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31.
32.
Ayesha Kausar 《Fullerenes, Nanotubes and Carbon Nanostructures》2017,25(2):109-123
This review focuses on an inimitable multilayer fullerene material commonly referred as carbon nano onion (CNO). Among carbon nanomaterials, CNO is the least studied form. CNO has unique 0-D structure, small diameter of <10 nm, high electrical conductivity, fine dispersibility, and other superior structural and physical features. Different preparation and functionalization routes have been used for this unique nanocarbon structure. The article summarizes essential available categories of polymer/CNO composite such as polyaniline/CNO, polypyrrole/CNO, polythiophene/CNO, poly(?-caprolactone)/CNO, polystyrene/CNO, poly(diallyldimethyl-ammonium chloride)/CNO, and polyenediyne/CNO. Moreover, significant technical application of CNO-based materials has been discussed in supercapacitor, solar cell, Li-ion battery, dielectric, and biomedical materials. 相似文献
33.
Molecular‐Level Design of Hierarchically Porous Carbons Codoped with Nitrogen and Phosphorus Capable of In Situ Self‐Activation for Sustainable Energy Systems 下载免费PDF全文
Wei Ai Xuewan Wang Chenji Zou Zhuzhu Du Zhanxi Fan Hua Zhang Peng Chen Ting Yu Wei Huang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(8)
Hierarchically porous carbons are attracting tremendous attention in sustainable energy systems, such as lithium ion battery (LIB) and fuel cell, due to their excellent transport properties that arise from the high surface area and rich porosity. The state‐of‐the‐art approaches for synthesizing hierarchically porous carbons normally require chemical‐ and/or template‐assisted activation techniques, which is complicate, time consuming, and not feasible for large scale production. Here, a molecular‐level design principle toward large‐scale synthesis of nitrogen and phosphorus codoped hierarchically porous carbon (NPHPC) through an in situ self‐activation process is proposed. The material is fabricated based on the direct pyrolysis of a well‐designed polymer, melamine polyphosphate, which is capable of in situ self‐activation to generate large specific surface area (1479 m2 g?1) and hierarchical pores in the final NPHPC. As an anode material for LIB, NPHPC delivers a high reversible capacity of 1073 mAh g?1 and an excellent cyclic stability for 300 cycles with negligible capacity decay. The peculiar structural properties and synergistic effect of N and P codopants also enable NPHPC a promising electrocatalyst for oxygen reduction reaction, a key cathodic reaction process of many energy conversion devices (for example, fuel cells and metal air batteries). Electrochemical measurements show NPHPC a comparable electrocatalytic performance to commercial Pt/C catalyst (onset potential of 0.88 V vs reversible hydrogen electrode in alkaline medium) with excellent stability (89.8% retention after 20 000 s continuous operation) and superior methanol tolerance. 相似文献
34.
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
35.
Qian Wang Chengkai Yang Jijin Yang Kai Wu Cejun Hu Jing Lu Wen Liu Xiaoming Sun Jingyi Qiu Henghui Zhou 《Advanced materials (Deerfield Beach, Fla.)》2019,31(41)
Uncontrollable Li dendrite growth and low Coulombic efficiency severely hinder the application of lithium metal batteries. Although a lot of approaches have been developed to control Li deposition, most of them are based on inhibiting lithium deposition on protrusions, which can suppress Li dendrite growth at low current density, but is inefficient for practical battery applications, with high current density and large area capacity. Here, a novel leveling mechanism based on accelerating Li growth in concave fashion is proposed, which enables uniform and dendrite‐free Li plating by simply adding thiourea into the electrolyte. The small thiourea molecules can be absorbed on the Li metal surface and promote Li growth with a superfilling effect. With 0.02 m thiourea added in the electrolyte, Li | Li symmetrical cells can be cycled over 1000 cycles at 5.0 mA cm?2, and a full cell with LiFePO4 | Li configuration can even maintain 90% capacity after 650 cycles at 5.0 C. The superfilling effect is also verified by computational chemistry and numerical simulation, and can be expanded to a series of small chemicals using as electrolyte additives. It offers a new avenue to dendrite‐free lithium deposition and may also be expanded to other battery chemistries. 相似文献
36.
