A functional hyperbranched binder enabling ultra-stable sulfur cathode for high-performance lithium-sulfur battery

Binders are of vital importance in stabilizing the cathodes to enhance the cycling stability of lithiumsulfur(Li-S) batteries. However, conventional binders are typically confronted with the drawback of inability for adsorbing lithium polysulfide(Li PS), thus resulting in severe active material losing and rapid capacity fading. Herein, a novel water-soluble hyperbranched poly(amidoamine)(HPAA) binder with controllable hyperbranched molecular structure and abundant amino end groups for Li-S battery is designed and fabricated, which can improve efficient adsorption for Li PS and stability of the sulfur cathodes. Besides, the strong intermolecular hydrogen bonds in HPAA binder can contribute to the structural stability of S cathode and integration of the conductive paths. Therefore, the Li-S battery with this functional binder exhibits excellent cycle performance with a capacity retention of 91% after 200 cycles at 0.1 C.Even at a high sulfur loading of 5.3 mg cm-2, a specific capacity of 601 mA h g-1 can also be achieved.Density functional theory(DFT) calculation further demonstrates that the enhanced electrochemical stability derives from the high binding energy between amino groups and LiP S and the wide electrochemical window(6.87 e V) of HPAA molecule. Based on the above all, this functional polymer will lighten a new species of binders for eco-friendly sulfur cathodes and significantly promote the practical applications of high-performance Li-S batteries.

Variations in growth traits and wood physicochemical properties among Pinus koraiensis families in Northeast China

This study aimed to explore and improve the different economic values of Pinus koraiensis(Siebold and Zucc.)by examining the variations in 6 growth traits and 9 physicochemical wood properties among 53 P.koraiensis half-sib families.Growth traits assessed included height,diameter at breast height,volume,degree of stem straight-ness,stem form,and branch number per node,while wood properties assessed included density,fiber length and width,fiber length to width ratio,and cellulose,hemicel-lulose,holocellulose,lignin,and ash contents.Except for degree of stem straightness and branch number per node,all other traits exhibited highly significant variations(P<0.01)among families.The coefficients of variation ranged from 5.3(stem form)to 66.7%(ash content),whereas,the herit-ability ranged from 0.136(degree of stem straightness)to 0.962(ash content).Significant correlations were observed among growth traits and wood physicochemical properties.Principal component analysis identified four distinct groups representing growth traits,wood chemical and physical properties,and stem form traits.Multi-trait comprehensive evaluation identified three groups of elite families based on breeding objectives,including rapid growth,improved timber production for building and furniture materials,and pulpwood production.These specific families should be used to establish new plantations.

Genetic Improvement of Betula platyphylla Suk.in China:A Review

Birch(Betula platyphylla Suk.),distributed in Eurasia,North America,and Australia,is a kind of cold-resistant,fast-growing,and vital pulpwood tree species.It is also one of the most important ecological restoration tree species with high values of economic benefits in Northeast China.To improve the genetic gain and expand the economic benefit of B.platyphylla,many genetic improvements have been carried out.In China,B.platyphylla is widely distributed and varied,and there are many varieties with excellent genetic characteristics.In this paper,the genetic improvement of B.platyphylla was reviewed,and the previous research results were discussed from two aspects:conventional breeding and molecular breeding.Some problems and corresponding solutions in the genetic improvement were put forward to provide ideas for B.platyphylla breeding in the future.

Multiresidue determination and potential risks of emerging pesticides in aquatic products from Northeast China by LC-MS/MS

A simple method for determining 33 pesticides with a wide polarity range(log Kow0.6-4.5) in aquatic products was developed based on LC–MS/MS. The target analytes included three types of widely used pesticides: insecticides, fungicides and herbicides. Based on the optimization of ultrasonic assisted extraction and GPC clean-up procedures, the matrix effect, extraction recoveries and LOD were improved distinctively. LOQ of this method was below 0.5 ng/g for all pesticides, which is superior to values in the literature, and the matrix effect was reduced effectively(-14.7% to 7.5%). The method was successfully applied to investigate the pesticide residue levels of twenty-five samples including seven common kinds of fishes from Northeast China. The results showed that all targeted pesticides were present in the fish samples; however, their levels were low, except for atrazine, linuron,ethoprophos, tetrachlorvinphos, acetochlor and fenthion. Atrazine and linuron caught our attention because the concentrations of atrazine in fish samples from Liaoning province were in the range of 0.5-8 ng/g(w/w) with mean concentration of 2.3 ng/g, which were far above those of other pesticides. The levels of linuron were in the range of 0.6-6 ng/g(mean concentration 2.8 ng/g), which were the highest among all targeted pesticides in the Inner Mongolia. This is the first systematic investigation on the characteristics and levels of these pesticides in aquatic products from northeast China. Considering their toxicity and bioaccumulation, the potential risk of atrazine and linuron from consuming aquatic products should be paid more attention.