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991.
Qidi Wang Chenglong Zhao Yaxiang Lu Yunming Li Yuheng Zheng Yuruo Qi Xiaohui Rong Liwei Jiang Xinguo Qi Yuanjun Shao Du Pan Baohua Li Yong‐Sheng Hu Liquan Chen 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(42)
Sodium–ion batteries (NIBs), due to the advantages of low cost and relatively high safety, have attracted widespread attention all over the world, making them a promising candidate for large‐scale energy storage systems. However, the inherent lower energy density to lithium–ion batteries is the issue that should be further investigated and optimized. Toward the grid‐level energy storage applications, designing and discovering appropriate anode materials for NIBs are of great concern. Although many efforts on the improvements and innovations are achieved, several challenges still limit the current requirements of the large‐scale application, including low energy/power densities, moderate cycle performance, and the low initial Coulombic efficiency. Advanced nanostructured strategies for anode materials can significantly improve ion or electron transport kinetic performance enhancing the electrochemical properties of battery systems. Herein, this Review intends to provide a comprehensive summary on the progress of nanostructured anode materials for NIBs, where representative examples and corresponding storage mechanisms are discussed. Meanwhile, the potential directions to obtain high‐performance anode materials of NIBs are also proposed, which provide references for the further development of advanced anode materials for NIBs. 相似文献
992.
Ultrathin Layered SnSe Nanoplates for Low Voltage,High‐Rate,and Long‐Life Alkali–Ion Batteries
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Wei Wang Peihao Li Henry Zheng Qiao Liu Fan Lv Jiandong Wu Hao Wang Shaojun Guo 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(46)
2D electrode materials with layered structures have shown huge potential in the fields of lithium‐ and sodium‐ion batteries. However, their poor conductivity limits the rate performance and cycle stability of batteries. Herein a new colloid chemistry strategy is reported for making 2D ultrathin layered SnSe nanoplates (SnSe NPs) for achieving more efficient alkali‐ion batteries. Due to the effect of weak Van der Waals forces, each semiconductive SnSe nanoplate stacks on top of each other, which can facilitate the ion transfer and accommodate volume expansion during the charge and discharge process. This unique structure as well as the narrow‐bandgap semiconductor property of SnSe simultaneously meets the requirements of achieving fast ionic and electronic conductivities for alkali‐ion batteries. They exhibit high capacity of 463.6 mAh g−1 at 0.05 A g−1 for Na‐ion batteries and 787.9 mAh g−1 at 0.2 A g−1 for Li‐ion batteries over 300 cycles, and also high stability for alkali‐ion batteries. 相似文献
993.
Fabrication of Fe3O4 Dots Embedded in 3D Honeycomb‐Like Carbon Based on Metallo–Organic Molecule with Superior Lithium Storage Performance
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Chengfei Li Liuqing Li Zhaopeng Li Weihao Zhong Zhenghui Li Xiaoqing Yang Guoqing Zhang Haiyan Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(38)
A novel metallo–organic molecule, ferrocene, is selected as building block to construct Fe3O4 dots embedded in 3D honeycomb‐like carbon (Fe3O4 dots/3DHC) by using SiO2 nanospheres as template. Unlike previously used inorganic Fe3O4 sources, ferrocene simultaneously contains organic cyclopentadienyl groups and inorganic Fe atoms, which can be converted to carbon and Fe3O4, respectively. Atomic‐scale Fe distribution in started building block leads to the formation of ultrasmall Fe3O4 dots (≈3 nm). In addition, by well controlling the feed amount of ferrocene, Fe3O4 dots/3DHC with well‐defined honeycomb‐like meso/macropore structure and ultrathin carbon wall can be obtained. Owing to unique structural features, Fe3O4 dots/3DHC presents impressive lithium storage performance. The initial discharge and reversible capacities can reach 2047 and 1280 mAh g?1 at 0.05 A g?1. With increasing the current density to 1 and 3 A g?1, remarkable capacities of 963 and 731 mAh g?1 remain. Moreover, Fe3O4 dots/3DHC also has superior cycling stability, after a long‐term charge/discharge for 200 times, a high capacity of 1082 mAh g?1 can be maintained (80% against the capacity of the 2nd cycle). 相似文献
994.
Koen Nickmans Gerardus M. Bögels Carlos Sánchez‐Somolinos Jeffrey N. Murphy Philippe Leclère Ilja K. Voets Albertus P. H. J. Schenning 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(33)
While self‐assembled molecular building blocks could lead to many next‐generation functional organic nanomaterials, control over the thin‐film morphologies to yield monolithic sub‐5 nm patterns with 3D orientational control at macroscopic length scales remains a grand challenge. A series of photoresponsive hybrid oligo(dimethylsiloxane) liquid crystals that form periodic cylindrical nanostructures with periodicities between 3.8 and 5.1 nm is studied. The liquid crystals can be aligned in‐plane by exposure to actinic linearly polarized light and out‐of‐plane by exposure to actinic unpolarized light. The photoalignment is most efficient when performed just under the clearing point of the liquid crystal, at which the cylindrical nanostructures are reoriented within minutes. These results allow the generation of highly ordered sub‐5 nm patterns in thin films at macroscopic length scales, with control over the orientation in a noncontact fashion. 相似文献
995.
