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941.
Li Li Zhengjun Xie Gaoxue Jiang Yijing Wang Bingqiang Cao Changzhou Yuan 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(32)
Recently, binary ZnCo2O4 has drawn enormous attention for lithium‐ion batteries (LIBs) as attractive anode owing to its large theoretical capacity and good environmental benignity. However, the modest electrical conductivity and serious volumetric effect/particle agglomeration over cycling hinder its extensive applications. To address the concerns, herein, a rapid laser‐irradiation methodology is firstly devised toward efficient synthesis of oxygen‐vacancy abundant nano‐ZnCo2O4/porous reduced graphene oxide (rGO) hybrids as anodes for LIBs. The synergistic contributions from nano‐dimensional ZnCo2O4 with rich oxygen vacancies and flexible rGO guarantee abundant active sites, fast electron/ion transport, and robust structural stability, and inhibit the agglomeration of nanoscale ZnCo2O4, favoring for superb electrochemical lithium‐storage performance. More encouragingly, the optimal L‐ZCO@rGO‐30 anode exhibits a large reversible capacity of ≈1053 mAh g?1 at 0.05 A g?1, excellent cycling stability (≈746 mAh g?1 at 1.0 A g?1 after 250 cycles), and preeminent rate capability (≈686 mAh g?1 at 3.2 A g?1). Further kinetic analysis corroborates that the capacitive‐controlled process dominates the involved electrochemical reactions of hybrid anodes. More significantly, this rational design holds the promise of being extended for smart fabrication of other oxygen‐vacancy abundant metal oxide/porous rGO hybrids toward advanced LIBs and beyond. 相似文献
942.
Zhiming Zhou Xiaoyan Zhou Miao Zhang Sainan Mu Qirong Liu Yongbing Tang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(35)
Aqueous Zn‐based hybrid energy storage devices (HESDs) exhibit great potential for large‐scale energy storage applications for the merits of environmental friendliness, low redox potential, and high theoretical capacity of Zn anode. However, they are still subjected to low specific capacities since adsorption‐type cathodes (i.e., activated carbon, hard carbon) have limited capability to accommodate active ions. Herein, a hierarchical porous activated carbon cathode (HPAC) is prepared via an in situ two‐step activation strategy, different from the typical one‐step/postmortem activation of fully carbonized precursors. The strategy endows the HPAC with a high specific surface area and a large mesoporous volume, and thus provides abundant active sites and fast kinetics for accommodating active ions. Consequently, pairing the HPAC with Zn anode yields an aqueous Zn‐based HESD, which delivers a high specific capacity of 231 mAh g?1 at 0.5 A g?1 and excellent rate performance with a retained capacity of 119 mAh g?1 at 20 A g?1, the best result among previously reported lithium‐free HESDs based on carbon cathodes. Further, the aqueous Zn‐based HESD shows ultra‐long cycling stability with a capacity retention of ≈70% after 18 000 cycles at 10 A g?1, indicating great potential for environmentally friendly, low‐cost, and high‐safety energy storage applications. 相似文献
943.
944.
Liyuan Geng Dandan Yang Shilun Gao Zhaoxiang Zhang Feiyuan Sun Yiyang Pan Shaoqi Li Xiaohua Li Peng‐Fei Cao Huabin Yang 《Advanced Materials Interfaces》2020,7(3)
Comparing with nanometer‐sized Si (nano‐Si), the micrometer‐sized Si (micro‐Si) is more promising for the practical applications due to its low cost and scalable production method. Fabrication of micro‐Si with porous architecture can efficiently alleviate the high mechanical stress and severe mechanical fracture. Till now, it is still a challenge to achieve porous micro‐Si with controlled morphology, such as microsphere, from a cost‐efficient and environmentally friendly approach. Herein, a facile approach on fabricating Si microsphere with porous architecture via a low‐temperature aluminothermic reduction (LTAR) method using the low‐cost fumed silica (FS) as raw material is introduced. After compositing with graphite and then coating with amorphous carbon, the SiFS/graphite@carbon (SiFS/G@C) electrode displays superior reversible capacity (730 mAh g−1 after 100 cycles) and excellent rate capability (729.1 mAh g−1 at 1 A g−1). The electrochemical performance is much better than that of Si‐microparticles/G@C (Mic‐Si/G@C, 368 mAh g−1 at 100 mA g−1 after 100 cycles). These results show the great potential of SiFS/G@C electrode as an alternative high‐performance electrode material for lithium ion batteries. Moreover, the LTAR adopted in the current study significantly reduces the energy consumption for preparation of Si microspheres from low‐cost raw materials. 相似文献
945.
Yibo You Wei Tian Min Wang Fengren Cao Haoxuan Sun Liang Li 《Advanced Materials Interfaces》2020,7(13)
Cesium lead mixed‐halide perovskite (CsPbIBr2), as one of the all‐inorganic perovskites, has attracted great attention owing to its great ambient stability and suitable bandgap. Unfortunately, due to its low film coverage, high density of defects and unfavorable band energy level, the CsPbIBr2 based solar cells suffer from low efficiency. In this work, the Lewis base poly(ethylene glycol) (PEG) is adopted as additive to modify the pure CsPbIBr2. By optimizing the molecular weight and dosage of PEG, the resultant PEG:CsPbIBr2 film possesses suppressed non‐radiative electron–hole recombination, a favorable energy band structure and a weaker sensitive to the moisture. As a result, the device based on the PEG:CsPbIBr2 yields a champion power conversion efficiency (PCE) of 11.10%, with a open‐circuit voltage of 1.21 V, a short‐circuit current of 12.25 mA cm−2, and a fill factor of 74.82%, which is 44.3% higher than its counterpart without PEG. Moreover, the PEG modified device shows excellent long‐term stability, retaining over 90% of the initial efficiency after 600 h storage in ambient condition without encapsulation. In comparison, the device without PEG shows an inferior stability with PCE sharply dropping to 0% within 50 h. 相似文献
946.
