batterydata/paper-abstracts huggingface dataset:
To study the effect of different polymer binders on the electrochemical performance of tin electrodes for rechargeable lithium-ion batteries, poly(vinylidene fluoride) (PVDF), conventional polyimide (PI-OB), and synthesized polyimide containing amino benzoquinone (PI-AQOB) were used as the polymer binders for electrodes consisting of commercial powdered Sn particles and Super P. PI-AQOB was converted from polyamic acid (PA-AQOB) synthesized from 2,5-bis(4,4’-oxydianiline)-1,4-benzoquinone (AQODA) and 4,4’-biphthalic dianhydride (BPDA) by condensation polymerization and characterized by Fourier-transform infrared analysis. Compared to the electrode employing the traditional PVDF binder, those with the PI-AQOB binder exhibited significantly enhanced electrochemical performance in terms of rate capability, specific capacity, and cycling behavior. PI-AQOB provided a high initial lithiation capacity of 1529 mAh/g at a current density of 50mA/g. After 50 cycles, the PI-AQOB electrode maintained a higher specific capacity of 332 mAh/g than the Sn/PVDF electrode (only 65 mAh/g at a current density of 200mA/g). Furthermore, the Sn/PI-AQOB electrode exhibited good volume restoration compared to the electrodes with Sn/PVDF and Sn/PI, as indicated by scanning electron microscopic analysis. The PI-AQOB binder increased the mechanical and adhesive strength of the electrode by suppressing pulverization of the Sn anode during expansion/contraction of Sn particles in the lithiation/delithiation process.
Silicon and germanium are both recognized as a promising anode material for high-energy lithium-ion batteries. Si is best known for its superior energy storage capacity, while Ge exhibits better rate capability and cycleability. To better understand the underlying reasons behind their lithiation behavior differences, particularly the enhanced Li transport in Ge, we examine and compare Li-host lattice interactions and dynamics using density functional theory calculations. At the onset of lithiation, an isolated Li interstitial is found to form polar covalent bonds with four nearest host atoms, while the degree of covalency is noticeably greater for Li–Si than Li–Ge bonds. The relatively stronger Li–Si interaction, along with the stiffer Si lattice tend to be responsible for the suppressed Li mobility (D Li = 10−13 cm2 s−1) in c-Si, as compared to the c-Ge case (D Li = 10−11 cm2 s−1). With continued lithiation, D Li in a-Li x Si increases significantly from 10−12 to 10−7 cm2 s−1 (x = 0.14–3.57); contrarily, D Li in a-Li x Ge is around 10−7 cm2 s−1 and less concentration dependent. Our analysis shows that the rapid Li diffusion in a-Li x Ge is directly related to the facile atomic rearrangements of host Ge atoms even at the early stages of lithiation.
This paper proposes an improved interleaved voltage measurement method for battery packs in electric vehicles, which can distinguish between the sensor fault and cell fault without hardware or software redundancy. The coprime constraint in the basic interleaved measurement method is revisited with a new proof, and a graphical interpretation is introduced to visualize the constraint. Based on that, an improved measurement topology is developed to remove the coprime constraint which enables broader application. Moreover, the hardware implementation of the improved method is discussed based on cost and circuit design. The associated improvement in noise performance is mathematically formulated, and the noise limit and trend of the interleaved measurement method are derived. Simulation results match the noise analysis and experiments validate the broader application of the improved method.
Commercial NMC cells of 18650-type based on a Li x (Ni0.5Mn0.3Co0.2)O2 cathode and a graphitic anode were studied in situ using a combination of high-resolution monochromatic neutron powder diffraction and electrochemical analysis. The structural changes of the electrode materials during cell charge/discharge have been determined using Rietveld refinement and single profile decomposition techniques. A transformation of the graphitic anode to LiC12 and LiC6 through the formation of higher ordered lithium intercalated carbons was observed. A different behavior of electrochemically-driven lattice distortion was observed for NMC material in comparison to Li x CoO2 and its influence on the overall cell performance has been discussed in brief. Detailed analysis of the structural changes in the Li x (Ni0.5Mn0.3Co0.2)O2 cathode material revealed reversible Li/Ni cation mixing (5.6(8)%), which is state-of-charge independent below 1600 mAh and vanishing above 1800 mAh (∼0.8Q max).
