batterydata/paper-abstracts huggingface dataset:
Magnetite (Fe3O4) nanoparticles anchored graphene nanocomposites with different weight ratios of Fe3O4 and graphene nanosheets (GNSs) were prepared using hydrothermal method. The X-ray diffraction (XRD) pattern of the prepared nanocomposite reveals the presence of face centered cubic hexagonal crystalline Fe3O4 nanoparticles. Raman spectroscopic studies of the nanocomposites confirm the co-existence of Fe3O4 and graphene. The electron microscopy images of the nanocomposites revealed the formation of homogeneous nanocrystalline Fe3O4 particles on GNS surface. Among the three studied weight ratios (28:72, 40:60 and 60:40), the charge–discharge profile of the nanocomposite electrodes indicates that nanocomposite with 40:60 wt% of Fe3O4 and GNS as high capacity (930 mAh g−1) electrode for the lithium-ion (Li-ion) storage. And, the Li-ion storage capacity of the above nanocomposite is much higher than the pure GNS and Fe3O4 nanoparticle electrodes. The charge–discharge cycling study indicates that the Fe3O4/GNS (40:60) nanocomposite electrode has very high reversible capacity of 675 mAh g−1 with columbic efficiency of 97% after 50 cycles. The rate performance of the Fe3O4/GNS (40:60) nanocomposite electrode shows high reversible capacities at high rates due to the high conductive GNS support. The cyclic voltammetry experiment reveals the irreversible and reversible Li-ion storage in Fe3O4/GNS during the first and subsequent cycles.
This paper presents investigations on the dynamic behaviour of DMFCs. Experimental cell voltage responses to cell current step changes are investigated with transfer function analysis. The voltage response in most places shows significant overshooting behaviour (up to 80%) when applying cell current steps to the DMFC. Linear system analysis is applied to a set of dynamic models with different complexity, and a criterion for cell voltage overshooting is developed. In all models the dominating physico-chemical phenomenon is the transport of methanol through the membrane, causing cathodic overpotential overshooting. This is supported by experimental analysis. The proposed models and transfer functions are suitable for controller design.
A new and practical testing technique was developed for measuring the flow rate distribution between cells in a stack that did not contain any internal sensors. The flow rate distribution is obtained by measuring the hydrogen limiting current of each cell in the stack while a mixed gas of hydrogen and dimethyl ether is supplied to the anode and hydrogen to the cathode. In order to measure large flow rate deviations between cells, it is necessary to decrease the flow rate of the anode hydrogen and to sufficiently humidify the cells. The faster the increasing rate of the current, the more the apparent hydrogen limiting current increases than the theoretical electrochemical equivalent current. However, the relative flow rate deviations between cells can be obtained by a practical accuracy using the ratio of the apparent hydrogen limiting current. Humidification of the cell is indispensable for the measurement and a method using dry anode gas and humidified cathode gas is recommended. The preferred test conditions for measuring the flow rate distribution between cells in a PEFC stack are proposed.
A thiophene-functionalized monomer 1-phenyl-2,5-di(2-thienyl)-1H-pyrrole (PTP) was synthesized. The chemical polymerization of PTP (CPTP) was realized by using FeCl3 as the oxidant. The structures of both the monomer and the soluble polymer (CPTP) were investigated by Nuclear Magnetic Resonance (1H and 13C NMR) and Fourier Transform Infrared (FTIR). The average molecular weight of the chemically synthesized polymer was determined by gel permeation chromatography (GPC) as Mn=7.2×103. The electrochemical oxidative polymerization of PTP was carried out via constant-potential electrolysis. Characterizations of the resulting polymer were done by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV–vis Spectroscopy. The conductivity of sample was measured by four-probe technique. Moreover, the spectroelectrochemical and electrochromic properties of the polymer film were investigated. Spectroelectrochemical analysis of P(PTP) revealed electronic transitions at 413, 577 and 884nm corresponding to π–π* transition, polaron, and bipolaron band formations, respectively. Kinetic studies evaluated the switching ability of the P(PTP); the percent transmittance T% was found as 27%. The homopolymer of PTP was used to construct dual-type polymer electrochromic devices (ECDs) against poly(3,4-ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investigated.
