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The silicon anode is promising for high‐energy density lithium‐ion batteries owing to its ultrahigh theoretical capacity. However, the practical deployment of Si anodes is significantly hindered by its large volume change and unstable electrode/electrolyte interphase associated with routine electrolytes. Herein, a cyclic ether‐based electrolyte is designed and shows high compatibility with Si anodes. By simply decreasing the prevalence of ethereal oxygen groups and increasing the degree of molecule unsaturation of 1,2‐dimethoxyethane simultaneously, the resulting cyclic tetrahydrofuran (THF) presents a weak solvation capability and strong polymerization. Experimental and computational evidence demonstrates this rational design leads to a remarkable improvement in electrochemical performance of Si anodes. By forming a thin, elastic, and LiF‐rich inorganic‐polymeric solid‐electrolyte interphase film, the Si electrode cycled in THF‐based electrolyte exhibits long‐term cycling stability with a high reversible capacity of 1995.7 mAh g−1 after 400 cycles. The full‐cells with Si/graphite anodes and LiFePO4 cathodes maintain over 80% capacity retention after 600 cycles. [ABSTRACT FROM AUTHOR]

• A new prefabricated technique with use of wet joints and rebars is proposed. • Two field tests on prefabricated concrete targets subjected to projectile penetration are conducted. • Test data demonstrates penetration resistance of prefabricated and monolithic targets is comparable. • The interface effects on penetration resistance are numerically clarified. • The proposed prefabricated technique is numerically demonstrated. Prefabricated ultra-high-performance concrete (UHPC) target has the advantages of prominent anti-penetration capability and good construction quality. However, the interfaces in the prefabricated target would inevitably reduce its penetration resistance. To deal with this problem, a new prefabricated technique with the use of wet joints and rebars is proposed. To demonstrate the effectiveness of the proposed technique, two sets of projectile penetration tests on prefabricated targets assembled by prefabricated UHPC blocks, wet joints and rebars were firstly conducted and compared with corresponding experimental results of monolithic targets, demonstrating the comparable penetration resistance between prefabricated targets and corresponding monolithic targets. Then, based on the Kong–Fang model and SPG method, the numerical models of the two tests were developed and validated against the experimental data. The validated numerical models were further used to investigate the influences of interfaces, wet joints and rebars on the penetration resistance of prefabricated targets. The numerical results found that the horizontal interfaces have a limited influence on the penetration resistance while the vertical interfaces have a strong influence. It also numerically demonstrated the effectiveness of the proposed technique using wet joints and rebars to connect prefabricated blocks. The research results can provide an important reference for the use of prefabricated targets in protective engineering. [ABSTRACT FROM AUTHOR]

Silicon suboxide (SiOx, 0 < x < 2) is recognized as one of the next-generation anode materials for high-energy-density lithium ion batteries (LIBs) due to its high theoretical specific capacity and abundant resource. However, the severe mechanical instability arising from large volume variation upon charge/discharge cycles frustrates its electrochemical performance. Here we propose a well-designed sandwichlike structure with sandwiched SiOx nanoparticles between graphene sheets and amorphous carbon-coating layer so as to improve the structural stability of SiOx anode materials during cycling. Graphene sheets and carbon layer together construct a three-dimensional conductive network around SiOx particles, which not only improves the electrode reactions kinetics, but also homogenizes local current density and thus volume variation on SiOx surface. Moreover, Si−O−C bonds between SiOx and graphene endow the strong particle adhesion on graphene sheets, which prevents SiOx peeling from graphene sheets. Owing to the synergetic effects of the structural advantages, the C/SiOx@graphene material exhibits an excellent cyclic performance such as 890 mAh/g at 0.1 C rate and 73.7% capacity retention after 100 cycles. In addition, it also delivers superior rate capability with a capacity recovery of 886 mAh/g (93.7% recovery rate) after 35 cycles of ascending steps at current range of 0.1–5 C and finally back to 0.1 C. This study provides a novel strategy to improve the structural stability of high-capacity anode materials for lithium/sodium ion batteries. [ABSTRACT FROM AUTHOR]

Well-defined thermoresponsive amphiphilic poly(DL-lactide)- b-poly( N- vinylcaprolactam) (PDLLA- b-PNVCL) block copolymers with various block compositions were synthesized via a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Their structures were confirmed by proton nuclear magnetic resonance spectroscopy (H NMR) and gel permeation chromatography/multi-angle laser light scattering (GPC/MALLS) measurements. They exhibited reversible temperature-dependent aggregation behavior in aqueous media as characterized by turbidity and dynamic light scattering (DLS) measurements. Their lower critical solution temperatures (LCSTs) increased with the increase in the chain length of PNVCL block and the decrease of the copolymer solution concentrations. These amphiphilic block copolymers self-assembled into aggregates of various morphologies in their aqueous solution, depending on the compositions of the copolymers. As the PNVCL content in block copolymer increased, the morphology of the aggregates changed from spheres to large compound vesicles (LCVs)-like, to irregularly spherical micelles. The viscosity measurement and HNMR analyses proved that these copolymers were hydrolytically degradable and the degradation process was accelerated under basic and acidic environments, especially in acidic media. [ABSTRACT FROM AUTHOR]