batterydata/paper-abstracts huggingface dataset:
Objective The effectiveness of deep brain stimulation (DBS) depends on both the frequency and the temporal pattern of stimulation. We quantified responses to cycling DBS with constant frequency to determine if there was a critical on and/or off time for alleviating tremor. Methods We measured postural tremor in 10 subjects with thalamic DBS and quantified neuronal entropy in a network model of Vim thalamic DBS. We tested 12 combinations of cycling on/off times that maintained the same average frequency of 125Hz, four constant frequency settings, and baseline. Results Tremor and neural firing pattern entropy decreased as the percent on time increased from 50% to 100%. Cycling with stimulation on for at least 60% of the time was as effective as regular stimulation. All cycling settings reduced the firing pattern entropy of model neurons from the no stimulation condition by regularizing pathological firing patterns, either through synaptically-mediated inhibition or axon excitation. Conclusions These results indicate that pauses present in cycling stimulation decreased its effectiveness in suppressing tremor, and that changes in the amount of tremor suppression were strongly correlated with changes in the firing pattern entropy of model neurons. Significance Cycling stimulation may reduce power consumption during clinical DBS, and thereby increase the battery life of the implanted pulse generator.
We successfully combined electrospinning with in situ polymerization methods to synthesize the PANI-coated ZnFe2O4 nanofibers which possess the abundant pore structure. The lithium storage properties of PANI-coated ZnFe2O4 nanofibers as anode materials for lithium-ion batteries have been discussed for the first time. PANI nanoparticles were directly coated on the surface of the ZnFe2O4 nanofibers, increasing the electrical conductivity, and also acting as the protect shell to enhance the mechanical strength of material. The electrochemical performance showed that 15% PANI incorporated ZnFe2O4 composite nanofibers (ZP-15) exhibited the highest reversible capacity of 1142 mAhg−1 after 50 cycles, which was much higher than that of pure ZnFe2O4 nanofibers (628 mAhg−1), 10% PANI incorporated ZnFe2O4 composite nanofibers (ZP-10, 975 mAhg−1), and 20% PANI incorporated ZnFe2O4 composite nanofibers (ZP-20, 536 mAhg−1). Additionally, the ZP-15 composite nanofibers achieved outstanding cycling rate capacity of 852, 738, 609 and 539 mAhg−1 with current densities range from 500 to 5000 mA g−1, and exhibited a specific capacity of 1082 mAhg−1 when the current reverted to 50 mA g−1 from the high rate charge-discharge cycles. The enhanced electrochemical performance of PANI-coated ZnFe2O4 nanofibers can be attributed to the PANI providing a highly electrical conductive medium, which can promote electron transfer and facilitate the Li+ transport in the lithiation/delithiation process, also can reduce self-discharge; moreover, the PANI layer covered on the surface of ZnFe2O4 nanofibers can be as buffer matrix to restrain the stress of volume expansion to get stable structure.
Despite many studies and several extensive reviews of redox flow batteries (RFBs) over the last three decades, information on engineering aspects is scarce, which hinders progress with scale-up and implementation of this energy storage technology. This review summarises cell design requirements then critically considers design, construction and cell features together with their benefits and problems, leading to good practice through improved cell performance, knowledge and experience. Techniques for the characterisation of the reaction environment are illustrated by measurements of mass transport to (and from) electrode surfaces as a function of flow conditions, as well as pressure drop and electrolyte flow dispersion. The influence of design features on performance is illustrated by the effect of process conditions on the components of cell potential. Adequate attention to engineering aspects is seen to be critical to the effective performance of RFBs, particularly during scale-up and long-term operation. Techniques for the characterisation of reaction environment are summarised and a list of essential design and construction factors is provided. Finally, critical areas needing research and development are highlighted.
