batterydata/paper-abstracts huggingface dataset:
To develop more ideal bifunctional heteroatom-doped carbon electrocatalysts toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for regenerative fuel cells and rechargeable metal–air batteries, herein, tobacco-derived N-containing ordered mesoporous carbon (N-OMC) electrocatalysts with different N species distributions are designed. Results indicate that the as-prepared N-OMC with more pyrrolic and pyridinic Ns exhibits much higher activities for the ORR and OER than N-OMC with more graphitic N in both acidic and alkaline media, suggesting that the increase of pyrrolic and pyridinic Ns favors the improvement of ORR and OER activities of the N-containing carbon catalysts, and showing a great potential for the designing of more effective, lower-cost ORR and OER bifunctional electrocatalysts for future regenerative fuel cells and rechargeable metal–air batteries.
The development of new layered materials has experienced an evolution from graphene to metal oxide and metal chalcogenide nanosheets, and more recently to two-dimensional (2D) covalent organic frameworks, such as conjugated carbon nitride nanosheets (CNNs) with a spectral gap in the band structure. The anisotropic 2D geometric morphology, together with the aromatic π-conjugated framework, endows polymeric CNNs with unique properties, such as an enlarged surface area with a highly opened-up flat structure, reduced thickness with enhanced electron mobility and with intrinsic semiconductive features, which support their attractive bandgap- and surface-engineered applications ranging from energy-related topics to other new emerging fields. In this review, recent research advances in the establishment of two synthetic strategies for CNNs are firstly overviewed, namely, the top-down delamination of graphitic carbon nitride (CN) solids and the bottom-up assembly of molecular building blocks in a 2D manner. Efficient approaches aimed at advancing CNNs for target-specific applications, including hybridizing, doping, sensitization, copolymerization and nanorefinement, are also described as possible solutions.
The performance of Li-ion batteries deteriorates at elevated temperatures due to increased activity of electrode materials and parasitic reactions. Here Yi Cui and colleagues report much-improved battery cyclability at 60 °C and use cryo-electron microscopy to shed light on the origin of the phenomenon.
Properties of capacitors working with the same carbon electrodes (activated carbon cloth) and three types of electrolytes: aqueous, organic and ionic liquids were compared. Capacitors filled with ionic liquids worked at a potential difference of 3.5V, their solutions in AN and PC were charged up to the potential difference of 3V, classical organic systems to 2.5V and aqueous to 1V. Cyclic voltammetry, galvanostatic charging/discharging and impedance spectroscopy were used to characterize these capacitors. The highest specific energy was recorded for the device working with ionic liquids, while the highest power is characteristic for the device filled with aqueous H2SO4 electrolyte. Aqueous electrolytes led to energy density an order of magnitude lower in comparison to that characteristic of ionic liquids.
To improve the rate capability and cycle performance of the LiMnPO4 cathode, carbon-coated LiMn1-x Fe x PO4 (0 ≤ x ≤ 0.5) nanocomposites have been successfully prepared by hydrothermal process. The carbon-coating does not affect the morphology of LiMn1-x Fe x PO4 (0 ≤ x ≤ 0.5), but restrains the aggregation of particles, and an obvious carbon film with a thickness of about 2.5 nm can be observed on the surface of LiMn1-x Fe x PO4. Fe doping has an important influence on the morphology of LiMnPO4, and carbon-coated LiMn0·5Fe0·5PO4 obviously shows a nanorod morphology with a length of 100–200 nm. Carbon-coated LiMn0·5Fe0·5PO4 shows excellent rate capability, and delivers specific capacities of about 156.4, 151, 147.6, 145.7 and 137.3 mAh g−1 at 0.05, 0.1, 0.2, 0.5 and 1 C, respectively. However, carbon-coated LiMnPO4 only delivers specific capacities of about 109.5, 100, 82.4, 79 and 65.8 mAh g−1 at corresponding current densities. The carbon-coated LiMn0·5Fe0·5PO4 also shows a large initial specific capacity of 134.5 mAh g−1 at 5 C rate with outstanding capacity retention of 84.6% even after 100 cycles. The enhanced rate capability and cycling stability of carbon-coated LiMn0·5Fe0·5PO4 at high rate are attributed to the decreased charge transfer resistance, decreased electrode polarization, enhanced reversibility of extraction and insertion of Li-ions, and increased Li-ion diffusion coefficient. DFT calculation shows that Fe–O bond is stronger than Mn–O bond, and it can be expected that the thermodynamic stability of LiFe0·5Mn0·5O4 will be improved obviously in comparison with LiMnPO4, which well explains the better cycling stability of LiFe0·5Mn0·5O4 than LiMnPO4 observed experimentally.
