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111.
Intercalating Ti2Nb14O39 Anode Materials for Fast‐Charging,High‐Capacity and Safe Lithium–Ion Batteries 下载免费PDF全文
Chunfu Lin Shengjue Deng David J. Kautz Zhihao Xu Tao Liu Jianbao Li Ning Wang Feng Lin 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(46)
Ti–Nb–O binary oxide materials represent a family of promising intercalating anode materials for lithium‐ion batteries. In additional to their excellent capacities (388–402 mAh g–1), these materials show excellent safety characteristics, such as an operating potential above the lithium plating voltage and minimal volume change. Herein, this study reports a new member in the Ti–Nb–O family, Ti2Nb14O39, as an advanced anode material. Ti2Nb14O39 porous spheres (Ti2Nb14O39‐S) exhibit a defective shear ReO3 crystal structure with a large unit cell volume and a large amount of cation vacancies (0.85% vs all cation sites). These morphological and structural characteristics allow for short electron/Li+‐ion transport length and fast Li+‐ion diffusivity. Consequently, the Ti2Nb14O39‐S material delivers significant pseudocapacitive behavior and excellent electrochemical performances, including high reversible capacity (326 mAh g?1 at 0.1 C), high first‐cycle Coulombic efficiency (87.5%), safe working potential (1.67 V vs Li/Li+), outstanding rate capability (223 mAh g–1 at 40 C) and durable cycling stability (only 0.032% capacity loss per cycle over 200 cycles at 10 C). These impressive results clearly demonstrate that Ti2Nb14O39‐S can be a promising anode material for fast‐charging, high capacity, safe and stable lithium‐ion batteries. 相似文献
112.
通过熔融共混聚偏氟乙烯(PVDF)/CaCO3/复合稀释剂拟三元体系,采用热致相分离法(TIPS)制备了PVDF多孔膜。研究了复合稀释剂含量、CaCO3含量、粒径以及后期酸处理对膜结构的影响。结果表明:CaCO3含量和粒径对膜结构有明显的影响。在采用复合稀释剂的基础上,通过控制CaCO3粒子添加量,改变粒径,可以实现对膜结构的优化,并且经酸处理提高了PVDF膜孔隙率。 相似文献
113.
淀粉颗粒结构的研究进展 总被引:23,自引:0,他引:23
详述淀粉颗粒的形状大小、结晶结构、分子结构、颗粒的微孔特性等最新研究成果,同时对淀粉颗粒及淀粉化学改性的研究方向提出展望。 相似文献
114.
115.
V. V. Dmitriev D. A. Krasnikhin N. Mulders D. E. Zmeev 《Journal of Low Temperature Physics》2008,150(3-4):493-498
We have found a new stable spin state in the A-like phase of superfluid 3He confined to intrinsically anisotropic aerogel. The state can be formed by radiofrequency excitation applied while cooling
through the superfluid transition temperature and its NMR properties are different from the standard A-like phase obtained
in the limit of very small excitation. It is possible that this new state is formed by textural domain walls pinned by aerogel.
相似文献
116.
Havelock’s type of expansion theorems, for an integrable function having a single discontinuity point in the domain where it is defined, are utilized to derive analytical solutions for the radiation or scattering of oblique water waves by a fully extended porous barrier in both the cases of finite and infinite depths of water in two-layer fluid with constant densities. Also, complete analytical solutions are obtained for the boundary-value problems dealing with the generation or scattering of axi-symmetric water waves by a system of permeable and impermeable co-axial cylinders. Various results concerning the generation and reflection of the axisymmetric surface or interfacial waves are derived in terms of Bessel functions. The resonance conditions within the trapped region are obtained in various cases. Further, expansions for multipole-line-source oblique-wave potentials are derived for both the cases of finite and infinite depth depending on the existence of the source point in a two-layered fluid. 相似文献
117.
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119.
Cactus‐Like Hollow Cu2‐xS@Ru Nanoplates as Excellent and Robust Electrocatalysts for the Alkaline Hydrogen Evolution Reaction 下载免费PDF全文
Donghwan Yoon Jaeyoung Lee Bora Seo Byeongyoon Kim Hionsuck Baik Sang Hoon Joo Kwangyeol Lee 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(29)
The development of Pt‐free electrocatalysts for the hydrogen evolution reaction (HER) recently is a focus of great interest. While several strategies are developed to control the structural properties of non‐Pt catalysts and boost their electrocatalytic activities for the HER, the generation of highly reactive defects or interfaces by combining a metal with other metals, or with metal oxides/sulfides, can lead to notably enhanced catalytic performance. Herein, the preparation of cactus‐like hollow Cu2‐x S@Ru nanoplates (NPs) that contain metal/metal sulfide heterojunctions and show excellent catalytic activity and durability for the HER in alkaline media is reported. The initial formation of Ru islands on presynthesized Cu1.94S NPs, via cation exchange between three Cu+ ions and one Ru3+, induces the growth of the Ru phase, which is concomitant with the dissolution of the Cu1.94S nanotemplate, culminating in the formation of a hollow nanostructure with numerous thin Ru pillars. Hollow Cu2‐x S@Ru NPs exhibit a small overpotential of 82 mV at a current density of ?10 mA cm?2 and a low Tafel slope of 48 mV dec?1 under alkaline conditions; this catalyst is among state‐of‐the‐art HER electrocatalysts in alkaline media. The excellent performance of hollow Cu2‐x S@Ru NPs originates from the facile dissociation of water in the Volmer step. 相似文献
120.
Thermally Stable Metal‐Organic Framework‐Templated Synthesis of Hierarchically Porous Metal Sulfides: Enhanced Photocatalytic Hydrogen Production 下载免费PDF全文
Porous nanostructured materials are demonstrated to be very promising in catalysis due to their well accessible active sites. Thermally stable metal‐organic frameworks (MOFs) as hard templates are successfully utilized to afford porous metal oxides and subsequently metal sulfides by a nanocasting method. The resultant metal oxides/sulfides show considerable Brunauer–Emmett–Teller (BET) surface areas, by partially inheriting the pore character of MOF templates. Preliminary investigation on the obtained hierarchically porous CdS for water splitting, as a proof of concept, demonstrates its much higher activity than both corresponding bulk and nanosized counterparts, under visible light irradiation. Given the structural diversity and tailorability of MOFs, such synthetic approach may open an avenue to the synthesis of advanced porous materials for functional applications. 相似文献