batterydata/paper-abstracts huggingface dataset:
This study reports the development of a new system of porous, chemically cross-linked, gel polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF–HFP) copolymer as a polymer matrix, polyethylene glycol (PEG) as a plasticizer, and polyethylene glycol dimethacrylate (PEGDMA) as a chemical cross-linking oligomer. The electrolytes are prepared by a combination of controlled evaporation and thermal polymerization of PEGDMA. PVdF–HFP/PEG/PEGDMA gel polymer electrolytes with a composition of 5/3/2 exhibit both high ambient ionic conductivity, viz., >1mScm−1, and a high tensile modulus of 52MPa, because of their porous and network structures. All the blends of electrolytes are electrochemically stable up to 5V versus Li/Li+ in the presence of 1M LiPF6/ethylene carbonate–diethyl carbonate (EC–DEC). With these polymer electrolytes, rechargeable lithium batteries composed of carbon anode and LiCoO2 cathode have acceptable cycleability and a good rate capability.
Since the introduction of hybrid electric automobiles (‘hybrids’) around the turn of the century battery manufacturers have been faced with a new and demanding application. The battery in a hybrid must operate around a state-of-charge (SoC) base line that is well short of 100% SoC, normally within the range 50–80% SoC, in order to be able to accommodate incoming charge from the regenerative braking process. From such a baseline the battery must cope with a virtually continuous succession of charge and discharge events of relatively small magnitude (typically a few percent of the battery capacity) but at very high rates (15C discharge and 8C charge are not unusual). Such a duty is vastly different from that required in an all-electric vehicle and it is no surprise that batteries for hybrids need to be designed somewhat differently from batteries that have satisfied the earlier needs of automobiles. The first hybrids to achieve significant sales volumes employed nickel metal hydride batteries but this technology brought with it a substantial cost premium and during recent years much research effort has been devoted to the development of alternative means of storing the energy (more correctly the power) needed in hybrids. Much attention has focused on lithium ion batteries for this task but there has also been significant progress in the evaluation of lead–acid batteries and supercapacitors. The present special issue of the Journal of Power Sources is devoted to descriptions of some of this work.
A study is conducted of the performance of lithium iron(II) phosphate, LiFePO4, as a cathode material in a lithium secondary battery that features an ionic liquid electrolyte solution and a metallic lithium anode. The electrolyte solution comprises an ionic liquid of a N-methyl-N-alkyl-pyrrolidinium (alkyl=n-propyl or n-butyl) cation and either the bis(fluorosulfonyl)imide [(FSO2)2N−] or bis(trifluoromethanesulfonyl)imide [(F3CSO2)2N−] anion, together with 0.5molkg−1 of lithium bis(trifluoromethanesulfonyl)imide salt. For N-methyl-N-propyl-pyrrolidinium bis(fluorosulfonyl)imide, coin cells discharging at rates of C/10 and 4C yield specific capacities of 153 and 110mAhg−1, respectively, at an average coulombic efficiency of 99.8%. This performance is maintained for over 400 cycles at 50°C and therefore indicates that these electrolyte solutions support long-term cycling of both LiFePO4 and metallic lithium while, due to the negligible volatility of ionic liquids, surrounding the lithium in an inherently safe, non-flammable medium.
Lithiation-induced volume changes in Si result in fracture and fragmentation of Si anodes in Li-ion batteries. This paper reports the self-healing behaviour of cracks observed in micron-sized Si particles dispersed in a ductile Al matrix of a Si-Al electrode electrochemically cycled vs. Li/Li+ using a high lithiation rate of 15.6 C. Cross-sectional high-resolution transmission electron microscopy and Raman spectroscopy revealed that an amorphous layer with a depth up to ∼100 nm was formed at the surface of Si particles. In-situ optical microscopy performed during electrochemical experiments revealed development of cracks in Si particles as the voltage decreased to 0.02 V during lithiation. Self-healing of cracks in Si particles occurred in two steps: i) arresting of the crack growth at the Si/Al interface as the surrounding Al matrix had a higher fracture toughness and thus acted as a barrier to crack propagation, and ii) closure of cracks due to compressive stresses applied to the crack faces by the amorphous zones formed on each side of the crack paths.
