batterydata/paper-abstracts huggingface dataset:
Layer-by-layered SnS2/graphene (LL-SnS2/G) hybrid nanosheets are fabricated via a simple ball-milling of SnS2 nanoplates obtained through hydrothermal treatment and commercial graphene. When assessed as anode materials for LIBs, LL-SnS2/G shows a high initial reversible capacity of 696.27 mAh g−1 with a high initial coulombic efficiency (74.16%) at 200 mA g−1, and negligible capacity fading over 180 cycles. Moreover, LL-SnS2/G also has an excellent rate capability, which delivers a high capacity of 567.78 mAh g−1 at 2000 mA g−1. Benefits from synergism between SnS2 nanoplates with high specific capacity and graphene, the graphene increases the conductivity of SnS2, buffers the volume change during lithiation/de-lithiation processes, and provides an effective physical barrier between the active materials and the electrolyte to suppress the shuttle effect of polysulfides formed during de-lithiation processes. LL-SnS2/G shows excellent electrochemical performance and is a promising anode material candidate for lithium ion batteries.
Structural changes and their relationship with thermal stability of charged Li0.33Ni1/3Co1/3Mn1/3O2 cathode samples have been studied using time-resolved X-ray diffraction (TR-XRD) in a wide temperature from 25 to 600°C with and without the presence of electrolyte in comparison with Li0.27Ni0.8Co0.15Al0.05O2 cathodes. Unique phase transition behavior during heating is found for the Li0.33Ni1/3Co1/3Mn1/3O2 cathode samples: when no electrolyte is present, the initial layered structure changes first to a LiM2O4-type spinel, and then to a M3O4-type spinel and remains in this structure up to 600°C. For the Li0.33Ni1/3Co1/3Mn1/3O2 cathode sample with electrolyte, additional phase transition from the M3O4-type spinel to the MO-type rock salt phase takes place from about 400 to 441°C together with the formation of metallic phase at about 460°C. The major difference between this type of phase transitions and that for Li0.27Ni0.8Co0.15Al0.05O2 in the presence of electrolyte is the delayed phase transition from the spinel-type to the rock salt-type phase by stretching the temperature range of spinel phases from about 20 to 140°C. This unique behavior is considered as the key factor of the better thermal stability of the Li1−xNi1/3Co1/3Mn1/3O2 cathode materials.
This study shows that the amount of linearly decodable information for categorical-orthogonal object tasks (for example, position, scale, pose, perimeter and aspect ratio) increases up the ventral visual hierarchy, ultimately matching human levels in inferior temporal cortex. It also provides a computational model that explains how this pattern of information arises.
The importance of mobile groupware systems resides in the specific tasks that they can perform and other systems cannot. On the one hand, groupware systems allow groups of users to work together providing facilities that single-user systems are unable to offer. On the other hand, unlike stationary systems, mobile systems allow users to work on the move. The intersection of these two technologies offers a new support for activities, such as spontaneous collaboration, that could be facilitated neither by stationary groupware systems nor by mobile single-user systems. However, implementations of this new support are uncommon, probably because of the high development effort required and the seemingly little benefit obtained. In this paper, we aim to reduce this effort by facilitating the development of mobile groupware applications that support such activities. Our proposal to achieve this objective involves the design and implementation of the Face-to-Face Mobile Interaction (F2FMI) toolkit, whose goal is to provide generic and reusable software components required in most cases. We expect this strategy to yield a higher variety of successfully deployed applications, which in turn will demonstrate the benefits of supporting this kind of interactions through mobile devices.
