Nickel-rich layered metal oxide materials are prospective cathode materials for lithium ion batteries due to the relatively higher capacity and lower cost than LiCoO2. Nevertheless, the disordered ...arrangement of Li+/Ni2+ in local regions of these materials and its impact on electrochemistry performance are not well understood, especially for LiNi1–x–y Co x Mn y O2 (1–x–y > 0.5) cathodes, which challenge one’s ability in finding more superior cathode materials for advanced lithium-ion batteries. In this work, Ni–Co–Mn-based spherical precursors were first obtained by a solvothermal method through handily utilizing the redox reaction of nitrate and ethanol. Subsequent sintering of the precursors with given amount of lithium source (Li-excess of 5, 10, and 15 mol %) yields LiNi0.7Co0.15Mn0.15O2 microspheres with different extents of Li+/Ni2+ disordering. With the determination of the amounts of Li+ ions in transition metal layer and Ni2+ ions in Li layer using structural refinement, the impact of Li+/Ni2+ ions disordering on the crystal structure, valence state of nickel ions, and electrochemical performance were investigated in detailed. It is clearly demonstrated that with increasing the amount of lithium source, lattice parameters (a and c) and interslab space thickness of unit cell decrease, and more Li+ ions incorporated into the 3a site of transition metal layer which leads to an increase of Ni3+ content in LiNi0.7Co0.15Mn0.15O2 as confirmed by X-ray photoelectron spectroscopy and a redox titration. Moreover, the electrochemical performance for as-prepared LiNi0.7Co0.15Mn0.15O2 microspheres exhibited a trend of deterioration due to the changes of crystal structure from Li+/Ni2+ mixing. The preparation method and the impacts of Li+/Ni2+ ions disordering reported herein for the nickel-rich layered LiNi0.7Co0.15Mn0.15O2 microspheres may provide hints for obtaining a broad class of nickel-rich layered metal oxide microspheres with superior electrochemical performance.
Reconstructing a favorable surface layer could contribute to superior charge transfer and stabilize bulk structure and thus achieve the excellent electrochemical performance of lithium- and ...manganese-rich oxides, but it is still challenging. In this work, the surface structures of Li-rich oxides have been successfully reconstructed via a facile strategy utilizing hydrothermal glucose carbonization and the subsequent reduction procedure. Surface microstructure and chemical state analyses reveal that the reconstruction process involves roughening of the surface connects with the extraction of lithium ions and the reduction of Mn ions as well as the formation of a spinel phase due to the distortion of oxygen anions or the presence of oxygen deficiencies. The reconstructed Co-free Li-rich oxide using 0.025 g of glucose exhibits superior electrochemical performance. Its maximum discharge capacities are 237 and 193 mAh/g at 100 and 600 mA/g, respectively, and their corresponding capacity retention ratios are higher than 93% at the 100th cycle. Furthermore, reconstructing the surface structure also enhances the discharge capacity and cycling performance of Co-containing Li-rich cathodes. The findings in this work would offer hints for surface structure reconstruction of many oxides used in energy and other fields.
The occurrence of sulfur in coal direct liquefaction residue affects its further high quality and high value utilization. Electrochemical desulfurization is characterized by mild reaction conditions, ...simple operation, easy separation of sulfur conversion products and little influence on the properties of the liquefied residue. An anodic electrolytic oxidation desulphurization experiment was carried out on the liquefaction residue of the by-product of a coal-to-liquid enterprise in the slurry state. An electrochemical test and material characterization of raw materials before and after electrolysis showed that electrolytic oxidation can desulfurize the liquefaction residue under an alkaline condition. Linear sweep voltammetry (LSV) was used for the electrolysis experiments to obtain the optimal slurry concentration of 60 g/L. On this basis, the reaction kinetics were calculated, and the minimum activation energy in the interval at 0.9 (V vs. Hg/HgO) was 19.71 kJ/mol. The relationship between the electrolytic desulfurization of the liquefied residue and energy consumption was studied by the potentiostatic method. The influence of anodic potential and electrolytic temperature on the current density, cell voltage, desulfurization rate and energy consumption was investigated. The experimental results showed that the desulfurization rate and total energy consumption increase positively with the increase in reaction temperature and electrolytic potential in a certain range. The influence of the reaction temperature on the desulfurization rate and total energy consumption is more prominent than that of electrolytic potential, but the energy consumption of sulfur removal per unit mass does not show a positive correlation. Therefore, with the energy consumption per unit mass of sulfur removal as the efficiency index, the optimal experimental results were obtained: under the conditions of 0.8 (V vs. Hg/HgO) anode potential, 50 °C electrolytic temperature, 60 g/L slurry concentration and 14,400 s electrolytic time, the desulfurization rate was 18.85%, and the power consumption per unit mass of sulfur removal was 5585.74 W·s/g. The results of XPS, SEM, BET and IC showed that both inorganic and organic sulfur were removed by electrolytic oxidation, and the morphology, pore structure and chemical bond of the liquefied residue were affected by electrolytic oxidation. The research method provides a new idea and reference for the efficiency evaluation of desulfurization and hydrogen production from coal liquefaction residue.
