batterydata/paper-abstracts huggingface dataset:
The lithium ion intercalation/de-intercalation behavior of SrLi2Ti6O14 is studied using in-situ X-ray diffraction (in-situ XRD) and in-situ electrochemical impedance spectroscopy (in-situ EIS) techniques. Significant volume expansion and contraction is observed during Li+ intercalation and de-intercalation, respectively. At voltages of 2.5–0.5 V, the entire Li+ intercalation process can be divided into two stages. In stage I, corresponding to the 2.5–1.3 V range, ∼60.2% lithium intercalation capacity is obtained with only ∼40.3% relative lattice volume expansion. In contrast, only an ∼39.8% lithium intercalation capacity is obtained with 59.7% lattice volume expansion in stage II, which occurs in a voltage range of 1.3–0.5 V. The results from in-situ EIS reveal that a relatively small charge transfer resistance R ct can be obtained for charging/discharging at voltages of 2.5–1.3 V. Moreover, R ct increases with increasing lattice volume expansion when lithium is inserted into the SrLi2Ti6O14 lattice at voltages lower than 1.3 V. Cyclic testing in different voltage ranges shows that, compared with ranges of 2.5–0.8 V and 1.42–0.8 V, the best cyclic performance is achieved at voltages of 2.5–1.3 V. This may be attributed to reduced changes in the lattice volume and decreased lithium intercalation resistance.
Since the heterogeneity of oceanographic conditions drives abundance, distribution, and availability of prey, it is essential to understand how foraging predators interact with their dynamic environment at various spatial and temporal scales. We examined the spatio-temporal relationships between oceanographic features and abundance of fin whales (Balaenoptera physalus), the largest free-ranging predator in the Western Mediterranean Sea (WM), through two independent approaches. First, spatial modeling was used to estimate whale density, using waiting distance (the distance between detections) for fin whales along ferry routes across the WM, in relation to remotely sensed oceanographic parameters. At a large scale (basin and year), fin whales exhibited fidelity to the northern WM with a summer-aggregated and winter-dispersed pattern. At mesoscale (20–100km), whales were found in colder, saltier (from an on-board system) and dynamic areas defined by steep altimetric and temperature gradients. Second, using an independent fin whale satellite tracking dataset, we showed that tracked whales were effectively preferentially located in favorable habitats, i.e. in areas of high predicted densities as identified by our previous model using oceanographic data contemporaneous to the tracking period. We suggest that the large-scale fidelity corresponds to temporally and spatially predictable habitat of whale favorite prey, the northern krill (Meganyctiphanes norvegica), while mesoscale relationships are likely to identify areas of high prey concentration and availability.
A facile precursor-separated hydrothermal synthesis (PSHS) method was developed to synthesize LiFePO4 nano-crystallines at low temperature where the iron sulfate solution precursor was packed in polymer film to divide it from Phosphoric acid and Lithium hydroxide before reaction. X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) were adopted to characterize the morphology and crystal structure of the products. The electrochemical properties and conductivity of the products were also investigated. This method avoided the probably generated Fe3+ at the precursors mixing process. The particle size was reduced to nanoscale without any additives. The as-prepared product showed excellent electrochemical properties especially rate capability. The reaction mechanism of this method was also studied.
We present a novel and facile strategy to prepare porous N-doped carbon coated MnO (MnO@NC-Z) nanospheres through solvent-free in-situ growth of ZIF-8 on ZnMn2O4 followed by carbonization. The obtained MnO@NC-Z nanospheres are composed of numerous MnO nanoparticles that are uniformly coated by an ultrathin (∼5 nm) and nitrogen-rich (∼3.7 wt%) carbon layer derived from the in-situ grown ZIF-8 layer, which could not only restrict the volume expansion of MnO during the charge-discharge process but also substantially improve the electrical conductivity. Meanwhile, the synthesized MnO@NC-Z also possesses a high porosity and large specific surface area due to the porous structure of the ZIF-8 precursor and the evaporation of nano-sized Zn reduced from the ZIF-8 during the carbonization process, which could facilitate the fast transport of Li ions. As the anode in lithium-ion batteries (LIBs), the prepared MnO@NC-Z nanospheres deliver excellent performance with a high reversible capacity of 1261 mA h g−1 at 0.2 A g−1, brilliant rate performance of 305 mA h g−1 at a high rate of 5 A g−1, and excellent cycling stability for 1000 cycles at 1 A g−1 with a 96.5% capacity retention. Importantly, this solvent-free strategy of in-situ growth of ZIF-8 can also be extended to synthesize various metal oxides@carbon composites (e.g., FeOx@NC and CoOx@NC) for different applications such as energy storage and conversion.
