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41.
The ion exchange membrane can be used as an effective medium of electromigration for the separation of isotopes by the following reasons. 相似文献
42.
锂离子进入碳纳米管端口的速度V Li是影响锂离子电池充电性能的重要因素.采用分子动力学模拟方法,研究了直径、温度、电场强度和端口改性官能团四种因子对其影响.运用正交实验方法,分析得出了各因子及其不同水平的影响规律.结果表明,四种因子的影响力度由大到小依次为:电场强度、官能团类型、碳纳米管直径和温度.在本文的模拟条件下,随着电场强度和碳纳米管直径的增大,V Li逐渐增加,且在电场强度下的增幅会更显著;碳纳米管端口官能团分别改性为氢原子(—H),羟基(—OH),氨基(—NH2)以及羧基(—COOH)时,V Li会逐步降低;随着温度的增大,V Li先增加后减小,但整体波动偏幅不大. 相似文献
43.
Sulfur Immobilized in Hierarchically Porous Structured Carbon as Cathodes for Lithium–Sulfur Battery with Improved Electrochemical Performance 下载免费PDF全文
In order to overcome the main obstacles for lithium–sulfur batteries, such as poor conductivity of sulfur, polysulfide intermediate dissolution, and large volume change generated during the cycle process, a hard‐template route is developed to synthesize large‐surface area carbon with abundant micropores and mesopores to immobilize sulfur species. The microstructures of the C/S hybrids are investigated using field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Raman spectroscopy, X‐ray photoelectron spectroscopy, nitrogen adsorption–desorption isotherms, and electrochemical impedance spectroscopy techniques. The large surface and porous structure can effectively alleviate large strain due to the lithiation/delithiation process. More importantly, the micropores can effectively confine small molecules of sulfur in the form of S2–4, avoiding loss of active S species and dissolution of high‐order lithium polysulfides. The porous C/S hybrids show significantly enhanced electrochemical performance with good cycling stability, high specific capacity, and rate capability. The C/S‐39 hybrid with an optimal content of 39 wt% S shows a reversible capacity of 780 mA h g?1 after 100 cycles at the current density of 100 mA g?1. Even at a current density of 5 A g?1, the reversible capacity of C/S‐39 can still maintain at 420 mA h g?1 after 60 cycles. This strategy offers a new way for solving long‐term reversibility obstacle and designing new cathode electrode architectures. 相似文献
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Tian Wang Zhanwei Xu Jun Yang Xinyue Liu Yayi Cheng Jia Li Xuetao Shen Jianfeng Huang 《Particle & Particle Systems Characterization》2019,36(9)
2D MoS2 has a significant capacity decay due to the stack of layers during the charge/discharge process, which has seriously restricted its practical application in lithium‐ion batteries. Herein, a simple preform‐in situ process to fabricate vertically grown MoS2 nanosheets with 8–12 layers anchored on reduced graphene oxide (rGO) flexible supports is presented. As an anode in MoS2/rGO//Li half‐cell, the MoS2/rGO electrode shows a high initial coulomb efficiency (84.1%) and excellent capacity retention (84.7% after 100 cycles) at a current density of 100 mA g?1. Moreover, the MoS2/rGO electrode keeps capacity as high as 786 mAh g?1 after 1000 cycles with minimum degradation of 54 µAh g?1 cycle?1 after being further tested at a high current density of 1000 mA g?1. When evaluated in a MoS2/rGO//LiCoO2 full‐cell, it delivers an initial charge capacity of 153 mAh g?1 at a current density of 100 mA g?1 and achieves an energy density of 208 Wh kg?1 under the power density of 220 W kg?1. 相似文献
47.
Spinel lithium titanate (Li4Ti5O12) as novel anode material for room-temperature sodium-ion battery 下载免费PDF全文
This is the first time that a novel anode material, spinel Li4Ti5O12 which is well known as a “zero-strain” anode material for lithium storage, has been introduced for sodium-ion battery. The Li4Ti5O12 shows an average Na storage voltage of about 1.0 V and a reversible capacity of about 145 mAh/g, thereby making it a promising anode for sodium-ion battery. Ex-situ X-ray diffraction (XRD) is used to investigate the structure change in the Na insertion/deinsertion process. Based on this, a possible Na storage mechanism is proposed. 相似文献
48.
Efficient continuous-wave eye-safe region signal output from intra-cavity singly resonant optical parametric oscillator 下载免费PDF全文
We report an efficient continuous-wave (CW) tunable intra-cavity singly resonant optical parametric oscillator based on the multi-period periodically poled lithium niobate and using a laser diode (LD) end-pumped CW 1064 nm Nd:YVO4 laser as the pump source. A highly efficiency CW operation is realized through a careful cavity design for mode matching and thermal stability. The signal tuning range is 1401-1500 nm obtained by varying the domain period. The maximum output power of 2.2 W at 1500 nm is obtained with a 17.1 W 808 nm LD power and the corresponding conversion efficiency is 12.9%. 相似文献
49.
Positron scattering with atomic lithium is investigated by using a coupled-channel optical method.The ionization continuum and positronium formation channels are taken into account via a complex equivalent-local optical potential.The positronium formation cross sections and the ionization cross sections,as well as the total scattering cross sections,are reported at energies above 3 eV and compared with available experimental and theoretical data. 相似文献
50.
Mengjiao Xu Minxuan Wang Hao Xu Prof. Dr. Huaiguo Xue Prof. Dr. Huan Pang 《化学:亚洲杂志》2016,11(21):2967-2995
Electrospinning, as a novel nontextile filament technology, is an important method to prepare continuous nanofibers and has shown its remarkable advantages, such as a broadly applicable material system, controllable fiber size and structure, and simple process. Electrospun nanofiber membranes prepared by electrospinning have shown promising applications in many fields, such as supercapacitors, lithium‐ion batteries, and sodium‐ion batteries, owing to their large specific surface area and adjustable network pore structure. The principle of electrospinning and key points relevant to its usage in the preparation of high‐performance electrochemical energy storage materials are reviewed herein based on recent publications, particularly focusing on research progress of relative materials. Also, this review describes a distinctive conclusion and perspective on the future challenges and opportunities in electrospun nanomaterials. 相似文献