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Spontaneous reactions occurring at the surface of LiNi y Co(1−y)O2-based electrodes during contact with non-aqueous organic electrolytes have been investigated by FTIR and Raman spectroscopy. It is found that several types of compounds and/or functional groups are formed on the electrode surface and that these compounds appear to be dependent on the type of electrolyte used. Thus, for a LiClO4-propylene carbonate (PC) electrolyte, the main reaction is formation of Li-carbonate, whereas in the case of LiPF6-ethylene carbonate/dimethyl carbonate (EC/DMC) electrolyte formation of P-, O- and F-containing compounds dominate. Spectroscopic data also show a variation of the LiNi(1−y)Co y O2 crystalline structure during storage in an electrolyte which probably is due to a spontaneous deintercalation of the Li ions. An analysis of the newly formed species is presented and possible reaction mechanisms are discussed.
LiNi0.8Co0.1Mn0.1O2 cathode material with full-gradient structure is prepared by a novel co-precipitation method. Scanning electron microscope images show that the material presents regular spherical shape. X-ray diffraction pattern shows that the material has good layered structure. Energy dispersive X-ray spectroscopy analysis for the cross section of secondary particles shows that the relative molar content of Ni gradually decreases from 84% to 76% along the center to the edge of hemisphere, while the Mn content increases gradually. Moreover, the Co content also presents a slow gradient change. Electrochemical tests at room temperature show that the retention rates of discharge capacity for full-gradient material after 100 cycles at current density of 1C and 5C are 98.8% and 93.7%, respectively, which are obviously improved compared with intrinsic material. The gradient material also shows improved midpoint voltage and specific energy. Moreover, full-gradient material exhibits good cyclic stability at high temperature, and the capacity retention rate of 100 cycles is as high as 90% at 5C rate, which is obviously higher than 71.8% of intrinsic material. Impedance spectroscopy studies show that the solid-state diffusion coefficient of lithium ion in gradient material has been significantly improved, thus showing good electrochemical properties. The full-gradient material shows excellent application prospects in the field of power batteries.
Mg-doped on core-shell structured layered oxide LiNi0.6Co0.2Mn0.2O2 cathodes are synthesized by doping Mg into LiNi0.8Co0.1Mn0.1O2 core and LiNi0.2Co0.4Mn0.4 O2 shell，respectively or Mg co-doped both in core and shell. The influence of Mg doping on crystal structure are characterized by XRD，EDS，XPS and ICP-ES. Electrochemical tests show that doping Mg in the shell layer of Li[(Ni0.8Co0.1Mn0.1)2/3(Ni0.2Co0.4Mn0.4)1/3]O2 (S–Mg) exhibits the optimized electrochemical performance, with retention of 85.79% after 100 cycles at 0.2 C and a high discharge capacity of 128.4 mAh g−1 at 5 C, compared with C–S, C–Mg, and F–Mg cathodes. Mg-doped in shell layer of Ni-rich cathode material LiNi0.6Mn0.2Co0.2O2 can not only maintains the stability of material surface, but also reduces the material impedance. The expansion space of the crystalline host lattice caused by Mg doping in the shell will also promote the transport of Li+ during charging and discharging. Cation doping in shell is conductive to electrochemical performance of core-shell materials.
Spherical, high tap density, carbon-coated Li4Ti5O12 powders are synthesized by a spray-drying process followed by a facile pitch coating. XRD, SEM, TEM analyses show that the carbon layer uniformly coats the Li4Ti5O12 particles without producing any crystalline changes. We demonstrate that the carbon coating significantly increases the electrical conductivity of Li4Ti5O12 making it an efficient, high rate electrode for lithium cells. The electrochemical tests in fact confirm that the 3.25wt% carbon-coated Li4Ti5O12 electrode operates with ultra high rate capacity levels, i.e., 100C and has excellent capacity retention and charge–discharge efficiency for a life extending over 100 cycles.