A multi-layer core–shell structural LiFeBO3/C has been successfully synthesized via spray-drying and carbothermal method using LiBO2·8H2O, Fe(NO3)3·9H2O, and citric acid as starting materials. The Rietveld refinement results indicate the sample consists of two phases: LiFeBO3 [94(6)% w/w], and LiFeO2 [6(4)% w/w]. SEM images show that the LiFeBO3 powders consist of rough similar-spherical particles with a size distribution ranging from 1 μm to 5 μm. TEM results present that the LiFeBO3 spherical particles are well coated by nano-carbon webs and form a multi-layer core–shell structure. The amount of carbon was determined to be 6.50% by C/S analysis. The prepared LiFeBO3–LiFeO2/C presents an initial discharge capacity of 196.5 mAh g−1 at the current density of 10 mA g−1 between 1.5 and 4.5 V, and it can deliver a discharge capacity of 136.1 mAh g−1 after 30 cycles, presents excellent electrochemical properties, indicating the surface sensitivity in the air was restrained.
In this report, we have designed a novel SnO2 nanosheets/nickel/polyvinylidene fluoride ternary composite as anode materials for lithium ion batteries. The SnO2 nanosheets are uniformly coated on the surface of nickel/polyvinylidene fluoride conductive fiber, as confirmed by XRD, SEM, and TEM characterizations. As an anode material for lithium ion batteries, this as-prepared ternary composite delivers a high capacity of 865.4mAhg−1 at 200mAg−1 after 60 cycles. Furthermore, the SnO2 in this composite material exhibits a good capacity retention as well as rate capability. This result indicates the completely reversible reaction between Li4.4Sn and SnO2, greatly improving the specific capacity of SnO2. The ternary SnO2/Ni/PVDF composite limits the volume expansion on lithium insertion, and buffer spaces during charge/discharge, resulting in the excellent cyclic performances.
Attaining high energy density and power density in a single energy storage device is still a major challenge for electrochemical energy storage research community. Sodium-ion hybrid supercapacitor is a sustainable energy storage system which accomplishes the gap between battery and supercapacitor comprises of high energy density-battery type faradaic anode and high power density-supercapacitor type non-faradaic cathode. Here we have reported high surface area (1554m2 g−1) activated porous carbon obtained from naturally occurring viscous liquid honey as a cathode and sol-gel derived, V2O5 nanorods anchored reduced graphene oxide (rGO) nanocomposite as an anode for non- aqueous sodium-ion capacitor. When explored honey derived carbon as a non-faradaic cathode, it exhibits a higher specific capacitance of 224Fg−1 and V2O5@rGO anode delivers the maximum capacitance of 289Fg−1 at 0.01Ag−1 vs Na/Na+. The prepared V2O5@rGO anode has long stable cycle life (V2O5 nanorods@rGO retains 85% of the initial capacitance (112.2Fg−1) at the current density of 0.06Ag−1 after 1000 cycles). The assembled sodium-ion capacitor (NIC) using honey derived activated carbon (AC) and V2O5@rGO anode delivers the energy density of ≈65Whkg−1 and power density of ≈72Wkg−1 at 0.03Ag−1. The capacity retention is 74% after 1000 cycles at the current density of 0.06Ag−1. The assembled sodium-ion hybrid capacitor delivers maximum energy and power density and exhibits very long stable cycle life.
Porous nanowires of Co3O4/Carbon composite have been synthesized by using a simple and inexpensive electrospinning technique. The as-prepared materials were investigated by X-ray diffraction and scanning electron microscopy. The electrochemical properties of the composite have been characterized using cyclic voltammetry and galvanostatic methods. The results show a remarkably improved electrochemical performance in term of reversible capacity, rate capability, and cycling performance.
