batterydata/paper-abstracts huggingface dataset:
In this work, a simple and effective method to activate graphite felt (GF) electrode by using KOH as etching agent is studied for vanadium flow battery (VFB) application. The surface of GF is etched by KOH at 800°C to generate micropores and attain oxygen-containing functional groups, resulting in greatly improved electrolyte accessibility. Surface morphology, oxygen distribution and microstructure of the KOH etched graphite felts (eGFs) are characterized by SEM, EDX, XPS, XRD and Raman techniques. Due to the abundant exposed edge carbon sites and oxygen-containing functional groups introduced by KOH activation, electrochemical activity of eGFs towards both VO2+/VO2 + and V2+/V3+ redox couples are remarkably improved comparing with GF. In particular, eGF-2 (mass ratio of KOH/GF=1.25) exhibits the best electrochemical activity and VFB performance among all eGFs. Moreover, the VFB with eGF-2 electrode can run at current density up to 250mAcm−2 with the energy efficiency of 64%. Long-term cycle life test at higher current density of 150mAcm−2 confirms the outstanding stability of eGF-2 electrode.
The first child’s birth is for most mothers a profound experience carrying the potential to change life orientations and values. However, little is known of how becoming a mother influences the existential dimensions of life within the parental relationship for example how motherhood may change how we view our partner and what we find important. The aim of this study was to explore how becoming a mother might change the parental relationship seen from the mother’s perspective with a specific focus on dimensions related to existential meaning-making.
Numerical modelling of redox flow battery (RFB) systems allows the technical and commercial performance of different designs to be predicted without costly lab, pilot and full-scale testing. A numerical model of a redox flow battery was used in conjunction with a simple cost model incorporating capital and operating costs to predict the technical and commercial performance of a 120MWh/15MW utility-scale polysulphide-bromine (PSB) storage plant for arbitrage applications. Based on 2006 prices, the system was predicted to make a net loss of 0.45pkWh−1 at an optimum current density of 500Am−2 and an energy efficiency of 64%. The system was predicted to become economic for arbitrage (assuming no further costs were incurred) if the rate constants of both electrolytes could be increased to 10−5 ms−1, for example by using a suitable (low cost) electrocatalyst. The economic viability was found to be strongly sensitive to the costs of the electrochemical cells and the electrical energy price differential.
The charges stored within the pseudocapacitive materials are strongly affected by the charge-discharge rate because of their electrochemical reversibility, especially when employing a battery-type material in the asymmetric design. As a result, the charges stored in the positive and negative electrodes in asymmetric supercapacitors (ASCs) are usually not well balanced because of the wide-rate operation of ASCs. This work demonstrates how to construct an ASC with one electrode material of the battery type through the charge balance consideration using the nickel hydroxide//activated carbon (Ni(OH)2//AC) system as an example. Due to the fact that the electrochemical reversibility of Ni(OH)2 is worse than that of AC, the influences of the current density (at 0.5 and 80Ag−1) in evaluating the charge capacity of Ni(OH)2 on the cell capacitance, power ability, and stability of the ASC are investigated. The above parameters of this ASC are evaluated by cyclic voltammetric, constant current charge-discharge, and electrochemical impedance spectroscopic analyses. The proposed charge capacity has been demonstrated to be an important factor for determining the specific energy, power ability, and stability of ASCs. A general strategy for achieving the optimal performances of an ASC with one battery-type electrode is proposed in this work.
Publisher Summary The breadth of “texting” includes more than the simple transmission of text-based material from one mobile telephone to another. Increasingly, “text” messages are including photographs, sound files, and other attachments. These are being adapted into various forms of gaming and TV voting, and they are starting to move across platforms. Both I-mode and enhanced GSM telephones can send messages to Internet addresses, and vice versa. One can also engage in various types of “chat” and instant messaging sessions from mobile telephone terminals, albeit at a lower transmission rate. Text messaging allows maintaining contact with friends and colleagues, but at the same time it is inconspicuous. Texting has a varying role when it comes to the other general themes of mobile telephony such as safety, coordination, access, and the disturbing influence. It is a coordination tool more discreet than other forms of interaction. Texting is related very much to teens and young adults. Teens are carrying the technology with them as a part of their repertoire of communication possibilities.
