter, smaller silicon particle, lower silicon content, and porous carbon coating. This efficient and scalable approach to prepare high-capacity silicon-based anode with outstanding cyclability is fully compatible with industrial roll-to-roll processing technology, thus bearing a great potential for its future commercialization.
Through facile one step sol-gel method, Li2MnSiO4-based cathode materials have been successfully synthesized and co-modified with carbon and MoO2 coating. The phase compositions and morphology of the as-prepared products have been characterized by XRD, SEM and TEM. The physical characterization indicates the introduced MoO2 exists on the particle surface of orthorhombic Li2MnSiO4, forming a hybrid coating layer with amorphous carbon. Meanwhile, the addition of MoO2 improves the dispersion of particle size distribution. Therefore, the electrochemical performance of the pristine Li2MnSiO4/C has been significantly improved after coating MoO2, especially in the case of 1wt% MoO2 component. The optimal as-prepared sample exhibits a reversible capacity of 184.9mAh/g at 0.1C and maintains 127.5mAh/g even at a high rate of 1C. The excellent rate performance can be attributed to reduced interfacial resistance and enhanced lithium ion diffusion coefficient.
This work attempts to substitute V of Li3V2(PO4)3 (LVP) by the doped ion of manganese with the valence of +2, +3 and +4 and various ionic radiuses. A series of Mn-doped LVP composites (LVMP) by different manganese sources are synthesized by sol–gel and heat-treatment. Manganese ion with the valences of +3 and +4 have been successfully inserted into the lattice of Li3V2(PO4)3 to form a stable solid-solution even the substitution mole ratio reaches to 0.2, except the impurity phase of LiMnPO4 in LVMP when manganese ions with the valence of +2 involve in the substitution. Mn2+ exists in all three samples as expected, but the main valence state of Mn ions in LVMP-A, LVMP-B and LVMP-C are Mn4+, Mn3+ and Mn2+, respectively. LVMP-B (MnOOH as dopant) delivers the highest capacity of 137 mAh g−1, than LVMP-A (MnO2 as dopant) 125 mAh g−1 and LVMP-C (Mn3O4 as dopant) 123 mAh g−1. LVMP-B shows the best cycle performance, remaining 98% of the initial capacity after 50 cycles in range 3.0–4.3 V. Mn source of MnOOH properly substituted the structure of LVP enhances the lithium diffusion ability and stability of LVP during charge/discharge.
As Arnold Magnetic Technologies focuses its attention on rare earth metal elements, Liz Nickels looks at how the growing market for green energy has led companies in the West to consider restarting the extraction and manufacture of these strategically important materials…
A 16kWh power storage system applying Li-ion batteries has been jointly developed by Kyushu Electric and Mitsubishi Heavy Industries. The system comprises a Li-ion battery pack, an inverter and a battery protection system. Four cells, each with a capacity of 270Wh, are connected in a series to form a single 1.1kWh module battery. The Li-ion battery pack is made up of a series of 15 such module batteries. A 270Wh cell, in which Li–manganese oxide is used for the cathode and graphite for the anode, can expect to perform 3500 lifecycles during operating conditions of the rated 70% DOD. Even though power loss in the inverter and battery protection system must be further reduced, satisfactory response was found both in the batteries and inverter control, leading to the creation of a practical power storage system applying Li-ion batteries.
It is well established that lack of both electric supply capacity and reliability weaken the Nigerian economy. Recently, the reduction in solar photovoltaic (PV) costs along with the technical potential to couple PV to hybrid battery and diesel generators provides Nigerian businesses with an opportunity to reduce operating costs while defecting from the grid. This study investigates the potential of using off-grid hybrid energy systems for private industries within and near Lagos state currently with relatively high daily electricity demands that are met with supply through captive diesel generation. The results based on simulations of six industry sector load profiles developed from surveys found solar PV and diesel hybrid energy systems are economically viable for a wide array of industries in the Nigerian private sector including real estate, education, banking, automobile, hospitality and production. Five of the six sectors had discounted payback times for the systems under a year and ROIs >100%. The results established that the levelized cost of electricity is lower for every sector analysed with inclusion of solar PV, lower still with coupling of batteries and more reliable than the current grid-provided electricity. Nigeria as a whole will also benefit from widespread adoption of solar hybrid systems, as it will assist the balance of trade by reducing refined petroleum imports. In conclusion, the results of this study make it clear that every scale of Nigerian businesses could increase profitability with the use of solar hybrid systems.