A facile and simple solid-state reaction route is developed to synthesize F-doping and V-defect Na3V1.98(PO4)3-xF3x/C composites. F-doping is facilitated to decrease the particle size to diminish the pathway of Na+ diffusion. Beneficial by-products are generated due to F-doping and V-defect, Na3PO4 is a typical Na ion conductor and NaVO2 has the layer structure for rapid migration of Na+. The synergetic effect of F-doping and V-defect on the Na+ diffusion is significant. The kinetic behavior is dramatically enhanced and it is beneficial to reinforcing the electrochemical performance. Meanwhile, the extraction of the third Na+ at Na1 site is observed at 4.0 V corresponding to the V4+/V5+ redox couple. The optimized Na3V1.98(PO4)2.9F0.3/C composite delivers an initial charge capacity as high as 143.5 mAh g−1 and an 116.9 mAh g−1 discharge capacity at 0.1C. A reversible capacity of 100.6 mAh g−1 is obtained and it retains 89.3% capacity after 100 cycles at 1C. It presents the highest D Na + (3.66 × 10−13 cm2s−1), close to three orders of magnitude higher than the Na3V2(PO4)3/C (7.41 × 10−16 cm2s−1). Moreover, Ex situ XRD results demonstrate that broadened channels along x and y directions are favorable to improving D Na + and it exhibits the highest D Na + when charging to 3.4 V.
Objectives The aim of the current study was to develop sex and age-adjusted criterion-referenced fitness standards to predict independent physical functioning into later life. Design Cross-sectional. Setting National Survey of Physical Fitness and Physical Activity, Portugal. Participants A national representative sample of 3074 non-institutionalized older adults (65–84years). Measurements Projected capacity for physical independence was assessed by the Composite Physical Function (CPF) scale, and physical fitness was assessed using the Senior Fitness Test battery. ROC analyses were used to evaluate the classification accuracy of physical fitness components, and determine the best cutoff values of functional fitness to predict loss of independence. Stepwise multivariate logistic regression was used to identify sex and age category fitness components that were predictors of independence with follow-up ROC analysis to verify the model's discriminative capability. Results ROC curve analysis showed that the fitness tests were good in diagnosing physical independence (AUC>0.7). Logistic regression models demonstrated that different fitness components should be targeted according to age and sex, but with an emphasis on aerobic endurance and agility/dynamic balance. Overall, models provided higher AUC (males: 0.79–0.86; females: 0.73–0.85) when comparing the best fitness tests for each sex and age category. The sensitivity of newly developed models ranged from 80.5 to 87.7 in males and from 68.2 to 86.3 in females, while the specificity ranged from 62.1 to 73.8 in males and between 58.2 and 82.9 in females. Conclusion The Senior Fitness Test provides a good field tool that allows the identification of fitness levels that older adults need to achieve to be physically independent later in life, and permits the accurate planning and implementation of exercise-based interventions for older adults.
This paper aims to develop a multi-colored electrochromic device based on mixed mono- and bi-substituted 4,4′-bipyridine derivatives containing an ester group. A series of these derivatives were synthesized, and their electrochemical and electrochromic properties were studied through cyclic voltammetry and ultraviolet–visible spectroscopy. The mono- and bi-substituted 4,4′-bipyridine derivatives containing an ester group displayed different onset bias and colored state. Mono-substituted 4,4′-bipyridine derivatives showed a magenta colored state at an onset bias of − 1.3 V; bi-substituted 4,4′-bipyridine derivatives showed violet colored states at an onset bias of − 0.8 V. A multi-colored electrochromic device was achieved by mixing mono- and bi-substituted 4,4′-bipyridine derivatives as the electrochromic layer.
In this paper a detailed in-situ XRD investigation of structural properties as well as lithium diffusion coefficient determination of LiMn2O4, LiMn1.5Ni0.5O4 and LiMn1.5Ni0.45Cu0.05O4 cathode materials are presented. Kinetics of Li+ intercalation/deintercalation mechanism are corroborated with structural changes of the cathode materials during electrochemical reactions. In was found that substitution of Mn by Ni and Cu in LiMn2O4 ions leads to single-phased electrochemical operational mechanism in LixMn1.5Ni0.45Cu0.05O4 in the whole examined lithium concentration range.
