Nano Energy
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2018
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IF 13.12
Fangyu Xiong,Qinyou An,Lixue Xia,Yan Zhao,Liqiang Mai,Haizheng Tao,Yuanzheng Yue
Among the various types of cathode materials for sodium ion batteries , NaFePO 4 attracts much attention owing to its high theoretical capacity (155 mA h g −1 ), low cost, high structural stability, and non-toxicity. Nevertheless, the NaFePO 4 with maricite structure, thermodynamically stable phase, has been considered as electrochemically inactive for sodium-ion storage. In this work, we succeeded in tuning the degree of disorder in NaFePO 4 cathode material by a mechanochemical route to enhance electrochemical performances of Na-ion batteries. The derived NaFePO 4 cathodes containing both amorphous and maricite phases exhibit much improved sodium storage performance with an initial capacity of 115 mA h g −1 at 1 C and an excellent cycling stability of capacity retention of 91.3% after 800 cycles. By X-ray absorption near edge and Raman spectroscopy , we revealed the atom-scale structural origin of the enhanced Na-storage performances of the amorphous NaFePO 4 electrode. The transformation of edge-sharing FeO 6 octahedra into various FeO n polyhedra upon amorphization was found to be a key to attain the superior performances for Na ion batteries.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
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IF 19
Zhenjiang Li,Huifeng Tian,Sasaki U,Xudan Huang,Mouyang Cheng,Xiaocang Han,Yinghang Ma,PeiChi Liao,Zhixin Yao,Yihan Wang,Lina Yang Zhang,Ge Yin,Yijie Luo,Wenxi Li,Xuanyu Zhang,Junjie Guo,Xiaoxu Zhao,Lifen Wang,Ji Chen,Lei Liu
Amorphous monolayer carbon (AMC), a new type of carbon nanomaterials created by merging modulations of the crystallinity and dimension, is of particular research interest since it has shown unprecedented properties that its crystalline counterpart–graphene–does not possess. The conductivity of AMC is controlled by its degree of disorder and can be continuously tuned with nine orders of magnitude. As one emergent carbon nanomaterial, the fundamental properties of AMC and its potential in applications remain largely unexplored. However, its current synthesis relies on one specific, lab-synthesized molecule, hampering further extensive investigations. Here, the feasible synthesis of AMC is reported by chemical vapor deposition using commercial polycyclic molecules, which prove to be effective in repeatably obtaining AMC with a controllable degree of disorder and large sizes. By the backward-compatible regrowth, the in-plane, crystalline-amorphous heterostructures are demonstrated in one monolayer of carbon with mechanical continuity across the homojunction. Conductance measurements confirm in such monolayers the precise controls over both the spatial location and electrical properties, which are not only conductive or insulating but continuously tuned. These results represent a significant step toward understanding the mechanism of AMC growth and pave the way for electronic devices using 2D amorphous materials.
研究领域:
材料科学
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纳米技术
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凝聚态物理
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化学合成
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2023
·
IF 9.9
Zhiyong Xiong,Liang Yue,Yi Zhang,Haifeng Ding,Lixin Bai,Qing Zhao,Tiehan Mei,Jun Cao,Yuruo Qi,Maowen Xu
Air-oxidation is an effective strategy to obtain promising carbon materials from asphalt for sodium-ion batteries. However, this method would generate a vast amount of gaseous pollutant, which pose challenges for recycling. Herein, a simple, cost-effective and environmentally friendly liquid-phase oxidation method is proposed. The oxygen-containing functional groups (-NO 2 ) are introduced into asphalt, which effectively prevents the melting of asphalt and rearrangement of carbon layers during subsequent carbonization process. As a result, a carbon material with notable disorder degree, large interlayer spacing and abundant closed pores, is prepared. The as-prepared product demonstrates an impressive initial Coulombic efficiency of 88.3 % and an enhanced specific capacity of 317.0 mA h g −1 , which is 2.6 times that of the pristine product. Moreover, when assembled with a Na 3.32 Fe 2.34 (P 2 O 7 ) 2 cathode, the full-cell delivers a high reversible capacity of 271.7 mA h g −1 at 30 mA g −1 with superb cycle life. This study offers a novel oxidation strategy and provides a solution for producing highly disordered carbon anodes from soft carbon precursors.
研究领域:
材料科学
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能量存储
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可持续化学
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电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）