Synthesis of Uniquely Structured Yolk–Shell Metal Oxide Microspheres Filled with Nitrogen‐Doped Graphitic Carbon with Excellent Li–Ion Storage Performance
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Novel structured composite microspheres of metal oxide and nitrogen‐doped graphitic carbon (NGC) have been developed as efficient anode materials for lithium‐ion batteries. A new strategy is first applied to a one‐pot preparation of composite (FeOx‐NGC/Y) microspheres via spray pyrolysis. The FeOx‐NGC/Y composite microspheres have a yolk–shell structure based on the iron oxide material. The void space of the yolk–shell microsphere is filled with NGC. Dicyandiamide additive plays a key role in the formation of the FeOx‐NGC/Y composite microspheres by inducing Ostwald ripening to form a yolk–shell structure based on the iron oxide material. The FeOx‐NGC/Y composite microspheres with the mixed crystal structure of rock salt FeO and spinel Fe3O4 phases show highly superior lithium‐ion storage performances compared to the dense‐structured FeOx microspheres with and without carbon material. The discharge capacities of the FeOx‐NGC/Y microspheres for the 1st and 1000th cycle at 1 A g?1 are 1423 and 1071 mAh g?1, respectively. The microspheres have a reversible discharge capacity of 598 mAh g?1 at an extremely high current density of 10 A g?1. Furthermore, the strategy described in this study is generally applied to multicomponent metal oxide–carbon composite microspheres with yolk–shell structures based on metal oxide materials. 相似文献
996.
We synthesized Cu3.8Ni/CoO and Cu3.8Ni/MnO nanoparticles via an easy and scalable solution synthesis.The synthesized Cu3.8Ni/CoO and Cu3.8Ni/MnO nanoparticles were annealed to remove the organic surfactants without phase transitions or side reactions.Electrons can be transferred via metallic Cu3.8Ni,which will not react with lithium ions.The heterogeneous structures of Cu3.8Ni/CoO and Cu3.8Ni/MnO nanopartides could enhance the lithium ion mobility and improve the life cycle,and these materials are therefore promising candidates as highpower-density and high-energy-density anode materials for lithium-ion batteries in diverse applications,such as electrical vehicles. 相似文献
997.
We report the photovoltaic effects of n-type topological insulator (TI) Bi2Te3 films grown on p-type Si substrates by chemical vapor deposition (CVD).The films containing large nanoplates with a smooth surface formed on p-Si exhibit good p-n diode characteristics under dark and light illumination conditions and display a good photovoltaic effect under the broadband range from ultraviolet (UV) to near infrared (NIR) wavelengths.Under the light illumination with a wavelength of 1,000 nm,a short circuit current (Isc) of 19.2 μA and an open circuit voltage (Voc) of 235 mV are achieved.The maximum fill factor (FF) increases with a decrease in the wavelength or light density,achieving a value of 35.6% under 600 nm illumination.The photoresponse of the n-Bi2Te3/p-Si device can be effectively switched between the on and off modes in millisecond time scale.These findings are important for both the fundamental understanding and solar cell device applications of TI materials. 相似文献
998.
Carbon nanosheets with a tunable mesopore size,large pore volume,and good electronic conductivity are synthesized via a solution-chemistry approach.In this synthesis,diaminohexane and graphene oxide (GO) are used as the structural directing agents,and a silica colloid is used as a mesopores template.Diaminohexane plays a crucial role in bridging silica colloid particles and GO,as well as initiating the polymerization of benzoxazine on the surfaces of both the GO and silica,resulting in the formation of a hybrid nanosheet polymer.The carbon nanosheets have graphene embedded in them and have several spherical mesopores with a pore volume up to 3.5 cm3·g-1 on their surfaces.These nuerous accessible mesopores in the carbon layers can act as reservoirs to host a high loading of active charge-storage materials with good dispersion and a uniform particle size.Compared with active materials with wide particle-size distributions,the unique proposed configuration with confined and uniform particles exhibits superior electrochemical performance during lithiation and delithiation,especially during long cycles and at high rates. 相似文献
999.
Xinghua Chang Teng Wang Zhiliang Liu Xinyao Zheng Jie Zheng Xingguo Li 《Nano Research》2017,10(6):1950-1958
We report a simple method of preparing a high performance,Sn-based anode material for lithium ion batteries (LIBs).Adding H2O2 to an aqueous solution containing Sn2+ and aniline results in simultaneous polymerization of aniline and oxidation of Sn2+ to SnO2,leading to a homogeneous composite of polyaniline and SnO2.Hydrogen thermal reduction of the above composite yields N-doped carbon with hierarchical porosity and homogeneously distributed,ultrafine Sn particles.The nanocomposite exhibits excellent performance as an anode material for lithium ion batteries,showing a high reversible specific capacity of 788 mAh·g-1 at a current density of 100 mA·g-1 after 300 cycles and very good stability up to 5,000 mA·g-1.The simple preparation method combined with the good electrochemical performance is highly promising to promote the application of Sn based anode materials. 相似文献
1000.
This study proposes a battery charge equalization circuit with a multi-winding transformer. A full-bridge converter with soft switching is applied at the primary side of a multi-winding transformer for reducing the switching loss and increasing the system efficiency. A voltage doubler type rectifier is used at the secondary side of multi-winding transformer to decrease the number of transformer windings and the conduction loss. The important advantages of the proposed circuit include the following: The charge current is limited by the transformer leakage inductance without any choke inductor, and charge equalization is realized by adjusting the transformer’s turn ratio. A measurement index, charge equalization performance (C.E.P.), is introduced for the performance measurement of the charge equalization method. In experiments, four LiFePO4 battery modules are connected in series and discharged at different C-rates. The experimental results show that the discharging time of the series-connected battery modules can be greatly increased using the proposed battery charge equalization circuit. 相似文献