The antimony oxide/reduced graphene oxide (Sb2O3/rGO) nanocomposites are used as anode of Li-ion and Na-ion batteries (LIBs and NIBs). However, it is unclear about Li-ion and Na-ion storage mechanism in Sb2O3/rGO nanocomposites. Herein, the conversion-alloying mechanisms of Sb2O3/rGO anodes for Na-ion and Li-ion storage are comparatively studied with a combined in-situ XRD and quasi in-situ XPS method. The distinct behaviours are monitored during (de)lithiation and (de)sodiation with respect to crystal structure and chemical composition evolution. It is evidenced that the Na-ion can be easily transported to the inner part of the Sb2O3, where the Li-ion almost cannot reach, leading to a fully transformation during sodiation. In addition, the conversion reaction product of amorphous Na2O display their better chemical stability than amorphous Li2O during electrochemical cycles, which contribute to a stable and long cycling life of NIBs. This work gain insight into the high-capacity anodes with conversation-alloying mechanism for NIBs.
The high energy consumption of GPS modules has kept long-term outdoor localisation with battery-powered devices an unsolved challenge. While low-power sensors can trigger GPS sampling to reduce energy consumption, validating the long-term reliability of these sensors in unconstrained environments is challenging due to sensor drifts and the lack of ground truth data in the field. We describe the design of our feature-rich platform and our progressive approach for characterising and validating its multiple sensing modalities in long-term deployments. Using empirical data collected from both controlled experiments and wild flying foxes, we characterise the tracking accuracy, wireless connectivity, energy harvesting, and cross-validate sensing modalities against their GPS counterparts. The results show that accelerometer, magnetometer, and pressure sensor can estimate flying speed and altitude well with relatively small errors in the wild. We further study the utility of multi-modal activity recognition under real-world conditions and demonstrate the potential for significantly increased resolution in triggering GPS samples.
For the first time, the effects of designed siloxane derivative N-triethoxysilylpropyl 3,4,5-tris(tetradecyloxy) benzamide (Compound 1) as an electrolyte additive on the electrochemical properties of gelled electrolyte valve-regulated lead-acid (VRLA) battery were investigated. Results show that Compound 1 decreased gelled electrolyte resistance and possibly triggered the formation of large inorganic crystals due to the poly-condensation reaction. In addition, the hydrogen evolution process was inhibited and the stability of gelled electrolyte by the experiment of released liquid was significantly improved by addition of Compound 1.
The main purpose of this paper was to explore strategies of how to design the interface with brand-new techniques for collecting running parameters of small-scaled wind-power electricity generators as well as its monitoring and controlling Graphic Interface System software. Affected by shortage of oil energy, the whole world was positively developing renewable energy such as solar, wind-power, biologic, tide etc. For Taiwan, the renewable energy policy was actively pushed by government and civic organizations, and how to encourage industrial manufacturers to invest the related technologies of renewable energy; furthermore, to research and develop advanced techniques in this field so that those techniques could create another prosperous business for Taiwan after 3C business. In this study, WSN (Wireless Sensor Network) and its related modules such as ZigBee and Bluetooth would be combined together to construct transmitting interface of running parameters of small-scaled wind-power electricity generator. The study content included building ZigBee wireless network, communication interfaces of ZigBee and Bluetooth with microprocessor, coding and decoding techniques of ZigBee and Bluetooth, and software programming of graphic interface system (GIS). This study was sponsored by Taiwan Education Ministry under Teaching Superiority Project, and the system implemented in real wind-power electricity generator system and the research outcomes has been proved to be very successful and stable.
The water stability of the fast lithium ion conducting glass–ceramic electrolyte, Li1+x+y Al x Ti2−x Si y P3−y O12 (LATP), has been examined in distilled water, and aqueous solutions of LiNO3, LiCl, LiOH, and HCl. This glass–ceramics are stable in aqueous LiNO3 and aqueous LiCl, and unstable in aqueous 0.1M HCl and 1M LiOH. In distilled water, the electrical conductivity slightly increases as a function of immersion time in water. The Li–Al/Li3−x PO4−y N y /LATP/aqueous 1M LiCl/Pt cell, where lithium phosphors oxynitrides Li3−x PO4−y N y (LiPON) are used to protect the direct reaction of Li and LATP, shows a stable open circuit voltage (OCV) of 3.64V at 25°C, and no cell resistance change for 1 week. Lithium phosphors oxynitride is effectively used as a protective layer to suppress the reaction between the LATP and Li metal. The water-stable Li/LiPON/LATP system can be used in Li/air secondary batteries with the air electrode containing water.
