batterydata/paper-abstracts huggingface dataset:
Direct membrane deposition (DMD) was recently introduced as a novel polymer electrolyte membrane fabrication method. Here, this approach is extended to fabricate 12 μm thin nanocomposite fuel cell membranes. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers are directly electrospun onto gas diffusion electrodes. By inkjet-printing Nafion ionomer dispersion into the pore space of PVDF-HFP nanofiber mats, composite membranes of 12 μm thickness were fabricated. At 120 °C and 35% relative humidity, stoichiometric 1.5/2.5 H2/air flow and atmospheric pressure, the power density of the DMD fuel cell (0.19 W cm-2), was about 1.7 times higher than that of the reference fuel cell (0.11 W cm-2) with Nafion HP membrane and identical catalyst. A lower ionic resistance and, especially at 120 °C, a reduced charge transfer resistance is found compared to the Nafion HP membrane. A 100 h accelerated stress test revealed a voltage decay of below 0.8 mV h-1, which is in the range of literature values for significantly thicker reinforced membranes. Finally, this novel fabrication approach enables new degrees of freedom in the design of complex composite membranes. The presented combination of scalable deposition techniques has the potential to simplify and thus reduce cost of composite membrane fabrication at a larger scale.
In the present work temperature dependence of heat capacity of Li4/3Ti5/3O4 has been measured for the first time in the range from 6 to 330K by precision adiabatic vacuum calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C ° p ( T ) , enthalpy H ° ( T ) − H ° ( 0 ) , entropy S ° ( T ) − S ° ( 0 ) and Gibbs function G ° ( T ) − H ° ( 0 ) , for the range from T →0 to 670K. Raman and IR investigations have also been performed. The high-temperature X-ray diffraction method was used for the determination of thermal expansion coefficients.
Lithium trifluoromethanesulfonate:polyethylene oxide (PEO) polymer electrolytes modified by 1,1,3,3,5,5-meso-hexaphenyl-2,2,4,4,6,6-meso-hexamethyl-6-pyrrole (C6P) and nanosize silica filler were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and electrochemical means. An increase in the lithium transference number is observed upon incorporation of even a small amount of C6P. Silica facilitates interchain ion hopping in polymer electrolytes and possibly introduces an additional interfacial ion-conduction path without decreasing t +. Stable solid electrolyte interphase resistance (SEI) was achieved in the polymer electrolytes containing calix[6]pyrrole and silica. It was found that lithium single-ion-conductive polymers with good electrochemical stability and ion transport properties have the potential for considerably boosting the performance of lithium/molybdenum oxysulfide all-solid-state thin film batteries.
As the popularity of renewable energy systems grows, small wind turbines are becoming a common choice for off-grid household power. However, the true benefits of such systems over the traditional internal combustion systems are unclear. This study employs a life-cycle assessment methodology in order to directly compare the environmental impacts, net-energy inputs, and life-cycle cost of two systems: a stand-alone small wind turbine system and a single-home diesel generator system. The primary focus for the investigation is the emission of greenhouse gases (GHG) including CO2, CH4, and N2O. These emissions are calculated over the life-cycle of the two systems which provide the same amount of energy to a small off-grid home over a twenty-year period. The results show a considerable environmental benefit for small-scale wind power. The wind generator system offered a 93% reduction of GHG emissions when compared to the diesel system. Furthermore, the diesel generator net-energy input was over 200 MW, while the wind system produced an electrical energy output greater than its net-energy input. Economically, the conclusions were less clear. The assumption was made that diesel fuel cost over the next twenty years was based on May 2008 prices, increasing only in proportion to inflation. As such, the net-present cost of the wind turbine system was 14% greater than the diesel system. However, a larger model wind turbine would likely benefit from the effects of the ‘economy of scale,’ producing superior results both economically and environmentally.