Wireless low-power technologies have been the focus of a large research effort, for example, in the wireless sensor network and other short range technologies domains. Although bringing extended autonomy to battery powered stations, such technologies are known to be negatively influenced by similar technologies contending for the medium and, especially, by technologies using higher power transmissions over the same frequency bands. A frequency band that is becoming increasingly crowded with competing technologies is the 2.4GHz Industrial, Scientific and Medical band, encompassing, for example, Bluetooth and ZigBee, two low-power communication standards which are the base of several real-time protocols. Although these technologies employ mechanisms to improve their coexistence, they are still vulnerable to transmissions from uncoordinated stations with similar technologies or to higher power technologies such as Wi- Fi, which hinders the support of wireless dependable real-time communications in open environments. Therefore, this survey presents a comprehensive study of the most commonly used wireless low-power technologies operating in the 2.4GHz Industrial, Scientific and Medical (ISM) band and real-time protocols built upon them. The survey of the real-time protocols using these technologies is focused on factory automation applications, due to their more demanding timeliness and reliability requirements.
Samples of small particle size bismuth and electroplated Ni–Sn alloy were tested as anodes for lithium ion batteries to highlight the effects of volume changes during charge and discharge on the cycling life of the electrodes. Bismuth was used for its relatively “high” potential of Li–Bi alloys formation (0.8–0.6V) which prevents other components within the electrode from being electrochemically active versus lithium in this potential window. Electrochemical tests have shown that the capacity fade during cycling is largely dependant of the amount of Bi in the electrode. Electroplated Ni–Sn alloys were directly used as anodes and do not need to be reground nor mixed with additives. Different electroplating conditions, leading to different morphology, highlight the leading role of the particle size of the active materials used in the lithium ion cells.
We present an acoustic study of segmental and prosodic properties of words produced by a female speaker of Chinese with left-hemisphere brain damage. We measured the location of the point vowels /a, e, ə, i, y, o, u/ and determined their separation in the vowel plane, and their perceptual distinctivity. Similarly, the acoustic properties of the four lexical tones were measured in the F0 × time space. The data for our brain-damaged speaker were compared with those of a healthy control speaker. Results show that the patient's vowels hardly suffered from her lesion (relative to the vowel dispersion in the healthy control speaker), but that the identifiability of the four lexical tones was greatly compromised. These findings show that the tonal errors in aphasic speech behave independently of the segmental errors, even though both serve to maintain lexical contrasts in Chinese, and are therefore part of the lexical specification of Chinese words. The present study suggests that the specification of segmental and tonal aspects of lexical entries in Chinese, and in tone languages in general, are located or processed separately in the brain.
TiO2 (B) has been investigated as a possible candidate to replace Li4Ti5O12 as a negative electrode for Li-ion battery. The starting compound was synthesized by a simple solid state reaction followed by hydrolysis. Long term stability of the TiO2 (B) electrode can be obtained by limiting lithium intercalation between 0.25 and 0.35 Li+ per unit formula. High cycling rates (up to 24C) have been used without noticeable degradation of the electrode. A non-aqueous hybrid energy storage device using TiO2 (B) as the negative electrode and activated carbon as the positive was assembled. The maximum hybrid cell voltage can be set between 2.75V and 3.5V. The cells exhibit energy densities between 45Wkg−1 and 80Wkg−1 with power densities in the range 240–420Wkg−1 which is compatible with a fast charging/discharging storage device, intermediate between electrochemical double layer capacitor and Li-ion batteries.
