batterydata/paper-abstracts huggingface dataset:
Developing advanced electrode materials with hierarchical porous structure is one of the promising strategies to achieve superior properties in lithium-ion batteries (LIBs). Herein, this study reports the design and fabrication of MoS2 nanosheets @ 3D interconnected porous graphitic carbon anchored on carbonized cotton cloth (CC/PGC@MoS2) as an anode for LIBs. The uniform interconnected porous PGC@MoS2 is not only grown on the surface of carbon fibers of CC, but also filled in the spaces among carbon fibers to achieve a dense and interconnected conductive network. The intermediate graphitic carbon network in CC/PGC@MoS2 nanostructure can greatly enhance the electronic conductivity, provide short ion transport paths and create abundant active sites. Benefiting from its unique structure, the CC/PGC@MoS2 electrode delivers a high reversible capacity (reversible capacity of 1095.1 mA h g−1 at 0.1 A g−1), excellent rate capability, and remarkable cycling stability (reversible capacity of 816 mA h g−1 at 1.0 A g−1 after 400 cycles), making it promise as an electrode material for LIBs. This study provides a new strategy for designing carbon-based materials with superior electrochemical properties.
Electrospinning is used to fabricate sodium ion conducting fiber membranes composed of polyethylene oxide (PEO), sodium tetrafluoroborate (NaBF4), and succinonitrile (SN) as plasticizer. As compared to conventionally prepared lithium electrolyte membranes with identical composition (PEO:SN:LiBF4), those membranes exhibit conductivities up to 10−4 S cm−1 at 328 K (activation energy ∼36 kJ mol−1, 36:8:1 membrane), which favors such systems as a solid-state electrolyte alternative for batteries. The conduction mechanism is evaluated and the ion mobility are examined. We identified the segment mobility of the polyethylene oxide as the main driving force for the enhanced ion mobility in the membranes. The introduction of SN has only a minor influence on the conductivity and segment mobility at room temperature, but extents the anion and cation mobility to temperatures below ambient. For the 36:8:1 (PEO:SN:NaBF4) membrane we found the highest ion mobility of all membranes under investigation. A comparison of the present sodium membranes with lithium systems of the same composition shows that the overall performance of the sodium systems is comparable. Taking plasticizer-free sodium membranes into account they perform even better than the lithium containing counterparts, and plasticizer-modified membranes show only half an order of magnitude lower conductivities than comparable lithium ones.
The DLVO-style theory of surface energies and surface forces is extended to describe the charge transfer energy due to redox processes at an electrode, including nonelectrostatic ion interactions. Formulae for the corresponding disjoining pressure are given. Illustrative calculations are made for a coupled 0.01M Fe||Cu concentration cell. Nonelectrostatic interactions are found to reduce electrode potentials but increase electrode charges. Forces between graphite electrodes are calculated in two geometries: between two cathodes in the Fe cell and between two anodes in the Cu cell. Nonelectrostatic redox ion interactions, in particular strong nonelectrostatic physisorption of the Cu+ ion combined with a peak in the electrode charge, introduce a repulsive peak at a Debye-length separation (2nm), that transforms the cathode–cathode interaction from attractive to repulsive and magnifies an existing repulsive peak in the anode–anode interaction. The strength of the peak varies with a Hofmeister series in the “inert” counterion.
Flexible and thick carbon nanofiber (CNF) electrodes are developed for symmetric supercapacitor application. Free-standing CNF mats with diameter of 335 ± 60 nm are produced via solution blowing technique and the microstructure and porosity are analyzed. The electrochemical performances of CNF are firstly investigated by determining the maximum operating voltage window in aqueous electrolytes with various pH. Then, CNF electrodes with high mass loading and thicknesses up to 1.2 mm are used for symmetric supercapacitor cells with 6 M KOH solution as an electrolyte. It is found that electrodes with mass loading of 25 mg/cm2 can be cycled up to 10,000 cycles without capacity loss, at current of 2 A/g and 1.4 V cut-off voltage. While electrodes with higher mass loading retain 85% of their capacity. Post-mortem analysis shows that the capacity loss of the thicker electrodes is a result of decreased ion diffusion during cycling. The lower ion diffusion appears due to crystal-like products formed as a result of side reactions with the electrolyte.