Na/Li‐Ion Batteries: Co9S8/MoS2 Yolk–Shell Spheres for Advanced Li/Na Storage (Small 14/2017) 下载免费PDF全文
37.
38.
研究了碳酸氢铵-还原剂体系选择性浸出废旧三元锂电池中锂、镍、钴的过程。考察了浸出温度、碳酸氢铵浓度、还原剂的种类和浓度、固液比及浸出时间等对有价金属浸出率的影响,并通过XRD、SEM-EDS和FT-IR等表征方法对选择性浸出机理进行了初步探明。结果表明:在浸出温度80 ℃、浸出时间2.5 h、碳酸氢铵浓度2.5 mol/L、固液比50 g/L、还原剂亚硫酸钠浓度0.6 mol/L的条件下,锂、镍、钴的浸出率分别为96.86%、96.36%、93.43%,而锰几乎不被浸出。碳酸氢铵-亚硫酸钠还原浸出体系可以实现从废旧三元锂电池材料中高效、选择性回收锂、镍和钴。 相似文献
39.
采用脉冲激光沉积(PLD)技术在Si(111)衬底上生长了Eu3+、Li+共掺杂的ZnO薄膜。分别对样品进行了X射线衍射(XRD)谱测试和光致发光(PL)谱分析,重点研究了退火处理对样品结构和发射光谱的影响。XRD谱测试表明,样品具有很好的C轴择优取向。PL谱研究表明,当用325nm光激发样品时,样品的发射光谱仅由ZnO基质的紫外发射和蓝光发射组成,并没有发现稀土Eu3+的特征发光峰;样品的蓝光发射源于电子从Zn填隙形成的浅施主能级到Zn空位形成的浅受主能级跃迁;和真空中退火的样品相比,O2中制备的样品的蓝光发射减弱,紫外发光增强。用395nm的光激发时,退火前样品分别在594nm和613nm处存在两个明显的Eu3+特征发光峰,退火后的样品仅发现Eu3+位于594nm的特征发光峰,这表明,退火处理不利于稀土离子的特征发射,但O2中退火的样品ZnO基质红绿波段发射光谱明显增强。 相似文献
40.
Layered Orthorhombic Nb2O5@Nb4C3Tx and TiO2@Ti3C2Tx Hierarchical Composites for High Performance Li‐ion Batteries 下载免费PDF全文
Chuanfang Zhang Seon Joon Kim Michael Ghidiu Meng‐Qiang Zhao Michel W. Barsoum Valeria Nicolosi Yury Gogotsi 《Advanced functional materials》2016,26(23):4143-4151
Engineering electrode nanostructures is critical in developing high‐capacity, fast rate‐response, and safe Li‐ion batteries. This study demonstrates the synthesis of orthorhombic Nb2O5@Nb4C3Tx (or @Nb2CTx) hierarchical composites via a one‐step oxidation —in flowing CO2 at 850 °C —of 2D Nb4C3Tx (or Nb2CTx) MXene. The composites possess a layered architecture with orthorhombic Nb2O5 nanoparticles decorated uniformly on the surface of the MXene flakes and interconnected by disordered carbon. The composites have a capacity of 208 mAh g?1 at a rate of 50 mA g?1 (0.25 C) in 1–3 V versus Li+/Li, and retain 94% of the specific capacity with 100% Coulombic efficiency after 400 cycles. The good electrochemical performances could be attributed to three synergistic effects: (1) the high conductivity of the interior, unoxidized Nb4C3Tx layers, (2) the fast rate response and high capacity of the external Nb2O5 nanoparticles, and (3) the electron “bridge” effects of the disordered carbon. This oxidation method was successfully extended to Ti3C2Tx and Nb2CTx MXenes to prepare corresponding composites with similar hierarchical structures. Since this is an early report on producing this structure, there is much room to push the boundaries further and achieve better electrochemical performance. 相似文献