The nanostructure of nickel oxide was controlled using two different synthesis methods and its influence on cyclability, charge/discharge capacity and mass transport of Li+ ions at the Li-ion battery anode was examined. Effective diffusion coefficients were calculated using the current pulse relaxation technique and a new model was derived and applied to deconvolute the mass transport of Li+ through the NiO and Li2O+Ni phases. The NiO phase diffusion coefficients were found to be independent of the material geometry; however, the diffusion coefficient of Li+ in the Li2O+Ni phase was strongly dependent on the electrode geometry. Results suggest that controlled nanosized crystallites of NiO are preferred as they result in smaller average grain boundary sizes for the Li2O+Ni phase formed during cell charging. This has several benefits including better accessibility of the Li2O+Ni phase during discharge, yielding improved cycle life, a decreased Li+ path length leading to lower tortuosity and a larger grain boundary area allowing more in-plane Li+ transport.
NiO–Ni nanocomposite was prepared by calcining a mixture of Ni2(OH)2CO3 and ethanol in a tube furnace at 700°C for 45min in air. The microstructure and morphology of the powders were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). In the composite, nanoscale Ni particles (<10nm) were dispersed in the NiO matrix (about 100nm). Electrochemical tests showed that the nanocomposite had higher initial and reversible capacity than pure NiO. The presence of the nanoscale Ni phase had improved both of the initial coulombic efficiency and the cycling performance, due to its catalytic activity, which would facilitate the decomposition of Li2O and the SEI during the charge process.
For the Lithium-Sulfur (Li-S) battery to be competitive in commercialization, it is requested that the sulfur electrode must have deliverable areal capacity>8 mAh cm−2, which corresponds to a sulfur loading>6mgcm−2. At this relatively high sulfur loading, we evaluated the impact of binder and carbon type on the mechanical integrity and the electrochemical properties of sulfur electrodes. We identified hydroxypropyl cellulose (HPC) as a new binder for the sulfur electrode because it offers better adhesion between the electrode and the aluminum current collector than the commonly used polyvinylidene fluoride (PVDF) binder. In combination with the binder study, multiple types of carbon with high specific surface area were evaluated as sulfur hosts for high loading sulfur electrodes. A commercial microporous carbon derived from wood with high pore volume showed the best performance. An electrode with sulfur loading up to 10mgcm−2 was achieved with the optimized recipe. Based on systematic electrochemical studies, the soluble polysulfide to insoluble Li2S2/Li2S conversion was identified to be the major barrier for high loading sulfur electrodes to achieve high sulfur utilization.
Pseudocapacitance is generally associated with either surface redox reactions or ion intercalation processes without a phase transition. Typically, these two mechanisms have been independently studied, and most works have focused on optimizing one or the other in different material systems. Here we have developed a strategy based on solubility contrast, in which the contribution from the two capacitive mechanisms is simultaneously optimized. Taking layered birnessite MnO2 as a model, controllable nanostructures and oxygen vacancies are achieved through a simple coprecipitation process. Simultaneously controlling crystallite size and defect concentration is shown to enhance the charging-discharging kinetics together with both redox and intercalation capacitances. This synergistic effect results from enhanced ionic diffusion, electronic conductivity, and large surface-to-volume ratio. In addition, considerable cycling durability is achieved, resulting from improved framework strength by defect creation and the absence of proton (de)intercalation during discharge/charge. This work underscores the importance of synergistically regulating nanostructure and defects in redox-active materials to improve pseudocapacitive charge storage.
The intercalation of Li ions in natural graphite that was purified by chemical and thermal processes was investigated. A new chemical process was developed that involved a mixed aqueous solution containing 30% H2SO4 and 30% NH x F y heated to 90°C. The results of this process are compared to those obtained by heating the natural graphite from 1500 to 2400°C in an inert environment (thermal process). The first-cycle coulombic efficiency of the purified natural graphite obtained by the chemical process is 91 and 84% after the thermal process at 2400°C. Grinding the natural graphite before or after purification had no significant effect on electrochemical performance at low currents. However, grinding to a very small particle size before purification permitted optimization of the size distribution of the particles, which gives rise to a more homogenous electrode. The impurities in the graphite play a role as microabrasion agents during grinding which enhances its hardness and improves its mechanical properties. Grinding also modifies the particle morphology from a 2- to a 3-D structure (similar in shape to a potato). This potato-shaped natural graphite shows high reversible capacity at high current densities (about 90% at 1C rate). Our analysis suggests that thermal processing is considerably more expensive than the chemical process to obtain purified natural graphite.
