University of Electronic Science and Technology of China

About: University of Electronic Science and Technology of China is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Computer science & Antenna (radio). The organization has 50594 authors who have published 58502 publications receiving 711188 citations. The organization is also known as: UESTC.

Freestanding 1T MoS2/graphene heterostructures as a highly efficient electrocatalyst for lithium polysulfides in Li–S batteries

Abstract: A novel approach to effectively suppress the “polysulfide shuttle” in Li–S batteries is presented by designing a freestanding, three-dimensional graphene/1T MoS2 (3DG/TM) heterostructure with highly efficient electrocatalysis properties for lithium polysulfides (LiPSs). The 3DG/TM heterostructure is constructed by few-layered graphene nanosheets sandwiched by hydrophilic, metallic, few-layered 1T MoS2 nanosheets with abundant active sites. The porous 3D structure and the hydrophilic feature of 1T-MoS2 are beneficial for electrolyte penetration and Li-ion transfer, and the high conductivities of both graphene and the 1T MoS2 nanosheets facilitate electron transfer. These merits lead to a high electrocatalytic efficiency for LiPSs due to excellent ion/electron transfer and the presence of sufficient electrocatalytic active sites. Therefore, the cells with 3DG/TM exhibit outstanding electrochemical performance, with a high reversible discharge capacity of 1181 mA h g−1 and a capacity retention of 96.3% after 200 cycles. The electrocatalysis mechanism of LiPSs is further experimentally and theoretically revealed, which provides new insights and opportunities to develop advanced Li–S batteries with highly efficient electrocatalysts for LiPS conversion.

Dual-Band Bandpass Filters Using Stub-Loaded Resonators

Abstract: Dual-band bandpass filters using novel stub-loaded resonators (SLRs) are presented in this letter. Characterized by both theoretical analysis and full-wave simulation, the proposed SLR is found to have the advantage that the even-mode resonant frequencies can be flexibly controlled whereas the odd-mode resonant frequencies are fixed. Based on the proposed SLR, a dual-band filter is implemented with three transmission zeros. To further improve the selectivity, a filter with four transmission zeros on either side of both passbands is designed by introducing spur-line. The measured results validate the proposed design.

Boosted Electrocatalytic N2 Reduction to NH3 by Defect-Rich MoS2 Nanoflower

Abstract: The industrial artificial fixation of atmospheric N-2 to NH3 is carried out using the Haber-Bosch process that is not only energy-intensive but emits large amounts of greenhouse gas. Electrochemical reduction offers an environmentally benign and sustainable alternative for NH3 synthesis. Although Mo-dependent nitrogenases and molecular complexes effectively catalyze the N-2 fixation at ambient conditions, the development of a Mo-based nanocatalyst for highly performance electrochemical N-2 fixation still remains a key challenge. Here, greatly boosted electrocatalytic N-2 reduction to NH3 with excellent selectivity by defect-rich MoS2 nanoflowers is reported. In 0.1 m Na2SO4, this catalyst attains a high Faradic efficiency of 8.34% and a high NH3 yield of 29.28 mu g h(-1) mg(cat.)(-1) at (-)0.40 V versus reversible hydrogen electrode, much larger than those of defect-free counterpart (2.18% and 13.41 mu g h(-1) mg(cat.)(-1)), with strong electrochemical stability. Density functional theory calculations show that the potential determining step has a lower energy barrier (0.60 eV) for defect-rich catalyst than that of defect-free one (0.68 eV).

A CRISPR-Cpf1 system for efficient genome editing and transcriptional repression in plants.

Abstract: CRISPR–Cpf1 has emerged as an effective genome editing tool in animals. Now, a study shows that this system can edit plant genomes at nearly 100% efficiency at independent sites. Moreover, it can be repurposed for modulating plant transcriptome.

Vertical Co9S8 hollow nanowall arrays grown on a Celgard separator as a multifunctional polysulfide barrier for high-performance Li–S batteries

Abstract: Lithium–sulfur (Li–S) batteries have been regarded as one of the most promising next-generation energy-storage devices, due to their low cost and high theoretical energy density (2600 W h kg−1). However, the severe dissolution of lithium polysulfides (LiPSs) and the fatal shuttle effect of the sulfur cathode seriously hinder the practical applications of Li–S batteries. To address such issues, we present here, for the first time, a novel metal organic framework (MOF)-derived Co9S8 nanowall array with vertical hollow nanoarchitecture and high electrical conductivity, which is grown in situ on a Celgard separator (Co9S8–Celgard) via a feasible and scalable liquid-reaction approach, as an efficient barrier for LiPSs in Li–S batteries. Benefiting from the direct in situ growth of vertical Co9S8 hollow nanowall arrays as a multifunctional polar barrier, the Co9S8–Celgard separator possesses large surface area, excellent mechanical stability, and particularly strong LiPS-trapping ability via chemical and physical interactions. With these advantages, even with a pure sulfur cathode with a high sulfur loading of 5.6 mg cm−2, the Li–S cells with the Co9S8–Celgard separator exhibit outstanding electrochemical performance: the initial specific capacity is as high as 1385 mA h g−1 with a retention of 1190 mA h g−1 after 200 cycles. The cells deliver a high capacity of 530 mA h g−1 at a 1C rate (1675 mA g−1) even after an impressive number of 1000 cycles with an average capacity fade of only 0.039% per cycle, which is promising for long-term cycling application at high charge/discharge current densities, and pouch-type Li–S cells with the Co9S8–Celgard separator display excellent cycling performance. When the optimized cathode with the sulfur loading in well-designed yolk–shelled carbon@Fe3O4 (YSC@Fe3O4) nanoboxes is employed, the cell with Co9S8–Celgard delivers a high initial capacity of 986 mA h g−1 at a 1C rate with a capacity retention as high as 83.2% even after a remarkable number of 1500 cycles. This work presents a strategy to grow on the separator a multifunctional polar interlayer with unique nanoarchitecture and high conductivity to chemically and physically trap the LiPSs, thus significantly enhancing the performance of Li–S batteries.