ZnO was coated on LiNi0.5Co0.25Mn0.25O2 cathode (positive electrode) material for lithium ion battery via sol–gel method to improve the performance of LiNi0.5Co0.25Mn0.25O2. The X-ray diffraction (XRD) results indicated that the lattice structure of LiNi0.5Co0.25Mn0.25O2 was not changed distinctly after surface coating and part of Zn2+ might dope into the lattice of the material. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) proved that ZnO existed on the surface of LiNi0.5Co0.25Mn0.25O2. Charge and discharge tests showed that the cycle performance and rate capability were improved by ZnO coating, however, the initial capacity decreased dramatically with increasing the amount of ZnO. Differential scanning calorimetry (DSC) results showed that thermal stability of the materials was improved. The XPS spectra after charge–discharge cycles showed that ZnO coated on LiNi0.5Co0.25Mn0.25O2 promoted the decomposition of the electrolyte at the early stage of charge–discharge cycle to form more stable SEI layer, and it also can scavenge the free acidic HF species from the electrolyte. The electrochemical impedance spectroscopy (EIS) results showed ZnO coating could suppress the augment of charge transfer resistance upon cycling.
In this paper, we propose a permission-based message efficient mutual exclusion (MUTEX) algorithm for mobile ad hoc networks (MANETs). To reduce messages cost, the algorithm uses the “look-ahead” technique, which enforces MUTEX only among the hosts currently competing for the critical section. We propose mechanisms to handle dozes and disconnections of mobile hosts. The assumption of FIFO channel in the original “look-ahead” technique is also relaxed. The proposed algorithm can also tolerate link or host failures, using timeout-based mechanisms. Both analytical and simulation results show that the proposed algorithm works well under various conditions, especially when the mobility is high or load level is low. To our knowledge, this is the first permission-based MUTEX algorithm for MANETs.
In this article, detailed modeling, simulation, and analysis of an isolated wind-hydrogen hybrid energy system is presented. Dynamic nonlinear models of all the major subsystems are developed based on sets of empirical and physical relationships. The performance of the integrated hybrid energy system is then analyzed through digital simulation. Design of dynamic controllers and supervisory control schemes are also presented. Expected behaviors during sudden load variation, wind speed change and hydrogen pressure drop are observed under both stochastic and step-variation conditions. MATLAB-SimulinkTM is employed for dynamic system modeling. This exercise, in essence, outlines a process of wind-hydrogen off-grid system control synthesis and performance evaluation. Finally, results of the analysis are summarized, limitations of the simulation study are identified, and scope for future work is indicated.
A Gemini surfactant (N-dodecyl propylenediamine γ-diquaternium bromide) assisted hydrothermal route was presented for the facile synthesis of nanotile-like molybdenum disulfide/graphene (NTL-MoS2/G) hybrid. The effect of the Gemini surfactant on the microstructure and electrochemical lithium storage performance of the NTL-MoS2/G hybrid is investigated. It is found that MoS2 sheets in the hybrid display a nanotile-like morphology with 3–6 layers and are homogenously anchored on the surface of graphene. Due to their more edges, the nanotile-like MoS2 sheets facilitate lithium ion insertion/extraction and electrolyte access. The NTL-MoS2/G hybrid exhibits much higher reversible capacity with significantly enhanced cyclic stability and rate capability than the pristine MoS2. The improvement in electrochemical performances of the hybrid can also be contributed to the robust composite structure and synergistic effects between NTL-MoS2 and graphene sheets.