Due to breathing O2 from the air, vertebrates can suffer from diseases originating from oxidative stress. These, however, can be relieved by various antioxidants. Similarly, proton exchange membrane fuel cells (PEMFCs) suffer from the major problem of limited lifetimes, caused by chemical attacks by reactive oxygen species (ROS). Inspired by vertebrates, we herein show that the incorporation of a natural antioxidant, α-tocopherol (α-TOH), the most abundant component of vitamin E, which acts as a free radical scavenger, enables a maintenance of performance for PEMFCs which is impossible to achieve for fuel cells in the absence of α-TOH. It is notable that oxidized α-TOH can in turn be reduced by permeated H2 during fuel cell operation, resulting in its regeneration. Such reversibility leads to a chemical circulation system, which not only ensures the effective recycling of α-TOH, but also permits efficient protection of proton exchange membranes (PEMs) and thus allows their long-term operation.
The mesoporous Si/Ti molecular sieve was successfully synthesized from tetrabutyl titanate, tetraethoxysilane and EO20PO70EO20 by sol-gel combined with following pyrolysis processes and confirmed by XRD and TEM. The poly (vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))-based composite polymer electrolyte (CPE) membranes doped with Si/Ti molecular sieve were fabricated by phase inversion method and the desirable CPEs were obtained after being activated in liquid electrolytes, which are investigated by SEM, XRD, TG, LSV and EIS measurements. The results show that the CPE doped with 10% Si/Ti molecular sieve (vs P(VDF-HFP) in weight) presents the most uniform surface with abundant interconnected micro-pores and possesses excellent mechanical tensile strength with high decomposition temperature about 400°C and wide electrochemical working window about 4.7V; adding Si/Ti molecular sieve into the system can significantly decrease the crystallinity and improve the ionic conductivity of the as-prepared CPEs, in which the ionic conductivity and lithium ion transference number at room temperature are up to 3.263mScm−1 and 0.4292, respectively, and the reciprocal temperature dependence of ionic conductivity follows Vogel-Tamman-Fulcher relation. Furthermore, the anti-shrinkage rate of the as-prepared CPE membrane distinctly outperforms the commercial polyolefin membrane at 120°C about 2h. The interfacial resistance of the assembled Li/CPE/Li simulated cell can rapidly increase to a steady value about 548Ω from the initial value about 362Ω at 30°C during 5days storage, and the assembled Li/CPE/LiCoO2 coin cell with the electrolyte also show excellent rate and cycle performance, which indicates that this kind of CPE is an exciting potential candidate as polymer electrolyte for the lithium ion battery.
Carbon felt (CF) and activated carbon (AC) based electrodes for sodium polysulfide/bromine redox flow battery (PSB) were prepared and compared with a laboratory scale PSB flow cell in terms of structure and application performances. The structural properties of the two types of electrodes were characterized by filamentary analog and BET analysis, respectively. Catalyst coating, discharge behavior analysis and thermogravimetric analysis-mass spectrometry (TG-MS) were carried out to make out the different dominant factor in the application performances of the two materials. Compared to AC based electrode (ACE), despite of the relatively low surface area, CF demonstrates almost the same application performances, much more gains in electrochemical activity towards negative half-cell reactions by catalyst coating, and more even discharge voltage curve and stable cycling performance. At current density of 40mAcm−2, an average energy efficiency of up to 81% over 50 cycles (about 600h) has been achieved with cobalt coated CF, but with ACE only 64.7% within 16 cycles, which decreases quickly due to the loss of surface area resulted from sulfur depositing. The difference in structure related to mass transport makes the application performances gap between the two types of materials in PSB.
