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Ji Qian Feng Wu Yusheng Ye Menglu Zhang Yongxin Huang Yi Xing Wei Qu Li Li Renjie Chen 《Liver Transplantation》2018,8(16)
Sodium‐ion batteries (SIBs) are considered to be a promising alternative for large‐scale electricity storage. However, it is urgent to develop new anode materials with superior ultralong cycle life performance at high current rates. Herein, a low‐cost and large‐scalable sulfur‐doped carbon anode material that exhibits the best high‐rate cycle performance and the longest cycle life ever reported for carbon anodes is developed. The material delivers a reversible capacity of 142 mA h g?1 at a current rate up to 10 A g?1. After 10 000 cycles the capacity is remained at 126.5 mA h g?1; 89.1% of the initial value. Density functional theory computations demonstrate that the sulfur‐doped carbon has a strong binding affinity for sodium which promotes sodium storage. Meanwhile, the kinetics analysis identifies the capacitive charge storage as a large contributor to sodium storage, which favors ultrafast storage of sodium ions. These results demonstrate a new way to design carbon‐based SIBs anodes for next‐generation large‐scale electricity storage. 相似文献
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Subtle Roles of Sb and S in Regulating the Thermoelectric Properties of N‐Type PbTe to High Performance 下载免费PDF全文
Gangjian Tan Constantinos C. Stoumpos Si Wang Trevor P. Bailey Li‐Dong Zhao Ctirad Uher Mercouri G. Kanatzidis 《Liver Transplantation》2017,7(18)
A high ZT (thermoelectric figure of merit) of ≈1.4 at 900 K for n‐type PbTe is reported, through modifying its electrical and thermal properties by incorporating Sb and S, respectively. Sb is confirmed to be an amphoteric dopant in PbTe, filling Te vacancies at low doping levels (<1%), exceeding which it enters into Pb sites. It is found that Sb‐doped PbTe exhibits much higher carrier mobility than similar Bi‐doped materials, and accordingly, delivers higher power factors and superior ZT . The enhanced electronic transport is attributed to the elimination of Te vacancies, which appear to strongly scatter n‐type charge carriers. Building on this result, the ZT of Pb0.9875Sb0.0125Te is further enhanced by alloying S into the Te sublattice. The introduction of S opens the bandgap of PbTe, which suppresses bipolar conduction while simultaneously increasing the electron concentration and electrical conductivity. Furthermore, it introduces point defects and induces second phase nanostructuring, which lowers the lattice thermal conductivity to ≈0.5 W m?1 K?1 at 900 K, making this material a robust candidate for high‐temperature (500–900 K) thermoelectric applications. It is anticipated that the insights provided here will be an important addition to the growing arsenal of strategies for optimizing the performance of thermoelectric materials. 相似文献
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Synergistically Optimizing Electrical and Thermal Transport Properties of BiCuSeO via a Dual‐Doping Approach 下载免费PDF全文
Yong Liu Li‐Dong Zhao Yingcai Zhu Yaochun Liu Fu Li Meijuan Yu Da‐Bo Liu Wei Xu Yuan‐Hua Lin Ce‐Wen Nan 《Liver Transplantation》2016,6(9)
The layered oxyselenide BiCuSeO system is known as one of the high‐performance thermoelectric materials with intrinsically low thermal conductivity. By employing atomic, nano‐ to mesoscale structural optimizations, low thermal conductivity coupled with enhanced electrical transport properties can be readily achieved. Upon partial substitution of Bi3+ by Ca2+ and Pb2+, the thermal conductivity can be reduced to as low as 0.5 W m?1 K?1 at 873 K through dual‐atomic point‐defect scattering, while a high power factor of ≈1 × 10?3 W cm?1 K?2 is realized over a broad temperature range from 300 to 873 K. The synergistically optimized power factor and intrinsically low thermal conductivity result in a high ZT value of ≈1.5 at 873 K for Bi0.88Ca0.06Pb0.06CuSeO, a promising candidate for high‐temperature thermoelectric applications. It is envisioned that the all‐scale structural optimization is critical for optimizing the thermoelectricity of quaternary compounds. 相似文献
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Wesley A. Henderson Daniel M. Seo Qian Zhou Paul D. Boyle Joon‐Ho Shin Hugh C. De Long Paul C. Trulove Stefano Passerini 《Liver Transplantation》2012,2(11):1343-1350
The phase behavior and ionic conductivity of tetraethylammonium bis(trifluoromethane‐sulfonyl)imide (Et4NTFSI) salt mixtures with LiTFSI have been examined. In addition, the phase behavior and crystal structure of neat LiTFSI is also reported. Two (1‐x) Et4NTFSI‐(x) LiTFSI (x = 0.50 and 0.67, where x is the mol fraction) mixed‐salt crystalline phases form. Large variations in ionic conductivity are observed; these are attributed to solid‐solid phase transitions of the neat Et4NTFSI salt creating disordered plastic crystalline phases and the formation of a low‐melting eutectic composition between the neat Et4NTFSI salt and the 1/1 Et4NTFSI/LiTFSI (x = 0.50) phase. Although Et4NTFSI and LiTFSI melt at 102 and 234 °C, respectively, the two salts form a eutectic system with a melting temperature of 32 °C. Based upon the findings reported, a new conductivity mechanism is proposed for plastic crystalline salt‐lithium salt electrolytes which is not ascribed to solid‐state diffusion/conduction. 相似文献
