共查询到20条相似文献,搜索用时 15 毫秒
1.
Dr. Yuxi Xu Zhaoyang Lin Dr. Xing Zhong Ben Papandrea Prof. Yu Huang Xiangfeng Duan 《Angewandte Chemie (International ed. in English)》2015,54(18):5345-5350
A solvent‐exchange approach for the preparation of solvated graphene frameworks as high‐performance anode materials for lithium‐ion batteries is reported. The mechanically strong graphene frameworks exhibit unique hierarchical solvated porous networks and can be directly used as electrodes with a significantly improved electrochemical performance compared to unsolvated graphene frameworks, including very high reversible capacities, excellent rate capabilities, and superior cycling stabilities. 相似文献
2.
Fabrication of Fe‐Doped LiCoO2 Sandwich‐Like Nanocomposites as Excellent Performance Cathode Materials for Lithium‐Ion Batteries 下载免费PDF全文
Li Liu Dr. Huijuan Zhang Jiao Yang Yanping Mu Prof. Dr. Yu Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):19104-19111
In this article, the two‐layer sandwiched graphene@LiFe0.2Co0.8O2 nanoparticles (SG@LFCO) have been prepared and investigated as high‐rate and long‐life cathode materials for rechargeable lithium‐ion batteries. The materials possess a high‐surface area (267.1 m2 g?1) and lots of void spaces. By combining various favorable conditions, such as Fe doping, coating graphene, and designing novel morphology, the as‐prepared materials deliver a specific capacity of 115 mAh g?1 at 10 C. At the 0.1 C cycling rate, the capacity retention of 97.2 % is sustained after 250 cycles and a coulombic efficiency of around 97.6 % is obtained. 相似文献
3.
Germanium Quantum Dots Embedded in N‐Doping Graphene Matrix with Sponge‐Like Architecture for Enhanced Performance in Lithium‐Ion Batteries 下载免费PDF全文
Jinwen Qin Xia Wang Prof. Dr. Minhua Cao Changwen Hu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9675-9682
Germanium quantum dots embedded in a nitrogen‐doped graphene matrix with a sponge‐like architecture (Ge/GN sponge) are prepared through a simple and scalable synthetic method, involving freeze drying to obtain the Ge(OH)4/graphene oxide (GO) precursor and subsequent heat reduction treatment. Upon application as an anode for the lithium‐ion battery (LIB), the Ge/GN sponge exhibits a high discharge capacity compared with previously reported N‐doped graphene. The electrode with the as‐synthesized Ge/GN sponge can deliver a capacity of 1258 mAh g?1 even after 50 charge/discharge cycles. This improved electrochemical performance can be attributed to the pore memory effect and highly conductive N‐doping GN matrix from the unique sponge‐like structure. 相似文献
4.
One‐Pot Synthesis of Carbon‐Coated Nanostructured Iron Oxide on Few‐Layer Graphene for Lithium‐Ion Batteries 下载免费PDF全文
Dr. Zhenyu Sun Dr. Edyta Madej Dr. Christian Wiktor Ilya Sinev Prof. Roland A. Fischer Prof. Gustaaf van Tendeloo Prof. Martin Muhler Prof. Wolfgang Schuhmann Dr. Edgar Ventosa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):16154-16161
Nanostructure engineering has been demonstrated to improve the electrochemical performance of iron oxide based electrodes in Li‐ion batteries (LIBs). However, the synthesis of advanced functional materials often requires multiple steps. Herein, we present a facile one‐pot synthesis of carbon‐coated nanostructured iron oxide on few‐layer graphene through high‐pressure pyrolysis of ferrocene in the presence of pristine graphene. The ferrocene precursor supplies both iron and carbon to form the carbon‐coated iron oxide, while the graphene acts as a high‐surface‐area anchor to achieve small metal oxide nanoparticles. When evaluated as a negative‐electrode material for LIBs, our composite showed improved electrochemical performance compared to commercial iron oxide nanopowders, especially at fast charge/discharge rates. 相似文献
5.