In this work we report a non-aqueous electrolyte that supports long-term operation of the Li/air battery in dry ambient environments based on a non-hydrolytic LiSO3CF3 salt and a low volatility propylene carbonate (PC)/tris(2,2,2-trifluoroethyl) phosphate (TFP) solvent blend. By measuring and analyzing the viscosity of PC/TFP solvent blends, the ionic conductivity of electrolytes, and the discharge performance of Li/air cells as a function of the PC/TFP weight ratio, we determined the best composition of the electrolyte is 0.2m (molality) LiSO3CF3 7:3wt. PC/TFP for Li/O2 cells and 0.2m LiSO3CF3 3:2wt. PC/TFP for Li/air cells. Discharge results indicate that Li/air cells with the optimized electrolyte are significantly superior in specific capacity and rate capability to those with baseline electrolytes. More interestingly, the improvement in discharge performance becomes more significant as the discharge current increases or the oxygen partial pressure decreases. These results agree neither with the viscosity of the solvent blends nor the ionic conductivity of the electrolytes. We consider that the most likely reason for the performance improvement is due to the increased dissolution kinetics and solubility of oxygen in TFP-containing electrolytes. In addition, the electrolyte has a 5.15V electrochemical window, which is suitable for use in rechargeable Li/air batteries.
A well-controlled chemical synthetic protocol was developed to prepare a novel conductive, polypyrrole (PPy)/cellulose nanocrystal (CNC) system that is simple, cost-effective and scalable. Carboxylic acid groups were grafted onto CNC via a TEMPO-mediated oxidation providing strong hydrogen bonding to enhance adsorption of pyrrole monomers (Py). In-situ chemical polymerization of Py was further performed on a single high aspect ratio CNC. The nanotemplating of CNC controlled the deposition and growth of the polymer layer, which enhanced the electrochemical properties of PPy. Improved processibility of PPy was achieved due to the high mechanical strength and good dispersibility of CNC. By varying the ratio of Py to surface hydroxyl groups of CNCs (Py/OH) systematically, an optimal composition of Py/OH of 16:1 was observed. The mechanism of the electrochemical performance change associated with Py/OH molar feeding ratio was also studied in detail using different spectrometry and SEM methods. PPy/CNC hybrid nanostructures possessed an attractive specific capacitance of 248 F g−1, suitable for supercapacitor applications and exceeding the performance of comparable systems based on carbon nanotubes and graphenes. Compared with other cellulose-polypyrrole systems whose end-products are typically entangled fiber mat, aerogel or cake-form, our CNC nanorods can be readily dispersed and added as fillers into different matrices. The PPy/CNC hybrid nanostructure is extremely light, conductive, cheap, renewable, environmentally friendly, and our solution-phase chemical synthesis is simple to implement and easy to scale up.
Recently, Shang et al. (Angew Chem Int Ed 57(3):774–778, 2018) have developed a method to synthesize ultrathin (around 1.9 nm) graphyne nanosheets. We reported here the mixed-mode I–II fracture toughnesses and crack growth angles of single-layer graphyne sheets using molecular dynamics (MD) simulations and the finite element (FE) method based on the boundary layer model, respectively. The various carbon–carbon bonds of graphyne sheets in the FE method are equated with the nonlinear Timoshenko beams based on the Tersoff–Brenner potential, where all the parameters of the nonlinear beams are completely determined based on the continuum modeling. All the results from the present FE method are reasonable in comparison with those from our MD simulations using the REBO potential. The present results show that both the critical stress intensity factors (SIFs) and the crack growth angle strongly depend on the chirality and loading angle
This paper presents an optimal sizing method for plug-in proton exchange membrane (PEM) fuel cell and lithium-ion battery (LIB) powered city buses. We propose a theoretical model describing the relationship between components’ parameters and vehicle performance. Analysis results show that within the working range of the electric motor, the maximal velocity and driving distance are influenced linearly by the parameters of the components, e.g. fuel cell efficiency, fuel cell output power, stored hydrogen mass, vehicle auxiliary power, battery capacity, and battery average resistance. Moreover, accelerating time is also linearly dependant on the abovementioned parameters, except of those of the battery. Next, we attempt to minimize fixed and operating costs by introducing an optimal sizing problem that uses as constraints the requirements on vehicle performance. By solving this problem, we attain several optimal sizing rules. Finally, we use these rules to design a plug-in PEM fuel cell city bus and present performance results obtained by on-road testing.