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Xiaolei Shi Angyin Wu Tianli Feng Kun Zheng Weidi Liu Qiang Sun Min Hong Sokrates T. Pantelides Zhi‐Gang Chen Jin Zou 《Liver Transplantation》2019,9(11)
Herein, a high figure of merit (ZT) of ≈1.7 at 823 K is reported in p‐type polycrystalline Cd‐doped SnSe by combining cation vacancies and localized‐lattice engineering. It is observed that the introduction of Cd atoms in SnSe lattice induce Sn vacancies, which act as p‐type dopants. A combination of facile solvothermal synthesis and fast spark plasma sintering technique boosts the Sn vacancy to a high level of ≈2.9%, which results in an optimum hole concentration of ≈2.6 × 1019 cm?3 and an improved power factor of ≈6.9 µW cm?1 K?2. Simultaneously, a low thermal conductivity of ≈0.33 W m?1 K?1 is achieved by effective phonon scattering at localized crystal imperfections, as observed by detailed structural characterizations. Density functional theory calculations reveal that the role of Cd atoms in the SnSe lattice is to reduce the formation energy of Sn vacancies, which in turn lower the Fermi level down into the valence bands, generating holes. This work explores the fundamental Cd‐doping mechanisms at the nanoscale in a SnSe matrix and demonstrates vacancy and localized‐lattice engineering as an effective approach to boosting thermoelectric performance. The work provides an avenue in achieving high‐performance thermoelectric properties of materials. 相似文献
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From Surface ZrO2 Coating to Bulk Zr Doping by High Temperature Annealing of Nickel‐Rich Lithiated Oxides and Their Enhanced Electrochemical Performance in Lithium Ion Batteries 下载免费PDF全文
Florian Schipper Hana Bouzaglo Mudit Dixit Evan M. Erickson Tina Weigel Michael Talianker Judith Grinblat Larisa Burstein Michael Schmidt Jordan Lampert Christoph Erk Boris Markovsky Dan Thomas Major Doron Aurbach 《Liver Transplantation》2018,8(4)
One of the major hurdles of Ni‐rich cathode materials Li1+x(NixCozMnz)wO2, y > 0.5 for lithium‐ion batteries is their low cycling stability especially for compositions with Ni ≥ 60%, which suffer from severe capacity fading and impedance increase during cycling at elevated temperatures (e.g., 45 °C). Two promising surface and structural modifications of these materials to alleviate the above drawback are (1) coatings by electrochemically inert inorganic compounds (e.g., ZrO2) or (2) lattice doping by cations like Zr4+, Al3+, Mg2+, etc. This paper demonstrates the enhanced electrochemical behavior of Ni‐rich material LiNi0.8Co0.1Mn0.1O2 (NCM811) coated with a thin ZrO2 layer. The coating is produced by an easy and scalable wet chemical approach followed by annealing the material at ≥700 °C under oxygen that results in Zr doping. It is established that some ZrO2 remains even after annealing at ≥800 °C as a surface layer on NCM811. The main finding of this work is the enhanced cycling stability and lower impedance of the coated/doped NCM811 that can be attributed to a synergetic effect of the ZrO2 coating in combination with a zirconium doping. 相似文献
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Boer Tan Sonia R. Raga Anthony S. R. Chesman Sebastian O. Fürer Fei Zheng David P. McMeekin Liangcong Jiang Wenxin Mao Xiongfeng Lin Xiaoming Wen Jianfeng Lu Yi‐Bing Cheng Udo Bach 《Liver Transplantation》2019,9(32)
To date, the most efficient perovskite solar cells (PSCs) employ an n–i–p device architecture that uses a 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) hole‐transporting material (HTM), which achieves optimum conductivity with the addition of lithium bis(trifluoromethane)sulfonimide (LiTFSI) and air exposure. However, this additive along with its oxidation process leads to poor reproducibility and is detrimental to stability. Herein, a dicationic salt spiro‐OMeTAD(TFSI)2, is employed as an effective p‐dopant to achieve power conversion efficiencies of 19.3% and 18.3% (apertures of 0.16 and 1.00 cm2) with excellent reproducibility in the absence of LiTFSI and air exposure. As far as it is known, these are the highest‐performing n–i–p PSCs without LiTFSI or air exposure. Comprehensive analysis demonstrates that precise control of the proportion of [spiro‐OMeTAD]+ directly provides high conductivity in HTM films with low series resistance, fast hole extraction, and lower interfacial charge recombination. Moreover, the spiro‐OMeTAD(TFSI)2‐doped devices show improved stability, benefitting from well‐retained HTM morphology without forming aggregates or voids when tested under an ambient atmosphere. A facile approach is presented to fabricate highly efficient PSCs by replacing LiTFSI with spiro‐OMeTAD(TFSI)2. Furthermore, this study provides an insight into the relationship between device performance and the HTM doping level. 相似文献
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Fanglin Wu Guk‐Tae Kim Matthias Kuenzel Huang Zhang Jakob Asenbauer Dorin Geiger Ute Kaiser Stefano Passerini 《Liver Transplantation》2019,9(43)