Li2ZnTi3O8 (LZTO) was synthesized by solid-state reaction using TiO2-anatase, Li2CO3, Zn(CH3COO)2·2H2O as raw materials. Three well-designed modified samples including LZTO-K (keqin black), LZTO-M (carbon microspheres) and LZTO-S (super-P) were prepared by extra adding carbon materials as loose and porous agent in the synthesis process without any crystal structure change. Among the all samples, LZTO-M exhibits excellent electrochemical performances in terms of high capacities (209.6, 187.2, 178.0, 161.8, 154.4 mAh g−1 at current densities of 0.1, 0.5, 1.0, 2.0, 3.0 A g−1, respectively) after 100 circulations and shows remarkable stable cycling performance, retaining capacity of 133.6 mAh g−1 compared with that (82.6 mAh g−1) of LZTO over 500 cycles at 3.0 A g−1. The utilization of carbon microspheres not only reduces particle size of LZTO-M and makes particles well-distributed, but also promotes loose structure with uniform porous and increases the surface area.
New emerging large scale battery market has demanded low cost and high power or energy density materials. Sodium (Na) is a promising candidate for an anode material because of its low cost and natural abundance. Also molybdenum disulfide (MoS2) is an attractive cathode material with layered structure. In this study a Na/MoS2 cell was assembled so as to evaluate its electrochemical properties as a rechargeable battery. In the first discharge Na/MoS2 cell showed two characteristic plateaus at 0.93V and 0.8V. Galvanostatic charge/discharge cycle was carried out in different voltage ranges according to the discharge depths (0.85V and 0.4V). The electrochemical behaviors of Na/MoS2 cells at each discharge depth were analyzed through characterization of the crystallographic changes by employing ex situ X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Finally, Na/MoS2 reaction mechanism was suggested.
A family of organophosphorus compounds including triphenyl phosphite (TPP), trimethyl phosphite (TMP), tris(2,2,2-trifluoroethyl) phosphite (TFEP), and tris(trimethylsilyl) phosphite (TMSP) is investigated as additives for the stabilization of high-voltage LiNi0.5Mn1.5O4 (LNMO) cathode-electrolyte interface. Our investigation reveals that the cycling performance of Li/LNMO half cells with the TMP, TFEP or TMSP additive is drastically improved at 60 °C compared to the baseline electrolyte. Among the various phosphite-based additives tested, TMSP additive enables facile Li ion transport at high C rates and significantly enhances the storage performance of the Li/LNMO cells at 60 °C. To understand the effects of the phosphite-based additives on electrolyte oxidative decomposition at high voltages, the surface chemistry of the cathode after precycling is investigated via ex-situ X-ray photoelectron spectroscopy (XPS). Additionally, the roles of phosphite-based additives to suppress LiPF6 hydrolysis and to remove HF are examined via 19F and 31P NMR spectroscopies.
A measurement protocol involving a handgrip dynamometer and surface electromyography (EMG) electrodes (n=4) placed on finger flexor and extensor muscles was used to assess the biomechanical effect of gloves on forearm muscles. The purpose of this study was to assess gloves with different EMG indices measuring muscle fatigue and muscle activation. Thirty subjects (15 males and 15 females) performed a 60s static fatigue handgrip contraction at 35% of their maximal voluntary contraction for each experimental condition (1. barehand; 2. moderately stiff glove; 3. very-stiff glove). Ten of these subjects performed the assessment twice to assess reliability. Only the EMG indices for the relative activation of forearm muscles showed any potential for glove assessment, the EMG fatigue indices showing poor sensitivity and reliability results. The results from extensor muscles were particularly interesting because they were more sensitive than flexor muscles to experimental conditions. Moreover, the EMG index representing the average of the two extensor muscles studied here was the only parameter that was gender-independent, an advantageous measurement characteristic if a test is to be developed for normalization purposes. However, the reliability of this index was unsatisfactory. More research is needed to refine this EMG protocol, considering that EMG measurements of the numerous and small forearm muscles are apparently difficult. Relevance to industry Gloves often impair hand performance and productivity so that the workers are less inclined to use them and consequently more prone to injury. To help glove manufacturers enhance their products, objective measures to assess hand performance when wearing gloves are required. A test involving EMG measures would give information on the internal loading of forearm muscles when different types of gloves are used.