The aim of this paper is to study techno-economic feasibility of microhydro–photovoltaic–biomass and biogas–diesel–battery hybrid energy system (HES) in off-grid mode for a rural area in Uttarakhand state, India. The considered HES is designed for energy access in 5 un-electrified villages. Size optimization and sensitivity analysis of considered system is performed by using HOMER software in order to meet the electricity requirements of study area. The selection of optimum configuration is based on the lowest value of cost of energy (COE) and net present cost (NPC) along with the maximum value of renewable fraction (RF) and lowest harmful emissions (CO2). By considering economy and environment as the main concerns, comparative analysis of four different types of models is presented here. Based on sensitivity analysis, 3 configurations out of four different models are selected. By considering economy and environment as the main driving factors, one configuration out of three configurations, is selected as the optimum configuration for the study area which comprises total NPC $5,33,654, COE $0.197/kWh, RF 94% and CO2 emission 15,930kg/yr.
Formation of solid electrolyte interface (SEI) on the surface of graphite in Li/graphite cells was studied using the electrochemical impedance spectroscopy (EIS) technique. Results show that EIS of the cells varies considerably with cell voltage. In particular, resistance (R sei) of the SEI increases significantly with lithiation and decreases reversibly in the subsequent delithiation in a narrow voltage range between 0.15 and 0.04V. According to the change of the R sei during the first lithiation process, we might divide the formation of the SEI into two voltage regions: the first region generally occurs above 0.15V and the second region below 0.15V. The SEI formed in the first region is less conductive, and that formed in the second region is highly conductive. It is shown that ionic conductivity of the preliminarily formed SEI is greatly affected by the kind of solvents and salts of the electrolyte. We observed that the R sei increases in the order of LiBF4 >LiSO3CF3 >LiBOB>LiPF6 for salt, and of NMP>EMC>MB for solvent. Addition of vinylene carbonate into the electrolyte results in a significant increase of the R sei.
A measurement system for the mapping of current distribution in a free-breathing polymer electrolyte membrane fuel cell (PEMFC) is introduced. In the measurement system, the ridges of the flow-field are made of gold-plated stainless steel and the rest of the measurement plate is made of a non-conducting material. The gas diffusion layer is not segmented and the error resulting from this is analyzed computationally. The effect of the cell temperature on the current distribution is studied with the measurement system. It appears that the measurement system is useful for PEMFC characterization and even large spatial variations of current density can be measured with it. According to the results, the optimum operating temperature for the studied cell is around 60°C without external humidification. In addition, it is concluded that the molecular diffusion is dominating mass transport mechanism at low temperatures but the current density profile is more homogeneous at elevated temperatures.
A hybrid electrochemical power supply is a concept that circumvents the need for designing any single power source to meet some extraordinary application requirement. A hybrid allows using components designed for near optimal operation without having to make unnecessary performance sacrifices. In many cases some additional synergistic effects appear. In this study, an electrochemical capacitor was employed as a power assist for a battery. An engine starting load was numerically modeled in the time domain and simulations were carried out. Actual measurements were then taken on the cranking of a diesel engine removed from a 5.0-tonne military truck and cranked in an environmental chamber. The cranking currents delivered by each power source were measured in the accessible current loops. This permitted the model parameters to be identified and, by doing that, studies using the analytical model demonstrated the merit of this hybrid application. The general system response of the battery/capacitor configuration was then modeled as a function of temperature. Doing this revealed electrical the interaction between the hybrid components. This study illustrates another case for advocating hybridized power systems.
Fuel cell electric vehicles (FCEVs) have been considered as the future vision for the automotive industry. An increasing number of concepts and prototypes have been introduced in the last decade. In parallel with the technological development, recent discussions about global warming and climate change bring public support for emission free vehicles. Despite of the advancements and support, the speed of introduction of FCEVs is still not at the desirable levels. From a transition management perspective, the present paper seeks to answer the underlying factors behind the implementation of the FCEVs. The discussion goes beyond a technical one to cover broad factors and interests of stakeholders with an ‘eagle-eye view’. Following a discussion the key drivers of change for the FCEV sector and wild cards with disruptive effects, the paper proposes a strategic roadmap template to set an agenda for a successful transition towards FCEVs.
In rural areas, drones are designed to replace road deliveries so as to overcome infrastructure challenges; though drones notably consume less fuel and consequently have a smaller impact on the environment, their full life cycle assessment should still be evaluated to comprehensively understand their environmental impact. This study presents a life cycle assessment study on drone delivery in Thailand using CML2001, the life cycle impact assessment (LCIA) method, to convert life cycle inventory data into environmental impacts. The observed results show that an online shopping system using drone delivery is one of the most environmentally friendly transportation options throughout a wide range of scenarios. However, the parts production contributed to significant impacts on environmental issues while the drone operation showed the least impact to all impact categories. The dominant contributors to global warming, abiotic depletion (ADP elements and fossil), acidification air, eutrophication, ozone layer depletion, and photochemical ozone creation impact categories were the coal mining and electricity generating station operation. However, the carbon fibers and the battery, are the main contributors to other impact categories, which include the human toxicity, freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, and terrestric ecotoxicity.