An accurate battery state-of-health (SOH) monitoring is crucial to guarantee safe and reliable operation of electric vehicles (EVs). In this paper, an incremental capacity analysis (ICA) method for battery SOH estimation is proposed. This uses grey relational analysis in combination with the entropy weight method. First, an interpolation method is employed to obtain incremental capacity (IC) curves. The health indexes are then extracted from the partial IC curves for grey relational analysis, and the entropy weight method is used to evaluate the significance of each health index. The battery SOH is assessed by calculating the grey relational degree between the reference and comparative sequences. Experimental tests are conducted on two battery cells with the same specifications to verify the efficacy of the proposed method. The results show that the maximum estimation error is limited to within 4%, thus proving its effectiveness.
We introduce three dominance criteria to compare the performance of alternative value at risk (VaR) forecasting models. The three criteria use the information provided by a battery of VaR validation tests based on the frequency and size of exceedances, offering the possibility of efficiently summarizing a large amount of statistical information. They do not require the use of any loss function defined on the difference between VaR forecasts and observed returns, and two of the criteria are not conditioned by the choice of a particular significance level for the VaR tests. We use them to explore the potential for 1-day ahead VaR forecasting of some recently proposed asymmetric probability distributions for return innovations, as well as to compare the asymmetric power autoregressive conditional heteroskedasticity (APARCH) and the family of generalized autoregressive conditional heteroskedasticity (FGARCH) volatility specifications with more standard alternatives. Using 19 assets of different nature, the three criteria lead to similar conclusions, suggesting that the unbounded Johnson SU, the skewed Student-t and the skewed Generalized-t distributions seem to produce the best VaR forecasts. The unbounded Johnson SU distribution performs remarkably well, while symmetric distributions seem clearly inappropriate for VaR forecasting. The added flexibility of a free power parameter in the conditional volatility in the APARCH and FGARCH models leads to a better fit to return data, but it does not improve upon the VaR forecasts provided by GARCH and GJR-GARCH volatilities.
We present electrochemical properties of lithium alanate (LiAlH4) dissolved in aprotic ethers – diethyl ether (Et2O) and tetrahydrofuran (THF) – under an Ar atmosphere of 1atm at 298K. Specific conductivities of both LiAlH4–THF and LiAlH4–Et2O solutions are measured by AC four-terminal method. Cyclic voltammetry is performed with using a beaker-type electrochemical cell consisted of a Ni wire, Ni mesh and Li wire as a working, counter and reference electrode, respectively. In order to clarify the electrochemical behavior, anodic polarization of LiAlH4–THF solution is measured. The current density of 1.0M LiAlH4–THF solution reaches to 1Acm−2, which is higher than the LiAlH4–Et2O solution. Quantitative analysis of H2 gas generated on the working electrode during the potentiostatic electrolysis tells that the number of electrons involved in the anodic reaction at the limiting current is one in case of the LiAlH4–THF solution. We propose conceivable electrochemical reactions of LiAlH4 in the non-aqueous ethereal solutions.
Na-ion battery has been investigated as a potential candidate for Li-ion battery because of its abundant sodium resource. One of the advanced anodes for Na-ion battery is NaTi2(PO4)3 due to the open 3D framework, good thermal structure and high Na+ conductivity. However, the NaTi2(PO4)3 material possesses a low electrical conductivity, which hinders its application for large-scale sodium storage. Herein, the nanosized NaTi2(PO4)3@C crystals embedded in 2D sulfur-doped graphene sheets are synthesized using a simple method. The 2D sulfur-doped graphene sheets can easily facilitate the transport of electrons/ions and inhibit the volume change during the insertion/extraction of Na+ ions, resulting in superior rate property. The synthesized electrode shows the high discharge capacity (130.1 mAh g−1 at 0.1 C), excellent rate property (112.8 mAh g−1 at 10 C) and stable cycle life (95.8 mAh g−1 over 500 cycles at 20 C), revealing its great application for Na-ion battery. This novel strategy could be applied to synthesize other advanced electrode materials for electrochemical sodium storage.