Sodium ion batteries (SIBs) have achieved much attention and actively developed. Among possible anode materials of SIBs, nanosized metallic antimony is one of the most promising ones. However, the large volume changes of Sb and insufficient cyclability still remain a huge challenge for the large-scale applications. Herein, the effect of different Sb contents (named as C@Sb, C@Sb-L and C@Sb-H) on electrode performance, morphology, stability, and sodium storage mechanism has been systematically evaluated for the first time by a feasible electrospinning technique. As a result, the as-prepared C@Sb nanofibers exhibit excellent sodium storage performance with high-rate performance of 272.1 mAh g−1 at 20 A g−1, large reversible discharge capacity of 437.6 mAh g−1 after 300 cycles at 1 A g−1 and ultralong cycling life of 4000 cycles at 5 A g−1, such a cycling performance and high-rate capability for the C@Sb anode has rarely been reported. The significantly enhanced performance is ascribed to the synergetic effects between the well-dispersed ultrafine Sb nanoparticles and the N-rich 3D conductive carbon network structure. This homogeneously dispersed structure of ultrafine Sb nanoparticles encapsulated in the carbon network can dramatically improve the volume change and particle aggregation of Sb during ultralong charge/discharge process, thus solving the major problems of pulverization, loss of electrical contact and low utilization rate facing Sb anode. In addition, the full cell of Na3V2(PO4)3@C//C@Sb shows a high output potential of about 2.75 V and a discharge capacity of 264.3 mAh g−1 after 500 cycles at 1 A g−1. Those promising results should provide the basis for the potential large-scale application of Sb-based materials as high-performance anode for SIBs.
The passive layer formed on lithium in a PEO20–LiTFSI–5%PC gel polymer electrolyte after different electrochemical processes was characterized using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and electrochemical impedance spectroscopy (EIS). EIS indicates that the interface resistance of lithium electrodes increases with time after fresh lithium deposition, whereas the interfacial resistance has no change with time after lithium deposition/dissolution process. The XPS analysis as well as FTIR data show that the main compositions of the passive layer are ROCO2Li, Li2CO3, LiOH, LiX (X=F, S, N, SO2CF3) and Li oxides, mostly due to the reactions occurred between lithium and PC, LiTFSI, and trace impurities (H2O, O2), and the lithium dissolution process has no distinctive effect on the composition of passive layer. XPS depth profile of the passive film detected by XPS and sputtering experiments further demonstrates that the presence of Li2CO3/LiOH is in the outer layer and Li2O, LiF mainly in the inner part of the passive layer.
Waste prevention has been addressed in the literature in terms of the social and behavioural aspects, but very little quantitative assessment exists of the environmental benefits. Our study evaluates the environmental consequences of waste prevention on waste management systems and on the wider society, using life-cycle thinking. The partial prevention of unsolicited mail, beverage packaging and food waste is tested for a “High-tech” waste management system relying on high energy and material recovery and for a “Low-tech” waste management system with less recycling and relying on landfilling. Prevention of 13% of the waste mass entering the waste management system generates a reduction of loads and savings in the waste management system for the different impacts categories; 45% net reduction for nutrient enrichment and 12% reduction for global warming potential. When expanding our system and including avoided production incurred by the prevention measures, large savings are observed (15-fold improvement for nutrient enrichment and 2-fold for global warming potential). Prevention of food waste has the highest environmental impact saving. Prevention generates relatively higher overall relative benefit for “Low-tech” systems depending on landfilling. The paper provides clear evidence of the environmental benefits of waste prevention and has specific relevance in climate change mitigation.
