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311.
焙烧温度对锂离子电池正极材料Li2MnSiO4/C 电化学性能的影响 总被引:2,自引:0,他引:2
采用液相法合成了Li2MnSiO4/C复合正极材料,并研究了不同焙烧温度对材料的结构、形貌和电化学性能的影响.利用热重(TG)分析了材料前驱体的热行为,确定了合成Li2MnSiO4/C复合正极材料的焙烧温度范围为600-800℃.X射线衍射(XRD)测试结果表明,不同温度下合成的样品材料均具有正交结构,且空间群为Pmn21,同时利用扫描电子显微镜(SEM)对所得样品材料的微观形貌及颗粒大小进行了表征.将所得Li2MnSiO4/C复合正极材料组装成扣式电池,并在不同的电流密度下进行充放电测试,结果表明:700℃合成的样品材料电化学性能最佳,具有较高的库仑效率及很好的循环稳定性. 相似文献
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Hsuan‐Ying Chen Wei‐Yi Lu Yen‐Jen Chen Sodio C. N. Hsu Siou‐Wei Ou Wei‐Te Peng Nai‐Yuan Jheng Yi‐Chun Lai Bo‐Sheng Wu Hsuan Chung Yun Chen Ta‐Chou Huang 《Journal of polymer science. Part A, Polymer chemistry》2013,51(2):327-333
This study synthesized a series of titanium iminophenoxide complexes and investigated their suitability as catalysts for the ring‐opening polymerization of L ‐lactide (L ‐LA) and ε‐caprolactone (CL). Complexes with bidentate ligands demonstrate higher catalytic activity than their tridentate counterparts since the third coordination atom needs to contend with L ‐LA and CL. Differences in the geometric framework of bidentate ligands also influence the catalytic activity. Type II ligands (N, N‐trans form of Ti complex) prevent the coordination of monomers to Ti thereby decreasing the initiation rate. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
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Hongxiang Chen Dongliang Yang Qinghua Zhang Shifeng Jin Liwei Guo Jun Deng Xiaodong Li Xiaolong Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4624-4628
We report a new type of MAX phase (M=transition metals, A=main group elements, and X=C/N), Nb3As2C, designated as 321 phase. It differs from all the previous Mn+1AXn phases in that it consists of an alternate stacking of one MX layer and two MA layers in its unit cell, while only one MA layer is allowed in usual MAX phases. The new 321 phase exhibits a bulk modulus of Nb3As2C up to 225(3) GPa as determined by high‐pressure synchrotron X‐ray diffraction, one of the highest values among MAX phases. Isostructural 321 phases V3As2C, Nb3P2C, and Ta3P2C are also found to exist. First‐principles calculations reveal the outstanding elastic stiffness in 321 phases. Among all 321 phases, Nb3P2C is predicted to have the highest elastic properties. These 321 phases, represented by a chemical formula Mn+1AnX, were added as new members to the MAX family and their other properties deserve future investigations. 相似文献
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Wenjian Lao Xuejun Sun Jinmao You Qingyu Ou 《Monatshefte für Chemie / Chemical Monthly》2000,16(2):803-811
A rapid one-pot synthesis of substituted carbazole-9-acetic and -propionic acids under microwave irradiation is described.
N-Alkylation and hydrolysis was carried out in DMF without catalyst. The absorption and fluorescence spectroscopic characteristics of the title compounds are discussed. 相似文献
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Hongxiang Tan 《Applied Surface Science》2008,255(2):353-356
Double-walled microspheres trapping gentamicin sulphate were prepared from poly(l-lactic acid) (PLLA) and poly(l-lactic-co-glycolic acid) (PLGA) as a delivery system for highly hydrophilic antibiotics. The surface and cross-section morphology of the microspheres were characterized by SEM and FTIR. The diameters of the microspheres were ranging from about 50 μm to 700 μm. A low initial burst was achieved. The encapsulation efficiency was more than 70% and the cumulative drug release was about 40% for 30 days. The results indicated that the double-walled microspheres were able to achieve higher encapsulation efficiency and lower initial burst for highly water-soluble drugs. 相似文献
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