In technologically important Li-rich layered cathode materials, the synthesis time is a critical determinant to overcome the practical difficulties. Normal technology costs at least one day or even more to obtain final Li-rich cathode material. Full microwave synthesis is performed here to obtain final Li1.2Mn0.56Ni0.16Co0.08O2 within 60 min with high time-efficiency and power economization. The as-prepared Li-rich oxides keep the spherical hierarchical structure of the precursor. Compared to the same material obtained by traditional calcination, it exhibits well-formed layered structure with higher ordered ion arrangement. X-ray photoelectron spectroscopy (XPS) indicates that microwave assisted heating contributes to a more ordered and stable surface with desired Mn, Co, Ni element states and less impurity. Thus, the as-prepared material reveals remarkable electrochemical property with high discharge capacity of 159.3 mAh g−1 at high current density of 2000 mA g−1. And 88.6% specific capacity is remained after 300 cycles at such high current density. Furthermore, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) are carried out to overall investigate and estimate the material. It is concluded that such full microwave synthesis is really promising as one of the dominant way to obtain Li-rich layered cathode material for applications.
A novel method is introduced in this study to consider flexibility taking into account both system design and operation strategy by using fuzzy logic. A stochastic optimization algorithm is introduced to optimize the system design and operation strategy of the energy system while considering the flexibility. GPU (Graphics Processing Unit)-accelerated computing is introduced to speed up the computation process when computing the expected values of the objective functions considering a pool up to 5832 scenarios. Subsequently, a Pareto optimization is conducted considering Net Present Value (NPV), Grid Integration (GI) level (which represents the autonomy level of the energy system) and system flexibility. The case study assesses an energy system design problem for the city of Lund in Sweden. According to the obtained NPV and GI Pareto front, a renewable energy penetration level covering more than 45% of the annual demand of the energy hub (an integrated energy system consisting of wind turbines, solar PV panels, internal combustion generator and a battery bank) can be achieved. However, the flexibility of the system notably decreases when the renewable energy penetration level exceeds above 30%. Furthermore, the results show that poor system flexibility notably increases the risk of higher-loss of load probability and operation cost. It is also shown that the utility grid acts as a virtual storage when integrating renewable energy sources. In this context, a grid dependency level of 25–30% (of the annual energy demand) is sufficient while reaching a renewable energy penetration level of 30% and maintaining the system flexibility.
A facile and scalable process is established to prepare titanium dioxide/carbon (TiO2/C) composite nanotubes possessing a large specific surface area and an enhanced conductivity, with which H-titanate nanotubes are used as a precursor and glucose as a shape-stabilizing agent to retain the tubular morphology of the precursor during heat treatment. The effects of glucose dosage and calcination temperature on the microstructure and electrochemical properties of as-prepared TiO2/C composite nanotubes are investigated. The results show that TiO2/C composite nanotubes exhibit markedly improved electrochemical properties as compared with pristine TiO2 sample. The incorporation of carbon helps to retain the tubular morphology of the precursor and improves the electrochemical properties of the target products. In general, the microstructure and electrochemical properties of as-prepared TiO2/C composite nanotubes are closely dependent on the dosage of carbon and calcination temperature as well. The electrode made of TiO2/C composite nanotubes calcinated at 400°C, with a carbon content of 5%, possesses good high-rate capability (110mAhg−1 at 20C) as well as excellent cycle life and capacity, showing promising application as an anode material for lithium-ion batteries.