For achieving the goal of peaking carbon dioxide emissions and achieving carbon neutrality, developing hydrogen energy, the green and clean energy, shows a promising perspective for solving the ...energy and ecological issues. Herein, firstly, we used the hydrothermal method to synthesize the ZnS(en)0.5 as the precursor. Then, ZnS/ZnO composite was obtained by the in situ transformation of ZnS(en)0.5 with heat treatment under air atmosphere. The composition, optical property, morphology, and structural properties of the composite were characterized by X-ray photoemission spectroscopy (XPS), Ultraviolet-visible absorption spectra (Uv-vis Abs), Scanning electron microscopy (SEM) and Transmission electron microscopy image (TEM). Moreover, the content of ZnO in ZnS/ZnO was controlled via adjustment of the calcination times. The visible-light response of ZnS/ZnO originated from the in situ doping of N during the transformation of ZnS(en)0.5 to ZnS/ZnO under heat treatment, which was verified well by XPS. Photocatalytic hydrogen evolution experiments demonstrated that the sample of ZnS/ZnO-0.5 h with 6.9 wt% of ZnO had the best H2 evolution activity (1790 μmol/h/g) under visible light irradiation (λ > 400 nm), about 7.0 and 12.3 times that of the pure ZnS and ZnO, respectively. The enhanced activities of the ZnS/ZnO composites were ascribed to the intimated hetero-interface between components and efficient transfer of photo-generated electrons from ZnS to ZnO.
In this paper, a novel noise adaptive moving horizon estimation (NAMHE) method is proposed to improve the accuracy of state of charge(SOC) estimation of Li-ion batteries under the unknown noise ...conditions. Specifically, based on the maximum likelihood principle, the unknown statistical characteristics of the noises can be estimated to modify the recurrence expression of the NAMHE. Then, the SOC estimation algorithm is designed by combining the equivalent circuit model and the proposed NAMHE. Furthermore, the convergence of the estimation error expectation is obtained for the NAMHE algorithm. Finally, the simulation results clarify that the SOC estimation error under the different unknown noise conditions can be effectively reduced by the proposed method, compared with the traditional MHE method.
Background IgG4-related disease (IgG4-RD) was characterized by single or multiple masses in organs, which may mimic various inflammatory and malignant diseases. Here, we summarize 4 patients with ...aggressive manifestations of IgG4-RD that mimic nasopharynx cancer to provide some new sights for the diagnosis of IgG4-RD. Case summary Four patients were included in our series. The age ranged from 53 to 64 years old, and the duration of the disease ranged from 4 to 6 months. The chief complaints included headache, rhinorrhea, or diplopia. All patients had more than 10 IgG4+ plasma cells/HPF in immunohistochemistry with plasma lgG4 levels ranging from 218 mg/dL to 765 mg/dL. All of them met the diagnostic criteria of lgG4-RD. Conclusion The described case is highly similar to the clinical manifestations of nasopharyngeal carcinoma. Although pathology is the gold standard, there are still limitations. Serological IgG4 can help confirm the diagnosis. Timely diagnosis of IgG4-RD is of great significance in preventing secondary organ damage in patients with active diseases.