To fabricate all-solid-state Li batteries using three-dimensionally ordered macroporous Li1.5Al0.5Ti1.5(PO4)3 (3DOM LATP) electrodes, the compatibilities of two anode materials (Li4Mn5O12 and Li4Ti5O12) with a LATP solid electrolyte were tested. Pure Li4Ti5O12 with high crystallinity was not obtained because of the formation of a TiO2 impurity phase. Li4Mn5O12 with high crystallinity was produced without an impurity phase, suggesting that Li4Mn5O12 is a better anode material for the LATP system. A Li4Mn5O12/3DOM LATP composite anode was fabricated by the colloidal crystal templating method and a sol–gel process. Reversible Li insertion into the fabricated Li4Mn5O12/3DOM LATP anode was observed, and its discharge capacity was measured to be 27mAhg−1. An all-solid-state battery composed of LiMn2O4/3DOM LATP cathode, Li4Mn5O12/3DOM LATP anode, and a polymer electrolyte was fabricated and shown to operate successfully. It had a potential plateau that corresponds to the potential difference expected from the intrinsic redox potentials of LiMn2O4 and Li4Mn5O12. The discharge capacity of the all-solid-state battery was 480μAhcm−2.
The diamino-aryl-1,4,5,8-naphtalenetetra-carboxylic diimide molecule (NTCDA-(aryl-NH2)2) was successfully prepared by N-acylation reaction of 1,4,5,8-naphtalenetetra-carboxylic dianhydride (NTCDA) with 4-nitroaniline, followed by a simple reduction of nitro groups in amino functions. The molecules were characterized by elemental analysis, SEM, IR and TGA. A Li-ion electrode with NTCDA-(aryl-NH2)2 as active material was tested and a reversible behavior was observed with a multiple electrons process delivering about 100 mAh g−1 at an average potential of 2.45 V vs. Li/Li+. The diazotization of NTCDA-(aryl-NH2)2 and its attachment on a carbon surface was investigated. An irreversible cathodic wave at around 0.0 V vs. Ag/AgNO3 that is associated to the reduction of the in-situ generated NTCDA-(aryl-N2 +)2 ions was observed. The blocking effect of the grafted layer deposited on the glassy carbon surface was verified with ferrocene as a redox probe. This molecule was further immobilized on Ketjen black carbon in a one-pot reaction by spontaneous reduction of freshly formed NTCDA-(aryl-N2 +)2 ions. The redox-active carbons with a loading of grafted groups estimated between 26.4 and 36.7 wt % cycled at high rate for thousands of cycles. Two other diamines prepared according to the same method were also investigated, as well as their immobilization on Ketjen black surface.
We demonstrate a facile approach for the fabrication of new silica (SiO2) nanoparticles/polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP)-coated polyethylene terephthalate (PET) nonwoven composite separators for use in lithium-ion batteries. By varying the SiO2/PVdF-HFP composition ratio, we can fine-tune the porous structure of the composite separators. At a low SiO2/PVdF-HFP ratio, a nonporous structure featuring the PVdF-HFP matrix and SiO2 domains is obtained. By contrast, an unusual porous structure (i.e., highly-percolated interstitial voids formed between close-packed SiO2 nanoparticles) is developed at a high SiO2/PVdF-HFP ratio, where PVdF-HFP serves as a binder to interconnect SiO2 powders. This drastic change in the morphology of the composite separators is further confirmed by observing their air permeability and ionic conductivity. Meanwhile, a PET nonwoven is employed as a mechanical substrate to suppress thermal shrinkage of the composite separators. On the basis of morphological characterization, the effects of the composition ratio-dependent structural evolution of the composite separators on the electrochemical performance of cells are investigated. Notably, the composite separator fabricated from a composition ratio of SiO2/PVdF-HFP=90/10 (wt%/wt%) provides superior cell performance owing to a well-tailored microporous structure, as compared to a commercialized polyethylene (PE) separator.
