Versatile Asymmetric Separator with Dendrite-Free Alloy Anode Enables High-Performance Li-S Batteries.

Lithium-sulfur batteries (LSBs) with extremely-high theoretical energy density (2600 Wh kg-1 ) are deemed to be the most likely energy storage system to be commercialized. However, the polysulfides shuttling and lithium (Li) metal anode failure in LSBs limit its further commercialization. Herein, a versatile asymmetric separator and a Li-rich lithium-magnesium (Li-Mg) alloy anode are applied in LSBs. The asymmetric separator is consisted of lithiated-sulfonated porous organic polymer (SPOP-Li) and Li6.75 La3 Zr1.75 Nb0.25 O12 (LLZNO) layers toward the cathode and anode, respectively. SPOP-Li serves as a polysulfides barrier and Li-ion conductor, while the LLZNO functions as an "ion redistributor". Combining with a stable Li-Mg alloy anode, the symmetric cell achieves 5300 h of Li stripping/plating and the modified LSBs exhibit a long lifespan with an ultralow fading rate of 0.03% per cycle for over 1000 cycles at 5 C. Impressively, even under a high-sulfur-loading (6.1 mg cm-2 ), an area capacity of 4.34 mAh cm-2 after 100 cycles can still be maintained, demonstrating high potential for practical application.

Fast Evaporation Enabled Ultrathin Polymer Coatings on Nanoporous Substrates for Highly Permeable Membranes.

Thin polymer coatings covering on porous substrates are a common composite structure required in numerous applications, including membrane separation, and there is a strong need to push the coating thicknesses down to the nanometer scale to maximize the performances. However, producing such ultrathin polymer coatings in a facile and efficient way remains a big challenge. Here, uniform ultrathin polymer covering films (UPCFs) are realized by a facile and general approach based on rapid solvent evaporation. By fast evaporating dilute polymer solutions spread on the surface of porous substrates, we obtain ultrathin coatings (down to ∼30 nm) exclusively on the top surface of porous substrates, forming UPCFs with a block copolymer of polystyrene-block-poly(2-vinyl pyridine) at room temperature or a homopolymer of poly(vinyl alcohol) (PVA) at elevated temperatures. Upon selective swelling of the block copolymer and crosslinking of PVA, we obtain highly permeable membranes delivering ∼2-10 times higher permeance in ultrafiltration and pervaporation than state-of-the-art membranes with comparable selectivities. We have invented a very convenient but highly efficient process for the direct preparation of defective-free ultrathin coatings on porous substrates, which is extremely desired in different fields in addition to membrane separation.

Nonporous Gel Electrolytes Enable Long Cycling at High Current Density for Lithium-Metal Anodes.

Lithium-metal anodes with high theoretical capacity and ultralow redox potential are regarded as a "holy grail" of the next-generation energy-storage industry. Nevertheless, Li inevitably reacts with conventional liquid electrolytes, resulting in uneven electrodeposition, unstable solid electrolyte interphase, and Li dendrite formation that all together lead to a decrease in active lithium, poor battery performance, and catastrophic safety hazards. Here, we report a unique nonporous gel polymer electrolyte (NP-GPE) with a uniform and dense structure, exhibiting an excellent combination of mechanical strength, thermal stability, and high ionic conductivity. The nonporous structure contributed to a uniform distribution of lithium ions for dendrite-free lithium deposition, and Li/NP-GPE/Li symmetric cells can maintain an extremely low and stable polarization after cycling at a high current density of 10 mA cm-2. This work provides an insight that the NP-GPE can be considered as a candidate for practical applications for lithium-metal anodes.

Nanoporous polysulfones with in situ PEGylated surfaces by a simple swelling strategy using paired solvents.

We report the formation of three-dimensionally interconnected nanoporosities with in situ PEGylated pore walls simply by swelling the block copolymers of polysulfone and poly(ethylene glycol) in paired solvents. The produced nanoporous polymers are expected to find important applications in membranes, batteries, chromatography, and haemodialysis.

Draft genome of the Chinese mitten crab, Eriocheir sinensis.