A facile and continuous method to prepare porous polypropylene (PP)/polyethylene (PE) multilayer membranes as separators for lithium-ion batteries via multilayer coextrusion and CaCO3 template method is proposed. Scanning electron microscopy (SEM) images indicate that the membrane exhibits abundant and well-connected sub-micron porous structure. Besides, the physical and electrochemical properties of the membranes, such as thickness, porosity, electrolyte uptake, ionic conductivity, electrochemical stability, thermal stability, and battery performance, are characterized and compared with the commercial separators with trilayer construction of PP and PE (e.g., Celgard® 2325). The results indicate that the multilayer PP/PE separators exhibit higher porosity as well as higher electrolyte uptake and retention than Celgard® 2325, which will definitely increase the ionic conductivity, and consequently improve the battery performances. More importantly, the PP/PE multilayer separators not only show effective thermal shutdown function, but also shows significant advantages of high thermal stability up to 160 °C. The thermal shutdown function of PP/PE multilayer membranes can be adjusted widely in the temperature range from 127 °C to 165 °C, which is wider than that of the commercial separators. The above results combined with the convenient and cost-effective preparation process makes porous PP/PE multilayer membranes a promising alternative to the commercialized trilayer lithium-ion battery separators.
An electrochemical–thermal coupling model is developed to describe the LiFePO4/graphite battery discharge and charge processes. Various heat generations/consumptions including Joule heat, reversible entropy heat, contact resistance heat, irreversible electrochemical reaction heat, ionic migration heat, and convective heat release to the ambient during charge or discharge processes are calculated in detail. The developed model is first validated by experimental data. Then systematic and comprehensive thermal analyses with respect to various discharge processes are performed based on the simulated results. For the specific cell considered, the irreversible electrochemical reaction heat and contact resistance heat are found to be the two main heat generation sources; for discharge processes of higher C-rate, the contact resistance heat take more proportion of the total heat generation as it is directly proportional to the squared discharge current density; the ionic migration heat is a sink with magnitude being about 1/3 of the Joule heat. The reversible entropy heat changes its sign from a negative heat sink to a positive heat source during a discharge process and its changing magnitude may be comparable to the irreversible electrochemical reaction heat for all the discharge processes of different C-rates.
Lithium-ion hybrid supercapacitors (Li-HSCs) and dual-ion batteries (DIBs) are two types of energy storage devices that have attracted extensive research interest in recent years. Li-HSCs and DIBs have similarities in device structure, tendency for ion migration, and energy storage mechanisms at the negative electrode. However, these devices have differences in energy storage mechanisms and working potentials at the positive electrode. Here, we first realize the integration of a Li-HSC and a DIB to form a dual-ion hybrid supercapacitor (DIHSC), by employing mesocarbon microbead (MCMB)-based porous graphitic carbon (PGC) with a partially graphitized structure and porous structure as a positive electrode material. The MCMB-PGC-based DIHSC exhibits a novel dual-ion battery-capacitor hybrid mechanism: it exhibits excellent electronic double-layer capacitor (EDLC) behavior like a Li-HSC in the low-middle wide potential range and anion intercalation/de-intercalation behavior like a DIB in the high-potential range. Two types of mechanisms are observed in the electrochemical characterization process, and the energy density of the new DIHSC is significantly increased.
It is a well known fact that eight countries have 81% of all world crude oil reserves, six countries have 70% of all natural gas reserves and eight countries have 89% of all coal reserves. Energy is central to achieving the interrelated economic, social, and environmental aims of sustainable human development. But if we are to realise this important goal, the kinds of energy we produce and the ways we use them will have to change. Otherwise, environmental damage will accelerate, inequity will increase, and global economic growth will be jeopardised. Energy produced and used in ways that support human development in all its social, economic and environmental dimensions is what is meant by sustainable energy. The generation of energy by clean, efficient and environmental-friendly means is now one of the major challenges for engineers and scientists. This paper reviews a proposed energy-related solution to global warming, air pollution mortality, and energy security. It discusses recent topics related directly to energy production such as fuel cells (FCs) which represent a promising clean and efficient energy conversion technology. The paper also focuses on those technologies which, in terms of cost, cleanliness, reliability and availability, have the potential to compete with conventional energy conversion systems and to reach commercialisation phase before 2015.