A new approach has been designed to convert typical Stöber silica spheres to Zn2Ti3O8 (ZTO) hollow spheres with different shell thicknesses as anode materials for Lithium ion batteries. The morphologies, structures and synthesis process of ZTO hollow spheres are systematically investigated. X-ray diffraction (XRD) analysis shows that the good ZTO crystal is formed after being sintered at 500°C for 2h. The galvanostatic cycle tests exhibit excellent cycling stability, reversibility and low voltage. At a current density of 200mAg−1, the discharge specific capacities of 186.2mAhg−1, 173.6mAhg−1 and 169.9mAhg−1 have been achieved after 100 cycles, 200 cycles and 300 cycles, respectively. The superior electrochemical performance could be attributed to the hollow structure and characteristics of ZTO crystals. Cyclic voltammetry (CV) curves show symmetrical and stable redox peaks at 1.1V and 1.5V for ZTO hollow spheres after the first cycle. Electrochemical impedance spectroscopy (EIS) measurement analysis also indicates that ZTO hollow spheres as anode materials for LIBs have excellent electrochemical performance.
Focused ion beam and scanning electron microscopy tomography (FIB-SEMt) is commonly used to extract reactant transport relevant parameters from nano-porous materials in energy applications, such as fuel cells or batteries. Here we present an approach to virtually model the errors in FIB-SEMt which are caused by the FIB cutting distance. The errors are evaluated in terms of connectivity, solid volume fraction (SVF), conductivity, diffusivity, as well as mean grain and pore sizes. For state-of-the-art FIB-SEMt experiments, where a hydrogen fuel cell catalyst layer with 60 nm mean grain size and 40% SVF is sectioned with a cutting distance of 15 nm, the error in our simulation ranges up to 51% (conductivity), whereas other parameters remain largely unaffected (Laplace diffusivity, 4%). We further present a method, employing virtual coarsening and back interpolation, to reduce FIB cutting distance errors in all investigated parameters. Both error evaluation and correction are applicable to sphere based porous materials with relevance for the energy conversion and storage sector such as polymer electrolyte membrane fuel cell catalyst layer (PEMFC CL), battery carbon binder domain (CBD) or supercapacitor electrodes.
Niobium pentoxide, Nb2O5, is an intercalation-type material with a high theoretical capacity of ∼404 mAh g−1 for Li-ion batteries. However, electrochemical properties of Nb2O5 largely depend on its various polymorphs with different crystal structures, and their low electrical conductivity acts as the main obstacle. Here, we report high-temperature calcined monoclinic Nb2O5 and semiconducting NbO2 composite as a high-power anode material. Monoclinic Nb2O5 itself as a main active material shows a high capacity of ∼280 mAh g−1, and NbO2 with a small band gap of ∼0.5 eV not only improves electrical conductivity but also gives a capacity of ∼110 mAh g−1. To have a synergic effect of these two materials, the Nb2O5/NbO2 composite is prepared via simple post-calcination of as-prepared Nb2O5 under a reduction atmosphere. It shows a discharge capacity of ∼214 mAh g−1 at 0.05 C, a high initial Coulombic efficiency of 94.7%, a superior rate capability of ∼40 mAh g−1 at 100 C, and a robust cycle performance of 81% retention over 900 cycles.
The compatibility with graphitic anode has been one key problem in developing flame-retarding additives for lithium ion batteries. To understand the interactions between flame-retarding additives and graphitic anode, two phosphonate esters (dimethyl methylphosphonate DMMP and diethyl ethylphosphonate DEEP) are selected and characterized as flame retardant addtives. DEEP is reported as a flame-retarding additive for the first time. Their interactions with graphite anode are characterized via current-static charge–discharge, ex-situ XRD, FE-SEM and AC impedance. The results reveal that the two phosphonate esters demonstrate different reaction mechanisms with graphitic anode, which result in different anode compatibility. These findings may be useful for designing better flame-retarding additives for lithium ion batteries.
Commercially important, high-voltage, lithium cathodes, such as LiCoO2 and LiMn2O4 have been synthesized from nitrates, following the ‘soft-chemistry’ approach using starch as the combustion-assisting component. The minimum temperature required for phase formation and the degree of crystallinity has been evaluated from thermal studies and X-ray diffraction analysis, respectively. The starch-assisted combustion (SAC) method produces mono-dispersed powders of grain size below 1.5μm as observed from scanning electron microscopy and particle-size analysis. The electrochemical activity of the synthesized oxide powders has been examined via cyclic voltammetric and charge–discharge studies using lithium coin cells. Cyclic voltammetric data shows excellent reversibility with respect to Li+ and confirms the effect of crystallinity of the compounds on the electrochemical performance of the cathode materials. The electrochemical stability and performance of the cathodes over 30cycles have been demonstrated with a capacity fade of <10% of the initial capacity. The simplicity and flexibility of this approach towards the synthesis of various other cathode materials is also discussed.