Policies and laws encouraging the development of renewable energy systems in China have led to rapid progress in the past 2 years, particularly in the solar cell (photovoltaic) industry. The development of the photovoltaic (PV) and wind power markets in China is outlined in this paper, with emphasis on the utilization of lead-acid batteries. The storage battery is a key component of PV/wind power systems, yet many deficiencies remain to be resolved. Some experimental results are presented, along with examples of potential applications of valve regulated lead-acid (VRLA) batteries, both the absorbed glass mat (AGM) and gelled types.
Laccases are used in numerous applications, from green degradation of various xenobiotic compounds, waste detoxification, textile dye bleaching, and delignification of lignocellulose materials to biofuel production. In this study, the recombinant Yarrowia lipolytica YL4 strain carrying the white-rot fungus Trametes versicolor laccase IIIb gene was used for laccase production from beet molasses as an agro-industrial residue. Response surface methodology was used to statistical optimization of the production of laccase by Y. lipolytica using an industrial medium containing molasses which allows a six times increase in laccase activity compared to primary medium contains glucose after 144 h. In bioreactor cultivation after 48 h, laccase production reached to 3.7- and 22.5-fold more than optimized and primary media in shake-flask cultures, respectively. Laccase productivity in bioreactor (0.0937 U/h) was higher than shake-flask culture (0.0084 U/h). The present study provides valuable information about statistical optimization of bioprocess development for cost-effective production of laccase and other heterologous proteins in Y. lipolytica from beet molasses as sole carbon source, thus allowing the valorization and decreasing environmental pollution of this agro-industrial waste.
In this study, we demonstrate a facile method to fabricate a flexible alloyed copper/silicon core-shell nanoflowers structure anchored on the three-dimensional graphene foam as a current collector. This combination provides flexible and free-standing structure and three-dimensional conductive network, allowing unique properties for current collection and transmission. The copper oxide nanoflowers are synthesized on the three-dimensional graphene foam by a simple electrodeposition and etching, which serves as an outstanding template to retard the stress effects during the lithiation/delithiation of silicon. After the silicon coating uniformly deposited on the copper oxide nanoflowers, a simple hydrogen annealing was applied to reduce copper oxide nanoflowers and form the copper/silicon alloy, remarkably enhancing the conductivity of silicon. Moreover, this structure can be directly assembled without any conductive additive or binder. In electrochemical testing, the resulting copper/silicon core-shell nanoflowered electrode demonstrates a high initial capacity of 1869 mAh g−1 at 1.6 A g−1, with a high retention rate of 66.6% after 500 cycles. More importantly, at a high current density of 10 A g−1, this anode still remains a high capacity retention >63% (compared with the highest capacity 679 mAh g−1), offering enormous potential for energy storage applications.
Three-dimensional hollow microtubular carbonized kapok fiber/cobalt-nickel binary oxide hybrid composites were successfully prepared based on the low-cost natural kapok fiber by combining a simple hydrothermal technique and calcination method. The three-dimensional hollow tubular structure was kept well during the preparation process. The surface morphologies of the as-prepared three-dimensional carbonized kapok fiber/cobalt-nickel binary oxide hybrids changed from the cross-linked fibrous network to the nanoflakes with the increase in the calcination temperature. The composites prepared at 600°C for 2h exhibited a high specific capacity with 502.4Cg−1 at discharge currents of 0.25Ag−1 in 6.0M KOH, and the capacity retention was still maintained at 97.5% after 5000 cycles demonstrating good electrochemical stability. In addition, a hybrid supercapacitor device was also assembled using active carbon and the as-prepared composite as negative and positive electrodes, respectively. It could be operated within a wide potential window of 0.0–1.6V with a high specific energy of 23.2Whkg−1. In addition, the hybrid supercapacitor also exhibited excellent rate capability as well as long-term stability after 5000 cycles. The high reversible capacity of the obtained electroactive hybrid composites can be ascribed to the unique hollow tubular structure, the large surface area, the high defective carbon matrix and the synergetic effect of hybrid electroactive components. Therefore, the as-prepared three-dimensional hollow microtubular hybrids are expected to develop high-performance supercapacitor.