Ultrafine particles of Co–P were synthesized by direct ball milling of Co and P powders and also investigated as a reversible hydrogen storage electrode material. The electrochemical results demonstrated that the reversible charge–discharge capacity of the Co–P electrode can reach more than 300mAh/g. In addition, the cycling ability and high rate capability of the Co–P electrode are excellent with only 5% capacity decay after 100 cycles at a high rate of 300mA/g. The temperature-programmed desorption measurements (TPD) of the Co–P electrode revealed that the charge and discharge reactions of the Co–P electrode proceeds predominantly through electrochemical hydrogen storage mechanism and the electrooxidation of cobalt contributes only a negligible part to the reversible electrochemical capacity.
Advances in a process based on simple and environmentally compatible operations, aimed to the treatment and recycling of spent lithium-ion batteries, are reported in this paper. This process is safe, economic, and recovers as much of the battery materials as possible. It operates mainly in a selective dissolution in dilute acid, a chemical treatment of the filtrate and a thermal treatment of the solid residue. The validity of the process and its reproducibility have been evaluated at each step of the separation. This method involves very simple equipment and can be scaled-up for commercial production. Based on the projected quantities of lithium ion batteries available for recycling in the next few years, there is a significant market opportunity for a successful technology.
In the present study, an integrated planning model was developed to find economically/environmentally optimized paths toward future smart electricity systems with high level penetration of intermittent renewable energy and new controllable electric devices at the supply and demand sides respectively for regional scale. The integrated model is used to (i) plan the best power generation and capacity mixes to meet future electricity demand subject to various constraints using an optimization model; (ii) obtain detailed operation patterns of power plants and new controllable electric devices using an hour-by-hour simulation model based on the obtained optimized power generation mix. As a case study, the model was applied to power generation planning in the Tokyo area, Japan, out to 2030 in light of the Fukushima Accident. The paths toward best generation mixes of smart electricity systems in 2030 based on fossil fuel, hydro power, nuclear and renewable energy were obtained and the feasibility of the integrated model was proven.
Wind energy is inexhaustible renewable. Unlike conventional fossil fuels, wind energy is clean, abundant energy that will be available for future generations. However, wind speed is a highly stochastic component which can deviate very quickly. Output power of the wind energy conversion system (WECS) is proportional to the cube of wind speed, which causes the output power fluctuation of the wind turbine. The power fluctuation causes frequency fluctuation and voltage flicker inside the power grid. In order to reduce the power fluctuation, various approaches have been proposed in the last decades. This article deals with the review of several power smoothing strategies for the WECS. Power smoothing methods of the WECS are primarily separated into two categories such as energy storage based power smoothing method and without energy storage based power smoothing method. The main objectives of this paper are to introduce operating principles for different power smoothing methods. The energy storage based power smoothing method is effective but installation and maintenance costs of a storage device are very high. According to the literatures review, without energy storage based power smoothing method can reduce the cost of the WECS extensively. Various methods have been proposed to generate a smooth output power of the WECS without energy storage devices. Simulation results are compared among the available methods. From the review of simulation results, the kinetic energy of the inertia control method is the highly efficient power smoothing approach.
Lithium ion battery anodes derived from Sn and Sn oxides have been of considerable interest because they can store twice lithium ions more than the graphite. However, large volume change occurs when lithium ions are inserted and extracted from these active materials, which causes internal damage to electrode and results in the loss of capacity and recharge ability. Here, we prepared sandwich-like CNTs@SnO2/SnO/Sn anodes by using composite electrodeposition and anodic oxidation on three-dimensional (3D) Ni foam. It is shown that the phases of C, Sn2+, Sn4+ and Sn are the sandwich-like structure in CNTs@SnO2/SnO/Sn anode. Such a 3D anode can provide more superior electrochemical, mechanical properties and extra space to get good cycle performance with the first discharge capacity of 1260mAhg−1 and 99% coulombic efficiency.
This work uses real-time in situ neutron powder diffraction to study the electrode lattice response and anode phase evolution in a commercial lithium-ion battery. We show that the time-resolved lattice response of the Li x CoO2 cathode and Li x C6 anode under non-equilibrium conditions varies proportionally with the applied current, where higher current results in faster structural change. Higher current also reduces the Li x CoO2 cathode c lattice parameter and the LiC6 quantity that forms at the charged state of the battery, both of which are related to lower battery capacity. At the anode, we find that the Li x C6 phase evolution is current-dependent.