Pumped hydro energy storage (PHS) currently is the only electricity grid storage technology with substantial deployment throughout the world, representing over 99% of storage capacity, but other storage technologies such as batteries are increasingly finding application. In Europe, the implementation of storage systems is expected to increase because of the integration of intermittent, nondispatchable renewable energy sources. Nevertheless, there is no overview available of the power and energy ratings of large-scale stationary storage at the supranational level. In the absence of officially collected statistics on energy capacity, publicly available information is collected from storage owners, freely accessible databases, scientific articles, reports, brochures and government websites. The status of PHS and other large-scale storage technologies in the EU-28 countries, supplemented by Norway and Switzerland, is presented. First, this paper defines a measure of energy storage capacity, to allow comparison of pumped hydro storage plants with other storage technologies. Next, a set of technical parameters of current large-scale storage plants is presented, as well as an overview of planned storage projects. The estimate of PHS power ratings in the EU-28 exceeds previous estimates, with a total of 160 plants and 45.283GW rated power in turbine mode and a full cycle storage capacity of 602GWh. When adding Norway and Switzerland, a total of 188 operational PHS plants is shown with 1313GWh. The data is used to obtain EU-wide discharge curves and national indicators of utilization and significance.
X-ray diffraction (XRD), in situ X-ray absorption spectroscopy (XAS), and chemical lithiation experiments were used to evaluate the phases associated with the electrochemistry of the mixed-metal layered LiMn0.5Ni0.5O2 oxide electrode. These results, along with coin-cell cycling data from the substituted layered (1−x)Li2TiO3·(x)LiMn0.5Ni0.5O2 composite oxide electrode are reported. The cycling behavior of Li/0.05Li2TiO3·0.95LiMn0.5Ni0.5O2 (x=0.95) cells over an extended voltage window (4.3 or 4.6–1.25V) under moderate current rate have yielded rechargeable capacities above 250mAh/g. These large capacities and structural data suggest that both the composite (1−x)Li2TiO3·(x)LiMn0.5Ni0.5O2 and LiMn0.5Ni0.5O2 (standard) layered electrodes operate predominantly off two-electron redox couples, Ni4+/Ni2+ and Mn4+/Mn2+, approximately between 4.6 and 2.0V, and between 2.0 and 1.0V versus metallic Li, respectively. The LiMn0.5Ni0.5O2 layered oxide is shown to reversibly react chemically or electrochemically with Li to form a stable, but air-sensitive dilithium compound, Li2Mn0.5Ni0.5O2 (Li2MO2; M=metal ion) that can be indexed to the space group P-3m1.
This paper concerns the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. The metals were dissolved by a reductive-acid leaching with sulphuric acid in the presence of oxalic acid as reductant. Leaching tests were realised according to a full factorial design, then simple regression equations for Mn, Zn and Fe extraction were determined from the experimental data as a function of pulp density, sulphuric acid concentration, temperature and oxalic acid concentration. The main effects and interactions were investigated by the analysis of variance (ANOVA). This analysis evidenced the best operating conditions of the reductive acid leaching: 70% of manganese and 100% of zinc were extracted after 5h, at 80°C with 20% of pulp density, 1.8M sulphuric acid concentration and 59.4gL−1 of oxalic acid. Both manganese and zinc extraction yields higher than 96% were obtained by using two sequential leaching steps.
Nanoscaled tin (Sn) particles were embedded in the mesopores of hard carbon spherules (HCS) to form a composite anode material for lithium ion batteries. The structure of the obtained composite was characterized by X-ray diffraction (XRD) and the electrochemical performances were evaluated by galvanostatic cycling and cyclic voltammetry. It is found that embedding Sn nanoparticles into HCS not only results in a composite material with high-lithium storage capacity and capacity retention, but also increases the initial coulombic efficiency of the composite. Based on the infrared spectroscopic analysis, the enhanced initial coulombic efficiency is attributed to the nano-tin-induced decomposition of the ROCO2Li species in the solid electrolyte interphase (SEI) layer.
