batterydata/paper-abstracts huggingface dataset:
Most composite anode systems research on lithium ion batteries to date focus on pristine unalloyed Si as the electrochemically active component combined with a suitable matrix component that is electrochemically inactive or relatively inactive to lithium ions. Herein, we report the generation of composites by electrochemical synthesis in situ, denoted as Li–Si/C based on Li–Si alloys synthesized as dispersoids in a carbon (C) matrix, as potential anode materials for lithium ion batteries. The electrochemical performance of the Li–Si/C composite of different compositions generated has been systematically studied in order to identify a suitable Li–Si–C composition that could be most effective as a lithium ion anode. The resultant alloy would also exhibit stable electrochemical capacities while expecting to deliver high energy density during discharge with suitable cathode systems. This study shows that the Li–Si/C composite of composition 64at.% C–21.6at.% Li–14.4at.% Si, comprised of Li–Si alloy of compositions in the vicinity of Li–40at.% Si dispersed in the C matrix cycled within the stable potential window of 0.02–0.5V, has the potential characteristics of being a promising anode material displaying excellent capacity retention (∼0.13% loss per cycle) with high specific capacity (∼700mAhg−1), and also expected to deliver high energy density during discharge in the full cell configuration employing a suitable cathode.
The adsorption of 63Ni from aqueous solutions using NKF-6 zeolite was investigated by a batch technique under ambient conditions. The adsorption was investigated as a function of contact time, pH, ionic strength, foreign ions, humic substances (FA/HA) and temperature. The kinetic adsorption was well described by the pseudo-second-order rate equation. The adsorption of 63Ni on NKF-6 zeolite was strongly dependent on pH and ionic strength, and the adsorption of 63Ni increased with increasing NKF-6 zeolite content. At low pH values, the presence of FA enhanced the adsorption of 63Ni on NKF-6 zeolite, but the presence of HA had no drastic effect. At high pH values, the presence of FA or HA decreased the adsorption of 63Ni on NKF-6 zeolite. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic parameters (i.e., ΔH 0, ΔS 0 and ΔG 0) for the adsorption of 63Ni were determined from the temperature dependent isotherms at 293.15, 313.15 and 333.15 °K, respectively, and the results indicate that the adsorption reaction was favored at high temperature. The results suggest that the adsorption process of 63Ni on NKF-6 zeolite is spontaneous and endothermic.
Nanomaterials with different morphologies were placed in discrete layers through the thickness of a negative electrode for a Li ion battery to exploit effectively the intrinsic energy storage capabilities of each nanomaterial morphology and to improve the overall dynamics of Li ion diffusion. The two layer electrode showed a combination of high volumetric capacity and rate capability that surpassed the performance of conventional randomly blended electrodes comprising the same nanomaterials. Local Li ion concentrations were measured through the electrode thickness and clearly showed the benefits of the layered structure over the alternatives. The two layer electrode was fabricated by a flexible and scalable suspension atomization and spray deposition technique with generic potential for improved layered electrodes in a wide range of applications.
In this work,
we develop a device, called ‘Walk-Even’, that can provide real-time feedback to correct gait asymmetry commonly exhibited in post-stroke survivors and persons with certain neurological disorders. The device computes gait parameters, including gait time, swing time, and stance time of each leg, to detect gait asymmetry and provide corresponding real-time biofeedback by means of auditory and electrotactile stimulation to actively correct the user’s gait. The system consists of customized force-sensor-embedded insoles adjustable to fit any shoe size, electrotactile and auditory feedback circuits, microcontroller, and wireless XBee transceivers. The device also offers data saving capability. To validate its accuracy and reliability, we compared the gait measurements from our device with a commercial gait and balance assessment device, Zeno Walkway. The results show good correlation and agreement in a validity study with six healthy subjects and reliability study with seventeen healthy subjects. In addition, preliminary testing on six post-stroke patients after an 8-week training shows that the Walk-Even device helps to improve gait symmetry, foot pressure and forefoot loading of the affected side. Thus, initial testing indicates that the device is accurate in measuring the gait parameters and effective in improving gait symmetry using real-time feedback. The device is portable and low cost and has the potential for use in a non-clinical setting for patients that can walk independently without assistance. A more extensive testing with stroke patients is still ongoing.