Alkali metal ion intercalation into layered transition-metal dichalcogenide structures is a promising approach to make next generation rechargeable batteries for energy storage. It has been noted that the number of Na-ions which can be reversibly intercalated and extracted per MoS2 is limited, and the chemical and electrochemical processes/mechanisms remain largely unknown, especially for nano-sized materials. Here, sodiation of MoS2 nanosheets are studied by in-situ electron diffraction and the phase transformations in sodiation are identified with the aid of DFT calculations to reveal the reaction mechanism. Several thermodynamically stable/metastable structures are identified in the sodiation pathway of MoS2 nanosheets, previously unnoticed in bulk MoS2. The gradual reduction of Mo4+ upon Na-ion intercalation leads to a transition of the Mo-S polyhedron from a trigonal prism to an octahedron around 0.375 Na per MoS2 inserted (i.e. Na0.375MoS2). When the intercalated Na-content is larger than 1.75 per MoS2 structural unit (i.e. Na1.75MoS2), the MoS2 layered structure collapses and the intercalation reaction is replaced by an irreversible conversion reaction with the formation of Na2S and metal Mo nanoparticles. The calculated sodiation pathways reproduce the experimental sodiation voltages. The current observations provide useful insights in developing sodium-ion batteries with high cycling stability.
Impedance measurements of galvanostatically synthesized polypyrrole films using different polymerization charges, are reported at several stages of oxidation and analyzed in terms of distributed impedance models (transmission lines). Different physical mechanisms involved in the capacitive response observed at low frequencies are described in terms of Cole–Cole relaxation functions associated to ionic diffusion and charge storage processes with a distribution of diffusion lengths. The film thickness (polymerization charge) modifies the characteristic frequency of the observed relaxation, which varies heavily from 1 to 100 mHz, while the large specific capacitance (100–200 F cm−3) is found to be independent of the film size. A transition between two types of deposition mechanism from 3D nucleation and growth to 1D transversal growth after nuclei overlapping, explains the change of behavior of the relaxation characteristic frequency observed at Q≈60 mC cm−2. The value of this frequency at the transition point, where the diffusion length should be of the order of the film thickness, indicates that the diffusion coefficient D lies within the range 0.5–1.0×10−12 cm2 s−1, which is a more realistic value than those obtained by previous analyses.
A kind of closed-microporous hybrid with poly(acrylic acid)-poly(ethylene glycol)-polypyrrole (PAA-PEG-PPy) was synthesized template-free by in situ polymerization and micro-phase separation of PPy in PAA-PEG gel. This novel structure hybrid was used as a matrix in preparing polymer gel electrolytes for quasi-solid-state dye-sensitized solar cells (QS-DSSC). It shows high liquid electrolyte absorbency and salt tolerance, which are benefits for improving photovoltaic performance of QS-DSSC.
Here, we have designed and successfully fabricated an interwoven nanocable architecture constructed by V2O5 nanosheets encapsulated within multi-graphitic nanotubes as a novel high performance flexible cathode for Li ion batteries. Such an integrated electrode designed via the multiscale system exhibits ultrafast and stable Li ion storage performance, with a capacity higher than 90 mA h g−1 even at 100 C and only 0.04% capacity decay per cycle over 200 cycles. To the best of our knowledge, this is the first example of the facile synthesis of flexible V2O5 encapsulated into carbon nanotube positive electrodes and the successful demonstration of a flexible full cell showing surprisingly consistent cycling stability and excellent mechanical properties with V2O5@G as cathodes and their allotrope as anodes. Remarkably, an energy density of ca. 360 W h kg−1 at a power rate of 15.2 kW kg−1 is achieved, which belongs to one of the best results reported so far on V2O5-based electrode materials. Coupled with a simple and scalable production protocol, the strategies are highly promising for both novel cathode exploration and for the practical fabrication and application of flexible energy storage devices.
The genotoxic potential of pyrroloquinoline quinone (PQQ) disodium salt (BioPQQ™) was evaluated in a battery of genotoxicity tests. The results of the bacterial mutation assay (Ames test) were negative. Weak positive results were obtained in 2 separate in vitro chromosomal aberration test in Chinese hamster lung (CHL) fibroblasts. Upon testing in an in vitro chromosomal aberration test in human peripheral blood lymphocytes, no genotoxic activity of PQQ was noted. In the in vivo micronucleus assay in mice, PQQ at doses up to 2000mg/kg body weight demonstrated that no genotoxic effects are expressed in vivo in bone marrow erythrocytes. The weak responses in the in vitro test CHL cells were considered of little relevance under conditions of likely human exposure. PQQ disodium was concluded to have no genotoxic activity in vivo.