batterydata/paper-abstracts huggingface dataset:
Considering the charming merits and natural defects of Li4Ti5O12 (LTO), we build a hierarchical LTO/C composite through a rational hydrothermal route by utilizing the low-cost glucose as carbon source. The obtained composite consists of some grain-like secondary particles (10–15nm) pasted on the relatively bulk LTO sheets (50–100nm). Due to the introduction of carbon, the composite has the smaller particle size, lower polarization and superior electrical conductivity. Besides, the as-prepared sample exhibits good cycling stability and outstanding rate performance. It delivers the discharge capacity of 174.1mAhg−1 at 1C and left 131.7mAhg−1 even at 50C, which is apparently superior than pristine LTO. Furthermore, the discharge capacity maintains 93.4% after 500 cycles at 1C and 80.5% after 1000 cycles at 50C. Even after 3000 ultralong cycles at 5C, the value still retains 74.2% which is much higher than that of pure LTO (38.4%). The ideal proportion of carbon modified in LTO is also explored. The LTO/C-3.74wt% composite is demonstrated to possess optimal electrochemical performance.
To replace conventional carbon, silicon has been widely proposed as a next-generation negative electrode (anode) material for lithium-ion batteries. In this study, Si and SiMo x -alloy deposited by an RF-magnetron sputtering system is investigated by means of X-ray diffraction, ex situ Raman spectroscopy and transmission electron microscopy. Electrochemical tests are conducted and four different Si and SiMo x -alloy electrodes and their structures and textual properties are characterized with X-ray photoelectron spectroscopy. The surface morphologies of the electrodes are also observed using field-emission scanning electron microscopy. The electrochemical properties of the electrodes are examined through cycling tests and electrochemical impedance spectroscopy. The results show that rough Cu foil and Mo as alloy materials help Si to retain its discharge capacity and overcome volume expansion during charging and discharging. After a few cycles, the Si electrode severely loses capacity, whereas the SiMo x -alloy electrodes display good cycle retention and high capacity. The SiMo0.79 electrode gives an initial capacity of 1319mAhg−1 that decreases to 1180mAhg−1 after 100 cycles (89.4%).
A new technique for synthesizing double layer anodes with silicon monoxide and Li powder has been developed to reduce the initial capacity loss of silicon monoxide anodes. Double layer anode (DLA) cells are fabricated using Li emulsified powders on a Cu foil and silicon monoxide powders on a Cu mesh collector and their electrochemical behaviors are studied. The DLA cells show reduced initial irreversibility and enhanced coulombic efficiency. The coulombic efficiency of the first cycle of the DLA cell is over 100% and its capacity remains as 700mAhg−1 up to 20 cycles. SEM observation shows that the Li-powder layer in DLA compensated for the initial irreversible loss and vanished after several cycles.
The study aims to identify potential neurocognitive indicators of an enhanced risk for developing psychosis. N =44 patients meeting clinical inclusion criteria for initial prodromal states (IPS) who developed psychosis within a median interval of 10 months were compared to N =39 IPS patients not developing psychosis within a minimum interval of 1 year (median 36 months), and to N =44 healthy controls on a comprehensive neuropsychological test battery (pattern recognition, divided and sustained attention, spatial and verbal working memory, verbal/visual memory, speed of processing, executive and intellectual functions). IPS patients who converted to psychosis performed worse than healthy controls on all broad neurocognitive domains. They were more impaired than IPS patients not developing psychosis on the Subject Ordered Pointing Task (SOPT; working memory), verbal memory functions, verbal executive, verbal IQ and speed of processing tests. After a Bonferroni–Holms adjustment for multiple testing differences on SOPT, Digit-Symbol Test, and verbal IQ remained significant (effect sizes d =0.54–0.88). Neurocognitive predictors had a sensitivity of 0.75 and a specificity of 0.79. Results support several cognitive domains as indicators of vulnerability to psychosis, and additionally suggest that subtle deficits in verbal abilities (working and long-term memory, executive and intellectual functions) and decreased speed of processing may help to predict conversion to psychosis in a clinically defined IPS group.