Yongmin Wu Dr. Zhenhai Wen Hongbin Feng Prof. Jinghong Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(18):5631-5636
A simple approach for loading LiFePO4 (LFP) nanoparticles on graphene (G) that could assemble amorphous LiFePO4 nanoparticles into a stable, crystalline, graphene‐modified layered materials (G‐S‐LFP, S=sucrose) by using graphene as building block and sucrose as a linker has yet to be developed. On the basis of differential scanning calorimetric and transmission electron microscopy analysis of the samples from controlled experiment, a possible mechanism was proposed to explain the “linker” process of LFP and graphene with sucrose as the linker. The electrochemical properties of the samples as cathode material for lithium‐ion batteries were studied by cyclic voltammogrametry and galvanostatic methods. Results showed that G‐S‐LFP displayed superior lithium‐storage capability with current density changes randomly form 0.5 to 10 C. The significant improvement for rate and cycle performance could be attributed to the high conductivity of the graphene host, the high crystallinity, and the layered structure. 相似文献
6.
Dr. Malin Li Dr. Yu Gao Dr. Nan Chen Dr. Xing Meng Prof. Chunzhong Wang Dr. Yaoqing Zhang Dr. Dong Zhang Prof. Yingjin Wei Dr. Fei Du Prof. Gang Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11405-11412
Cu3V2O8 nanoparticles with particle sizes of 40–50 nm have been prepared by the co‐precipitation method. The Cu3V2O8 electrode delivers a discharge capacity of 462 mA h g?1 for the first 10 cycles and then the specific capacity, surprisingly, increases to 773 mA h g?1 after 50 cycles, possibly as a result of extra lithium interfacial storage through the reversible formation/decomposition of a solid electrolyte interface (SEI) film. In addition, the electrode shows good rate capability with discharge capacities of 218 mA h g?1 under current densities of 1000 mA g?1. Moreover, the lithium storage mechanism for Cu3V2O8 nanoparticles is explained on the basis of ex situ X‐ray diffraction data and high‐resolution transmission electron microscopy analyses at different charge/discharge depths. It was evidenced that Cu3V2O8 decomposes into copper metal and Li3VO4 on being initially discharged to 0.01 V, and the Li3VO4 is then likely to act as the host for lithium ions in subsequent cycles by means of the intercalation mechanism. Such an “in situ” compositing phenomenon during the electrochemical processes is novel and provides a very useful insight into the design of new anode materials for application in lithium‐ion batteries. 相似文献
7.
Xianbo Yu Bin Qu Yang Zhao Chunyan Li Prof. Yujin Chen Prof. Chunwen Sun Prof. Peng Gao Dr. Chunling Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(5):1638-1645
A general strategy based on the nanoscale Kirkendall effect has been developed to grow hollow transition metal (Fe, Co or Ni) oxide nanoparticles on graphene sheets. When applied as lithium‐ion battery anodes, these hollow transition metal oxide‐based composites exhibit excellent electrochemical performance, with high reversible capacities and long‐term stabilities at a high current density, superior to most transition metal oxides reported to date. 相似文献
8.
《中国化学》2017,35(10):1575-1585
Binder‐free, nano‐sized needlelike MnO2 ‐submillimeter‐sized reduced graphene oxide (nMnO2‐srGO ) hybrid films with abundant porous structures were fabricated through electrophoretic deposition and subsequent thermal annealing at 500 °C for 2 h. The as‐prepared hybrid films exhibit a unique hierarchical morphology, in which nMnO2 with a diameter of 20—50 nm and a length of 300—500 nm is randomly anchored on both sides of srGO . When evaluated as binder‐free anodes for lithium‐ion half‐cell, the nMnO2‐srGO composites with a content of 76.9 wt% MnO2 deliver a high capacity of approximately 1652.2 mA •h•g−1 at a current density of 0.1 A•g−1 after 200 cycles. The high capacity remains at 616.8 mA •h•g−1 (ca. 65.1% capacity retention) at a current density as high as 4 A•g−1. The excellent electrochemical performance indicates that the nMnO2‐srGO hybrid films could be a promising anode material for lithium ion batteries (LIBs ). 相似文献
9.
