采用溶胶–凝胶法合成了LaFeO3, 并以蔗糖为碳源, 通过热处理方法合成了不同碳包覆量的LaFeO3/C复合材料. 采用XRD、SEM和电化学性能测试等分析方法对所制备材料的结构、表面形貌和电化学性能进行了研究, 利用Raman光谱和TEM分析材料中碳的存在状态. 结果表明, 不同碳含量的LaFeO3/C复合材料均为正交晶系的钙钛矿结构, 蔗糖经高温分解后在LaFeO3颗粒表面和颗粒间形成的包覆层为非晶碳; 电化学分析表明, 碳包覆LaFeO3的电化学性能优于未包覆的LaFeO3, 其中碳含量为5wt%的材料电化学性能最好, 首次放电容量最高可达390 mAh/g. 碳包覆对LaFeO3/C电极的交换电流密度I0影响较大, 随碳包覆量增加, I0值增大, 但碳包覆对LaFeO3/C电极的离子扩散系数影响不明显.
LaFeO3 nanostructure powders oxide was synthesized by sol-gel method and then LaFeO3/C composite materials containing different amounts of carbon were prepared by heat treatment using sucrose as a carbon source. The crystal structure, surface morphologies and electrochemical properties of the obtained composites coated with various carbon contents were investigated by the techniques of XRD, SEM, TEM, Raman spectroscope and electrochemical method. It was found that single phase nanostructure with perovskite-type LaFeO3 was obtained by Sol-Gel method and the crystal structure of LaFeO3/C could not be changed after coating carbon. Under high temperature, sourose was decomposed into amorphous carbon, which coated on the surface of LaFeO3 particles and formed network-like structure between LaFeO3 particles. Electrochemical measurements showed that the carbon- coated composites were superior in the electrochemical performance to the LaFeO3. LaFeO3/C electrodes possessed high discharge capacities, among which the sample adding with 5wt% carbon had the largest discharge capacity of 390 mAh/g. With increasing amount of carbon coated, the exchange current density I0 significantly enhanced, while effect of the coated carbon on the diffusion coefficient of ions was not obvious.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] | |
| [10] | |
| [11] | |
| [12] | |
| [13] | |
| [14] | |
| [15] | |
| [16] | |
| [17] | |
| [18] | |
| [19] | |
| [20] | |
| [21] | |
| [22] | |
| [23] | Yu Yanmin, Zhao Naiqin, Shi Chunsheng, et al. Electrochemical hydrogen storage of expanded graphite decorated with TiO2 nanoparticles. International Journal of Hydrogen Energy, 2012, 37(7): 5762&ndash |
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