This paper addresses the problem of management and coordination of energy resources in a typical microgrid, including smart buildings as flexible loads, energy storages and renewables. The overall goal is to provide a comprehensive and innovative framework to maximize the overall benefit, still accounting for possible requests to change the load profile coming from the grid and leaving every single building or user to balance between servicing those requests and satisfying his own comfort levels. The user involvement in the decision-making process is granted by a management and control solution exploiting an innovative distributed model predictive control approach with coordination. In addition, also a hierarchical structure is proposed, to integrate the distributed MPC user-side with the microgrid control, also implemented with an MPC technique. The proposed overall approach has been implemented and tested in several experiments in the laboratory facility for distributed energy systems (Smart RUE) at NTUA, Athens, Greece. Simulation analysis and results complement the testing, showing the accuracy and the potential of the method, also in the perspective of implementation.
Si–SiO2–C composites are synthesized by ball milling the mixture of SiO, graphite and coal pitch, and subsequent heat treatment at 900°C in inert atmosphere. The electrochemical performance and microstructure of the composites are investigated. XRD and TEM tests indicate that the carbon-coating structure of Si–SiO2–C composites form in pyrolysis process, which can remarkably improve the electrochemical cycling performance. The coal pitch as carbon precursor and graphite demonstrate the same important effect on the Li-alloying/de-alloying property of the Si–SiO2–C composites. The Si–SiO2–C composites exhibit the electrochemical reversible Li-alloying/de-alloying capacity of 700mAhg−1 and excellent cyclic stability even at about the 90th cycle.
Nanocomposites of nickel manganese layered double hydroxide (NiMn-LDH) and reduced graphene-oxide (rGO) with different loadings of rGO were synthesized by a simple solution-based in situ crystallization process. The synthesized composites were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron (FE-SEM) and high-resolution transmission electron (HR-TEM) microscopic techniques, energy dispersive X-ray analysis (EDX), and surface area and pore size analyses. The electrochemical activities of the NiMn-LDH/rGO nanocomposites were examined in aq. KOH in a three electrode assembly. It turned out that the composite of NiMn-LDH/rGO (NM/RG2) exhibited the highest electrochemical activity with excellent stability when compared to other compositions as well as pristine NiMn-LDH and rGO. The large surface area and enhanced conductivity due to the presence of the rGO in the NiMn-LDH/rGO composite are responsible for such high electrochemical activity. A solid-state hybrid energy-storage device consisting of NiMn-LDH/rGO composite as a positive electrode and rGO negative electrode exhibited the higher energy and power densities. The proto-type hybrid energy-storage device assembled using NiMn-LDH/rGO and rGO, was used to demonstrate the operation of a toy fan and a LED.
A facile and scalable in situ synthesis strategy is developed to fabricate MoS2/C nanosheets encapsulated in Sn@SnOxnanoparticlesasahigh-performancelithiumionbatteryanodematerial. (*) With assistance of NaCl particles, MoS2/C nanosheets can be in situ synthesized with Sn@SnOx nanoparticles encapsulated. In the constructed architecture, the MoS2/C nanosheets can not only avoid the direct exposure of Sn@SnOx to the electrolyte and preserve the structural and interfacial stabilization of Sn@SnOx nanoparticles, but also accommodate the mechanical stress induced by the volume change of Sn@SnOx nanoparticles during the charge/discharge process. As a result, tested as an anode material, the Sn@SnOx@MoS2@C composite exhibits super-high rate capability (950mAhg−1 at 0.2Ag−1, 815mAhg−1 at 0.5Ag−1, 715mAhg−1 at 1.0Ag−1, 625mAhg−1 at 2.0Ag−1 and 500mAhg−1 at 5.0Ag−1) and extremely excellent cycling performance at high rate (a high capacity of 530mAhg−1 is achieved after 800 cycles at current density of 2.0Ag−1). The outstanding electrochemical performance of the composite indicates high potential as anode material for high-performance lithium ion battery.