This paper presents a comprehensive assessment of sensorimotor deficits in the mouse after focal ischaemia induced by occlusion of the middle cerebral artery. Twenty four hours after induction of middle cerebral artery occlusion, mice showed deficits in a range of sensory and motor tasks as assessed by the SHIRPA protocol. In addition they exhibited a decrease in rotarod performance and locomotor activity. Some behaviours, such as locomotor activity, were also impaired in sham operated animals compared to normal controls, although these impairments were not as marked as those exhibited by the ischaemic mice. This is the first comprehensive analysis of the short term effects of permanent focal ischaemia in mice. In a second series of experiments in the rat, rates of recovery over time were examined. Simple (neurological grades, rotarod) and complex (sticky label test) tasks were examined in rats after middle cerebral artery occlusion up to 7 days post-ischaemia. Ischaemic rats had a profound deficit in contralateral performance on the sticky label task with no evidence of recovery. A less marked deficit was also observed in ipsilateral performance of this task. These deficits were still present 7 days after ischaemia. Ischaemic rats also exhibited a deficit on rotarod performance but this had recovered 7 days post-ischaemia. Thus different sensorimotor tasks have different rates of recovery after focal cerebral ischaemia in the rat. Further characterisation of these tasks will enhance their utility meaningful preclinical means of assessing functional recovery of the administration of potential neuroprotective and regenerative therapies.
Charcot foot arthropathy is a potentially limb-threatening condition that leads to progressive destruction of the bones and joints in the neuropathic foot. One of its main causes is diabetes mellitus whose prevalence is steadily increasing. The acute phase is often misdiagnosed thus leading to foot deformity, ulceration and increased risk of amputation. There is a paucity of literature on this condition from sub-Saharan Africa. This study aimed at determining the extent of Charcot foot arthropathy, the radiological patterns of Charcot foot arthropathy and patient’s factors associated with Charcot foot arthropathy among adult patients with longstanding diabetes in an African setting.
Unlike traditional fossil fuel plants, the wind and the sun provide power only when the renewable resource is available. To accommodate large scale use of renewable energy sources for efficient power production and utilization, energy storage systems are necessary. Here, we introduce a scalable energy storage system which operates by performing cycles during which energy generated from renewable resource is first used to produce highly concentrated brine and diluate, followed up mixing these two solutions in order to generate power. In this work, we present theoretical results of the attainable energy density as function of salt type and concentration. A linearized Nernst-Planck model is used to describe water, salt and charge transport. We validate our model with experiments over wide range of sodium chloride concentrations (0.025–3 m) and current densities (−49 to +33 A m−2). We find that depending on current density, charge and discharge steps have significantly different thermodynamic efficiency. In addition, we show that at optimal current densities, mechanisms of energy dissipation change with salt concentration. We find the highest thermodynamic efficiency at low concentrate concentrations. When using salt concentrations above 1 m, water and co-ion transport contribute to high energy dissipation due to irreversible mixing.
This work aims exploring the high performance porous separators that can be activated into gel electrolyte membranes for lithium ion batteries. A comb-like copolymer poly (dimethylsiloxane) graft poly (propylene oxide)-block-poly (ethylene oxide) (PDMS-g-(PPO-PEO)) was synthesized and blended with poly (vinylidene ﬂuoride) (PVDF) to fabricate porous separators via a typical phase inversion process, and then the separators absorbed liquid electrolyte solution and formed into polymer electrolyte membranes. By measuring the composition, morphology and ion conductivity etc, the influence of PDMS-g-(PPO-PEO) on structure and properties of blend separators were discussed. Compared with pure PVDF separator with comparable porous structure, the adoption of PDMS-g-(PPO-PEO) decreased the crystallinity and increased the liquid electrolyte uptake and stability effectively. It was also found that the electrode/electrolyte interfacial resistance could be reduced greatly. The resulting electrolyte membrane using separator with PVDF/PDMS-g-(PPO-PEO) mass ratio in 8/2 exhibited highest ionic conductivity in 4.5×10−3 S/cm at room temperature, while the electrochemical stability was up to 4.7V (vs. Li/Li+). Coin cells assembled with such separators also exhibited stable cycle performance and improved rate capabilities, especially when discharge rate higher than 0.5C.