Data collected on a cruise in January 2008, using a laser optical plankton counter, conductivity–temperature–depth sensors, and a lowered acoustic Doppler current profiler, was used to study the mesoscale distribution and advection of overwintering Calanus finmarchicus in its deep water winter habitat off the shelf of northern Norway. The overwintering animals were generally located immediately below the Atlantic Water (AW) in Arctic Intermediate Water (AIW), in the 600–1200m depth range. The depth of the interface between AW and AIW varied considerably in the area and this was clearly reflected in the C. finmarchicus distribution. Maximum abundance varied from about 80indm−3 to more than 200indm−3 at the different stations. Current measurements showed the richness of mesoscazle eddies, with speeds exceeding 70cms−1 at the surface and rapidly decreasing with depth. In the main overwintering layer the eddy features were also clearly seen, but with speeds generally below 20cms−1. C. finmarchicus were found in the whole survey area, but they were not homogeneously distributed. Advection of the copepods resulted in relatively high local rates of change in overwintering C. finmarchicus abundance with mean value of 8% per day in the area. It is clear that mesoscale physical processes greatly contribute to the variability in the abundance of overwintering C. finmarchicus off the shelf of northern Norway. The collected data are also a valuable addition to the generally sparse datasets on the C. finmarchicus winter distribution and the role of the Lofoten basin in the large scale system is also discussed.
Transition metal sulfides are promising high-capacity anode materials for sodium ion batteries in terms of the conversion reaction with multiple electron transfers. Nonetheless, some inherent challenges such as sluggish sodium ion diffusion kinetics, large volume change and poor cycle stability limit their implementation. Addressing these issues necessitates a comprehensive understanding on the complex sodium ion storage mechanism especially at the initial cycle. Here, taking nickel subsulfide as a model material, we reveal the complicated conversion reaction mechanism upon the first cycle by combining in operando 2D transmission X-ray microscopy with X-ray absorption spectroscopy, ex-situ 3D nano-tomography, high-energy X-ray diffraction and electrochemical impedance spectroscopy. This study demonstrates that the microstructure evolution, inherent slow sodium ion diffusion kinetics, and slow ion mobility at the two-phase interface contribute to the high irreversible capacity upon the first cycle. Such understandings are critical for developing the conversion reaction materials with the desired electrochemical activity and stability.
The amorphous GeO x (x <1) was synthesized and investigated its suitability as a Na-ion battery anode. GeO x was synthesized by oxidizing Zintl-phase NaGe with isopropyl alcohol at room temperature. The amorphous GeO x showed good electrochemical Na storage as an anode for Na-ion batteries, with first reversible capacity of 342mAhg−1, high power of 237mAhg−1 (6Ag−1), and cycle performance, retaining a capacity of 216mAhg−1 after 40 cycles.
In this work, we report a novel cathode composed of three-dimensional intersected graphene nanoribbons skeleton decorated with RuO2 catalyst, where graphene nanoribbons are obtained by unzipping multi-walled carbon nanotubes. The graphene nanoribbons framework exhibits a three-dimensional intersected structure and a large specific surface area, leading to a higher capacity than multi-walled carbon nanotubes. The RuO2 introduced via a facile dropping method enhances the oxygen evolution reaction kinetics and obviously reduces the charge overpotential. More importantly, the Li–O2 battery with RuO2 decorated graphene nanoribbons cathode presents an excellent cycling stability of 424cycles at a curtailed capacity of 1000 mAh g−1, which can be attributed to the synergistic effect between the intersected band-like graphene and highly effective RuO2 particles. The Li2O2 deposited on graphene nanoribbons shows a totally different surface morphology compared with that on multi-walled carbon nanotubes due to the different structures of carbon substrates. This work provides a promising design of highly efficient air electrodes for high-performance Li–O2 batteries.