As the interest in energy storage units is increasing in the power sector, significant effort is being put into evaluating technological and business opportunities. However, many studies narrow their examinations and pursue a single goal, which may create false enthusiasm for energy storage. To tackle such issues, complex technical-economical case studies are necessary, with solid input data and real life applications, where the application of storage could generate revenue. In this paper, a recent study is presented, which aimed to examine the profitability of an energy storage unit, installed at an industrial or commercial consumer. The storage strategy was created through an optimization process considering two aspects: to decrease the power draw from the grid during peak hours and to decrease energy consumption of peak hours by shifting the needs to off-peak periods. A quasi-automatic decision support system was developed, which can determine parameters of the storage unit based on user defined inputs. Market potential of the idea was evaluated using data of a group of potential customers. Results have shown that the specified application can create positive net present value under certain circumstances.
Lithium transport through such transition metal oxides as Li1+δ [Ti5/3Li1/3]O4, Li1−δ NiO2 and Li δ V2O5 was investigated by analysis of current transients. All the experimental current transients in shape deviated markedly from the Cottrell character during the whole intercalation/deintercalation, and the initial current level varied linearly with the applied potential step according to Ohm's law. Moreover, it was observed that the current transient during phase transformation is characterised by a ‘current plateau’. The current transient was simulated as a function of applied potential by numerical analysis assuming ‘cell-impedance-controlled’ lithium transport. The numerically simulated current transient featured quantitative behaviour characteristic of non-Cottrell behaviour and exhibited a ‘current plateau’. The lithium transport mechanism through the oxides is discussed in terms of ‘cell-impedance-controlled’ intercalation/deintercalation.
Chao-Jun Li gives a personal perspective on research that won the 2001 Presidential Green Chemistry Challenge Award (academic category)
Chao-Jun Li received a Ph.D at McGill University and did postdoctoral research at Stanford University. Since 1994, he has been at the Chemistry Department of Tulane University as an Assistant Professor, Associate Professor (1998), and Professor (2000–present). He received a National Science Foudnation’s Early CAREER Award (1998), a Tulane's Eli Lilly Teaching Fellowship (1996), an Outstanding Young Scientist Award (Overseas) from the NFS of China (2000). He served as an International Co-coordinator for the Green Chemistry Workshop in China.
Silicon is considered to be a promising candidate as the anode material for next-generation lithium-ion batteries. However, Si-based material is still facing great challenge to be commercialized due to the unsatisfied cycle life and rate capability. Here, we demonstrate a facile and low-cost method to prepare two-dimension (2D) silicon nanosheets from natural vermiculite, which is an earth-abundant non-metallic mineral with stratified structure. The obtained porous 2D silicon material (Ver-Si) exhibits promising electrochemical performance with a reversible capacity of 900 mAh g−1 and high capacity retention. The promising electrochemical performance is originated from the unique 2D mesoporous structure, which can facilitate charge (Li-ion and electron) transportation and electrolyte penetration, as well as accommodate the volume changes during cycling.
Introduction Les troubles psychocomportementaux (TPC) sont fréquents dans la maladie d’Alzheimer (MA). Leur impact quotidien pèse sur l’évolution cognitive et fonctionnelle des patients et la qualité de vie de leur entourage. Objectifs Évaluer les bénéfices cognitifs, fonctionnels et comportementaux de la mémantine chez des patients ayant des TPC aux stades modérés à sévères de MA. Méthodes À partir de trois essais randomisés mémantine contre placebo sur 24/28 semaines, chez des patients aux stades modérés à sévères de MA (n = 983), était sélectionnée une sous-population de 593 patients au score de Neuro-Psychiatric Inventory (NPI)1 pour au moins un des trois items Agitation/Agressivité (77 %), Délire (57 %), Hallucinations (29 %). Les patients sous placebo (n = 287) et mémantine (n = 306) étaient comparables aux plans démographiques, cognitifs et comportementaux. Résultats La mémantine améliorait significativement les 3 items du NPI (p < 0,01) à 12 semaines (55 % contre 44 % au placebo) et à 24/28 semaines (58 % contre 45 % au placebo). La mémantine était efficace (p < 0,001) sur la cognition (Severe Impairment Battery), l’analyse fonctionnelle (Alzheimer Disease Cooperative Study Activities of Daily Living), l’impression globale (Clinician's Interview-Based Impression of Change plus Caregiver Input). Les TPC survenaient moins sous mémantine (24 % contre 37 % au placebo, 24/28 semaines, p < 0,01). Discussion Agitation, agressivité, délires et hallucinations aggravent l’évolution cognitive et fonctionnelle des patients, accélèrent leur institutionnalisation, et retentissent sur la qualité de vie des aidants. La mémantine diminue l’intensité des TPC présents et prévient aussi leur émergence. Cet effet bénéfique a des conséquences significatives sur la cognition et les activités de la vie quotidienne. Conclusion La mémantine améliore ou stabilise les patients ayant des TPC aux stades modérés à sévères de MA. Elle traite également ces TPC et prévient leur émergence.