(Sn-Ti)O2 solid solution nanoparticles (denoted (Sn-Ti)O2-500) are prepared by application of one step of chemical treatment followed by calcination in N2 at 500°C for 2h. Transmission electron microscopic (TEM) observations reveal a nanoparticle shape change from needle-like to rod-like after heat treatment. Formation of a (Sn-Ti)O2 solid solution is confirmed by X-ray diffraction (XRD) analysis. The electrochemical properties of the (Sn-Ti)O2 solid solution are studied by cyclic voltammetric and coin cell tests. Electrochemical property results show that (Sn-Ti)O2-500 delivers a specific capacity of about 300mAhg−1, excellent cycle-life performance and high rate-capability during the delithiation process. Inductively coupled plasma results indicate a Sn content in (Sn-Ti)O2-500 of about 10.1% tin to titanium. The promising electrochemical characteristics of (Sn-Ti)O2-500 appear well suited for high-power negative electrodes of lithium ion batteries.
Metallic sodium is an ideal anode for high energy batteries because of its low cost, high natural abundance and suitable redox potential. However, the practical application of Na metal in rechargeable Na batteries is seriously limited by uneven Na plating and stripping process during cycling, which leads to Na dendrite formation and low Coulombic efficiencies (CEs). Here, we report that three-dimensional (3D) porous Cu can significantly promote the stability of Na plating/stripping, which features high CEs of 99.4% after 400 cycles at 1 mA cm−2 and low voltage hysteresis voltage (20 mV). Moreover, 3D porous structure provides highly stable and efficient plating/stripping of Na metal up to 6 mA cm−2. The excellent performance can be attributed to large specific surface area of 3D porous Cu and its good wettability of electrolyte, which is beneficial to actual current density reduction and non-dendritic growth. Due to the superior performance of anode, the full battery coupled with Na3V2(PO4)3 cathode exhibited excellent performance that demonstrates its feasibility in practical applications.
We develop a model-based framework which supports approximate quantitative verification of implantable cardiac pacemaker models over hybrid heart models. The framework is based on hybrid input–output automata and can be instantiated with user-specified pacemaker and heart models. For the specifications, we identify two property patterns which are tailored to the verification of pacemakers: “can the pacemaker maintain a normal heart behaviour?” and “what is the energy level of the battery after t time units?”. We implement the framework in Simulink based on the discrete-time simulation semantics and endow it with a range of basic and advanced quantitative property checks. The advanced property checks include the correction of pacemaker mediated Tachycardia and how the noise on sensor leads influences the pacing level. We demonstrate the usefulness of the framework for safety assurance of pacemaker software by instantiating it with two hybrid heart models and verifying a number of correctness properties with encouraging experimental results.
Tetragonal Li10GeP2S12 (LGPS) is the best solid Li electrolyte reported in the literature. In this study we present the first in-depth study on the structure and Li ion dynamics of this structure type. We prepared two different tetragonal LGPS samples, Li10GeP2S12 and the new compound Li7GePS8. The Li ion dynamics and the structure of these materials were characterized using a multitude of complementary techniques, including impedance spectroscopy, 7Li PFG NMR, 7Li NMR relaxometry, X-ray diffraction, electron diffraction, and 31P MAS NMR. The exceptionally high ionic conductivity of tetragonal LGPS of ∼10−2 S cm−1 is traced back to nearly isotropic Li hopping processes in the bulk lattice of LGPS with EA ≈ 0.22 eV.
Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. In this paper, we develop a novel detailed balance model for STEGs and apply this model to both state-of-the-art and idealized materials. This model uses thermoelectric compatibility theory to provide analytic solutions to device efficiency in idealized materials with temperature-dependent properties. The results of this modeling allow us to predict maximum theoretical STEG efficiencies and suggest general design rules for STEGs. With today's materials, a STEG with an incident flux of 100 kW m−2 and a hot side temperature of 1000 °C could achieve 15.9% generator efficiency, making STEGs competitive with concentrated solar power plants. Future developments will depend on materials that can provide higher operating temperatures or higher material efficiency. For example, a STEG with zT = 2 at 1500 °C would have an efficiency of 30.6%.