We introduce a one-step process that consists of thermal disproportionation and impurity doping to enhance the reversible capacity and electrical conductivity of silicon monoxide (SiO)-based negative electrode materials in Li-ion batteries. Transmission electron microscope (TEM) results reveal that thermally treated SiO at 900 °C (H–SiO) consists of uniformly dispersed nano-crystalline Si (nc-Si) in an amorphous silicon oxide (SiOx) matrix. Compared to that of prinstine SiO, the electrochemical performance of H–SiO shows improved specific capacity, due mainly to the increased reversible capacity by nc-Si and to the reduced volume expansion by thermally disproportionated SiOx matrix. Further electrochemical improvements can be obtained by boron-doping on SiO (HB–SiO) using solution dopant during thermal disproportionation. HB–SiO electrode without carbon coating exhibits significantly enhanced specific capacity superior to that of undoped H–SiO electrode, having 947 mAh g−1 at 0.5C rate and excellent capacity retention of 93.3% over 100 cycles. Electrochemical impedance spectroscopy (EIS) measurement reveals that the internal resistance of the HB–SiO electrode is significantly reduced by boron doping.
This paper proposes a real-time energy management system (EMS) suitable for rooftop PV installations with battery storage. The EMS is connected to a smart grid where the price signals indirectly control the power output of the PV/battery system in response to the demand variation of the electricity networks. The objective of the EMS is to maximize the revenue over a given time period while meeting the battery stored energy constraint. The optimization problem is solved using the method of Lagrange multipliers. The uniqueness of the proposed EMS remains in the reactive real-time control mechanism that compensates for the PV power forecast error. The proposed EMS requires only forecasting the average PV power output over the total optimization period. This is in contrast to the predictive power scheduling techniques that require accurate instantaneous PV power forecast. The proposed EMS method is verified by benchmarking against the predictive brute-force dynamic programming (DP) approach. The simulation analysis considers days with varying solar irradiance profiles. The simulation analysis shows the proposed EMS operating under practical assumptions, where the battery storage capacity is subject to constraints and the PV power output is not known a priori.
We present a fabrication of scalable coaxial core/shell silicon (Si)-graphene fiber prepared by dual-nozzle-induced wet-spinning assembly for high-performance Si anode. Over 50 wt% of Si nanoparticles mixed with graphene oxide suspension can be incorporated in the core with the outstanding dispersibility of unique silver-coated Si nanoparticles in aqueous media. The core fiber is further encapsulated by graphene shell which not only provides conducting pathways, but also alleviates severe volume expansion of Si core. This novel core/shell Si anode with double locked graphene architecture delivers more stable cycle performance and superior rate capability than anodes composed of simple mixture of Si-graphene composites.
The investigation of the aging and degradation mechanism of lithium ion batteries in automotive and energy storage applications is of particular importance for the acceptance of the battery technology. However, several factors interact to generate complicated battery aging phenomena, thus leading to limited accuracy of the established models when applied to degradation prediction under complex real running conditions. Here, a coupled electrochemical-thermal-mechanical model is presented for the degradation investigation of lithium-ion batteries. The model includes both side reactions on anode and the loss of active material of cathode and is employed to study the aging behavior of the battery applying different C-rates and ambient temperatures. Simulation results indicate that the aging of the battery is dominated by various aging factors under different operating conditions. Higher ambient temperature can accelerate SEI formation reaction, while low temperature can cause severe lithium-plating. Active material loss is affected by cycling current significantly and becomes the dominant aging factor under extremely high C-rate. The model is fitted under two accelerated aging cycles and agrees well with the experimental results.
It is commonly believed that sulci offer a natural path to reach deep-seated lesions. However, it has also been argued that this approach carries a risk of damaging the vessels during the opening of the sulcus. We therefore were prompted to test the possibility of finding a transcortical path identified as non-functional by intraoperative brain mapping. A successful resection is presented of a left posterior isthmus clear cell ependymoma through a selected corridor based on functional mapping in an awake patient. MRI performed at 12 months showed no tumour recurrence. Pre- and postoperative extensive testing confirmed an improvement of the patient's cognitive functions. Therefore, we were able to demonstrate the feasibility of a functionally tailored transcortical approach as an alternative to the transulcal approach for deep-seated lesions. This concept should be validated in a larger patient series.