Active carbon@La2NiO4/NiO hybrid coatings are synthesized using different molar ratios of La/Ni to improve the electrochemical performance of active carbon materials. The morphology and microstructure of the composites are investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). Cyclic voltammetry (CV), galvanostatic charge/discharge test (GCD), and electrochemical impedance spectroscopy (EIS) are performed to characterize electrochemical performance. At a molar ratio of La/Ni 1:2, the electrochemical electrode shows that the resistance of the composite is 2.97Ω, which is half of that in pure active carbon. The highest energy density of 70.37Whkg−1 is obtained at a current density of 1Ag−1, whereas the highest power density of 32.4kWkg−1 is achieved at a current density of 10Ag−1. The CV results present a high specific capacitance of 710.48Fg−1 at a scan rate of 1mVs−1 in 7M KOH aqueous solution.
The practical use of lithium–sulfur (Li–S) batteries is largely hindered by their poor cycling stability because of the shuttling of soluble lithium polysulfides (LiPSs) in a slow redox reaction. Physical and chemical confinement by carbon or noncarbon hosts has been used to block LiPS shuttling, but this may only be a complete solution to the problem if it combines with LiPS fast conversion into an insoluble sulfide. Here we report a twinborn TiO2–TiN heterostructure that combines the merits of highly adsorptive TiO2 with conducting TiN and achieves smooth trapping–diffusion–conversion of LiPSs across the interface. TiO2 has high adsorption for LiPSs while TiN promotes their conversion into insoluble Li2S. The fast diffusion of LiPSs from TiO2 to TiN helps achieve both high trapping efficiency and fast conversion. By loading such a heterostructure onto graphene, which acts as a physical barrier, a compact and thin coating is fabricated on the separator, and LiPS shuttling is greatly restrained even with a high sulfur loading. A capacity of 927 mA h g−1 after 300 cycles is obtained under a low current density of 0.3C. Over 2000 cycles, capacity retentions of 73% and 67% at 1C are achieved for sulfur loadings of 3.1 and 4.3 mg cm−2. Such an interlayer is expected to promote the practical use of Li–S batteries because of the simple processing and the resulting outstanding capacity and cyclic performance. Such a heterostructure suggests a new way to produce multifunctional interlayers that improve the performance of energy storage devices.
The nanocomposites of MoS2 nanosheets and microporous nitrogen-doped carbon dodecahedron (MNCD) are prepared through the pyrolysis of metal-organic framework (MOF) and subsequent growth of MoS2. The porous and active surface of MNCDs enables uniform growth of ultrathin MoS2 nanosheets. When the MNCD@MoS2 composite is used as the anode material of Li-ion batteries, a reversible capacity of 915 mAh g−1 can be obtained even at the extremely high current density of 10 A g−1. The ultrafast charge/discharge ability of MNCD@MoS2 can be attributed to its unique core-shell structure with the inner MNCDs serving as the reservoir of Li-ions and transport media of electrons.
The paper describes the operation and thermal analysis of a new prototype to determine thermal balance of radiative cooling. The aim of the study is to establish a simple but accurate procedure to calculate the radiative heat exchange between two bodies to be used in the determination of sky temperature, clear sky index or plate emissivity. The radiative transfer calculation has been based on the power required to maintain a constant temperature at the radiative plate of the prototype, provided that the convection and conduction terms are well known. The methodology is applicable to a further advanced system, which avoids convection and reduces conduction to maximise radiative effects, minimising errors and providing more accurate results. Tests have been carried out at a plate temperature of 40 °C, which was optimum for the prototype size and operating conditions. Higher or lower temperatures have lead to a reduction of the fraction of radiative transfer or to the use of very low external power, which complicates the prototype design and makes the temperature control system very costly. Tests carried out in the prototype have shown a perfect matching between total heat transfer and supplied power with an error of less than 5%. This result allows high precision determination of sky temperature, clear sky index or plate emissivity from the use of the proposed methodology.