Haiyan Zhang Hongcheng Xu Ke Cao Liang Wang Libo Gao Meng Mu Min Liu Weidong Wang Xinkang Hu Yang Lu Yuejiao Wang 《纳微快报(英文)》2020,(11):229-241
Developing flexible sensors with high working performance holds intense interest for diverse applications in leveraging the Internet-of-things (IoT) infrastruct... 相似文献
947.
Kangzhe Cao Huiqiao Liu Yongheng Jia Zhang Zhang Yong Jiang Xiaogang Liu Ke‐Jing Huang Lifang Jiao 《Advanced Materials Technologies》2020,5(6)
Potassium‐ion batteries (KIBs) are considered as promising alternatives to lithium‐ion batteries due to the abundant resources, low cost, and low redox potential of K. However, KIBs anode materials suffer challenges owing to the large K+ radius and slow reaction dynamics, which result in low reversible capacity and inferior rate capability. Herein, Sb nanoparticles (about 4 nm) confined in an interconnecting carbon porous nanofibers (Sb@C PNFs) are constructed as flexible integrated KIBs anode. In this architecture, Sb nanoparticles are encapsulated and vessel‐like channels are contained in the N‐doping carbon porous nanofibers, which are adopted as the continuous 3D conductive framework and current collector. Benefiting from the shortened K+ diffusion distance, efficient electrolyte diffusion passages, and reserved space for holding volume swelling, the flexible Sb@C PNFs integrated electrode exhibits excellent K+ storage behaviors (capacities of 399.7 mAh g−1 at 0.1 A g−1 and 208.1 mAh g−1 at 5.0 A g−1 are delivered, respectively, and a capacity of 264.0 mAh g−1 is remained even cycled at 2.0 A g−1 after 500 cycles), and is among the best anode materials up to date. Moreover, the high reversible alloying and dealloying process between cubic K3Sb and as‐formed amorphous Sb in the Sb@C PNFs is confirmed. 相似文献
948.
Ming Zhao Zhiheng Lyu Minghao Xie Zachary D. Hood Zhenming Cao Miaofang Chi Younan Xia 《Small Methods》2020,4(5)
This article reports a facile method for the synthesis of Pd‐Ru nanocages by activating the galvanic replacement reaction between Pd nanocrystals and a Ru(III) precursor with I ‐ ions. The as‐synthesized nanocages feature a hollow interior, ultrathin wall of ≈2.5 nm in thickness, and a cubic shape. Our quantitative study suggests that the reduction rate of the Ru(III) precursor can be substantially accelerated upon the introduction of I ‐ ions and then retarded as the ratio of I ‐ /Ru3+ is increased. The Pd‐Ru nanocages take an alloy structure, with the Ru atoms in the nanocages crystallized in a face‐centered cubic structure instead of the hexagonal close‐packed phase taken by bulk Ru. Using Pd nanocubes with different edge lengths, the dimensions of the nanocages in the range of 6−18 nm can readily be tuned. When tested as catalysts toward the electro‐oxidation of ethylene glycol and glycerol, respectively, the Pd‐Ru cubic nanocages prepared from 18 nm Pd cubes exhibit 5.1‐ and 6.2‐fold enhancements in terms of mass activity relative to the commercial Pd/C. After 1000 cycles of accelerated durability test, the mass activities of the nanocages are still 3.3 and 3.7 times as high as that of the pristine commercial Pd/C catalyst, respectively. 相似文献
949.
950.
Can Wang Kaijun Wang Qifan Mao Shuo Li Xiaoyan Cao Xin Huang Yacheng Liu Zhenggui Gu 《中国稀土学报(英文版)》2020,38(11):1190-1200
Herein, a new mechanism involving Lewis acid-oxygen vacancy interfacial synergistic catalysis for aniline N,N-diethylation with ethanol was proposed, and the SO42−/Ce0.84Zr0.16O2–WO3–ZrO2 catalyst (SCWZ) with both Lewis acid sites and oxygen vacancies was synthesized by the hydrothermal method, which shows better catalytic activity than the reported solid acidic catalysts. Besides, the SO42−/ZrO2 (SZ) and SO42−/WO3–ZrO2 (SWZ) catalysts were also prepared and compared with SCWZ to investigate the synergistic effect of each component. The SO42− and WO3 mainly generate Lewis acid by bonding with ZrO2, which is beneficial for the fracture of the N–H bond in aniline. The Ce0.84Zr0.16O2 solid solution mainly plays a vital role in generating the oxygen vacancies as the interface active species, which can participate in stripping –OH from ethanol, then the carbocation will also be released, which only needs 1.3805 kcal/mol energy, calculated by density functional theory (DFT), to be input. In comparison, the traditional reaction mechanism needs the Brønsted acidic sites to promote the protonation of ethanol, then dehydration and subsequent formation of carbocation followed, and 108.6846 kcal/mol energy needs to be input, which is far higher than that of the new mechanism. The apparent activation energy (Ea) over SCWZ was measured by experiment to be 34.09 kJ/mol, which is much lower than that of SWZ (47.10 kJ/mol) and SZ (54.37 kJ/mol), illustrating comparatively preferable kinetics for SCWZ than that of SWZ and SZ. Besides, the conversion of aniline and selectivity to N,N-diethylaniline over SCWZ reach almost 100% and 73%, respectively. The SCWZ can be renewed for 4 times without rapid deactivation, and the longevity of SCWZ is longer than that of SWZ and SZ, as the loaded SO42− and tetragonal ZrO2 are stabilized by Ce0.84Zr0.16O2 and WO3, respectively. 相似文献