Exploiting methylated amino resin as a multifunctional binder for high-performance lithium-sulfur batteries

The practical application of Li-S batteries is severely restricted by limited cycle life and low sulfur loading.Here,a common industrial paint,methylated amino resin(MAR),was employed as a novel multifunctional binder to address these issues.The S cathodes by using MAR binder(S@MAR) demonstrate an excellent reversible capacity of 480.9 mA·h·g^(-1) after 400 cycles at a rate of 0.5 C,and the sulfur loading in the electrode could achieve as high as 3.0 mg·cm^(-2).These achievements are ascribed to the superior mechanical property for volume expansion,better adsorption ability toward poly sulfides,and more favorable Li+transportation of MAR,compared to the conventional binders of polyvinylidene difluoride and carboxymethylcellulose.This study paves a new way for obtaining high-energy-density Li-S batteries by the simple application of multifunctional binder that are inherently cost-effective.

Facile One-Pot Green Synthesis and Antibacterial Activities of GO/Ag Nanocomposites

New materials with good antibacterial activity synthesized by simple, environmentally friendly method have attracted numerous research interests. Taking advantage of Ag and graphene oxide （GO）, the GO/Ag nanocomposites were prepared by a facile, green ＂one-pot＂ reaction to achieve superior antibacterial properties. AgNO3 is as a precursor of Ag nanoparticles （Ag NPs）, and the grape seeds extract as an environmentally friendly reducing and stabilizing agent. The asprepared GO/Ag nanocomposites were characterized by various technologies. The results indicated that the silver ion was reduced by the grade seeds extract and Ag NPs were decorated on the surface of GO nanosheets successfully. The average size of the Ag NPs anchored on the GO surface was 40-50 nm. In this study, we prepared GO/Ag nanocomposites with different Ag NPs to GO ratios and carefully investigated their antibacterial activities. We found that the GO/Ag nanocomposites show better antibacterial activity when the concentration of AgNO3 is 2 mM. GO/Ag nanocomposites have a minimum inhibitory concentration 23.8 μg/mL, lower than bare Ag NPs 25.5 μg/mL. We try to explain the antibacterial mechanism based on optical microscopy observation.

Correlation of Morphology Evolution with Superior Mechanical Properties in PA6/PS/PP/SEBS Blends Compatibilized by Multi-phase Compatibilizers

In this study, the maleic anhydride （MAH） and styrene （St） dual monomers grafted polypropylene （PP） and poly[styrene-b- （ethylene-co-butylene）-b-styrene] （SEBS）, i.e. PP-g-（MAH-co-St） and SEBS-g-（MAH-co-St） are prepared as multi-phase compatibilizers and used to compatibilize the PA6/PS/PP/SEBS （70/10/10/10） model quaternary blends. Both PS and SEBS are encapsulated by the hard shell of PP-g-（MAH-co-St） in the dispersed domains （about 2 μm） of the PA6/PS/PP-g-（MAH-co-St）/SEBS （70/10/10/10） quaternary blend. In contrast, inside the dispersed domains （about 1 μm） of the PA6/PS/PP/SEBS-g-（MAH-co-St） （70/10/10/10） quaternary blend, the soft SEBS-g-（MAH-co-St） encapsulates both the hard PS and PP phases and separates them. With increasing the content of the compatibilizers equally, the morphology of the PA6/PS/（PP＋PP-g-（MAH-co-St））/（SEBS＋SEBS-g-（MAH-co-St）） （70/10/10/10） quaternary blends evolves from the soft （SEBS＋SEBS-g-（MAH-co-St）） encapsulating PS and partially encapsulating PP （about 1 μm）, then to PS exclusively encapsulated by the soft SEBS-g-（MAH-co-St） and then separated by PP-g-（MAH-co-St） inside the smaller domains （about 0.6 μm）. This morphology evolution has been well predicted by spreading coefficients and explained by the reaction between the matrix PA6 and the compatibilizers. The quaternary blends compatibilized by more compatibilizers exhibit stronger hierarchical interfacial adhesions and smaller dispersed domain, which results in the further improved mechanical properties. Compared to the uncompatibilized blend, the blend with both 10 wt% PP-g-（MAH-co-St） and 10 wt% SEBS-g-（MAH-co-St） has the best mechanical properties with the stress at break, strain at break and impact failure energy improved significantly by 97%, 71% and 261%, respectively. There is a strong correlation between the structure and property in the blends.