All-solid-state lithium batteries (ASSLBs) based on sulfide solid electrolytes (SEs) have received great attention because of the high ionic conductivity of the SEs, intrinsic thermal safety, and higher energy density achievable with a Li metal anode. However, studies on practical slurry-cast composite electrodes show an extremely limited battery performance than the binder-free pelletized electrodes because of the poor interfacial robustness between the active materials and SEs by the presence of a polymeric binder. Here, we employ a low-temperature post-sintering process for the slurry-cast composite electrodes in order to overcome the binder-induced detrimental effects on the electrochemical performance. The LiI-doped LiPS SEs are chosen because the addition of iodine not only improves the Li-ion conductivity and Li metal compatibility but also lowers the glass-transition and crystallization temperatures. Low-temperature post-sintering of composite cathodes consisting of a LiNiCoMnO-active material, LiI-doped LiPS SE, polymeric binder, and conducting agent shows a significantly improved electrochemical performance as compared to a conventional slurry-cast electrode containing pre-annealed SEs. Detailed analyses by electrochemical impedance spectroscopy and galvanostatic intermittent titration technique confirm that post-sintering effectively reduces the interfacial resistance and enhances the chemomechanical robustness at solid-solid interfaces, which enables the development of practical slurry-cast ASSLBs with sulfide SEs.

Halide-doped sulfide solid electrolytes have attracted great attention due to their high lithium-ion conductivity, Li-metal compatibility, and deformability for use in all-solid-state Li batteries. Although the effects of halide mixing in Li 6 PS 5 X and Li 4 PS 4 X (X = halogen) solid electrolytes are fully investigated, studies on the origin of the remarkable increase in the ionic conductivity by dual halide doped Li 7 P 2 S 8 X (X = I, Br) solid electrolytes are scarce. Here, we systematically investigate the crystal phase evolution in glassy matrix and the corresponding ionic conductivity variation, revealing that a metastable Li 10 GeP 2 S 12 -like Li 3 PS 4 phase with halide-doped glassy matrix is responsible for the outstanding performance.

This study investigated the hydraulic impact scope and dissolved oxygen (DO) concentration distribution by the micro-bubble aeration in the Juksan Lake located in Asan city in Chungcheongnam-do province. A tracing experiment for hydraulic impact scope was used which constituted a 20% rhodamine solution. A 160 m-guideline was installed in the horizontal direction of the micro-bubble jet flow and the rhodamine concentration, water temperature, and DO concentration were measured at depths of 1 m, 2 m, and 3 m at intervals of 10 m. In the Juksan Lake, the effective range of jet flow discharged by the micro-bubble generator was about 40 m, and after then the jet plume moved up to 80 m to 120 m through the advection and diffusion processes of ambient water. DO concentration in the lake was maintained at 7.4-12.6 mg/L during tracking experiment. The DO of the lake sediments improved from 0.2 mg/L to 8.0 mg/L after applying micro-bubble aeration.In conclusion, the micro-bubble aeration can be an effective technology for the management and improvement of water quality in an agricultural reservoir. KEYWORDS:

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According to the progress of electronics industry, electronic devices have been diversified to various forms such as roll-up displays, smart cards, and wearable devices. Flexible electronic devices are demanding has various properties such as lightweight, ultrathin, and flexibility. Therefore, batteries as their power sources are required to have same properties. In addition, high energy density and operational safety are needed. Until now commercial lithium-ion batteries (LIBs) are the only viable candidates for flexible devices. Recently, the flexible lithium/sulfur (Li/S) battery has been proposed with a high theoretical energy density of 2600 Wh kg-1. As most active materials considered in these studies are rigid and brittle, flexible cathodes were achieved by the physical combination of rigid active materials with flexible current collectors such as carbon-based materials or polymers. This integrated design has two inevitable disadvantages; (1) during deformation the active material can detach from the current collector; (2) the capacity per electrode is reduced by the presence of electrochemically inactive materials such as current collector, binder and conducting agents. Therefore, there is a strong need for a new approach to the flexible cathode which consists of only active material without a separate current collector. Sulfurized polyacrylonitrile (SPAN) composite could be a good candidate due to its good electric conductivity, high sulfur utilization, and stable cycle life. In addition, it can be fabricated as either particle or nanofiber. However, the SPAN electrodes reported so far were prepared by mixing SPAN, conductive agent, and binder which were pasted on metallic current collector. In carbon nanotube paper and graphene paper, it is well-known that the strain during deformation decreases with the diameter of the fiber. Therefore, in this work, the SPAN nanofiber web cathode which does not include conductive agent, binder, as well as current collector was fabricated from PAN nanofiber web and sulfur by heat treatment process. Also, pre-lithiated carbon felt was used as anode in order to make all flexible full cell and investigated its electrochemical properties.