Yanshan University

About: Yanshan University is a education organization based out in Qinhuangdao, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 19544 authors who have published 16904 publications receiving 184378 citations. The organization is also known as: Yānshān dàxué.

Interface-Engineered Li7La3Zr2O12-Based Garnet Solid Electrolytes with Suppressed Li-Dendrite Formation and Enhanced Electrochemical Performance

Abstract: High grain-boundary resistance, Li-dendrite formation, and electrode/Li interfacial resistance are three major issues facing garnet-based solid electrolytes Herein, interfacial architecture engineering by incorporating 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMP-TFSI) ionic liquid into a garnet oxide is proposed The "soft" continuous BMP-TFSI coating with no added Li salt generates a conducting network facilitating Li+ transport and thus changes the ion conduction mode from point contacts to face contacts The compacted microstructure suppresses Li-dendrite growth and shows good interfacial compatibility and interfacial wettability toward Li metal Along with a broad electrochemical window larger than 55 V and an Li+ transference number that practically reaches unity, LiNi08 Co01 Mn01 O2 /Li and LiFePO4 /Li solid-state batteries with the hybrid solid electrolyte exhibit superior cycling stability and low polarization, comparable to those with commercial liquid electrolytes, and excellent rate capability that is better than those of Li-salt-based ionic-liquid electrolytes

Improved the microstructure and mechanical properties of AlFeCoNi high-entropy alloy by carbon addition

Abstract: A new set of AlFeCoNiCx (x = 0, 0.02, 0.04, 0.08, 0.17) high-entropy alloys (HEAs) were designed and fabricated. The microstructure, phase evolution and mechanical behaviors of the alloys were systematically investigated. Results show that the matrix alloy exhibits coarse columnar structure, while the C-doped alloys exhibit typical dendrite microstructure. The dendritic region (DR) is composed of single B2 phase, while the interdendritic region (ID) consists of FCC and E21 phases and presents an ultrafine cellar structure caused by the coexisting of ordering and spinodal decomposition. Interestingly, both the strength and compressive strain greatly increased with the increase of carbon content. Particularly, the AlFeCoNiC0.08 HEA possessed the most excellent mechanical properties, superior to many other HEAs with the yield strength, fracture strength, and fracture strain as high as 1115 MPa, 2517 MPa and 48.8%, respectively. The mechanical properties of the AlFeCoNiC0.17 alloy were weakened by the presence of graphite. Further, it is found that there is close relationship between the fracture morphology and alloy properties. Overall, in this study the improved microstructure and mechanical properties of the AlFeCoNi HEA have been accomplished by carbon doping, and our findings could shed light on a new alloy-design route to achieve bulk ultrafine structure materials with desired properties via the direct solidification.

Biocompatible and flexible graphene oxide/upconversion nanoparticle hybrid film for optical pH sensing

Abstract: Free-standing optical hybrid film which is composed of positively-charged polyethylenimine-coated NaYF4: Yb, Er nanoparticles and negatively-charged graphene oxide (GO) has been developed to measure pH based on the pH-dependent luminescence quenching effect caused by GO. The isothermal titration calorimetry analyses indicate that the interaction between GO and NaYF4: Yb, Er nanoparticles becomes stronger with increasing pH, leading to a more significant fluorescence quenching of NaYF4: Yb, Er nanoparticles at high pH values. The excellent mechanical properties of the hybrid film endow the thin-film pH sensor with better repeatability and higher stability during the measurements. Quantitatively, the upconversion luminescence intensity of the hybrid film exhibits a linear trend over the pH range of 5.00-8.00. Because of excitation with a 980 nm laser, as expected, the hybrid film sensor is also sensitive to the urine measurements with reduced background absorption. In addition to its good biocompatibility, our free-standing hybrid film sensor would be a promising candidate for biological, medical, and pharmaceutical applications.