Mesoporous MnCo2O4 with a Flake‐Like Structure as Advanced Electrode Materials for Lithium‐Ion Batteries and Supercapacitors 下载免费PDF全文
Anjon Kumar Mondal Dr. Dawei Su Shuangqiang Chen Prof. Alison Ung Hyun‐Soo Kim Prof. Guoxiu Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1526-1532
A mesoporous flake‐like manganese‐cobalt composite oxide (MnCo2O4) is synthesized successfully through the hydrothermal method. The crystalline phase and morphology of the materials are characterized by X‐ray diffraction, field‐emission scanning electron microscopy, transmission electron microscopy, and Brunauer–Emmett–Teller methods. The flake‐like MnCo2O4 is evaluated as the anode material for lithium‐ion batteries. Owing to its mesoporous nature, it exhibits a high reversible capacity of 1066 mA h g?1, good rate capability, and superior cycling stability. As an electrode material for supercapacitors, the flake‐like MnCo2O4 also demonstrates a high supercapacitance of 1487 F g?1 at a current density of 1 A g?1, and an exceptional cycling performance over 2000 charge/discharge cycles. 相似文献
10.
Facile Mechanochemical Synthesis of Nano SnO2/Graphene Composite from Coarse Metallic Sn and Graphite Oxide: An Outstanding Anode Material for Lithium‐Ion Batteries 下载免费PDF全文
Fei Ye Bote Zhao Prof. Ran Ran Prof. Zongping Shao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(14):4055-4063
A facile method for the large‐scale synthesis of SnO2 nanocrystal/graphene composites by using coarse metallic Sn particles and cheap graphite oxide (GO) as raw materials is demonstrated. This method uses simple ball milling to realize a mechanochemical reaction between Sn particles and GO. After the reaction, the initial coarse Sn particles with sizes of 3–30 μm are converted to SnO2 nanocrystals (approximately 4 nm) while GO is reduced to graphene. Composite with different grinding times (1 h 20 min, 2 h 20 min or 8 h 20 min, abbreviated to 1, 2 or 8 h below) and raw material ratios (Sn:GO, 1:2, 1:1, 2:1, w/w) are investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, field‐emission scanning electron microscopy and transmission electron microscopy. The as‐prepared SnO2/graphene composite with a grinding time of 8 h and raw material ratio of 1:1 forms micrometer‐sized architected chips composed of composite sheets, and demonstrates a high tap density of 1.53 g cm?3. By using such composites as anode material for LIBs, a high specific capacity of 891 mA h g?1 is achieved even after 50 cycles at 100 mA g?1. 相似文献
11.
Excellent Performance of Few‐Layer Borocarbonitrides as Anode Materials in Lithium‐Ion Batteries 下载免费PDF全文
Borocarbonitrides (BxCyNz) with a graphene‐like structure exhibit a remarkable high lithium cyclability and current rate capability. The electrochemical performance of the BxCyNz materials, synthesized by using a simple solid‐state synthesis route based on urea, was strongly dependent on the composition and surface area. Among the three compositions studied, the carbon‐rich compound B0.15C0.73N0.12 with the highest surface area showed an exceptional stability (over 100 cycles) and rate capability over widely varying current density values (0.05–1 A g?1). B0.15C0.73N0.12 has a very high specific capacity of 710 mA h g?1 at 0.05 A g?1. With the inclusion of a suitable additive in the electrolyte, the specific capacity improved drastically, recording an impressive value of nearly 900 mA h g?1 at 0.05 A g?1. It is believed that the solid–electrolyte interphase (SEI) layer at the interface of BxCyNz and electrolyte also plays a crucial role in the performance of the BxCyNz . 相似文献
12.