New organic acid mixtures have been investigated to recover the valuable metal ions from the cathode material of spent Li-ion batteries. The cathodic active material (LiCoO2) collected from spent Li-ion batteries (LIBs) is dissolved in mild organic acids, iminodiacetic acid (IDA) and maleic acid (MA), to recover the metals. Almost complete dissolution occurred in slightly excess (than the stoichiometric requirement) of IDA or MA at 80°C for 6h, based on the Co and Li released. The reducing agent, ascorbic acid (AA), converts the dissolved Co(III)- to Co(II)-L (L=IDA or MA) thereby selective recovery of Co as Co(II)-oxalate is possible. The formation of Co(III)- and Co(II)-L is evident from the UV–Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive-complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids.
Lithium-sulfur (Li-S) batteries have been recognized as one of the promising next-generation energy storage devices owing to their high energy density, low cost and eco-friendliness. As for cathode’s performance, the main challenges for developing highly-efficient and long-life Li-S batteries are to retard the polysulfides diffusion into electrolyte and the reaction with metallic lithium (Li). Especially, the safety issues, derived from metallic Li in anode, must be overcome. Herein, we fabricated lithium sulfide@porous carbon composites (Li2S@PC) by an in-situ reaction between the lithium sulfate (Li2SO4) and the pyrolytic carbon from glucose. The nanosized Li2S particles were uniformly distributed in the carbon matrix, which not only significantly improve electronic conductivity of the electrode but also effectively trap the dissolved polysulfides. Furthermore, on the basis of the graphite’s electrochemical features in ether-based electrolyte, we assembled graphite-Li2S@PC full cells using the obtained Li2S@PC composites as the cathode, graphite as the anode and the DOL/DME with LiNO3 additive as the electrolyte. A unique strategy was proposed to activate the full-cells in descending order using constant voltage and current to charge the cut-off voltage. This Li-S full cell exhibits stable cycling performance at 0.5 C over 100 cycles. Because graphite-Li2S batteries are suitable to the lithium-ion batteries industry, our preliminary results here will shed a new light on the cell design and industrial production.
The high variability and uncertainty introduced into modern electrical distribution systems due to decentralized renewable energy generators requires new solutions for grid management and power quality assurance. One of these possible solutions includes grid integrated energy storage. The appropriate size and placement of decentralized storage is highly dependent on purpose of the battery system and expected operational strategy. However, battery operational strategies are difficult to simulate simultaneously during a sizing and placement planning calculation. The motivation of this paper is to propose an algorithm that is capable of integrating sizing, placement and operational strategies of batteries into an Optimal Power Flow (OPF) distribution grid planning tool. The choice of the OPF approach permits to account for grid constraints which is more adapted for grid-connected storage devices compared to other approaches in the state of the art that are based only on an email balance analysis. This paper presents an alternating current (AC) multi-temporal OPF algorithm that uses a convex relaxation of the power flow equations to guarantee exact and optimal solutions with high algorithmic performance. The algorithm is unique and innovative due to the fact that it combines the simultaneous optimization of placement and sizing of storage devices taking into account load curves, photovoltaic (PV) production profiles, and distribution grid power quality constraints. The choice to invest in battery capacity is highly sensitive to the price of battery systems. The investment in battery systems solely for reducing losses an operational costs was proven not to be cost effective, however when battery systems are allowed to buy and sell electricity based on variable market prices they become cost effective. The assumptions used for this study shows that current battery system prices are too high to be cost effective even when allowing battery system market participation.