Lithium insertion into Sn and SnSb x metallic hosts and the subsequent cycling behavior in polyethylene oxide (PEO)-based polymer electrolytes are examined. Inserted lithium can hardly be extracted from the electrode constituted by coarse tin powder due to the electrical isolation after dramatic host volume changes. Decreasing the host particle size and using intermetallic SnSb x alloy powders greatly enhance the electrode Li extraction capacity and its retention on cycling. The high irreversible capacity in the first cycle linked to the use of ultrafine host powders is compensated by introducing a certain amount of Li2.6Co0.4N into the electrode. Some factors influencing the cell performance are presented and discussed.
Electrode materials are being developed to realise sodium-ion batteries that can provide energy storage solutions. Here, we develop amorphous carbon coated Na7Fe7(PO4)6F3, prepared by combining hydrothermal and solid state reaction methods, as an insertion electrode for sodium-ion batteries applications. Na7Fe7(PO4)6F3 particles are surrounded by a thin layer (∼1.5–2 nm) of amorphous carbon. The Na7Fe7(PO4)6F3/C composite cathode undergoes reversible sodium intercalation/de-intercalation with an average operational potential of ∼3.0 V (vs Na+/Na). This cathode has a capacity of 65 mA h g−1 at 100 mA g−1 current after 60 cycles and features twice higher capacity than that of an uncoated Na7Fe7(PO4)6F3 sample. Therefore, the carbon-coated Na7Fe7(PO4)6F3 composite presents feasible sodium intercalation/de-intercalation capacity, offering possibilities for developing a low cost, high performance sodium-ion battery positive electrode.
The exfoliation of bulk-layered materials into 2D-nanosheets dramatically enhances their surface area and opens up novel properties. The exploitation of these advantageous properties for use in energy storage is, however, conditioned by the effective utilization of the available surface area and the effective combination of 2D-nanosheets holding complementary properties. In this work, a 2D graphene-manganese oxide nanosheet hybrid, in which graphene was interleaved between manganese oxide nanosheets, was synthesized following a novel single-step liquid-phase co-exfoliation method. This active material was used to manufacture supercapacitor electrodes using a scalable spray deposition method. The interleaving of graphene between manganese oxide nanosheets enabled a better use of the pseudocapacitive properties of the manganese oxide nanosheets (the hybrid was tested in a 0.5M K2SO4 aqueous electrolyte) achieving a geometric capacitance of 80mF cm−2 (single electrode), volumetric capacitances of 300F cm−3 (single electrode) and 40.9F cm−3 (symmetric device), and volumetric energy and power of 5.5mWh cm−3 and 2,193.1mW cm−3 (symmetric device), respectively. This performance is promising in the context of micro-supercapacitor applications, where performance per unit area and per unit volume are relevant for miniaturization. This work demonstrates the remarkable versatility of liquid-phase exfoliation to synthesize hybrids with tailored properties providing the proof-of-concept work for further investigation and exploitation of 2D hybrids for supercapacitor applications.
Introduction: Approximately one third of schizophrenia patients show partial or no response to pharmacotherapy. Despite intensive investigations, the phenomenological and biological characteristics of such patients are far from elucidated. This study examined the premorbid behavioral and intellectual functioning of schizophrenia patients who showed poor response to antipsychotic treatment. Method: One hundred twenty-nine schizophrenia patients who showed poor response to treatment were ascertained from a national register and matched by gender, age and education to 129 patients who showed adequate response. The groups were compared on premorbid measures of behavioral and intellectual functions. Results: As a group, treatment-resistant male patients had significantly lower (worse) social functioning [p =0.002], and individual autonomy [p <0.0001] scores before the onset of the illness compared to treatment non-resistant patients. Male and female treatment-resistant patients did not differ from non-resistant patients in premorbid intellectual functioning [p >0.1]. Conclusions: Low premorbid social functioning and individual autonomy, but not intellectual functioning, could serve as predictors of poor treatment response in schizophrenia.