The off grid electrification by utilizing Integrated Renewable Energy System (IRES) is proposed to satisfy the electrical and cooking needs of the seven-uneletrified villages in the Almora district of Uttarakhand state, India. Four different scenarios are considered during modeling and optimization of IRES to ensure reliability parameters such as energy index ratio (EIR) and expected energy not supplied (EENS). The optimum system reliability, total system cost and cost of energy (COE) have also been worked out by introducing the customer interruption cost (CIC). The four different renewable energy scenarios have been compared for the considered study area using the LINGO software version 10. The fourth renewable energy scenario accounting 44.99% micro hydropower (MHP), 30.07% biomass, 5.19% biogas and 4.16% solar energy along with the additional resources of wind (1.27%) and energy plantation (12.33%) has been found to be the best among the different options considered. Furthermore, the optimal reliability for the fourth IRES system has been found to be 0.95 EIR at the optimized cost of Rs 19.44 lacs with estimated COE of Rs 3.36per kWh. The COE obtained using LINGO software and HOMER software has also been compared and briefly discussed for all the four scenarios. In order to verify feasibility and cost of system for different biomass fuel prices, a sensitivity analysis has also been carried out and it has been found that the fourth scenario is more sustainable than the other considered options.
Ultrathin nitrogen-doped carbon nanofibers (NCNFs) with unique structure are prepared by electrospinning. The ultrathin NCNFs are produced in the form of large-area membranes by carbonizing electrospun polyacrylonitrile (PAN) nanofibers in NH3. The diameter of the NCNFs can be effectively reduced due to the etching reactivity of NH3 with carbon and the average diameter down to 20nm is obtained. The NCNFs carbonized in NH3 possess unique structure that many graphitic layers protrude from the fiber surface with their edges exposed. The nitrogen doped in the NCNFs is mainly from that contained in the PAN molecules and partially from ambient NH3. The membranes of the ultrathin NCNFs exhibit high electrocatalytic activity, long-term operation stability, and excellent tolerance to crossover effect during oxygen reduction reaction in fuel cells. The high electrocatalytic activity of the ultrathin NCNFs may be mainly ascribed to their small diameter and exposed graphitic layer edges apart from N doping. Due to the simplicity in production, low cost, absence of metal residue, and the material form of freestanding membrane with large area the ultrathin NCNFs derived from electrospinning hold high promise for the practical application of fuel cells.
H3NOHCl is used for the first time as anode material for lithium-ion batteries. Electrochemical results show that H3NOHCl with particle size of 4–12 μm can deliver an initial charge capacity of 1018.6 mAh g−1, which is much higher than commercial graphite. After 30 cycles, the reversible capacity can be kept at 676.1 mAh g−1 at 50 mA g−1. Up to 50 cycles, H3NOHCl still maintains a lithium storage capacity of 368.9 mAh g−1. Even cycled at 200 mA g−1, H3NOHCl can deliver a charge capacity of 715.7 mAh g−1. It suggests that H3NOHCl has high lithium storage capacity, excellent cycling stability and outstanding rate performance. Besides, the electrochemical reaction between H3NOHCl and Li is also investigated by various ex-situ techniques. It can be found that H3NOHCl irreversibly decomposes into Li3N and LiCl during the initial discharge process and LiNO2 can be formed after a reverse charge process.
The rate capacity and cycleability of a battery electrode are strongly determined by their chemistry and nano/microstructures. This is particularly true in developing next-generation lithium-ion batteries for electric vehicles. In this article, we report synthesis of nanometer tin based negative electrodes encapsulated in microporous copper substrates, which exhibit simultaneously high-rate and long-life performances. This intermetallic compound consists of an amorphous phase rich in Co, located at the boundaries of nanoscale crystalline Sn–Sb grains. The rate capacity retention is ~71.5% while increasing charge rate from 0.15C (698.9mAhg−1) to 25.0C (500mAhg−1 at ~16Ag−1). Such a high rate performance is a result of novel chemistry (Sn50Sb44Co6) and high electrical conductivity of Cu framework. The cycling capacity is 549mAhg−1 at 0.2C (1C=650mAg−1) after 300 cycles, and 493.6mAhg−1 at 0.4C after 600 cycles. The Co-rich amorphous phase, along with the three dimensional porous structure, contributes to mitigating volume expansion/shrinkage during discharge/charge of the electrode. Our results suggest that the ternary Sn–Sb–Co intermetallic compound with the desirable chemistry and structure is a promising candidate as a high-rate and long-life negative electrode for lithium-ion batteries.