Publisher Summary The purpose of a control system is to compare the plan to reality and issue commands to the servos or other output devices to make reality follow the plan. A closed loop system is one that measures the error between the rabbit and hound and attempts to minimize the gap without becoming erratic. The classical control theory has been in existence for a very long time. Engineering courses have traditionally taught mathematical techniques involving poles and zeros and very abstract mathematics that beautifully describe the conditions under which a control can be designed with optimal performance. Normally, this involves producing a control system that maintains the fastest possible response to changing input functions without becoming underdamped. Notwithstanding the wondrous advances in computer aided design systems (CAD), dynamically modeling such highly complex systems reliably is often impractical because of the many variables and unknowns. For this reason, when most engineers are confronted with such a task, they seek to find simpler techniques.
Nitrogen doped hierarchically porous 3D porous carbon-graphene/polyaniline (3D PC-g/PANi) hybrid nanocomposites are prepared by a simple in-situ polymerization process. 3D PC is synthesized using bio-waste Bombax malabaricum seeds as the carbon precursor and the interconnected 3D PC-g are prepared by a simple refluxing and activation process with a large specific surface area of 2418 m2 g−1. The specific capacitance (Cp) of 3D PC-g and 3D PC-g/PANi electrodes are 610 and 1198 F g−1 in 1 M H2SO4, respectively at a very high current density of 2 A g−1. Also, a symmetric supercapacitor (SSC) exhibits a high energy density (Ed) of 61 Wh kg−1 and 117 Wh kg−1in 1 M H2SO4 and 0.5 M Na2SO4 electrolytes, respectively. It still persist a high power density (Pd) of 15 kW kg−1 and 20 kW kg−1 with an Ed of 49.1 Wh kg−1 and 84.4 Wh kg−1 at a very high current density of 30 A g−1. Further, an asymmetric supercapacitor (ASC) based on 3D PC-g/PANi as positive and hierarchical porous N-doped porous carbon covered gC3N4 nanosheets (N-P(gCN)-700) as a negative electrode is successfully fabricated, which exhibit a high Ed of 97.5 Wh kg−1 in 0.5 M Na2SO4. The presented results are higher than most of earlier reported PANi based composite carbon electrode materials. Further, the assembled SSC and ASC devices exhibit 94% and 91% capacitance retention even after 10,000 cycles. Furthermore two ASC connected in series can power up red LED for 30 min after charging for 60 s.
This study evaluates the relationship established between active/inactive material of LiFePO4 (LFP) composites and the contributions arising from electronic conduction/Li+ ionic transport during electrochemical performance of a Li-ion cell. A traditional electrode preparation technique is used to assembly four electrode compositions (LFP/C-SP: 94/06, 86/14, 80/20 and 74/26), selected around the percolation threshold, which are subsequently characterized using voltammetry, rate capabilities, electrochemical impedance spectroscopy and scanning electron microscopy. ∼7wt% of carbon Super P (C-SP) is determined as the electric percolation threshold from the conductivity curves collected for binary components: LFP:C-SP and PVDF:C-SP. Cyclic voltammetry and rate capability plots reveal that electronic conduction (∼10−2 Scm−1) of composites (80/20 and 74/26) above the percolation threshold do not present any impact in the rate capabilities of LFP cathode, whence this increase of C-SP only shrinks capacity, which is more emphasized at high C-rates. Thus, it is suggested that the excess of binder and conductive carbon beyond the percolation threshold generates the ion-blocking effect of PVDF, and ionic transport pathways are extended. A well interconnected network with an efficient amount of binder avoiding particle segregation and carbon disconnection is determined for the 86/14 ratio, likewise, obtaining better rate capabilities, electrode stability and properties during 50 cycles. This differs from the traditional composition used to assembly these composites (80/20).