Solar energy is regarded as the most promising source of electricity considering its large magnitude on earth every day. The effective use of such an intermittent energy source relies on development of affordable, inexhaustible and clean solar energy conversion and storage technologies. Here, we design a novel solar-driven regenerative electrochemical system for simultaneous photoelectric energy harvesting and storage. With rational screening of redox species and comprehensive electrochemical study, a high Seebeck coefficient of −1.8 mV K−1 is achieved by solely exploiting earth-abundant materials based on the thermogalvanic effect. A high energy conversion efficiency (1.23%, and 11.9% versus the Carnot efficiency) is achieved under a low temperature gradient of 35 °C. Moreover, the durability of the proof-of-concept device has been examined under solar irradiation employing the bifunctional current collector/solar absorber with good electrical conductivity, efficient solar absorption and photothermal transduction. This innovative cell design integrating simultaneous energy conversion and storage represents an alternative approach towards cost-effective harnessing of solar energy and even more broad thermal energy in ambient environments.
The SnO2/carbon nanotubes encapsulated in graphene sheets (CSGN) composites are synthesized via a sonochemical method which is straightforward, low-cost and operable under ambient conditions. The open spaces formed by carbon nanotubes and graphene offering the accommodation of volume change and the access of an easy electrolyte-wetting, and the improved electrical conductivity by the presence of graphene and carbon nanotubes, lead to the superior cycling performance. As a result, the CSGN with SnO2 content of 61.4 wt% exhibits a reversible specific capacity of 842.9 mAh g−1 at the first cycle and retains 793.8 mAh g−1 after 50 cycles at a current density of 125mAg−1, indicating a high capacity retention rate of 94%. The cycling performance is attributed to the unique structure of CSGN and enhanced electrical conductivity, which may make much sense to the structure designing of other electrode materials for lithium ion batteries.
A nanochain of LiMn2O4 was prepared by a sol–gel method using an aqueous solution of metal salts containing starch. Its electrochemical behavior was characterized by cyclic voltammography, capacity measurement and cycling performance. The results obtained show that the nanochain LiMn2O4 cathode has a very good rate capability. It shows a reversible capacity of 100mAhg−1 at 100mAg−1 (about 1C) and 58mAhg−1 even at a charge rate of 20C. In addition, when the cathode is charged at 1C, 70mAhg−1 (70% capacity at 1C) can be achieved even at a discharge rate of 50C, with a cut-off voltage of 3.0V in 1M LiClO4 solution of EC/DEC/DMC (1:1:1, v/v/v). Furthermore, the cycling behavior of the cathode is also very satisfactory. This suggests that this nanochain LiMn2O4 has great promise for practical application as high rate cathode material for lithium ion batteries.
To apply widely the cathode material lithium manganese oxide (LiMn2O4) with spinel structure, temperature characteristics of LiMn2O4 electrode were studied to decrease the expansion extent by applying different additives in the electrolytes. Different addition contents of 1,3-propane sultone (1,3-PS) and propylene carbonate (PC) in the electrolytes were studied. The results showed PC and 1,3-PS could decrease the thickness variation of cells stored at elevated temperature. Lithium bis(oxalate) borate (LiBOB) additive was investigated to improve the storage characteristics at elevated temperature and cycling performance (25°C) of the cell with LiMn2O4 cathode. The results showed that LiBOB improved remarkably the storage characteristics and cycling performance of the cells. And an advanced electrolyte was developed.