To understand the toxicity of Pb-polluted shooting fields, oribatid mites Platynothrus peltifer were exposed to shooting field soils containing 47–2398 mg Pb/kg dry weight (DW) and having pHCaCl2
Lead (Pb) is ranked as the number two priority hazardous substance by the US EPA (Chen et al. 2002). Annual deposition of metallic lead at shooting ranges has reached 6000 tons in the Netherlands, Finland, Denmark, Canada, England and USA (Manninen and Tanskanen 1993; Scheuhammer and Norris 1995). In recent years, shooting ranges are under increasing scrutiny as a potentially significant source of lead contamination (Chen et al. 2002; Ming et al. 2012; Murray et al. 1997; Rooney et al. 1999).
A silicon/tin@amorphous carbon-graphite (Si/Sn@C-G) composite material was successfully prepared by a simple high energy ball milling and annealing process, exhibiting excellent electrochemical performance in lithium-ion batteries. Structural characterization showed that the phase separated Si/Sn mixture was coated by amorphous carbon and were highly dispersed into the graphitic sheets. As a result, the Si/Sn@C-G composite exhibited a high initial coulombic efficiency of 81.5% and a stable reversible capacity of 612.6 mAh g−1 even after 100 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy results indicated that the Sn acted as an active matrix and could obviously decrease the polarization resistance (Rp). And the ductile Sn could not only cushion the volumetric deformation of Si, but could also improve the Si dispersion. This work demonstrated a facile approach to synthesize highly stable Si/Sn@C-G composite in lithium-ions batteries.
Cell design and optimization of the components, including active materials and passive components, play an important role in constructing robust, high-performance rechargeable batteries. Seawater batteries, which utilize earth-abundant and natural seawater as the active material in an open-structured cathode, require a new platform for building and testing the cells other than typical Li-ion coin-type or pouch-type cells. Herein, we present new findings based on our optimized cell. Engineering the cathode components—improving the wettability of cathode current collector and seawater catholyte flow—improves the battery performance (voltage efficiency). Optimizing the cell component and design is the key to identifying the electrochemical processes and reactions of active materials. Hence, the outcome of this research can provide a systematic study of potentially active materials used in seawater batteries and their effectiveness on the electrochemical performance.
It was sometimes observed that the performance of a proton-exchange membrane fuel cell improved after the cell went through shutdown and restart cycles. Such a performance recovery led to a “saw-tooth” performance pattern when multiple shutdowns and restarts occurred during the endurance test of a fuel cell. The shutdowns included both planned shutdowns and unintended ones due to station trips or emergency stops (E-stops). The length of the shutdown periods ranged from a few minutes to several weeks. Although such a “saw-tooth” behavior could be attributed to multiple reasons such as: (1) catalyst surface oxidation state change; (2) catalyst surface cleansing; or (3) water management, we found that it was mainly related to water management in our cases after a systematic investigation employing both single cells and stacks.
Detecting tagged animals in coastal environments is often limited to stationary arrays of acoustic receivers that can decode transmissions from tags on animals. However, mobile autonomous platforms are becoming important tools that support the science of understanding biophysical relationships because they can concurrently detect tagged individuals and measure properties of their ocean habitat. To assess the effectiveness of these emerging platforms, proper validation and range detection studies are necessary. Here, we report on the deployment of a wave powered unmanned surface vessel, the Liquid Robotics Wave Glider SV3, equipped with a forward- and backward-facing acoustic receiver (VR2W) and transceiver (VR2Tx) at 4 m depth. Surveys were conducted around two stationary moorings equipped with receivers, transceivers or tags emitting signals with different power outputs.
The stability of various polymer binders was systematically investigated in the oxygen-rich environment required for the operation of Li–O2 batteries. Due to the coverage on air electrode surface by the discharge products and decomposition products of the electrolyte during the discharge process of Li–O2 batteries, the binder in the air electrode is hard to be detected making the evaluation of its stability problematic. Therefore, stability of the binder polymers against the reduced oxygen species generated during the discharge process was investigated by ball milling the polymers with KO2 and Li2O2, respectively. Most of the studied polymers are unstable under these conditions and their decomposition mechanisms are proposed according to the analyzed products. Polyethylene was found to exhibit excellent stability when exposed to superoxide and peroxide species and is suggested as a robust binder for air electrodes. In addition, the binding strength of the polymer significantly affects the discharge performance of Li–O2 batteries.