Nanocrystalline LiFe1−x Sn x PO4 (0≤ x ≤0.07) samples are synthesized using SnCl4·5H2O as dopant via an inorganic-based sol–gel method. The dependency of the physicochemical and electrochemical properties on the doping amount of tin are systemically worked out and regular changes are revealed. In the whole concentration range, the chemical valence of Fe2+ is not basically changed whereas tin is found in two different oxidation states, namely +2 and +4. The replacement of Fe2+ by supervalent Sn4+ would lead to electron compensation. Under the synergetic effects between the charge compensation and the crystal distortion, the electrical conductivities for the bulk samples first increase and then decrease with the increasing amount of Sn doping. Upon the doping amount, the apparent lithium-ion diffusion coefficient and the electrochemical performance also display the similar trends. The doping is beneficial to refine the particle size and narrow down the size distribution, however optimizing the doping amount is necessary. Compared with other samples, the sample with a doping amount of about 3mol% delivers the highest capacities at all C-rates and exhibits the excellent rate capability due to the high electrical conductivity and the fast lithium-ion diffusion velocity.
Lithium ion (Li-ion) battery, consisting of multiple electrochemical cells, is a complex system whose high electrochemical and thermal stability is often critical to the well-being and functional capabilities of electric devices. Considering any change in the specifications may significantly affect the overall performance and life of a battery, an investigation on the impacts of electrode thickness on the electrochemical and thermal properties of lithium-ion battery cells based on experiments and a coupling model composed of a 1D electrochemical model and a 3D thermal model is conducted in this work. In-depth analyses on the basis of the experimental and simulated results are carried out for one cell of different depths of discharge as well as for a set of cells with different electrode thicknesses. Pertinent results have demonstrated that the electrode thickness can significantly influence the battery from many key aspects such as energy density, temperature response, capacity fading rate, overall heat generation, distribution and proportion of heat sources.
State-of-charge (SOC) inconsistency impacts the power, durability and safety of the battery pack. Therefore, it is necessary to measure the SOC inconsistency of the battery pack with good accuracy. We explore a novel method for modeling and estimating the SOC inconsistency of lithium-ion (Li-ion) battery pack with low computation effort. In this method, a second-order RC model is selected as the cell mean model (CMM) to represent the overall performance of the battery pack. A hypothetical Rint model is employed as the cell difference model (CDM) to evaluate the SOC difference. The parameters of mean-difference model (MDM) are identified with particle swarm optimization (PSO). Subsequently, the mean SOC and the cell SOC differences are estimated by using extended Kalman filter (EKF). Finally, we conduct an experiment on a small Li-ion battery pack with twelve cells connected in series. The results show that the evaluated SOC difference is capable of tracking the changing of actual value after a quick convergence.
NaV6O15 anode materials are prepared by the hydrothermal method and the precursor calcinations. The phase structure and the morphology of as-synthesized materials are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The cyclic voltammogram curves of NaV6O15 electrodes in the saturated LiNO3 electrolyte show that there exist three redox couples, which is in accordance with the charge-discharge voltage-capacity curves. The electrochemical cycle behaviors of LiMn2O4//NaV6O15 aqueous rechargeable lithium battery (ARLB) at the current densities of 50, 100, 200, 500, 800 and 1000mAg−1 indicate that this ARLB has larger discharge capacity and better cycle ability at higher current density than that at lower current density, which is much more different from those in the traditional lithium ion battery. Most notably, this abnormal electrochemical phenomenon is very crucial in the applications of the large-scale power source and the energy storage devices.
The ionic conductivity decay problem of poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) when increase the lithium salt of the SPEs up to high concentration is here functionally overcome by the incorporation of a charge delocalized sp 3 boron based single ion conducting polymer electrolyte (SIPE) with poly(ethylene oxide) to fabricate solid-state sp 3 boron based SIPE membranes (S-BSMs). By characterizations, particularly differential scanning calorimeter (DSC) and ionic conductivity studies, the fabricated S-BSMs showed decreased melting points and increased ionic conductivity as steadily increase the content of sp 3 boron based SIPE, which significantly improved the low temperature performance of the all-solid-state lithium batteries. The fabricated Li | S-BSMs | LiFePO4 cells exhibit highly electrochemical stability and excellent cycling at temperature below melting point of PEO, which has never been reported so far for SIPEs based all-solid-state lithium batteries.