We report a novel anode consisting of detonation nanodiamond, SiO x nanoparticals and carbon nanosheets, to achieve high performance lithium-ion batteries. In the process of charge and discharge, the lithium ion batteries using the prepared nanocomposite anode show remarkable capacity performance with a specific capacity of 1182 mA h g−1 at a constant current of 100 mA g−1 after 100 cycles. With further increasing the current to 1000 mA g−1, a high specific capacity of 622 mA h g−1 can be realized after 750 cycles, indicating a superior long-term cycle stability. The improvement of cycle stability and specific capacity can be attributed to the introduction of nanodiamond to form an effective buffer structure and efficient Li+ transport pathway.
Ultra-thin silver electrodes for high power density pulse batteries are prepared by anodic oxidation and cathodic reduction of thin silver foils in 0.1mol/l HCl aqueous solution. The active layer thus formed has a porosity about 65%. The thickness of the active layer can be controlled by the charge passed in oxidation. Typically, silver foils 50μm thick are used as the raw material and finished in 80μm electrodes with nominal capacity 14C/cm2 on each side. These electrodes can be charged and discharged at very high rates (typically 10C charge and 102 C discharge) with about 90% utilization of the active material. Potential valleys, most possibly due to the resistive Ag2O, are observed on both steady-state and pulse discharges. To prevent the potential valleys, which are most annoying to pulse applications, charging is suggested to be confined within the low potential plateau region.
A systematic investigation has been carried out on the influence of the acid leaching process parameters on the simultaneous metal recovery (Zn and Mn) from the electrode paste of spent alkaline Zn–MnO2 and spent Zn–C batteries. By introducing a reducing agent namely 30% H2O2 in the H2SO4 leaching solution the extraction efficiency for Mn was increased from 43.5% (no addition of H2O2) up to 97.54% (50% excess H2O2 in comparison with the required stoichiometric amount of H2O2). This H2O2 addition proved to have no influence on Zn extraction efficiency which kept constant at a high level (∼98.4%). A less important influence has been noticed for the molar concentration of H2SO4 in the leaching solution. In the range 0.5 M up to 2 M molar concentration of H2SO4 the extraction efficiency was increased from 78.2% up to 98.4% for Zn and from 63.1% up to 97.2% for Mn. Leaching time up to 60 min proved to gradually increase the extraction efficiency up to 96% for Mn and 98% for Zn but further time increase has no more influence. An attempt has been made to recover the carbon from the leaching residue but its structural characterization is still required.
A three-dimensional reduced graphene oxide (3D-RGO) material has been successfully prepared by a facile hydrothermal method and is employed as the negative additive to curb the sulfation of lead-acid battery. When added with 1.0 wt% 3D-RGO, the initial discharge capacity (0.05 C, 185.36 mAh g−1) delivered by the battery is 14.46% higher than that of the control cell (161.94 mAh g−1); and the cycle life under the high-rate partial-state-of-charge (HRPSoC) condition is significantly improved by more than 224% from 8142 to 26,425 cycles. In comparison to the conventional carbon additions like the activated carbon and acetylene black, the 3D-RGO also exhibits the highest initial discharge capacity, the best rate capabilities and the longest HRPSoC cycling life. Finally, we propose a possible mechanism for 3D-RGO to suppress lead-acid battery sulfation, where the abundant pore structure and excellent conductivity of 3D-RGO may have a synergistic effect on facilitating the charge and discharge process of negative plate.
One of the most important challenges in the field of electrodeposition in aqueous media concerns the synthesis of inorganic nanomaterials with excellent control of the film microstructure, morphology and crystallinity. In this work, we present a ground-breaking method for tailoring highly crystalline nanoporous layers of ZnO upon transparent conductive oxide substrates which extends the limit of electrodeposition in aqueous media. Being surfactant and template-free, the design of a well-defined ZnO nanostructure has been achieved by means of an accurate control of the electro-assisted generation of hydrogen bubbles which play the role of a ‘gas template’ enabling the formation of dense to highly porous ZnO mesostructures depending on H2 evolution. Such layers were successfully introduced in solid-state dye-sensitized solar cells. In combination with an organic D-π-A dye (C220) and CuSCN as hole transporter material, we achieved 2.1% power conversion efficiency.