Composite electrodes for supercapacitors were prepared via electrochemical polymerization onto activated carbon. The capacitance properties were investigated using cyclic voltammetry (CV), AC impedance spectroscopy and charge–discharge tests. These electrodes show a specific capacitance of about 354Fg−1. This indicates that the in situ electro-polymerization of pyrrole onto carbon could improve the performance of carbon electrodes for use in supercapacitors.
This paper discusses variables and uncertainty associated with the measurement of ionic conductivity of heterogeneous solids. The conductivity data of heterogeneous solids of diverse chemistries have been analyzed. All these solids exhibit space charge and blocking effects. The coexistence of the two effects may lead to significant scatter and uncertainty in the measured values if the variables are not isolated and controlled.
Our prepared vacuum deposited silicon films on Ni and Cu substrates show excellent cycle performance opposing to the conventional silicon film having short cycle life. In this paper, the reasons for this long cycle behavior were studied by the measurements of scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electronic microscopy (TEM) and selected area electron diffraction (SAED). At first glance, it seemed that the vacuum deposited silicon films were amorphous from XRD. However, we found that the films consisted of nano-particles with polycrystalline structure. Large surface energy and specific volume of the nano-crystals kept the structure stable against collapsing during the expansion and shrinkage process under lithium insertion and extraction. Consequently, the vacuum deposited silicon films presented good cycling performance.
In this paper, a hybrid nanocomposite of cellulose fiber/multi-walled carbon nanotube (MWCNT)/reduced graphene oxide (rGO)/Cobalt oxide (Co3O4)/tin oxide (SnO2) is synthesized via a hydrothermal method for supercapacitor applications and characterized for their electrochemical performance and thermal stability. The morphology of the nanocomposites was characterized by using scanning electron microscope (SEM) and transmission electron microscope (TEM). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy were used to determine the chemical groups and crystal structure. Energy dispersive X-ray spectroscopy (EDX) confirmed the constitutional proportions of various elements in the composite. The electrode was fabricated from the nanocomposite and characterized by cyclic voltammetry (CV) that showed good cyclic stability with 88% capacitance retention after 1000 cycles and a capacitance of 215 F g−1 and 181 F g−1at a current density of 0.2 A g−1and 0.4 A g−1, respectively. The hybrid nanocomposite showed higher thermal stability than cellulose fiber/MWCNT and cellulose fiber/MWCNT/rGO composites. This simple, scalable and low-cost approach could open new opportunities for next-generation energy storage devices.
Mutations in the PARK7/DJ-1 gene are rare causes of autosomal-recessive hereditary Parkinson's disease. Loss-of-function mutations lead to the characteristic selective neurodegeneration of nigrostriatal dopaminergic neurons, which accounts for parkinsonian symptoms. Originally identified as an oncogene, DJ-1 is a ubiquitous redox-responsive cytoprotective protein with diverse functions. In addition to cell-autonomous neuroprotective roles, DJ-1 may act in a transcellular manner, being up-regulated in reactive astrocytes in chronic neurodegenerative diseases as well as in stroke. Thus, DJ-1, particularly in its oxidized form, has been recognized as a biomarker for cancer and neurodegenerative diseases. The crystal structure of DJ-1 has been solved, allowing detailed investigations of the redox-reactive center of DJ-1. Structure–function studies revealed that DJ-1 may become activated in the presence of reactive oxygen species, under conditions of oxidative stress, but also as part of physiological receptor-mediated signal transduction. DJ-1 regulates redox signaling kinase pathways and acts as a transcriptional regulator of antioxidative gene batteries. Therefore, DJ-1 is an important redox-reactive signaling intermediate controlling oxidative stress after ischemia, upon neuroinflammation, and during age-related neurodegenerative processes. Augmenting DJ-1 activity might provide novel approaches to treating chronic neurodegenerative illnesses such as Parkinson's disease and acute damage such as stroke.