This paper focuses on the efficient selection of a special type of subset of network nodes, which we call a k -SPR set, for the purpose of coordinating the routing of messages through a network. Such a set is a special k -hop-connected k -dominating set that has an additional property that promotes the regular occurrence of routers in all directions. The distributed algorithms introduced here for obtaining a k -SPR set require that each node broadcast at most three messages to its k -hop neighbors. These transmissions can be made asynchronously. The time required to send these messages and the sizes of the resulting sets are compared by means of data collected from simulations. The main contribution is the adaptation of some variations of the distributed greedy algorithms to the problem of generating a small k -SPR set. These variations are much faster than the standard distributed greedy algorithm. Yet, when used with a sensible choice for a certain parameter, our empirical evidence strongly suggests that the resulting set size will generally be very close to the set size for the standard greedy algorithms.
The novel Na-substituted Li1-xNaxNi0.5Mn1.5O4 has been synthesized to use as a cathode material for lithium ion battery via a solid-state method. Both crystal domain size and lattice parameter are influenced by the doping content of Na, without changing the basic spinel structure. The doping of Na ions not only increase the disordered distribution of nickel and manganese cations in spinel, but also increase two additional electron hopping paths, which contribute to a better charge transfer ability, relieve the ohmic polarization and electrochemical polarization of materials and improve lithium ion diffusion coefficient. After Na-doped, the discharge specific capacity rises up comparing to the sample without Na-doped. As a result, the excellent rate capability is achieved for the doping content of 5% Na in spinel, that the discharge capacity is increased by 3.4%, 9.4%, 9.1%, 8.7%, 6.5% and 3.4% in comparison with LNMO, presenting a discharge specific capacity of 121, 119.4, 118.5, 115.1, 108.4 and 101.3mAh·g−1 at the rates of 0.2, 0.5, 1, 2, 5 and 10C respectively, with tiny Mn3+ platform appearing. In addition, the sample presents a discharge capacity of 125mAh·g−1 at 1C, with a retention of 116.2mAh g−1 after 100 cycles. Even cycling at 5C rate and 55°C, the cell with 5% Na-doped LNMO cathode can has 82% of capacity retention after 400 cycles, indicating that it is a promising cathode material for lithium ion batteries.
Mountain View, California-based PolyFuel claims that its recently introduced, ultra-thin membrane delivers over 40% more power than any fuel cell membrane previously available.
Publisher Summary unbounded mobile communications (UMC) is a nascent market. Initially there were few handset manufacturers that would boldly step into this market. Since wireless carriers were concerned about WiFi cannibalizing their minutes or subscribers, they were more than mildly reluctant to back dual-mode offerings. Indeed, in some markets, certain models of phones were introduced with dual-mode configurations while the same design was introduced into other markets with the WiFi radios absent. In some cases, when the WiFi radios were present, the network services were hobbled to only support halfduplex traffic and not the voice-required full-duplex. In this manner, the WiFi connection could be used to surf the Web but could not sustain a real-time voice connection. Each operating system used for mobile handsets has its own unique approach for supporting, making, and breaking network connections, whether wireless or wireline. Most have a communication manager that is responsible for managing network connections, but there are design differences that may be important in a purchase decision from any one vendor. By intent, the communications manager is supposed to present an abstracted network interface that simplifies the operational management of network access. All require baseline configuration where all possible network connections are profiled (with proper security), including Bluetooth, WiFi, and USB connections.