Dr. Wen Liu Pilgun Oh Dr. Xien Liu Min‐Joon Lee Woongrae Cho Sujong Chae Prof. Dr. Youngsik Kim Prof. Dr. Jaephil Cho 《Angewandte Chemie (International ed. in English)》2015,54(15):4440-4457
High energy‐density lithium‐ion batteries are in demand for portable electronic devices and electrical vehicles. Since the energy density of the batteries relies heavily on the cathode material used, major research efforts have been made to develop alternative cathode materials with a higher degree of lithium utilization and specific energy density. In particular, layered, Ni‐rich, lithium transition‐metal oxides can deliver higher capacity at lower cost than the conventional LiCoO2. However, for these Ni‐rich compounds there are still several problems associated with their cycle life, thermal stability, and safety. Herein the performance enhancement of Ni‐rich cathode materials through structure tuning or interface engineering is summarized. The underlying mechanisms and remaining challenges will also be discussed. 相似文献
13.
《中国化学》2017,35(12):1853-1860
Recent success and application of the percolation theory have highlighted cation‐disordered Li‐rich oxides as high energy density cathode materials. Generally, this kind of cathode materials suffer from low cycling stability and rate performance. Doped Ti4+ ions can improve the long‐term cycling stability and rate performance of the Li‐rich oxides materials with obvious capacity fading. The electrochemical performance in Lix Ni2−4x /3Sbx /3O2 can benefit a lot from the nanohighway, which is a kind of nanoscale 0‐TM diffusion channels in the transition metal layer and provides low diffusion barrier pathways for the lithium diffusion. In this work, the doping effect of Ti on the structure and electrochemical properties in Li1.15Ni0 .47Sb0 .38O2 is studied. The Ti‐stabilized Li1.15−x Ni0.47Tix Sb0 .38O2 (x =0, 0.01, 0.03 and 0.05) have been prepared by a solid‐state method and the Li1.03Ni0 .47Sb0 .38Ti0 .03O2 sample exhibits outstanding electrochemical performance with a larger reversible discharge capacity, better rate capability and cyclability. Synchrotron‐based XANES , combined with ab initio calculations in the multiple‐scattering framework, reveals the Ti ions have been doped into the Li‐site in the lithium layer and formed a distortion TiO6 octahedron. This TiO6 local configuration in the lithium can keep the stability of nanohighway in the electrochemical process. In particular, the Li1.03Ni0 .47Sb0 .38Ti0 .03O2 compound can deliver a discharge capacities 132 and 76 mAh /g at 0.2 and 5 C, respectivly. About 86% capacity retention occurs at 1 C rate after 500 cycles. This work suggests capacity fading in the oxide cathode materials can be suppressed to construct and stabilize the nanohighway. 相似文献
14.
A Self‐Standing and Flexible Electrode of Yolk–Shell CoS2 Spheres Encapsulated with Nitrogen‐Doped Graphene for High‐Performance Lithium‐Ion Batteries 下载免费PDF全文
Dr. Wenda Qiu Dr. Jiqing Jiao Dr. Jian Xia Haimin Zhong Prof. Dr. Liuping Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(11):4359-4367
Flexible lithium‐ion batteries (LIBs) have recently attracted increasing attention with the fast development of bendable electronic systems. Herein, a facile and template‐free solvothermal method is presented for the fabrication of hybrid yolk–shell CoS2 and nitrogen‐doped graphene (NG) sheets. The yolk–shell architecture of CoS2 encapsulated with NG coating is designed for the dual protection of CoS2 to address the structural and interfacial stability concerns facing the CoS2 anode. The as‐prepared composite can be assembled into a film, which can be used as a binder‐free and flexible electrode for LIBs that does not require any carbon black conducting additives or current collectors. When evaluating lithium‐storage properties, such a flexible electrode exhibits a high specific capacity of 992 mAh g?1 in the first reversible discharge capacity at a current rate of 100 mA g?1 and high reversible capacity of 882 mAh g?1 after 150 cycles with excellent capacity retention of 89.91 %. Furthermore, a reversible capacity as high as 655 mAh g?1 is still achieved after 50 cycles even at a high rate of 5 C due to the yolk–shell structure and NG coating, which not only provide short Li‐ion and electron pathways, but also accommodate large volume variation. 相似文献
15.