There has been increasing interest in developing lithium-ion electrolytes that possess enhanced safety characteristics, while still able to provide the desired stability and performance. Toward this end, our efforts have been focused on the development of lithium-ion electrolytes which contain partially and fully fluorinated carbonate solvents. The advantage of using such solvents is that they possess the requisite stability demonstrated by the hydrocarbon-based carbonates, while also possessing more desirable physical properties imparted by the presence of the fluorine substituents, such as lower melting points, increased stability toward oxidation, and favorable SEI film forming characteristics on carbon. Specifically, we have demonstrated the beneficial effect of electrolytes which contain the following fluorinated carbonate-based solvents: methyl-2,2,2-trifluoroethyl carbonate (MTFEC), ethyl-2,2,2-trifluoroethyl carbonate (ETFEC), propyl-2,2,2-trifluoroethyl carbonate (PTFEC), methyl-2,2,2,2′,2′,2′-hexafluoro-i-propyl carbonate (MHFPC), ethyl-2,2,2,2′,2′,2′-hexafluoro-i-propyl carbonate (EHFPC), and di-2,2,2-trifluoroethyl carbonate (DTFEC). These solvents have been incorporated into multi-component ternary and quaternary carbonate-based electrolytes and evaluated in lithium–carbon and carbon–LiNi0.8Co0.2O2 cells (equipped with lithium reference electrodes). In addition to determining the charge/discharge behavior of these cells, a number of electrochemical techniques were employed (i.e. Tafel polarization measurements, linear polarization measurements, and electrochemical impedance spectroscopy (EIS)) to further characterize the performance of these electrolytes, including the SEI formation characteristics and lithium intercalation/de-intercalation kinetics.
Amorphous Sn–Ca alloys were synthesized by solution technique using NaBH4 as the reducing agent. The particles are found to be homogeneous with size ∼4μm. The alloys were tested using Li metal as counter electrode. The capacity has been found to be 400mAh/g and 62% of it was retained after 70 charge–discharge cycles. The ex situ XRD technique was used to illustrate the progress of Li intercalation. Cyclic voltammograms show that the two peaks located at 0.6 and 0.2V, respectively, correspond to the charge and discharge plateaus. The observation of voltage plateau at about 1.0V confirms the formation of solid electrolyte interface (SEI) on the surface of the anode. The intercalation of Li is through the formation Li5Sn2 phase, which was confirmed by HRTEM.
Graphene based materials coupled with transition metal oxides are promising electrode materials in asymmetric supercapacitors owing to their unique properties which include high surface area, good chemical stability, electrical conductivity, abundance, and lower cost profile over time. In this paper a composite material consisting of graphene oxide exfoliated with microwave radiation (mw rGO), and manganosite (MnO) is synthesised in order to explore their potential as an electrode material. The composite material was characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to explore the process occurring at the electrode/electrolyte interface. Long term cyclability and stability were investigated using galvanostatic charge/discharge testing. From the resulting analysis, an asymmetric supercapacitor was constructed with the best composite containing 90% MnO–10% mw rGO (w/w). The device exhibited a capacitance of 0.11F/cm2 (51.5F/g by mass) and excellent capacity retention of 82% after 15,000 cycles at a current density of 0.5A/g.
A practical approach for controlling the morphology and electrochemical properties of electroactive materials is proposed. In this study, manganese oxide films were galvanostatically deposited in the presence of a small amount of carbon nanotube (CNT). The resulting film cannot be considered as a CNT-based nanocomposite, as no CNT is detected by electron microscopy. However, the manganese oxide electrodeposited delivers an excellent pseudo-capacitive behavior to be used as a superior supercapacitor. The samples prepared by applying a current density of 3.0 mA cm−2 showed a specific capacitance of 280 F g−1. As it seems that the capacitance of this electrode is related to the chemisorption of the alkali cation, an extremely high specific capacitance of 434 F g−1 was achieved in a saturated medium of Li electrolyte. This high specific capacitance can be attributed to a bulk process. The presence of carbon nanotubes results in the formation of nanostructured films which provide a better accessibility for capacitive behavior. Although the exact mechanism for this phenomenon is still vague, the presence of carbon nanotubes (probably as a solid charge carrier) close to the electrode surface is apparently responsible for a different pathway for the electrodeposition process.