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Yanfei Zeng Yudai Huang Niantao Liu Xingchao Wang Yue Zhang Yong Guo Hong-Hui Wu Huixin Chen Xincun Tang Qiaobao Zhang 《Journal of Energy Chemistry》2021,(3):727-735
Dramatic capacity fading and poor rate performance are two main obstacles that severely hamper the widespread application of the Si anode owing to its large volume variation during cycling and low intrinsic electrical conductivity.To mitigate these issues,free-standing N-doped porous carbon nanofibers sheathed pumpkin-like Si/C composites(Si/C-ZIF-8/CNFs)are designed and synthesized by electrospinning and carbonization methods,which present greatly enhanced electrochemical properties for lithium-ion battery anodes.This particular structure alleviates the volume variation,promotes the formation of stable solid electrolyte interphase(SEI)film,and improves the electrical conductivity.As a result,the as-obtained free-standing Si/C-ZIF-8/CNFs electrode delivers a high reversible capacity of 945.5 mAh g-1 at 0.2 A g-1 with a capacity retention of 64% for 150 cycles,and exhibits a reversible capacity of 538.6 mA h g-1 at 0.5 A g-1 over 500 cycles.Moreover,the full cell composed of a freestanding Si/C-ZIF-8/CNFs anode and commercial LiNi1/3Co1/3Mn1/3O2(NCM)cathode shows a capacity of 63.4 mA h g-1 after 100 cycles at 0.2 C,which corresponds to a capacity retention of 60%.This rational design could provide a new path for the development of high-performance Si-based anodes. 相似文献
65.
Zhi Wang Yanfei Pan Yuanming Song Hongtao Cui 《Journal of Sol-Gel Science and Technology》2009,50(3):261-266
Highly efficient UV absorption films of CeO2–SiO2 and TiO2–CeO2–SiO2 were synthesized through an epoxide assisted sol–gel strategy. As proven by their UV–vis transmittance spectra, the obtained
films show very strong absorption in the UV region, at the same time, keeping the high transparency in the visible range.
Due to the unique chemistry of this route and the delicate selection of Ce precursor salts, the ceria in the film can be crystallized
at ambient temperature, resulting in the effective UV absorption and oxidation minimization of the films. These advantages
guarantee their application in the protection of heat-sensitive organic materials. 相似文献
66.
Gang Liu Linzhu Zhou Yanfei Guan Yue Su Chang‐Ming Dong 《Macromolecular rapid communications》2014,35(19):1673-1678
The biodegradable polymeric nanomedicines that may be integrated with multi‐stimuli‐sensitivity to achieve triggered or on‐demand drug release kinetics are challenging for polymer therapeutics and drug delivery systems. By controlling the structure transformation of one polypeptide‐b‐PEO copolymer, a novel multi‐responsive polypeptide‐based vesicle (polypeptidosome) presents the combined sensitivity of multiple physiological and clinic‐related stimuli, and both morphology and size of the polypeptidosome are changed during the triggered process. The designer polypeptide has unique structures composed of 1) light‐responsive o‐nitrobenzyl groups, 2) oxidizable thioether linkers, 3) photo‐caged redox thiol groups on parent poly(L‐cysteine), and 4) tunable conformation, which enable the polypeptidosome to have a peculiar multi‐response. The anticancer drug doxorubicin can be released in a controlled or on–off manner. The combination stimuli of UV irradiation and H2O2 oxidation induces a large effect and a lower IC50 of 3.80 μg doxorubicin (DOX) equiv/mL compared to 5.28 μg DOX equiv/mL of individual H2O2 trigger.
67.
Yonghua Du Jia‐ou Wang Longhua Jiang Lucas Santiago Borgna Yanfei Wang Yi Zheng Tiandou Hu 《Journal of synchrotron radiation》2014,21(4):756-761
Obtaining sub‐10 pm spatial resolution by extended X‐ray absorption fine structure (EXAFS) spectroscopy is required in many important fields of research, such as lattice distortion studies in colossal magnetic resistance materials, high‐temperature superconductivity materials etc. However, based on the existing EXAFS data analysis methods, EXAFS has a spatial resolution limit of π/2Δk which is larger than 0.1 Å. In this paper a new data analysis method which can easily achieve sub‐10 pm resolution is introduced. Theoretically, the resolution limit of the method is three times better than that normally available. The method is examined by numerical simulation and experimental data. As a demonstration, the LaFe1–xCrxO3 system (x = 0, 1/3, 2/3) is studied and the structural information of FeO6 octahedral distortion as a function of Cr doping is resolved directly from EXAFS, where a resolution better than 0.074 Å is achieved. 相似文献
68.
In this paper, an improved novel joint channel estimation algorithm is proposed for the 112 Gbit/s PDM CO-OFDM system. This method combines the advantages of the intra-symbol frequency domain averaging (ISFA) method and the time domain averaging (TA) method, which can realize more accuracy channel estimation. Simulation results show that this proposal could promise a relatively stable performance even under a rapidly time varying environment. It significantly outperforms the ISFA method by 2.2 dB when the DGD equals 1000 ps, and has the advantages of 0.5 dB over ISFA in considering the laser linewidth and frequency offset. 相似文献
69.
Four organotin complexes of the types [(Ph3Sn)(C2HN2S2)] ( 1 ), [(CH3)3Sn(C2HN2S2)]n ( 2 ), [(Bu2Sn)(C2HN2S2)2] ( 3 ), and [(Me2Sn)4(C2HN2S2)2(µ 3‐O)2(C2H5O)2] ( 4 ) have been obtained by 2‐mercapto‐1,3,4‐thiadiazole and triorganotin chloride or diorganotin dichloride. All the complexes were characterized by elemental analysis, IR and NMR spectroscopy, and X‐ray diffraction analyses, which revealed that complexes 1 and 3 are mononuclear structures, complex 1 can further form a one‐dimensional (1D) helical chain, and complex 3 can further form a 22‐membered macrocycle through the intermolecular C–H·N hydrogen bond; complex 2 is a 1D infinite chain linked by intermolecular N→Sn and S→Sn bonding interactions; complex 4 is a typical ladder structure. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 00:1–8, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21046 相似文献
70.
Wei Song Yanfei Wang Hailong Hu Bing Zhao 《Journal of Raman spectroscopy : JRS》2007,38(10):1320-1325
We show in this paper how zinc oxide (ZnO)/silver (Ag) composite microspheres can be prepared by the reduction of Ag(NH3)2+ with the reducing agent formaldehyde in aqueous solution on the surface of ZnO microspheres. During the preparation, Sn2+ was absorbed on the surface of ZnO microspheres for sensitization and activation, and then Ag(NH3)2+ was reduced to Ag nanoparticles by the reducing agent to obtain ZnO/Ag composite microspheres. SEM and TEM images revealed silver nanoparticles with a diameter ranging from tens to 100 nm. X‐Ray photoelectron spectra (XPS), X‐ray diffraction (XRD) patterns and UV‐vis spectra were used to characterize the structure of the ZnO/Ag composite microspheres. The origin of the surface‐enhanced Raman scattering properties was traced to the surface of the ZnO/Ag composite microspheres. The enhancement factor was estimated in detail, and the enhancement mechanism for the SERS effect was also investigated. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献