We analyze the performance of IEEE 802.15.4 MAC with superframe structure including the inactive period where each device is in non-saturated conditions. The superframe structure with a inactive period has the following two primary characterizations: (i) deferment of packet transmission until the following active period due to insufficient backoff slots for completing the packet transmission, (ii) high competition in the head part of the active period due to packets which were deferred from the previous active period and were arrived during the previous inactive period. These characterizations complicate the construction of a mathematical model of MAC with the superframe structure including a inactive period. In this paper, we construct a discrete time Markov chain (DTMC) model which takes into account these characterizations. By analyzing the DTMC, we obtain the main performance measures such as throughput, packet delay distribution, packet loss probability and energy consumptions of devices and the PAN coordinator. We demonstrate high accuracy of the proposed model by comparing the numerical results with simulation results. Finally, we optimize the lengths of the beacon interval and the active period to maximize the battery life of devices while satisfying quality-of-service (QoS) constraints on packet delay and packet loss probability.
In this paper, we present an ultrasonically controlled switching system that can save the battery power for implantable devices by turning the system on and off, on-demand. Ultrasonic control is employed to reduce the device size, increase the penetration depth, and reduce misalignment sensitivity associated with alternative techniques using permanent magnet and RF signal. As a proof-of-concept demonstration, a 665 kHz ultrasonic signal is used to activate a piezoelectric receiver which in turn switches a battery-powered RF system on-and-off. In-vitro tests show a reliable switching functionality at distances of up to 8 cm while consuming 43.5 nW (14.5 nA current consumption with 3 V power supply) when the system is in off-state, a factor of 10–100 times lower than the sleep-mode power consumption of typical RF SoC systems. The dimension of fabricated prototype is 6.3 × 16.7 × 2‍ mm3 allowing it to be easily incorporated into many existing implantable devices.
Thermal batteries are primary disposable systems specially designed to develop a high energy density in a short period. In the present work, the modeling of heat generation and propagation within three Ca/CaCrO4 thermal batteries has been carried out, using a transient model. The commercial CFD software Phoenics® has been used and, through a typical finite volume approach, the related 2D transport equations have been solved, giving the time-dependent temperature profiles. To check the quality of the model, the temperature of pseudo-equilibrium state (a typical thermodynamic parameter), has been analyzed. The temperatures related in the literature were close to those calculated. The results also indicate that the fusion of electrolytes is virtually an instantaneous process when compared to the time to reach the pseudo-equilibrium state, which indicates that the generation of electrical current occurs immediately after the thermite burning.
Silicon (Si) is considered to be a promising next-generation anode material for lithium-ion batteries. However, the large volume change during (de)lithiation processes causes fracture of Si electrodes, thereby limiting Si’s practical application in lithium-ion batteries. In this work, we formulate a variational-based fully chemo-mechanical coupled computational framework to study diffusion induced large plastic deformation and phase field fracture in Si electrodes. Into this framework we incorporate a recently developed reaction-controlled diffusion model to predict two-phase lithiation for amorphous Si (a-Si) and crystalline Si (c-Si) as well as diffusion induced anisotropic deformation for c-Si. The variational formulation suggests to consider the deformation field, the chemical potential, and the damage field as primary unknowns. The concentration field is considered as a local variable and is recovered from the chemical potential on the element level. We carry out several numerical simulations to show the performance of our computational model and point out the significance of accurately accounting for the presence of the reaction front when modeling diffusion induced fracture problems for both a-Si and c-Si electrodes. In addition, we investigate how the fracture energy release rate, electrode geometry, and geometrical constraints affect the fracture behavior of Si electrodes.