The eco‐friendly and low‐cost Co‐free Li1.2Mn0.585Ni0.185Fe0.03O2 is investigated as a positive material for Li‐ion batteries. The electrochemical performance of the 3 at% Fe‐doped material exhibits an optimal performance with a capacity and voltage retention of 70 and 95%, respectively, after 200 cycles at 1C. The effect of iron doping on the electrochemical properties of lithium‐rich layered materials is investigated by means of in situ X‐ray diffraction spectroscopy and galvanostatic intermittent titration technique during the first charge–discharge cycle while high‐resolution transmission electron microscopy is used to follow the structural and chemical change of the electrode material upon long‐term cycling. By means of these characterizations it is concluded that iron doping is a suitable approach for replacing cobalt while mitigating the voltage and capacity degradation of lithium‐rich layered materials. Finally, complete lithium‐ion cells employing Li1.2Mn0.585Ni0.185Fe0.03O2 and graphite show a specific energy of 361 Wh kg?1 at 0.1C rate and very stable performance upon cycling, retaining more than 80% of their initial capacity after 200 cycles at 1C rate. These results highlight the bright prospects of this material to meet the high energy density requirements for electric vehicles. 相似文献
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Metal‐organic coordination frameworks have been widely used as efficient precursors for the preparation of functional carbon‐based materials with various nanostructures. However, to date, the design of 2D carbon nanostructures from single coordination frameworks remains a great challenge. Herein, an efficient strategy for the fabrication of N‐rich porous carbon nanosheets from 2D Zn‐hexamine coordination framework nanosheets is developed. Remarkably, the N‐doping level of carbon nanosheets can attain 16.54 at%. In addition, the thickness of the carbon nanosheets can effectively be tuned by simply adjusting the molar ratio of the starting materials. As a proof‐of‐concept application, the as‐prepared carbon nanosheets as an anode material for sodium‐ion batteries exhibit an ultrafast sodium storage capability of 194 mAh g?1 even at 10 A g?1. As far as it is known, such a high‐rate capability has been rarely achieved in previous studies on carbonaceous anode materials for Na‐ion storage. Moreover, this approach is readily controllable and could be extended to prepare a series of 2D N‐doped carbon‐based nanomaterials on a large scale. 相似文献
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Simone Esposito Koen Deventer Lore Geldof Peter Van Eenoo 《Journal of peptide science》2015,21(1):1-9
Peptide hormones represent an emerging class of potential doping agents. Detection of their misuse is difficult due to their short half‐life in plasma and rapid elimination. Therefore, investigating their metabolism can improve detectability. Unfortunately, pharmacokinetic studies with human volunteers are often not allowed because of ethical constraints, and therefore alternative models are needed. This study was performed in order to evaluate in vitro models (human liver microsomes and S9 fraction) for the prediction of the metabolism of peptidic doping agents and to compare them with the established models. The peptides that were investigated include desmopressin, TB‐500, GHRP‐2, GHRP‐6, hexarelin, LHRH and leuprolide. Several metabolites were detected for each peptide after incubation with human liver microsomes, S9 fraction, and serum, which all showed endopeptidase and exopeptidase activity. In vitro models from different organs (liver vs. kidney) were compared, but no significant differences were recorded. Deamidation was not observed in any of the models and was therefore evaluated by incubation with α‐chymotrypsin. In conclusion, in vitro models are useful tools for forensic and clinical analysts to detect peptidic metabolic markers in biological fluids. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
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Yanjiao Ma Yuan Ma Gabriele Giuli Holger Euchner Axel Groß Giovanni Orazio Lepore Francesco d'Acapito Dorin Geiger Johannes Biskupek Ute Kaiser Hanno M. Schütz Anna Carlsson Thomas Diemant Rolf Jürgen Behm Matthias Kuenzel Stefano Passerini Dominic Bresser 《Liver Transplantation》2020,10(25)
The development of alternative anode materials with higher volumetric and gravimetric capacity allowing for fast delithiation and, even more important, lithiation is crucial for next‐generation lithium‐ion batteries. Herein, the development of a completely new active material is reported, which follows an insertion‐type lithiation mechanism, metal‐doped CeO2. Remarkably, the introduction of carefully selected dopants, herein exemplified for iron, results in an increase of the achievable capacity by more than 200%, originating from the reduction of the dopant to the metallic state and additional space for the lithium ion insertion due to a significant off‐centering of the dopant atoms in the crystal structure, away from the original Ce site. In addition to the outstanding performance of such materials in high‐power lithium‐ion full‐cells, the selective reduction of the iron dopant under preservation of the crystal structure of the host material is expected to open up a new field of research. 相似文献