Freestanding binder-free electrodes, as a new generation of electrode material, can effectively improve the energy density of lithium-ion batteries (LIBs). In this paper, novel structured Fe3O4/C composite nanofibers are successful synthesized by a simple electrospinning method followed by a thermal treatment process. The composite nanofibers have the unique internal voids between Fe3O4 nanoparticles and carbon matrix. The Fe3O4/C nanofibers film with good flexibility and excellent electrical conductivity can be directly used to fabricate half-cell without any current collector, binder and additional conductive agent. As anode material for LIBs, the Fe3O4/C composite nanofibers deliver high reversible capacity (762 mA h g−1 at 0.5 A g−1 after 300 cycles). The results show that the internal voids in flexible Fe3O4/C composite nanofibers effectively buffer volume expansion of Fe3O4 in lithium ion intercalation/deintercalation process and avoid the fracture of the nanofibers, which retain the structural integrity and improve the cycling stability of electrode. Therefore, the design and synthesis strategy of flexible nanofibers film are prospective for applications in next-generation flexible LIBs.
In this study, we used a spray-drying method to synthesize a hierarchically structured binary nanocomposite comprising highly porous NiO nanosheets and polyaniline:poly(sodium 4-styrenesulfonate) (PANI:PSS) materials. In this system, the porous NiO nanosheets—obtained through thermal decomposition of β-Ni(OH)2 derived from microwave-assisted hydrothermal treatment—dispersed well in the PANI:PSS solution. The homogeneous suspension was then processed through spray-drying and crosslinking of PANI:PSS and GOPS to form NiO/PANI:PSS microspheres. The PANI polymer served as a good conductor and thin spacer that prevented the NiO nanosheets from undergoing layer-to-layer stacking. Moreover, the crosslinked PANI:PSS acted as a binder that held all of the active materials together, leading to high mechanical integrity and excellent water-resistance. Through a synergistic effect in this unique nanoarchitecture, the NiO/PANI:PSS nanocomposite displayed a higher capacitance (834 F/g) at 1 A/g compared with that of NiO (380 F/g) and PANI:PSS (264.5 F/g) individually. Furthermore, the NiO/PANI:PSS composite displayed remarkable rate performance and outstanding cycling life—88.9% retention of specific capacitance after 3000 repeated charge/discharge tests—as a result of its low resistance and high (SSA). We fabricated asymmetric supercapacitors (ASCs) incorporating NiO/PANI:PSS and active carbon (AC) to further explore the capacitive performance of the composite. The as-fabricated devices also delivered remarkable performance, with an energy density of 32.84 Wh/kg, a power density of 375 W/kg, and excellent cycle life.
A nanocomposite of iron(III) oxide and tin(IV) oxide, Fe2O3(0.5)/SnO2(0.5), was prepared by a solid-phase reaction in an alkaline medium. The nanocomposite was characterized by X-ray diffraction, field-emission scanning electron microscopy, and Fourier transform infrared spectroscopy. A fast-response sensor was prepared by electrochemical deposition of the nanocomposite on a glassy carbon electrode. The prepared sensor has an excellent electrocatalytic activity toward the oxidation of epinephrine (EP), acetaminophen (AC), and tryptophan (Trp), therefore, this sensor was used for simultaneous determination of the above drugs. The separation of the oxidation peak potentials for EP–AC and AC–Trp were about 160 and 280 mV, respectively. The calibration curves obtained for EP, AC, and Trp were in the ranges of 0.6–270.0 µmol L−1, 4.5–876.0 µmol L−1, and 0.6–70.0 µmol L−1, respectively. The detection limits (S/N = 3) were 0.07, 0.2, and 0.1 µmol L−1 for EP, AC, and Trp, respectively. Finally, the sensor was used for determination of EP, AC, and Trp in pharmaceutical and biological samples.
