Despite the unparalleled theoretical gravimetric energy, Li-O 2 batteries are still under a research stage because of their insuffi cient cycle lives. While the reversibility in air-cathodes has been lately improved signifi cantly by the deepened understanding on the electrode-electrolyte reaction and the integration of diverse catalysts, the stability of the Li metal interface has received relatively much less attention. The destabilization of the Li metal interface by crossover of water and oxygen from the air-cathode side can indeed cause as fatal degradation for the cycle life as the irreversibility of the air-cathodes. Here, it is reported that cheap poreless polyurethane separator can effectively suppress this crossover while allowing Li ions to diffuse through selectively. The polyurethane separator also protects Li metal anodes from redox mediators used for enhancing the reversibility of the air-cathode reaction. Based on the Li metal protection, a persistent capacity of 600 mAh g −1 is preserved for more than 200 cycles. The current approach can be readily applicable to many other rechargeable batteries that suffer from similar interfacial degradation by side products from the other electrode.

A variety of advanced electrode structures have been developed lately to address the intrinsic drawbacks of lithium–sulfur batteries, such as polysulfide shuttling and low electrical conductivity of elemental sulfur. Nevertheless, it is still desired to find electrode structures that address those issues through an easy synthesis while securing large sulfur contents (i.e., > 70 wt %). Here, we report an orthogonal, “one-pot” synthetic approach to prepare a sulfur-embedded polybenzoxazine (S-BOP) with a high sulfur content of 72 wt %. This sulfur-embedded polymer was achieved via thermal ring-opening polymerization of benzoxazine in the presence of elemental sulfur, and the covalent attachment of sulfur to the polymer was rationally directed through the thiol group of benzoxazine. Also, the resulting S-BOP bears a homogeneous distribution of sulfur due to in situ formation of the polymer backbone. This unique internal structure endows S-BOP with high initial Coulombic efficiency (96.6%) and robust cyclability (92.7% retention after 1000 cycles) when tested as a sulfur cathode.

: In order to assess the survival success of microphytoplankton species in ship ballast water, we examined microphytoplankton diversity from international commercial ships berthed at Ulsan and Pyeongtaek Ports, Korea, and also subjected them to laboratory studies. The ages of ballast water in each ship ranged from 1 to 365 days. Vessels originated from coastal China (Weihai, Lianyunsang and Shanghai), Chile, and from the Yellow and Pacific Oceans. The numbers of species and phytoplankton standing crops in uploaded ballast water were significantly related to the age of ballast water. The most diverse taxonomic group was diatoms. In the laboratory study, the value of in vivo fluorescence in M/V Spring Lyra gradually increased with increasing nutrients such as nitrate and phosphate. Phytoplankton in new (9 days), medium (31 days) and old (365 days) ballast water successfully survived under typical nutrient condition of port water and F/2 medium at 15 o C and 20 o C, whereas phytoplankton in ballast water treatment did not survive, regardless of optimal temperature. Colonization process was dominated by diatoms; Skeletonema coastatum for M/V Spring Lyra, Thalassiosira pseudonana and Thalassiosira for M/V Han Yang, Thalassiosira pacifica and Odontella aurita for M/V Modern Express, and Chaetoceros pseudocurvisetus and Pseudo-nitzschia seriata for M/V Asian Legend. The successful establishment of non-native species was also related to nutrient richness. Our laboratory design can be applied as a practical tool to assess the survivability of invasive microphytoplankton introduced into local waters of Ulsan and Pyeongtaek.