The present-day in-situ stresses affect the drilling design, well pattern deployment, well completion modification, hydraulic fracturing and water injection of tight-oil sandstones. The measurement ...data of these stresses are commonly unavailable because of their high costs and limited core samples, therefore employing conventional logs for these stress determination is imperative for tight-oil sandstones. Firstly, the suitable calculation models for the present-day in-situ stress calculation by conventional logs were selected according to the geological characteristics of the sixth member of the Yanchang Formation (Chang 6) in Heshui area of the southern Ordos Basin, China. Then, the dynamic rock mechanical parameters were determined by conventional logs, and corrected by the static rock mechanical parameters obtained from the triaxial rock mechanical tests. Moreover, the pore fluid pressure was determined by the empirical formula method. Finally, the maximum and minimum horizontal compressive stresses (σH and σh), and the vertical stress (σv) of six wells were calculated according to the selected models of these stresses, respectively. The present-day in-situ stresses, determined by the proposed method in the paper, were verified by those obtained from acoustic emission tests and finite-element numerical simulations with the relative errors of less than 10%. The results show that the magnitudes of σH, σh and the horizontal differential stress (σH−h) in the study area mainly range from 32 to 43 MPa, 23 to 37 MPa and 5 to 8 MPa, respectively. The magnitude of the three-dimensional present-day in-situ stress increases with the increase of depth. The average gradients of σH, σv and σh are 0.018, 0.014 and 0.015 MPa/m, respectively, that is σH>σv>σh. In this stress state, the hydraulic fractures, with a trend of little expansion towards multiple directions, are commonly developed at a small angle intersecting with the direction of σH in the study area.
Allium mongolicum Regel (AM), widely distributed in western China, is a traditional Mongolian medicine herb. Two different solvents as water and methanol were used to extract AM, and their ...antioxidant capacity and inhibitory effects against key enzymes related to metabolic syndrome were assessed. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS and reducing power assays. In addition, the total phenolic content and total flavonoids content were quantificated and analyzed. Aqueous extract, having higher phenolic content (10.20 mg GAE/g DW) and flavonoid content (4.02 mg QE/g DW), showed better antioxidant and inhibitory effects against lipase and angiotensin‐converting enzyme (ACE); as for α‐glucosidase, the extract made by methanol showed better ability. In general, the aqueous extract of A. mongolicum Regel has the potential to be used as a functional food or nutraceutical in prevention and treatment of obesity and hypertension due to the high antioxidant and sound inhibitory potential against vital enzymes relevant to obesity and hypertension.
This study has given an experimental evidence that Allium mongolicum Regel is an excellent source of natural polyphenols and antioxidant. In addition, the aqueous extract of A. mongolicum Regel may be likely to have good application in the research and development of potential remedy for the administration of metabolic syndrome.
Based on core, imaging logging, and thin section data, the distribution features of natural fractures in the tight oil reservoirs of the Ordos Basin are examined. The tight reservoirs in the Ordos ...Basin are rich in natural fractures, the fractures are mainly high-angle structural shear fractures in continuous step arrangement. Affected by rock mechanical anisotropy and present stress field, the NE trending fractures are the dominating seepage flow direction. These fractures feature high angle, small cutting depth, small aperture and short extension, controlled by rock lithology and single layer thickness in development degree, natural fractures are most developed in fine siltstone, most undeveloped in mudstone. The thinner the single layer, the more developed the natural fractures will be. Based on distribution features of natural fractures and quantitative evaluation of natural fracture characteristic parameters, by using reservoir matrix and natural fracture geologic modeling, a comprehensive reservoir geologic model considering natural fractures was built, by using reservoir numerical simulation modeling inversion, the plane distribution of effective natural fractures was found out, and the contribution of natural fractures to single well production was quantitatively evaluated at around 30.0%−50.0%. The research results are of great significance for well-pattern deployment and optimization of development technical policies of similar reservoirs.
Waterflooding is an important functional process for low-permeability reservoir development. However, production practice shows that water breakthrough and floods along natural fractures are ...ubiquitous in low-permeability reservoirs. Therefore, controlling the water injection pressure to prevent water breakthrough and floods along natural fractures is an effective measure for improving the waterflooding development effect. In this paper, an approach is proposed for determining the water injection pressure based on the opening pressure of natural fractures in fractured low-permeability reservoirs. The opening pressures of natural fractures calculated by the analytical method in the paper and the formation-parting pressures are compared based on the production performance in two different fault blocks F16 and Z3 of the Zhouqingzhuang Oilfield in the Bohai Bay Basin, China. The results show that the calculated opening pressures of the natural fractures in fault blocks F16 and Z3 are 31.4 and 42.9 MPa, respectively, and they are close to the opening pressures of natural fractures obtained from the step-rate tests in injection wells (28.6 and 41.1 MPa); whereas, the formation-parting pressures (44.5 and 47.6 MPa) are greater than the opening pressures of natural fractures. This suggests that the opening pressures of natural fractures can be used, instead of the formation-parting pressure, for the maximum threshold of the water injection pressure. Its effectiveness has been confirmed via comparison to the production performances of the other two wells in the Zhouqingzhuang Oilfield and several fractured low-permeability reservoirs in the Ordos Basin, China. This study will have beneficial applications in the design of waterflooding development in low-permeability reservoirs characterized by the presence of natural fractures.
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