Yuanchun Ji Prof. Carsten Streb Prof. Yu‐Fei Song 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(51):18799-18804
An organo‐functionalized polyoxometalate (POM)–pyrene hybrid (Py‐Anderson) has been used for noncovalent functionalization of carbon nanotubes (CNTs) to give a Py‐Anderson‐CNT nanocomposite through π–π interactions. The as‐synthesized nanocomposite was used as the anode material for lithium‐ion batteries, and shows higher discharge capacities and better rate capacity and cycling stability than the individual components. When the current density was 0.5 mA cm?2, the nanocomposite exhibited an initial discharge capacity of 1898.5 mA h g?1 and a high discharge capacity of 665.3 mA h g?1 for up to 100 cycles. AC impedance spectroscopy provides insight into the electrochemical properties and the charge‐transfer mechanism of the Py‐Anderson‐CNTs electrode. 相似文献
16.
Compact Coupled Graphene and Porous Polyaryltriazine‐Derived Frameworks as High Performance Cathodes for Lithium‐Ion Batteries 下载免费PDF全文
Prof. Yuezeng Su Yuxin Liu Dr. Ping Liu Dr. Dongqing Wu Dr. Xiaodong Zhuang Prof. Fan Zhang Prof. Xinliang Feng 《Angewandte Chemie (International ed. in English)》2015,54(6):1812-1816
It is highly desirable to develop electroactive organic materials and their derivatives as green alternatives of cathodes for sustainable and cost‐effective lithium‐ion batteries (LIBs) in energy storage fields. Herein, compact two‐dimensional coupled graphene and porous polyaryltriazine‐derived frameworks with tailormade pore structures are fabricated by using various molecular building blocks under ionothermal conditions. The porous nanosheets display nanoscale thickness, high specific surface area, and strong coupling of electroactive polyaryltriazine‐derived frameworks with graphene. All these features make it possible to efficiently depress the dissolution of redox moieties in electrolytes and to boost the electrical conductivity of whole electrode. When employed as a cathode in LIBs, the two‐dimensional porous nanosheets exhibit outstanding cycle stability of 395 mAh g?1 at 5 A g?1 for more than 5100 cycles and excellent rate capability of 135 mAh g?1 at a high current density of 15 A g?1. 相似文献
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Yuxin Liu Prof. Ping Liu Prof. Dongqing Wu Yanshan Huang Yanping Tang Prof. Yuezeng Su Prof. Fan Zhang Prof. Xinliang Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5617-5622
Heteroatom doping is an effective method to adjust the electrochemical behavior of carbonaceous materials. In this work, boron‐doped, carbon‐coated SnO2/graphene hybrids (BCTGs) were fabricated by hydrothermal carbonization of sucrose in the presence of SnO2/graphene nanosheets and phenylboronic acid or boric acid as dopant source and subsequent thermal treatment. Owing to their unique 2D core–shell architecture and B‐doped carbon shells, BCTGs have enhanced conductivity and extra active sites for lithium storage. With phenylboronic acid as B source, the resulting hybrid shows outstanding electrochemical performance as the anode in lithium‐ion batteries with a highly stable capacity of 1165 mA h g?1 at 0.1 A g?1 after 360 cycles and an excellent rate capability of 600 mA h g?1 at 3.2 A g?1, and thus outperforms most of the previously reported SnO2‐based anode materials. 相似文献
20.
Dingrong Deng Dr. Yanjun Zhang Gen Li Xueyun Wang Dr. Li‐Hua Gan Dr. Li Jiang Prof. Chun‐Ru Wang 《化学:亚洲杂志》2014,9(5):1265-1269
Nanometer‐sized flakes of MnV2O6 were synthesized by a hydrothermal method. No surfactant, expensive metal salt, or alkali reagent was used. These MnV2O6 nanoflakes present a high discharge capacity of 768 mA h g?1 at 200 mA g?1, good rate capacity, and excellent cycling stability. Further investigation demonstrates that the nanoflake structure and the specific crystal structure make the prepared MnV2O6 a suitable material for lithium‐ion batteries. 相似文献