Development of high performance lithium polymer batteries (LPBs) with high thermal and electrochemical stabilities is now being intensively pursued for various applications like personal electronics, grid storage etc. In the present study, we report synthesis and characterization of a gel polymer electrolyte (GPE) based on polymer polyethylene oxide (PEO), salt lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and different amounts of added ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), complex impedance spectroscopy, ionic transference number studies, linear sweep voltammetry (LSV) and cyclic voltammetry (CV) studies exhibit promising characteristics of prepared GPEs for suitable application in LPBs. The GPEs show high thermal stability (i.e. no weight loss up to 310°C), high ionic conductivity (∼2.08×10−4 Scm−1 at 30°C), high lithium transference number ( t Li + =0.39) and high electrochemical stability window (∼4.6V). A low cost simple thermal lamination technique was used to encapsulate whole LPB assembly by sandwiching best performing GPE between a LiMn2O4 cathode and lithium metal anode. In galvanostatic charge/discharge cycles the prepared cell showed good electrochemical performance.
Publisher Summary With the dozens of processors controlling every aspect of today's automobiles, not a single aspect of the vehicle experience remains untouched by technology. There has been constant evolution in capabilities and manufacturer offerings for climate control, engine control, and entertainment over the last decade. The rapidly increasing performance trend of media processors is set to have a profound impact on another critical automotive component—the safety subsystem. This chapter opens with a discussion of an automotive driver assistance application, explaining how a video-based lane departure warning system can utilize a media framework. Then, attention turns to implementation of a JPEG algorithm, which contains a lot of the key elements of more complex image and video codecs. This discussion is extended to the MPEG realm, outlining how an MPEG-2 video encoder algorithm can be partitioned efficiently across a dual-core processor. Finally, this chapter discusses the porting of open-source C code to the Blackfin processor environment. After reading this chapter, the user will undergo an enlightening analysis of the code optimization process, which will help him or her find the best optimization process.
We investigated the negative electrode behaviors of several mesocarbon microbeads (MCMB) heat-treated over 2000°C in 1M LiPF6/propylene carbonate (PC) electrolyte under various charge–discharge current densities. A higher current density provided improved (a highly graphitized MCMB)/Li cell cycle stability as lower graphitized MCMB electrode was used. In addition, two pre-cycles at a higher current density also provided better cycle stability in subsequent cycles at a lower current density. For example, MCMB 6μm in diameter and heat-treated at 2800°C cycled stably at a current density of 0.2mAcm−2 after 2 pre-cycles at 0.5mAcm−2. A higher current density may provide an adequate surface film at the first charging.
This paper deals with the creation, growth and current decline of the Sudanese capital, Khartoum, since the early nineteenth century. It describes the distinct ways in which the two main settlements in the conurbation — Umm-Durman and Khartoum — have been planned, the former along Arab-Islamic lines and the latter as a British Colonial town. After independence in 1956, the capital enjoyed a prominent, if brief, period of flourish in most aspects of life. In the mid-1970s chaos set in. The `deplanning’ process was initially prompted by various motives and, since the early 1980s, has gradually been institutionalised. The positive planning features were obliterated after the town planning machinery was marginalised and almost dismantled. The once-beautiful town was vulgarised, vandalised, ruralised and `censored’ by the state under various labels and excuses. But towns, we know, have their own ways of saying things and it is all the more interesting when what the town says is in direct opposition to what the state officially declares. This paper tries to document the `deplanning’ of Khartoum by interpreting the messages the town sends, tracing the symptoms of this process and suggesting remedies for what has not been irretrievably lost.
In this paper, a new strategy for modeling and controlling a hybrid power generation system that contains a fuel cell (FC) and super capacitor (SC) system is proposed. The main drawback of FC systems is its slow dynamic because the FC current slope must be limited in order to prevent fuel starvation problems and to improve its efficiency and lifetime. To overcome this slow dynamic and to improve dynamic performance, a new control strategy is proposed to combine FC system with SC system. The proposed control strategy can be also used for cold starting and different types of FC systems with different dynamics. The control strategy is capable of determining the desired FC power to prolong FC system lifetime and keeps the AC and DC voltages around its nominal value in transient event by supplying propulsion power and recuperating FC energy. The minimum SC system is computed in new method and used to meet the load demand to constraint the DC bus voltage and enhances power regulation under various active and reactive load conditions. Two different case studies are used to obtain the simulation results using MATLAB/SIMULINK to verify the validity of the proposed control strategy.