The BeiDou global navigation satellite system (BDS), which is the first satellite navigation system that provides triple-frequency signals on B1, B2, and B3 for civil applications, has been applied widely around the Asian-Pacifica region. The current BDS precise point positioning (PPP) approaches are mainly based on the B1&B2 dual-frequency observations. To make full use of BDS’ triple-frequency observations, the motion sensors measurements, and the platform motion information, this paper proposes an inertial sensor, odometer, and heading measurement tightly aided BDS triple-frequency PPP model. In this model, inertial sensor biases, odometer scale factor, residuals of slant ionospheric delays, and inter-frequency code biases are estimated simultaneously in a unique extended Kalman filter. The Rauch-Tung-Striebel (RTS) smoother is further adopted to reduce the solution's noises and enhance the stability and relative measuring accuracy. To evaluate the capability of this method, a set of triple-frequency BDS raw observations, inertial measurements, odometer data, and heading measurements collected by a customized hardware system on Lanzhou-Urumqi high speed railway track in China, are processed and analyzed. Results illustrated that both positioning accuracy and cycle slip detection capability are upgraded significantly by applying B3 frequency observations in BDS PPP. About 13–55% position accuracy enhancements from B3 observations, inertial sensors, and RTS smoother, and over 70% heading improvements from the aids of heading measurements can be obtained. Moreover, such multi-sensor tight integration system can directly provide millimeter-level positioning accuracy in term of repeatability and provide sub-millimeter-level accuracy indirectly by transforming attitude solutions into distance solutions. Such accuracy is much higher than the state-of-art GNSS and such method presents potential capability in 3D geometry measuring.
The electrochemical performance of nanocrystalline anatase TiO2 electrodes made using sodium carboxymethyl cellulose (CMC) binder, alone and in combination with styrene butadiene rubber (SBR), has been investigated. The electrochemical behavior of these electrodes, which were made via a water-based process, has been compared with those of electrodes manufactured using traditional polyvinylidene difluoride (PVDF) and its copolymer with hexafluoropropylene (PVDF-HFP) in N-methyl-2-pyrrolidone solution. Without the need of any post coating treatment, such as roll pressing, CMC and CMC/SBR based electrodes possess higher specific capacity, rate capability, and cycling stability than those prepared using PVDF or PVDF-HFP as binding agent. Using the same water based process, CMC based LiNi1/3Mn1/3Co1/3O2 (NMC) electrodes have been prepared. The combination of CMC based TiO2 and NMC electrodes in a lab-scale lithium-ion full cell showed a stable cycling performance with a total energy density of more than 120 Wh kg−1. These results demonstrate that anatase TiO2 is an attractive candidate for the development of safer and greener lithium-ion batteries for future application in hybrid and electric vehicles and stimulate further research on this full lithium-ion cell combination.
This paper focuses on modeling, sizing and cost analysis of a photovoltaic (PV)/wind generator (WG)/diesel hybrid system considering two storage devices: battery and fuel cell (FC). In comparison with the traditional PV/WG/diesel/battery systems in which battery banks are used as the storage system, PV/WG/diesel/FC systems combine fuel cell, electrolyzer and hydrogen storage tanks as the energy storage system. For cost analysis, a mathematical model is introduced for each system’s component and then, in order to satisfy the load demand in the most cost-effective way, one discrete version of harmony search (HS) algorithm is developed to optimally size the systems components. As an efficient search method, HS has simple concept, is easy to implement, can escape local optima by use of probabilistic mechanisms, and only needs one initial solution to start its search. Two robust optimization techniques are used for comparison and validation purposes, the simulated annealing (SA) algorithm and HOMER software. In addition the economic aspects of PV/WG/diesel/FC system are compared with those of the traditional PV/WG/diesel/battery system and break down of the total annual cost of the systems is given in detail.
The next generation of tissue engineered constructs (TECs) requires the incorporation of a controllable and optimized microstructure if they are to chemically, mechanically, and biologically mimic tissue function. In order to obtain TECs with optimized microstructures, a combination of spatiotemporally regulated mechanical and biochemical stimuli is necessary during the formation of the construct. While numerous efforts have been made to create functional tissue constructs, there are few techniques available to stimulate TECs in a localized manner. We herein describe the design of a microdevice which can stimulate TECs in a localized, inhomogeneous, and predefined anisotropic fashion using ferromagnetically doped polydimethylsiloxane microflaps (MFs). Specifically, a sequential magneto-structural finite element model of the proposed microdevice is constructed and utilized to understand how changes in magnetic and geometrical properties of the device affect MF deflection. Our study indicates that a relatively small density of ferromagnetic material is required to result in adequate force and MF defection (175 μm ~7% TEC strain). We also demonstrate that MF to magnet distance is more important than inherent MF magnetic permeability in determining resulting MF deflection. An experimental validation test setup was used to validate the computational solutions. The comparison shows reasonable agreement indicating a 5.9% difference between experimentally measured and computationally predicted MF displacement. Correspondingly, an apparatus with two MFs and two magnets has been made and is currently undergoing construct testing. The current study presents the design of a novel magnetic microactuator for tissue engineering applications. The computational results reported here will form the foundation in the design and optimization of a functional microdevice with multiple MFs and magnets capable of stimulating TECs in nonhomogenous and preferred directions with relevant spatial resolution.