In this study the concentrations of the most important carbonyl compounds, formaldehyde and acetaldehyde, are measured in a highway environment in spring, summer and winter. Measurements were carried out in May, July and January along a two-lane highway, with daily traffic density 27 500 vehicles. Four sampling points were selected: (1) one from east and (2) west sides of the highway, (3) one at the central reservation of the highway and (4) one background site. The formaldehyde and acetaldehyde concentrations measured at both sides of a two-lane highway and at the central reservation suggest that the motor vehicle emissions are the source of these compounds throughout the year. The concentrations were, however, significantly lower at the roadsides than at the central reservation, especially in July. This could indicate rapid dilution of these compounds in the air. It is also possible that the vegetation along the roadside in summer may play a role as a sink or as a biogenic source for these compounds. The concentrations measured along the roadside in this study are comparable to those measured in polluted urban areas. The diurnal variation showed significant decrease of formaldehyde and acetaldehyde concentrations in the night indicating a decrease in primary source, i.e. traffic emissions. The seasonal variation was great as well, concentrations being lower in winter time, indicating lower secondary production of aldehydes. The formaldehyde and acetaldehyde effects on plants remains to be studied, since the formaldehyde and acetaldehyde pose a noteworthy risk to the vegetation exposed.
The free standing aluminum nanorods were grown on electrode and evaluated electrochemically as the anodes in the half-cell of Li-ion battery. The average diameter and length of the nanorods are 80nm and 200nm, respectively. The aligned nanorods demonstrated high capacity of 1243mAhg−1 at rate of 0.5C. A gradual decrease of the initial capacity was observed. The characterization of the anodes shows that the changes of the crystalline structure and morphology during cycling may be responsible for the capacity decay. The appropriate selection of the substrate can overcome the problems and lead the sustainable high capacity.
Carbon capture and storage can help reduce fossil-fuel power-plant emissions. Here the authors show that the energy return on input of thermal plants with carbon capture is in general lower than the energy return of most types of renewable energy even when combined with energy storage.
Recently, the LiFeSO4F material has been reported as the highest potential Fe-based cathode material for Li-ion batteries. Its working voltage vs. Li+/Li0 jumps from 3.6 V to 3.9 V when LiFeSO4F is synthesized with the fully ordered tavorite structure and the fully disordered triplite structure, respectively. The present study aims at rationalizing this voltage increase by means of DFT + U calculations combined with crystallographic and electrostatic analyses. We show that the triplite polymorph, although characterized by two distinct edge-shared crystallographic sites, locally exhibits corner-sharing connections between consecutive FeO4F2 octahedra, exactly as in the tavorite polymorph. As a consequence, edge-sharing connections exist in the lithiated triplite structure between consecutive FeO4F2 and LiO4F2 polyhedra. We then demonstrate that the origin of the voltage increase lies in the difference in the anionic networks of the two polymorphs, and more specifically in the electrostatic repulsions induced by the configuration of the fluorine atoms around the transition metal in the two polymorphs (trans- vs. cis-configurations in tavorite vs. triplite polymorphs). Such a finding should help in the design of novel high potential fluorosulphate materials, which beyond enhanced performances present sustainability attributes as they can be made from abundant elements and via low temperature eco-efficient processes.
The multidomain serine protease inhibitor lymphoepithelial Kazal-type related inhibitor (LEKTI) represents a key regulator of the proteolytic events occurring during epidermal barrier formation and hair development, as attested by the severe autosomal recessive ichthyosiform skin condition Netherton syndrome (NS) caused by mutations in its encoding gene, serine protease inhibitor Kazal-type 5 (SPINK5). Synthesized as a proprotein, LEKTI is rapidly cleaved intracellularly, thus generating a number of potentially bioactive fragments that are secreted. Here, we show that SPINK5 generates three classes of transcripts encoding three different LEKTI isoforms, which differ in their C-terminal portion. In addition to the previously described 15 domain isoform, SPINK5 encodes a shorter LEKTI isoform composed of only the first 13 domains, as well as a longer isoform carrying a 30-amino-acid residue insertion between the 13th and 14th inhibitory domains. We demonstrate that variable amounts of SPINK5 alternative transcripts are detected in all SPINK5 transcriptionally active tissues. Finally, we show that in differentiated cultured human keratinocytes all SPINK5 alternative transcripts are translated into protein and that the LEKTI precursors generate distinct secreted C-terminal proteolytic fragments from a similar cleavage site. Since several data indicate a biological role for the pro-LEKTI-cleaved polypeptides, we hypothesize that the alternative processing of the SPINK5 pre-messenger RNA represents an additional mechanism to further increase the structural and functional diversity of the LEKTI bioactive fragments.