Ag/PVP nanocomposites were prepared by a chemical reduction process. Then, a drop-casting method was employed to deposit the Ag/PVP nanocomposite thin film on the glass substrate. To study the optical and structural properties of the prepared sample, different characterization methods including UV–Vis absorption spectroscopy, scanning electron microscopy, XPS, and Raman spectroscopy were employed. The optical nonlinearity of the prepared thin films was evaluated by the Z-scan technique using a He–Ne laser beam (632 nm). Results showed that the nonlinear refraction index (n2 ~ 10−6 cm2/w) and nonlinear absorption coefficient (β ~ 10−1 cm/w) of the prepared Ag/PVP nanocomposite thin film are higher than the previously reported values. A weak thermal optical nonlinearity was also observed and the nonlinear response dominantly resulted from the electronic origin.
A long cycle-life, high-voltage supercapacitor featuring an activated carbon//poly(3-methylthiophene) hybrid configuration with N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid, a solvent-free green electrolyte, was developed. The cyclability of a laboratory scale cell with electrode mass loading sized for practical uses was tested at 60°C over 16,000 galvanostatic charge–discharge cycles at 10mAcm−2 in the 1.5 and 3.6V voltage range. The reported average and maximum specific energy and power, specific capacitance and capacity, equivalent series resistance and coulombic efficiency over cycling demonstrate the long-term viability of this ionic liquid as green electrolyte for high-voltage hybrid supercapacitors.
This work demonstrates a simple, large scale, cost effective facile route to a well crystallized only anatase TiO2 nanotube synthesized in Schlenk flask at 120°C for 12h in the 8M KOH solution (TNTK) without a Teflon line autoclaves. For the first time all the XRD peaks at 2θ degrees of 25.39, 39.92, 48.11, 54.04, 55.03, 62.73, 68.97, 70.46, 75.48 corresponding to (101), (004), (200), (105), (211), (204), (116), (220), and (215) appeared in the final products contrary to the hydrothermal method where one/two anatase phases, often accompanied by a 2θ peaks at 14.5°. The as prepared nanotubes shows an outer diameter of ∼10nm and inner diameter of ∼4.4nm with a micrometers of tube lengths. It possess a high BET surface area of 203.75 m2/g with band gap of 3.70eV, whereas 8M NaOH solution (TNSNa) at the same condition gives a scattered flowered structure with tapering petals of surface area 71.5 m2/g and a mixed crystal phase of anatase/rutile and sodium hexatitanate. When these nanotubes applied as anode materials in LIBs, it shows an excellent first discharge/charge capacity of 635/240mAhg−1 and retains 164mAhg−1 after 36 cycles much higher than that of titanium dioxide nanoparticles and scattered flowers. The excellent performance can be ascribed to the 1D morphology, enhanced conductivity, fewer localized states near the band edges, high surface area and robustness of tubules which could effectively withstand expansion/contraction occurring during the lithium ion insertion/extraction process. Details of the synthesized nanotubes and electrochemical properties were characterized by HR-TEM, TEM-EDS, FE-SEM, XRD, XPS, UV-vis, electrochemical, CV, impedance and BET surface area techniques.
Oxygen reduction reaction (ORR) and Lithium storage both play the key roles in energy conversion and storage devices. Here, we report a honeycomb-like nitrogen-doped carbon derived from enteromorpha algae (N-EA), using a one-step pyrolysis process at only 600 °C to simultaneously achieve doping, carbonization and activation. After anchoring CoFe2O4 on N-EA, CoFe2O4/N-EA, not only inherits the high surface area, porous structure, active nitrogen species from N-EA, but also benefits from the active sites and high theoretical specific capacity of Li storage from CoFe2O4. The synergistic effect makes CoFe2O4/N-EA an alternative catalyst to commercial Pt/C for ORR with superior activity and stability. Moreover, CoFe2O4/N-EA exhibits a remarkable cycle performance with a 100% capacity retention (∼900 mAh g−1) after 500 cycles at 0.5 A g−1. Green preparation, waste utilization, good ORR performance and Li storage property of CoFe2O4/N-EA could make it a promising candidate for fuel cells and LIBs.