This paper proposes an optimal energy management strategy based on the approximate Pontryagin’s Minimum Principle (A-PMP) algorithm for parallel plug-in hybrid electric vehicles (HEVs). When the driving cycles are known in advance, the Pontryagin’s Minimum Principle (PMP) can help to achieve the best fuel economy, but real-time control has been unavailable due to the massive computational load required by instantaneous Hamiltonian optimization. After observing some regular patterns in numeric PMP results, we were inspired to apply a novel piecewise linear approximation strategy by specifying the turning point of the engine fuel rate for the Hamiltonian optimization. As a result, the instantaneous Hamiltonian optimization becomes convex. Considering the engine state, there are only five candidate solutions for the optimization. For the engine off state, only one of the available torque split ratios (TSR) is one of these five candidates. The other four TSR candidates are for the engine on state, including the TSR when the engine operates at the best efficiency point for the current speed, the TSR when the engine delivers all the required torque and two terminal TSRs. The optimal TSR is the one with the smallest Hamiltonian of the current engine state. The engine state with the smallest Hamiltonian will be requested for the next time step. The results show that the A-PMP strategy reduced fuel consumption by 6.96% compared with the conventional “All-Electric, Charge-Sustaining” (AE–CS) strategy. In addition, the A-PMP shortened the simulation time from 6h to only 4min, when compared with the numeric PMP method. Unlike other approximation methods, the proposed novel piecewise linear approximation caused no severe distortion to the engine map model. The engine state switching frequency is also reduced by 43.40% via both the filter and the corresponding engine on/off optimal control strategy.
The main objective of this paper is to determine which voltage regulation strategies best allow grid-tied Photovoltaic (PV) Systems to be integrated into distribution networks. More particularly, this involves performing a literature review on the negative impacts of grid-tied PV systems on distribution networks, and also the current and proposed voltage regulation methods available. The next step is to assess, through simulation, which strategies allow the greatest amount of PV to be integrated with minimal effect on power quality. This will be done by simulating various Medium Voltage (MV) and Low Voltage (LV) radial feeders under varying load conditions and changing solar irradiance levels. Real network data will be incorporated with an accurate model for PV output power to accurately model high penetrations of PV. Our research highlights the necessity of reducing peak loadings through strategies such as energy storage, off-peak loading methods, and reactive power control of inverters to decrease the voltage deviations. It has been shown that voltage rise and reverse power-flows can and should be avoided on distribution feeders. Voltage unbalances can also be easily avoided by following the simple steps outlined in this paper. Now, a proactive approach should be taken by Governments, Distribution Networks System Providers, and customers with PV to ensure that as penetrations increase, Power Quality is not diminished.
The low temperature electrochemical performances of 700 and 350nm Li4Ti5O12 were compared. At high rate, room temperature and at low rate and low temperature (0, −10, −20 and −30°C), the 350nm Li4Ti5O12 showed higher capacity than the 700nm Li4Ti5O12. This difference is proposed to result from the shorter diffusion lengths and higher number of lithium insertion sites in the 350nm Li4Ti5O12 compared to the 700nm Li4Ti5O12. However, at high rate and low temperature, a transition in performance was observed, that is, the 700nm material had higher capacity. At high rate and low temperature, it is proposed that interparticle contact resistance becomes rate limiting owing to the temperature dependence of this property and this accounts for the different behavior at low temperature and high rate.