CaO-Templated Growth of Hierarchical Porous Graphene for High-Power Lithium-Sulfur Battery Applications
CaO-Templated Growth of Hierarchical Porous Graphene for High-Power Lithium-Sulfur Battery Applications
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用于高功率锂硫电池应用的 CaO 模板生长分级多孔石墨烯
DOI：
10.1002/adfm.201503726
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发表时间：
2016-01-26
影响因子：
19
通讯作者：
Wei, Fei
中科院分区：
文献类型：
--
作者：
Tang, Cheng;Li, Bo-Quan;Wei, Fei
结构层次化在生物学界和性能优化、效率高的功能材料中起着重要的作用。在过去的几十年里，分层多孔碳/石墨烯材料作为各种储能系统的有希望的候选者已经得到了广泛的研究，而对其分层孔隙度的有利调节仍然是一个挑战。在这里，多孔CaO作为催化剂和模板用于分层多孔石墨烯的通用化学气相沉积（CVD）。CVD过程中的气体气氛和所采用催化剂的纳米结构对所得材料的石墨化程度和分层孔隙度有显著影响。制备的材料具有丰富的微尺寸面内空位、中尺寸褶皱孔和大尺寸支撑腔，从而具有强表面包裹、短离子扩散路径、快速的质量传递、低界面阻力和坚固的框架。该材料具有优良的倍率性能、高的库仑效率和优异的稳定性，是锂硫电池阴极的良好支架材料。在5.0℃的电流速率下，石墨烯的容量为357(656)，在0.1℃时容量保持率为74%。本文首次报道了cao模板CVD生长石墨烯，为在金属氧化物催化剂上有效制备分层多孔石墨烯材料开辟了新的前景，在储能、催化、吸附、药物输送等方面具有广阔的应用前景。
Structural hierarchy plays an important role in the biological world and for functional materials with optimized properties and high efficiency. As promising candidates for various energy storage systems, hierarchical porous carbon/graphene materials have been intensively investigated over the past decades, while the favorable regulation of their hierarchical porosity remains a challenge. Herein, porous CaO serves as both the catalyst and template for a versatile chemical vapor deposition (CVD) of hierarchical porous graphene. The gas atmosphere during CVD and nanostructure of adopted catalysts impact significantly on the graphitization degree and hierarchical porosity of resultant materials. The as-fabricated material exhibits abundant microsized in-plane vacancies, mesosized wrinkled pores, and macrosized strutted cavities, thereby contributing to a strong surface entrapment, short ion diffusion pathways, rapid mass transport, low interfacial resistance, and robust framework. It is demonstrated as a favorable scaffold for lithium-sulfur battery cathodes with superior rate capability, high coulombic efficiency, and excellent stability. A high capacity of 357 (656 ) is manifested at the current rate of 5.0 C, exhibiting a 74% retention of the capacity at 0.1 C. The first use of CaO-templated CVD growth of graphene reported herein opens up new perspectives on the effective fabrication of hierarchical porous graphene materials on metal oxide catalysts with promising applications in energy storage, catalysis, adsorption, drug delivery, and so on.