摘要：
The development of new electrode materials with high storage capacity is indispensable for improving rechargeable lithium batteries. Herein, high performance TiO2 microspheres have been fabricated by a facile solvothermal method. The obtained TiO2 microspheres were investigated by the measurements of X-ray diffraction pattern, scanning electronic microscopy, and electrochemical tests. As the rates increase from 1C to 20C, the TiO2 composites display high discharge capacities of 414.6 mAh g-1 for the first cycle at 1 C and 244.6 mAh g-1 at 20 C over 100 cycles. CV experiments indicate that there are two peculiar pairs of cathodic/anodic peaks occurred in the range of 1.0-3.0V, which clearly demonstrates that the structure of the TiO2 microspheres here is quite different from the ordinary anatase TiO2. Excellent rate capability and cycle ability are ascribed presumablely to the unique structure.
关键词：
CuS cathode;Electrochemical properties;Lithium ion battery;Cyclic voltammetry
摘要：
A simple approach, for the first time, was presented for in situ preparation of the CuS cathode. The obtained CuS cathodes were investigated by the measurements of X-ray diffraction pattern, scanning electronic microscopy, and electrochemical performance. The results indicate the CuS cathodes are composed of plenty of nano flakes, which construct a large 3-D net structure. Moreover, the CuS cathodes exhibit reversible capacity of 447.4, 414.1, 389.9 and 376.0 mAh g−1 at 0.2 C, 0.5 C, 1 C and 2 C respectively and excellent cycle stability for more than 100 cycles. The possible mechanism of the unique stability of the CuS cathode was discussed.
摘要：
室温下,以高锰酸钾为锰源,在不同浓度盐酸溶液中合成了球形α-,γ-,δ-MnO2。该合成方法简单,不需要任何模板、表面活性剂和还原剂,室温下即可制备MnO2刺球。采用XRD、SEM对产物进行了结构和形貌的表征。考察了所制备的二氧化锰在锂离子电池中的充放电性能。结果表明,盐酸浓度对产物晶型、形貌和电化学性能产生重要影响。当盐酸浓度为4%时,MnO2为分布均匀的纳米刺球,首次放电比容量可以达到172 mA h.g-1,充放电循环50周后,比容量仍达到100mA h.g-1。
关键词：
Lithium Manganese Phosphates;Doping;Zinc;Lithium Ion Battery;Electrochemistry
摘要：
Olivine structure LiMnPO/C as cathode materials for Li-ion batteries were synthesized via a simple solid-state reaction. Improvement of the electrochemical performance of LiMnPO_4/C cathode material was realized significantly by the method of doping Zn. The obtained LiMn_0.95Zn_0.05PC_4/C electrode material was studied by the measurements of X-ray diffraction pattern, scanning electronic microscopy, electrochemical impedance spectroscopy and electrochemical performance. The results indicate that the LiMn_0.95Zn_0.05PC_4/C materials exhibit discharge specific capacity of 140.2 mA h g~-1 at 0.02 C rate and better rate capability. These excellent results are elucidated by E1S test, which showed that there was the decrease of charge transfer resistance and faster lithium-ion diffusion in LiMnPO_4/C cathode materials after Zn doping.
摘要：
TiO2–SiO2 mixed oxides were prepared by the homogeneous precipitation method, and the supports were characterized by XRD, IR and BET. Ligandless palladium supported on SiO2–TiO2 was prepared by the deposition–precipitation method and used as recoverable catalyst for Suzuki reactions. The results revealed that the supported catalyst Pd/SiO2–TiO2 exhibited excellent catalytic activity for the coupling of aryl bromides with arylboronic acid, and also exhibited moderate catalytic activity for the coupling of aryl chlorides. The catalyst was recycled by simple filtration and reused without further disposal, no significant Pd leaching and loss of catalytic activity was observed except the first reuse.
摘要：
Water and n‐butanol are immiscible. In this paper, i‐propanol was found to be surface active for both water and n‐butanol using surface tension measurement at 25.0±0.1°C, especially the system with i‐propanol in water displays a pronounced decrease in surface tension with a distinct inflexion point indicating aggregation. Investigation on phase behavior of water/i‐propanol/n‐butanol ternary system at 25.0±0.1°C showed i‐propanol could promote remarkably the miscibility of water and n‐butanol. Cyclic voltammetric technique was employed to locate the micro‐regions in single region, indicating the existence of three micro‐regions of water/n‐butanol, n‐butanol/water and bicontinuous region. Thus, a novel water/i‐propanol/n‐butanol microemulsion without general surfactant is expected to form. Dynamic light scattering also demonstrated the size (hydrodynamic diameter) distribution of the microemulsion, verifying further the formation of the microemulsion droplets.
摘要：
A novel method to synthesize sodium titanium phosphate (NaTi 2(PO4)3 microporous nanospheres with single-crystal-like features by using calf thymus DNA was described. The results show that before and after calcination, the size and shape of the particles prepared in the presence of DNA are nearly the same, indicating that the special morphology of the particles is not induced by the calcination. It is also seen that after addition of ethanol to the DNA-phosphoric acid solution, the single-stranded DNA change from a coil to a globular conformation. The microporous nanospheres are also used to catalyze the ketalization of cyclohexanone and 1,2-ethanediol to cyclohexanone ethylene ketal. The extremely high activity of the microporous nanospheres results from the special morphology and strong acidic surface.