Even though the volume of the earth's water is vast, less than 10 million of the 1 400 million cubic metres of water on the planet is of low salinity and suitable for use after applying conventional water treatment alone. The other 97.5% of the water on our planet is to be found in the oceans, where it is officially classified as seawater. Desalination provides a means of tapping this resource, and in this special feature, Filtration Industry Analyst takes a look at some of the driving forces behind desalination worldwide…
This paper presents an evolutionary battery impedance estimation method, which can be easily embedded in vehicles or nomad devices. The proposed method not only allows an accurate frequency impedance estimation, but also a tracking of its temporal evolution contrary to classical electrochemical impedance spectroscopy methods. Taking into account constraints of cost and complexity, we propose to use the existing electronics of current control to perform a frequency evolutionary estimation of the electrochemical impedance. The developed method uses a simple wideband input signal, and relies on a recursive local average of Fourier transforms. The averaging is controlled by a single parameter, managing a trade-off between tracking and estimation performance. This normalized parameter allows to correctly adapt the behavior of the proposed estimator to the variations of the impedance. The advantage of the proposed method is twofold: the method is easy to embed into a simple electronic circuit, and the battery impedance estimator is evolutionary. The ability of the method to monitor the impedance over time is demonstrated on a simulator, and on a real Lithium ion battery, on which a repeatability study is carried out. The experiments reveal good tracking results, and estimation performance as accurate as the usual laboratory approaches.
Skeletal remodelling is a continuous process during life and is still active also in extreme senescence. In the elderly, bone resorption often prevails over bone formation, causing bone loss and fragility. Elderly subjects are exposed to the risk of fractures, and loss of self-sufficiency, if considering that the proximal femur is the most frequently involved site. Bone remodelling can maintain circulating calcium within physiological ranges, at the expense of a substantial loss of this ion from the skeleton, particularly during senescence. Calcium metabolism is regulated at cellular/molecular level by a network of cytokines, growth factors, systemic hormones that act on bone in paracrine/autocrine/systemic fashion. Among the molecules involved in bone metabolism, parathyroid hormone (PTH) and vitamin D present some peculiar aspects during senescence. The osteometabolic features in a consistent group of centenarians have been evaluated. It results that a severe hypovitaminosis D was present in 99 out of 104 centenarians (25-OH vitamin D below 5nmol/L), and that it plays an important role as a factor inducing a vicious circle involving hypocalcemia, secondary hyperparathyroidism, together with biochemical features indicating a consistent bone loss. Serum C-terminal cross-linking telopeptide, a specific marker of bone resorption was elevated in 92% of these subjects. Moreover, it has been found that several femoral fractures had occurred after 90 years of age. These data offer a rational for the possible prevention of elevated bone turnover, bone loss and consequently the reduction of osteoporotic fractures and fractures-induced disability, in the oldest olds, through the simple supplementation with calcium and vitamin D.
Proliferation of low-cost, lightweight, and power efficient sensors and advances in networked systems enable the employment of multiple sensors. Distributed estimation provides a scalable and fault-robust fusion framework with a peer-to-peer communication architecture. For this reason, there seems to be a real need for a critical review of existing and, more importantly, recent advances in the domain of distributed estimation over a low-cost sensor network. This paper presents a comprehensive review of the state-of-the-art solutions in this research area, exploring their characteristics, advantages, and challenging issues. Additionally, several open problems and future avenues of research are highlighted.
Carbon aerogels are a unique class of high-surface-area materials derived by sol–gel chemistry. Their high mass-specific surface area and electrical conductivity, environmental compatibility and chemical inertness make them very promising materials for many energy related applications, specifically in view of recent developments in controlling their morphology. In this perspective we will review the synthesis of monolithic resorcinol–formaldehyde based carbon aerogels with hierarchical porosities for energy applications, including carbon nanotube and graphene composite carbon aerogels, as well as their functionalization by surface engineering. Applications that we will discuss include hydrogen and electrical energy storage, desalination and catalysis.