Effects of cathodal current, which draws cations away from the tongue and drives anions toward the tongue, depend on the ionic content of electrolytes through which the current is passed. To address the role of cations and anions in human salt tastes, cathodal currents of −40μA to −80μA were applied to human subjects’ tongues through supra-threshold salt solutions. The salts were sodium chloride, sodium bromide, potassium chloride, ammonium chloride, calcium chloride, sodium nitrate, sodium sulfate, sodium saccharin, sodium acetate and sodium benzoate, which taken together encompass salty, bitter, sour and sweet taste qualities. The taste of NaCl, the salty and bitter tastes of the other chloride salts and the taste of NaNO3 was inhibited, suggesting the current displaced stimulatory cations from salty and bitter receptors. However, bitter tastes of non-halide sodium salts were not inhibited, likely because other bitter receptors respond to anions. A discharge current at cathode-off ubiquitously evoked a metallic taste reminiscent of anodal taste used in clinical electrogustometry. Analogous effects on ambient NaCl responses were recorded from the hamster chorda tympani nerve. Increases in tastes of the saccharin and benzoate anions were not evoked during current flow, suggesting that cathodal current does not carry stimulatory anions to sweet receptors. Cathodal current may selectively inhibit salty and bitter–salty tastes for which proximal stimuli are cations.
This study examined the utility of structural and functional MRI at 1.5 and 3T in the presurgical evaluation and prediction of postsurgical cognitive outcome in temporal lobe epilepsy (TLE). Forty-nine patients undergoing presurgical evaluation for temporal lobe (TL) resection and 25 control subjects were studied. Patients completed standard presurgical evaluations, including the intracarotid amobarbital test (IAT) and neuropsychological testing. During functional imaging, subjects performed a complex visual scene-encoding task. High-resolution structural MRI scans were used to quantify hippocampal volumes. Both structural and functional imaging successfully lateralized the seizure focus and correlated with IAT memory lateralization, with improvement for functional imaging at 3T as compared with 1.5T. Ipsilateral structural and functional MRI data were related to cognitive outcome, and greater functional asymmetry was related to earlier age at onset. These findings support continued investigation of the utility of MRI and fMRI in the presurgical evaluation of TLE.
A population of simultaneously germinating conidia is an ideal inoculum of the powdery mildew pathogen, Oidium neolycopersici. In conditions of no or low wind velocity, O. neolycopersici successively stacks mature conidia on conidiophores in a chain formation (pseudochain), without releasing the precedent mature conidia. These pseudochain conidia represent a perfect inoculum, in which all conidia used for inoculation germinate simultaneously. However, we found that conidia must be collected before they fall to the leaf surface, because the germination rate was lower among conidia deposited on the leaf surface. We used an electrostatic spore collector to collect the pseudochain conidia, and their high germination rate was not affected by this treatment. The spore collector consisted of an electrified insulator probe, which created an electrostatic field around its pointed tip, and attracted conidia within its electric field. The attractive force created by the probe tip was directly proportional to voltage, and was inversely proportional to the distance between the tip and a target colony on a leaf. Pseudochain conidia were successfully collected by bringing the electrified probe tip close to target colonies on leaves. In this way, conidia were collected from colonies at 3-d intervals. This effectively collected all conidia from conidiophores before they dropped to the leaf surface. A high germination rate was observed among conidia attracted to the probe tip (95.5±0.6%). Conidia were easily suspended in water with added surfactant, and retained their germination ability. These conidia were infective and produced conidia in pseudochains on conidiophores after inoculation. The electrostatic spore collection method can be used to collect conidia as they form on conidiophores, thus obtaining an inoculum population in which all of the conidia germinate simultaneously.