With the rapid advancement of modern technology, wearable electronic devices become more and more indispensable to daily life. However, powering them in a stable and sustainable manner remains a challenge and highly desired. In this work, we proposed a humidity-resisting triboelectric nanogenerator (HR-TENG) to harvest energy from human biomechanical movements for wearable electronics. The electrospun nanofibrous membranes were rationally tailored to eliminate the adverse effects of water vapor on the electrical output and construct a high-performance humidity-resisting triboelectric nanogenerator. It could work with improved adaptability to the environmental humidity caused by human perspiration during sport. With human biomechanical motions, such as hand tapping, the wearable HR-TENG can respectively deliver a current and voltage output up to 28µA and 345V, corresponding to a power density of 1.3W/m2 under a relative humidity 55%. It was also demonstrated to sustainably power an electronic watch, a commercial calculator, a thermal meter and light up about 400 LEDs by harvesting the biomechanical energy from human movements under different ambient humidity. And its electrical output was still at a relatively high level when the relative humidity was increased from 30% to 90%. Given a collection of compelling features of being wearable, flexible and cost-effective, the HR-TENG could be utilized as a sustainable power source to drive wearable electronics during human sport even with heavy perspiration.
Development of novel electrode materials with unique architectural designs is necessary to attain high power and energy density lithium-ion batteries (LIBs). SnO2, with high theoretical capacity of 1494mAhg−1, is a promising candidate anode material, which has been explored with various strategies, such as dimensional reduction, morphological modifications and composite formation. Unfortunately, most of the SnO2-based electrodes are prepared by using complex chemical synthesis methods, which are not feasible to scale up for practical applications. In addition, concomitant irrecoverable initial capacity loss and consequently poor initial Coulombic efficiency still persistently plagued these SnO2-based anodes. To overcome hitherto conceived irreversible formation of Li2O by conversion reaction, to fully harness its theoretical capacity, this work demonstrates that a hierarchical structured SnO2-C nanocomposite with 68.5% initial Coulombic efficiency and reversible capacity of 725mAhg−1 can be derived from the mixtures of SnO2 and graphite, by using low cost industrial compatible high energy ball milling activation.
In this paper we report the physical investigation and the electrochemical performance of the carbon black SC3 from Cabot Corporation. The SC3 carbon black was investigated in terms of BET surface area, pore size distribution, resistivity and morphology. Composite electrodes containing SC3 as active material were prepared and used for the realization of electrochemical double layer capacitor (EDLC) and lithium-ion capacitor (LIC). In EDLC, at 5mAcm−2 charge–discharge currents, the carbon black displays a specific capacity of 40mAhg−1 and a specific capacitance of 115Fg−1. It also displays a very good cycling stability for over 50,000 cycles and excellent performance retention at currents up to 50mAcm−2. The performance retention at high currents outstandingly differentiates this carbon black from a few commercially available EDLC-grade activated carbons. Because of the high specific capacity of SC3, the carbon black electrodes were also used in combination with LiFePO4 electrodes in LIC. The results of this study indicate that SC3 carbon black is an interesting carbonaceous candidate for the realization of LIC.
A technique for building a high fidelity electrical-analogue battery model by identifying the model parameters at the module level, as opposed to the cell level, is proposed in this paper. The battery model, which is represented by electrical circuit components, can be easily integrated into popular simulation environments for system level design and predictive analysis. A novel bandwidth based time-domain procedure is introduced for identifying the model parameters by selective assignment of the limited bandwidth of the battery model approximation according to the natural bandwidth of the system that uses the battery. The aim of this paper is to provide an accurate off-line electrical-analogue battery model for simulation of larger systems containing large-format batteries, as opposed to a detailed electrochemical model suitable for simulation of internal battery processes. The proposed procedure has been experimentally verified on a 6.8Ah Ultralife UBBL10 Li-ion battery module which is a “microcosm” for a modern large-format battery pack. A maximum 0.25% error was observed during a performance test with arbitrary but bandwidth-limited charging and discharging intervals characteristic of a typical battery application.