A novel approach to achieving high areal capacitance and rate capability is demonstrated, whereby an active material is loaded onto a high surface area, filled Ni foam current collector. Micro/nano Ni-filled Ni foam (MNFNF) current collector was fabricated by initially filling commercial Ni foam with Ni slurry and sintering to yield micro Ni-filled Ni foam, followed by electrochemical deposition of nano Ni. This current collector has a greatly enhanced surface area compared to Ni foam, allowing for high mass loading of active material and thereby high areal capacitance and rate capability. Using NiCo2O4 prepared via hydrothermal reaction followed by annealing as the active material, an outstanding areal capacitance of 29.4 F cm-2 at 5 mA cm−2 discharge was achieved, while a high 80% of this capacitance (i.e. 23.5 F cm−2) was retained at 50 mA cm−2 discharge, ascribed to the high surface area and high conductivity of the MNFNF current collector. Regarding stability, only a 2% decrease in areal capacitance after 1000 charge/discharge cycles was observed. The approach employed here might be used to enhance the performance of other active materials besides NiCo2O4.
Remarkable progress has been made recently in the development of soft materials and devices for human-machine interface. Emerging soft-electronics with skin-inspired stretchable, healable and bio-degradable properties have diffused the boundaries of electronics and biology. Practical utilisation of these electronics relies on the development of a skin-inspired soft energy harvester to power them. Mechanical energy harvesters including triboelectric and piezoelectric nanogenerators have emerged as promising energy harvesters for soft-electronics. In this review, we highlight the recent progress in stretchable, self-healing, and bio-compatible soft triboelectric nanogenerators. We explicitly discussed the operating mechanism, design strategies, fabrication techniques, and performances of the stretchable and self-healing energy harvesters. Additionally, the progress of bio-compatible energy harvesters for effective interaction with biological systems is discussed. Finally, we present the perspectives, existing challenges and future road-map for the development of skin-inspired soft mechanical energy harvesters.
This paper introduces a new switching means giving a real time optimum connection mode of domestic appliances on either the electrical grid or a photovoltaic panel (PVP) output. A fuzzy algorithm makes the decision which ensures the optimal energy-management based on PVP generation and appliances states with respect to energy-saving criteria. Validation is driven on a 1kW peak (kWp) PVP and domestic appliances of different powers installed at the Energy and Thermal Research Centre (CRTEn) in the north of Tunisia. Results confirm that energy saved during daylight is 80–90% of the PVP generated energy.
The oxygen reduction reaction was studied in 0.5moldm−3 HClO4 solution on an electrode based on Ebonex-supported platinum electrocatalyst applied on rotation Au disk electrode (Au/Ebonex/Pt). Pt catalyst was prepared by impregnation method from 2-propanol solution of Pt(NH3)2(NO2)2 and Ebonex powder. Ebonex support (non-stoichiometric mixture of titanium oxides) was characterized by: X-ray diffraction, energy dispersive X-ray spectroscopy and BET techniques. The synthesized catalyst was analysed by TEM technique. The kinetics of oxygen reduction reaction on the Ebonex/Pt catalyst shows a significant enhancement in comparison with the same on polycrystalline Pt. Only a single Tafel slope of −0.106Vdec−1 is observed and the first-rate determining step in direct four-electron reduction is proposed as a main partway in the whole range of potential. The absence of PtOH layer, that inhibits oxygen reduction on polycrystalline Pt, was discussed through synergetic effect into the catalyst as a consequence of the interactions of Pt nanoparticles with Ebonex, on one hand, and, through the d-band coupling model where the surface reactivity is given by the energy shift of the surface d-states with respect to the Fermi level, on the other hand.
The effects of reduction agent on the electrochemical properties of Li3V2(PO4)3/C positive materials were studied. An one-step solid-state reaction route was applied to synthesize Li3V2(PO4)3/C samples. The humic acid, glucose and carbon were used as reduction agent. SEM images show that the particles of sample with humic acid as reduction agent merge with each other and form a porous structure, and yet the particles of sample synthesized using carbon as reduction agent are wrapped with small carbon particles and separate each other. Electrochemical tests show that the samples using humic acid and glucose as reduction agents have better cyclic performance than the one using carbon as reduction agent. At the 200th cycle, the sample using humic acid as reduction agent still keeps 145.2mAhg−1 at 1C charge and discharge rates. However, the sample using carbon as reduction agent shows a fast decline in capacity during cycling and has 54.5% capacity loss of the initial value after 200 cycles. The results indicate that different reduction agents can obviously affect the morphologies and electrochemical properties of the products.