Online product reviews are a major source of business intelligence (BI) that helps managers and marketers understand customers’ concerns and interests. The large volume of review data makes it difficult to manually analyze customers’ concerns. Automated tools have emerged to facilitate this analysis, however most lack the capability of extracting the relationships between the reviews’ rich expressions and the customer ratings. Managers and marketers often resort to manually read through voluminous reviews to find the relationships. To address these challenges, we propose the development of a new class of BI systems based on rough set theory, inductive rule learning, and information retrieval methods. We developed a new framework for designing BI systems that extract the relationship between the customer ratings and their reviews. Using reviews of different products from Amazon.com, we conducted both qualitative and quantitative experiments to evaluate the performance of a BI system developed based on the framework. The results indicate that the system achieved high accuracy and coverage related to rule quality, and produced interesting and informative rules with high support and confidence values. The findings have important implications for market sentiment analysis and e-commerce reputation management.
Twelvecm2 pouch type lithium-ion cells were assembled with graphite anodes, LiNi0.8Co0.15Al0.05O2 cathodes and 1M LiPF6/EC/DEC electrolyte. These pouch cells were cycled at different depths of discharge (100 and 70% DOD) at room temperature to investigate cycle performance and pulse power capability. The capacity loss and power fade of the cells cycled over 100% DOD was significantly faster than the cell cycled over 70% DOD. The overall cell impedance increased with cycling, although the ohmic resistance from the electrolyte was almost constant. From electrochemical analysis of each electrode after cycling, structural and/or impedance changes in the cathode are responsible for most of the capacity and power fade, not the consumption of cycleable Li from side-reactions.
The purpose of this paper is to present a developed cutting force model for multi-toothed cutting processes, including a complete set of parameters influencing the cutting force variation that has been shown to occur in face milling, and to analyse to what extent these parameters influence the total cutting force variation for a selected tool geometry. The scope is to model and analyse the cutting forces for each individual tooth on the tool, to be able to draw conclusions about how the cutting action for an individual tooth is affected by its neighbours. A previously developed cutting force model for multi-toothed cutting processes is supplemented with three new parameters; eccentricity of the spindle, continuous cutting edge deterioration and load inflicted tool deflection influencing the cutting force variation. A previously developed milling force sensor is used to experimentally analyse the cutting force variation, and to give input to the cutting force simulation performed with the developed cutting force model. The experimental results from the case studied in this paper show that there are mainly three factors influencing the cutting force variation for a tool with new inserts. Radial and axial cutting edge position causes approximately 50% of the force variation for the case studied in this paper. Approximately 40% arises from eccentricity and the remaining 10% is the result of spindle deflection during machining. The experimental results presented in this paper show a new type of cutting force diagrams where the force variation for each individual tooth when two cutting edges are engaged in the workpiece at the same time. The wear studies performed shows a redistribution of the individual main cutting forces dependent on the wear propagation for each tooth.
Lead acid batteries have been widely used and have dominated the global secondary battery market. It is very important to recycle the spent batteries efficiently to eliminate possible pollution and to ensure sustainable production. In this paper, we report our investigation on the solvothermal treatment of PbO2, which is one of the model compounds for the positive active mixture, in methanol and the subsequent calcination of its product. The results show that the solvothermal treatment of PbO2 in pure methanol at 140 °C can produce a mixture of PbO and lead oxide carbonate, which can be calcined at a temperature below 500 °C to produce α-PbO. The as-prepared PbO powders are rod-like particles of about 0.5 micrometer in diameter and several micrometers in length, which can achieve a high discharge capacity of 165 mAh g−1 at the discharge current density of 5 mA g−1, and more than 90 mAh g−1 at 200 mA g−1 with excellent cycle stability. This study demonstrates a new way for the reuse of lead dioxide in spent lead acid batteries to produce highly active PbO.