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The seepage responding mechanism of rock mass caused by the borehole water injection was crucial to the safe and economical operation of underground water-sealed storage. This study gave a detailed investigation to the above seepage responding mechanism, reflecting by the variation of relationship between injection pressure and flow volume. The characteristic related to rock mass condition was considered by numerical simulation, including fracture aperture, dip angle, tendency and density. And the orthogonal test was used to give some quantitative evaluation for the influence factors. Some conclusion could be given. Firstly, it could be found that the fracture aperture was determined to have the greatest influence to the relationship between injection pressure and volume from the orthogonal test result. Secondly, there would exist a crucial dip angle to form a relative complete hydraulic connection in the fracture net, which indicated a value of 35° from numerical simulation. The fracture density would also have a crucial value to form a relatively good connectivity fracture net, with the value of 1.67 × 10− 3n/m3. Thirdly, some enlightenments were given for the water curtain system design mainly about the suggestion for the layout of water curtain borehole in some certain rock mass condition. Suggestion about the geological survey was also given for the water curtain system. The innovation was mainly to reveal the relationship between the injection pressure and flow influenced by the rock mass condition, which would contribute to enrich the seepage mechanism in complex fracture and the theory of water curtain optimization. [ABSTRACT FROM AUTHOR]

Employing the solid polymer electrolyte (SPE) instead of traditional liquid electrolyte is an effective way to develop high safety and high-energy density solid-state lithium batteries. Herein, for the first time, the Ni3B2O3 (NBO) nanorods are incorporated into polyethylene oxide (PEO)-based SPE. Particularly, the optimized NBO-embedded SPE shows a high ionic conductivity of 8.5 × 10−5 S cm−1 at 30 °C, lowering the operating temperature of PEO-based SPE substantially. The corresponding LiFePO4/Li battery demonstrates a high discharge capacity of 154 mAh g−1 after 80 cycles at 0.2 C under 30 °C, with favorable capacity retention of 97.5%. The remarkable properties are attributed to the high ionic conductivity of modified SPE at ambient temperature, which is resulted from the decreased crystallinity and melting transition point, increased movement of PEO chain, and promotion of lithium salt dissociation, as well as the formation of the lithium ion migrating pathway on the interface between PEO and NBO nanorods. [ABSTRACT FROM AUTHOR]

Magnetic skyrmion tubes and bobbers are two types of different nanoscale spin configurations that can coexist in nanostructures of chiral magnets. They are then proposed to be utilized as binary bits to build racetrack memory devices. The ability to manipulate the two magnetic objects controllably by current in nanostructures is the prerequisite to realize the device. Here, we demonstrate by numerical simulations that a magnetic bobber and a skyrmion tube can be transformed to each other using spin-polarized current in nanostripes with stepped shape. We also show such stepped nanostructures can be readily applied as the write head for the skyrmion-bobber-based racetrack memory. [ABSTRACT FROM AUTHOR]

To suppress the capacity fade of Li-rich Li1.2Ni0.13Co0.13Mn0.54O2 material as cathode materials for lithium-ion battery, we introduce a LiF coating layer on the surface to improve the cycling performance of Li1.2Ni0.13Co0.13Mn0.54O2 material. The modified sample shows a capacity of 163.2 mAh g−1 with a capacity retention of 95% after 100 cycles at a current density of 250 mA g−1, while the pristine sample only delivers a capacity of 129.9 mAh g−1 with a capacity retention of 82%. Compared with the pristine material, the LiF-modified sample exhibits an obvious enhancement in the electrochemical performance, which will be very beneficial for this material to be commercialized on the new energy vehicles and other related areas. [ABSTRACT FROM AUTHOR]

The major obstacle for the application of high-voltage cathode materials is the anodic instability of the electrolyte. On the guidance of density functional theory calculation, we develop a new high-voltage electrolyte comprising 1 mol L LiPF dissolved in fluoroethylene carbonate (FEC) and ethyl difluoroacetate (DFEAc) (FEC/DFEAc = 3:7 in wt.% ratio). It shows a high conductivity (9.48 mS cm) and high anodic stability compared with the conventional electrolyte of 1 mol L LiPF dissolved in ethylene carbonate (EC) and ethyl-methyl carbonate (EMC) (EC/EMC = 3:7 in wt.% ratio). In addition, Li/LiNiCoMnO half-cells with the new electrolyte display an excellent cycling ability with capacity retention of 89.23% after 100 cycles at 4.6 V (vs. Li/Li). Although the electrolyte still will be oxidized at the cathode surface, the LiCO and carbon-fluoride species originated from DFEAc and FEC are beneficial to building a stable cathode/electrolyte interface as revealed by the TEM and XPS results. [ABSTRACT FROM AUTHOR]

Lithium bis(fluorosulfony)imide (LiFSI) is a promising alternative lithium salt to replace lithium hexafluorophosphate (LiPF) due to its high conductivity and excellent compatibility with electrode material. On the other hand, the aluminum corrosion caused by LiFSI hinders its application in lithium ion battery. To solve this problem, lithium difluoro(oxalato)borate (LiDFOB) is added to suppress the aluminum corrosion in LiFSI-based nonaqueous carbonate electrolyte. The electrochemical tests in three-electrode cells and graphite/LiCoO full cells confirm that the addition of LiDFOB is beneficial to suppress the aluminum corrosion. In addition, the mechanism is proposed that the oxidation products of LiDFOB form a passivating film at the aluminum surface to suppress the corrosion based on the experimental results from SEM and XPS tests. [ABSTRACT FROM AUTHOR]

Networks with multi-links are universal in the real world such as communication networks, transport networks, and social networks. It is important for us to investigate the control of complex dynamical network with multi-links. In this paper, both local and global stabilities of dynamical network with multi-links are analyzed by applying adaptive control theory and mathematical tools, and some new criteria are proposed to ensure the pinning synchronization. We find that the number of pinned nodes satisfies an inequality for synchronization. Additionally, we solve the problem of how much the coupling strength we need to achieve network synchronization with one pinned node in the network system with multi-links. Finally, numerical examples are used to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Spinel LiMn2O4 was synthesized by a solid-state method. A 204468-size battery was fabricated and stored at 55°C. The structure and morphology of the LiMn2O4 cathode were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) technique. Energy dispersive spectroscopy (EDS) was used to analyze the surface component of the carbon anode. The discharge capacities of LiMn2O4 stored for 0, 24, 48, and 96 h are 106, 98, 96, and 92 mAh·g−1, respectively. The cyclic performance is improved after storage. The capacity retentions of LiMn2O4 stored for 0, 24, 48, and 96 h are 83.8%, 85.8%, 86.9%, and 88.6% after 180 cycles. The intensity of all the LiMn2O4 diffraction peaks is weakened. Mn is detected from the carbon electrode when the battery is stored for 96 h. Cyclic voltammograms and electrochemical impedance spectroscopy (EIS) were used to examine the surface state of the electrode after storage. The results show that the resistance and polarization of LiMn2O4/electrolyte is increased after storage, which is responsible for the fading of capacity. [ABSTRACT FROM AUTHOR]