BACKGROUND: The Chinese mitten crab, Eriocheir sinensis, is one of the most studied and economically important crustaceans in China. Its transition from a swimming to a crawling method of movement during early development, anadromous migration during growth, and catadromous migration during breeding have been attractive features for research. However, knowledge of the underlying molecular mechanisms that regulate these processes is still very limited. FINDINGS: A total of 258.8 gigabases (Gb) of raw reads from whole-genome sequencing of the crab were generated by the Illumina HiSeq2000 platform. The final genome assembly (1.12 Gb), about 67.5 % of the estimated genome size (1.66 Gb), is composed of 17,553 scaffolds (>2 kb) with an N50 of 224 kb. We identified 14,436 genes using AUGUSTUS, of which 7,549 were shown to have significant supporting evidence using the GLEAN pipeline. This gene number is much greater than that of the horseshoe crab, and the annotation completeness, as evaluated by CEGMA, reached 66.9 %. CONCLUSIONS: We report the first genome sequencing, assembly, and annotation of the Chinese mitten crab. The assembled draft genome will provide a valuable resource for the study of essential developmental processes and genetic determination of important traits of the Chinese mitten crab, and also for investigating crustacean evolution.

Complete mitochondrial genome of stripped eel catfish (Plotosus lineatus).

The complete mitochondrial genome of stripped eel catfish, Plotosus lineatus, is sequenced in this study. The mitochondrial genome sequence is 16 480 bp in length, with the base composition of 24.7% A, 31.8% T, 27.8% G and 15.7% C. The G + C content is 43.5%. The mitochondria includes 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and one D-loop region. Except for NAD6 gene and eight tRNA genes, all other mitochondrial genes were encoded on the heavy strand. Plotosus lineatus was confirmed to be closely related to P. japonicus (GenBank: KR270437.1), based on our phylogenetic analysis on complete mitochondrial genome sequences of 13 species. Our complete mitogenome data are going to provide the basis for taxonomic and phylogenetic research of catfishes.

Highly porous metal oxide networks of interconnected nanotubes by atomic layer deposition.

Mesoporous metal oxide networks composed of interconnected nanotubes with ultrathin tube walls down to 3 nm and high porosity up to 90% were fabricated by atomic layer deposition (ALD) of alumina or titania onto templates of swelling-induced porous block copolymers. The nanotube networks possessed dual sets of interconnected pores separated by the tube wall whose thickness could be finely tuned by altering ALD cycles. Because of the excellent pore interconnectivity and high porosity, the alumina nanotube networks showed superior humidity-sensing performances.

Water-dispersible, uniform nanospheres by heating-enabled micellization of amphiphilic block copolymers in polar solvents.

Uniform nanospheres with tunable size down to 30 nm were prepared simply by heating amphiphilic block copolymers in polar solvents. Unlike reverse micelles prepared in nonpolar, oily solvents, these nanospheres have a hydrophilic surface, giving them good dispersibility in water. Furthermore, they are present as individual, separated, rigid particles upon casting from the solution other than continuous thin films of merged micelles cast from micellar solution in nonpolar solvents. These nanospheres were generated by a heating-enabled micellization process in which the affinity between the solvent and the polymer chains as well as the segmental mobility of both hydrophilic and hydrophobic blocks was enhanced, triggering the micellization of the glassy copolymers in polar solvents. This heating-enabled micellization produces purely well-defined nanospheres without interference of other morphologies. The micelle sizes and corona thickness are tunable mainly by changing the lengths of the hydrophobic and hydrophilic blocks, respectively. The heating-enabled micellization route for the preparation of polymeric nanospheres is extremely simple, and is particularly advantageous in producing rigid, micellar nanospheres from block copolymers with long glassy, hydrophobic blocks which are otherwise difficult to prepare with high efficiency and purity. Furthermore, encapsulation of hydrophobic molecules (e.g., dyes) into micelle cores could be integrated into the heating-enabled micellization, leading to a simple and effective process for dye-labeled nanoparticles and drug carriers.