The possibility of using vanadium pentoxide (V2O5) as a catalyst in rechargeable lithium–oxygen (Li–O2) batteries was studied. A V2O5-carbon composite was cast onto Ni foam to form a cathode. Electrochemical cells designed based on the flat cell manufactured by Hohsen Corporation were fabricated. The initial discharge capacity was 715 mA h g−1, and the maximum discharge capacity reached 2,260 mA h g−1 during the twelfth cycle. The cell had high capacity retention during cycling (1.24 % during cycles 2–8). V2O5 acted as a catalyst as well as an active material, improving the specific capacity and capacity retention of the non-aqueous Li–O2 cell more effectively than do other materials.
Objective. To evaluate the use of different treatment systems to increase the efficacy of the rehabilitation of patients with neglect syndrome (NS) after stroke. Materials and methods. The effects of observing a protocol for managing patients with NS and using Ceraxon (citicoline) on the extent of recovery of neurological functions, the level of daily adaptation, and elimination of NS were studied in stroke patients. Treatment results from 120 patients were analyzed. The extent of restoration of functions was assessed using the Lindmark scale, the level of daily adaptation using the Barthel scale and the Merton and Sutton scale, the state of cognitive functions using the MMSE and the Frontal Assessment Battery, and psychoemotional status using the Beck questionnaire. Treatment efficacy was also evaluated in terms of the absence of the characteristic signs of NS. Results and conclusion. These studies showed that complex rehabilitation following the protocol for managing patients with NS and Ceraxon significantly increased rehabilitation efficacy in this group of patients.
Interconnected carbon nanofibers networks (ICNNs) prepared through the carbonization of polypyrrole (PPy) precursor are utilized as conductive pathways and buffer to improve the Na storage performance of antimony (Sb) as anode for sodium-ion batteries (SIBs). The as-obtained Sb/ICNNs composite exhibits excellent cycle stability. The reversible capacity can remain 542.5 mAh g−1 with a high capacity retention of 96.7% after 100 cycles at a current density of 100 mA g−1. And the superior rate performance is also observed, the reversible capacity can still reach 325 mAh g−1 at a high current density of 3200 mA g−1. These great electrochemical performances observed above suggest that this type of composite can be a nice option for advanced SIBs anode materials and may be extended to other active materials/ICNNs composite electrode.
This paper describes how the business model of two leading Swedish municipally owned solid waste management companies exposes them to four different but related markets: a political market in which their legitimacy as an organization is determined; a waste-as-material market that determines their access to waste as a process input; a technical market in which these companies choose what waste processing technique to use; and a commercial market in which they market their products. Each of these markets has a logic of its own. Managing these logics and articulating the interrelationships between these markets is a key strategic challenge for these companies.
Periodic monitoring is sufficient for sweep coverage with a small number of mobile sensor nodes, whereas a continuous monitoring with static sensor nodes is required for the coverage problem in wireless sensor networks. Finding the minimum number of mobile sensor nodes with a uniform speed to guarantee sweep coverage is NP-hard and it cannot be approximated within a factor of 2 (Li et al., 2011). In this paper we have proposed a 2-approximation algorithm for solving the sweep coverage for a given set of points of interest (PoIs). The best known approximation factor is 3 for this problem (Li et al., 2011). Modification of the algorithm is also proposed for extending lifetime of the mobile sensors, sweep coverage in the presence of obstacles and failure of mobile sensors. When all PoIs are static sensor nodes, we have proposed a distributed approximation algorithm with approximation ratio 2, where the static sensor nodes compute the number of mobile sensor nodes and their positions. We have introduced sweep coverage for a given area of interest (AoI) and proved that the problem is NP-complete. A 2 2 -approximation algorithm is designed in order to solve the problem for a square region. An improvement over the approximation factor is designed for any rectangular region. Based on our simulation study we have shown that less number mobile sensor nodes are required for our point sweep coverage algorithm compared to the algorithm proposed in Du et al. (2010).
This work focuses on the stability of hybrid electrochromic displays that use only one electrochromic film, an industrial solid polymer electrolyte and a metallic counter electrode. The lifetime of these devices exceeds 200,000 cycles in tests with three different voltage ranges. Traces of metal deposits were found during cycling, which indicates that the metallic counter electrode combines the functions of current collector and counter electrode.