Electrochromic (EC) materials can be integrated in thin-film devices and used for modulating optical transmittance. The technology has recently been implemented in large-area glazing (windows and glass facades) in order to create buildings which combine energy efficiency with good indoor comfort. This critical review describes the basics of EC technology, provides a case study related to EC foils for glass lamination, and discusses a number of future aspects. Ample literature references are given with the object of providing an easy entrance to the burgeoning research field of electrochromics.
Power consumption is a critical problem affecting the lifetime of wireless sensor networks. A number of techniques have been proposed to solve this issue, such as energy-efficient medium access control or routing protocols. Among those proposed techniques, the data compression scheme is one that can be used to reduce transmitted data over wireless channels. This technique leads to a reduction in the required inter-node communication, which is the main power consumer in wireless sensor networks. In this article, a comprehensive review of existing data compression approaches in wireless sensor networks is provided. First, suitable sets of criteria are defined to classify existing techniques as well as to determine what practical data compression in wireless sensor networks should be. Next, the details of each classified compression category are described. Finally, their performance, open issues, limitations and suitable applications are analyzed and compared based on the criteria of practical data compression in wireless sensor networks.
Pyrolytic carbon-coated Si/C nanofibers (Si/C-CNFs) composites have been prepared through the sucrose coating and secondary thermal treatment of Si/CNFs composites produced via electrospinning and carbonization. This results in a structure in which Si nanoparticles are distributed along the fibers, with the fiber surface being coated with an amorphous carbon layer through pyrolysis of the sucrose. This carbon coating not only limits the volume expansion of the exposed Si nanoparticles, preventing their direct contact with the electrolyte, but also creates a connection between the fibers that is beneficial to Li+ ion transport, structural integrity, and electrochemical conductivity. Consequently, the Si/C-CNFs composite exhibits a more stable cycle performance, better rate performance, and higher conductivity than Si/CNFs alone. The optimal level of performance was attained with a 20:200 mass ratio of sucrose to deionized water, with a high retained capacity of 1215.2 mAh g−1 after 50 cycles, thus indicating that it is a suitable anode material for Li-ion batteries.
Lithium sulfur batteries (LSBs) are attractive owing to the high theoretical capacities of sulfur cathode active material (1672mAhg−1) and lithium anode active material (3862mAhg−1), which leads to a specific energy of approximately 2600Whkg−1. However, for any rechargeable batteries employing lithium metal as the anode, a major failure mechanism is uncontrolled dendrite formation, which presents serious safety issues, low Coulombic efficiency and poor cycle performance. Recently, researchers make great effort to overcome these problems. Here we summarize some methods for suppressing lithium dendrite growth based on the failure mechanism of LSBs, mainly including novel separator, anode modification and electrolyte modification. We also discuss the advantages and disadvantages of different methods and point out the challenges that still needed to be addressed for building better LSBs.
Water-oxygen electrochemistry is at the heart of key renewable energy technologies (fuel cells, electrolyzers, and metal-air batteries) due to the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Although much effort has been devoted to the development of improved bifunctional electrocatalysts, an inexpensive, highly active oxygen electrocatalyst, however, remains to be a challenge. In this paper, we present a facile and robust method to create gently reduced graphene oxide incorporated into cobalt oxalate microstructures (CoC2O4/gRGO) and demonstrate its excellent and stable electrocatalytic activity in both OER and ORR, arising from the inherent properties of the components and their physicochemical interaction. Our synthesis technique also explores a single pot method to partially reduce graphene oxide and form CoC2O4 structures while maintaining the solution processability of reduced graphene oxide. While the OER activity of CoC2O4/gRGO is exclusively due to CoC2O4, which transformed into OER-active Co species, the combination with gRGO significantly improves OER stability. On the other hand, CoC2O4/gRGO exhibits synergistic effect towards ORR, via a quasi-four-electron pathway, leading to a slightly higher ORR limiting current than Pt/C. Remarkably, gRGO offers dual functionality, contributing to ORR activity via the N-functional groups and also enhancing OER stability through the gRGO coating around CoC2O4 structures. Our results suggest a new class of metal-carbon composite that has the potential to be alternative bifunctional catalysts for regenerative fuel cells and metal-air batteries.