Layered manganese oxide (K x MnO2) powders were synthesized by simple decomposition of KMnO4 at 300–800°C in air. These manganese oxides were characterized by powder X-ray diffractometry, atomic absorption spectrometry, chemical redox titration, and X-ray photoelectron spectroscopy. Their electrochemical performances for secondary lithium batteries were investigated in a LiClO4–propylene carbonate (PC) solution. After removing side products, which were water soluble, the K x MnO2 (x≤0.484) cathode unerwent reversible electrochemical intercalation/deintercalation of lithium. When the K x MnO2 powders were synthesized at 300°C and then washed with water or acidic solution after the synthesis, they exhibited satisfactory behavior with a specific capacity of 130–140 mAh g−1 in the region of 3 V vs. Li/Li+ for more than 20 cycles.
In this study, we propose a new magnetically actuated anchoring system for wireless capsule endoscopes (WCE) by employing the principle of a switchable magnetic spring. A force model is derived to predict the magnetic force needed to support the interaction between the anchors and the intestinal lumen. The theoretical and experimental analysis conducted shows that the magnetic spring is capable of providing the force needed to activate the anchoring mechanism, which consists of four foldable legs. A prototype capsule with a size comparable with the size of a commercial WCE was designed, fabricated, and tested. The in-vitro tests with a real small intestine show that the proposed anchoring mechanism is able to raise the friction force between the anchoring legs and inner wall of the intestine by more than two times after its activation using an external magnetic field. Experimental results presented demonstrate that the proposed anchoring system, which has a low foot-print not taking up too much space on the capsule, can provide a reliable anchoring capability with the capsule inside the intestinal lumen.
Under the Kyoto Protocol, Japan was supposed to reduce six percent of the Greenhouse Gas (GHG) emission. However, in the year 2012, the statistics suggested that the GHG emission increased 9% compared with the year 1990. Even with the leading energy saving technologies and a lot of experience on handling with environmental issues, Japan still could not meet the target set by Kyoto Protocol. The demonstration area of “smart community” suggests Japanese exploration for low carbon strategies. It is the shift toward the emphasis on the GHG emission control in civil sector. The Japanese version of smart communities also suggests the promotion on the use of renewable and untapped energy resource as well as the collaborative energy to be used in the district level. Much more important than the technology itself, the concept of smart community in Japan makes the community and the city as a whole, setting up a system of cooperation between the industry, government and residents. Taking the city of Kitakyushu as case study, this paper introduces the current development of smart community in Japan, focusing on analyzing its potential and challenges.
Supercapacitors are electrochemical energy storage devices with high power density. However, application of supercapacitors is limited mainly due to their high leakage current. In this work, application of an ultra-thin layer of electrodeposited poly (p-phenylene oxide) (PPO) has been investigated as a blocking layer to reduce the leakage current. The polymer was first deposited on a glassy carbon electrode. The morphology of the film was studied by atomic force microscopy (AFM), and the film thickness was estimated to be ∼1.5 nm by using the electrochemical impedance spectroscopy (EIS) technique. The same deposition method was applied to coat the surface of the activated carbon electrodes of a supercapacitor with PPO. The specific capacitance, the leakage current, and the series resistance were measured in two devices with and without the blocking layer. The results demonstrate that the application of the PPO layer reduced the leakage current by ∼78%. However, the specific capacitance was decreased by ∼56%, when the blocking layer was applied. Due to the lower rate of self-discharge, the suggested approach can be applied to fabricate devices with longer charge storage time.
Advanced Li-ion batteries with high energy and power densities are urgently required in many applications including automobiles. Aging of these batteries and irreversible capacity loss are still the factors preventing their further use, and novel methods of their study are prerequisite for the understanding of degradation at nanoscale. In this work, we use Kelvin Probe Force Microscopy (KPFM) to assess the distribution of surface potential in graphite anodes of commercial Li-batteries before and after aging at high C rates. In the aged sample, we observed an apparent core-shell-type potential distribution on large crack-free particles. We attribute this core–shell potential distribution to the remnant Li+ ions stacked in graphite particles causing irreversible capacity loss. The results corroborate the “radial” model used to explain the specific capacity fading mechanism at high C rate cycling in commercial batteries.
VRLA batteries in hybrid electric vehicles are operated at a partial state of charge with high current draws for acceleration and regenerative braking. Adding larger amounts of carbon particles to the negative plate material extends battery life. Water loss and increasing internal resistance are a cause of a subsequent failure mode that is related to the carbon and other organic additives in the negative plate. Previous studies of the composition and volume of gases vented from valve-regulated lead-acid (VRLA) batteries and acid-limited batteries at various temperatures and current levels are reviewed and used to develop an understanding of carbon reactions and their effects on battery state of health.