Hierarchically Porous Graphene as a Lithium-Air Battery Electrode
Hierarchically Porous Graphene as a Lithium-Air Battery Electrode
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DOI：
10.1021/nl203332e
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发表时间：
2011-11-01
期刊：
影响因子：
10.8
通讯作者：
Zhang, Ji-Guang
中科院分区：
文献类型：
--
作者：
Xiao, Jie;Mei, Donghai;Zhang, Ji-Guang
在各种电化学储能系统中，锂-红外电池是最有前途的技术之一。我们证明了由功能化石墨烯片的不寻常的分层排列（没有催化剂）组成的新型空气电极在锂-O-2电池中提供了15000 mAh/g的异常高的容量，这是该领域有史以来报道的最高值。这种优异的性能归因于电极独特的双峰多孔结构，其由促进快速O-2扩散的微孔通道组成，而高度连接的纳米级孔为Li-O-2反应提供高密度的反应位点。此外，我们表明，石墨烯上的缺陷和官能团有利于形成孤立的纳米级Li 2 O2颗粒，并有助于防止空气电极中的空气阻塞。块状石墨烯中的分级有序的多孔结构通过促进该结构中的大多数石墨烯片的可接近性来实现其实际应用。
The lithium-ir battery is one of the most promising technologies among various electrochemical energy storage systems. We demonstrate that a novel air electrode consisting of an unusual hierarchical arrangement of functionalized graphene sheets (with no catalyst) delivers an exceptionally high capacity of 15000 mAh/g in lithium-O-2 batteries which is the highest value ever reported in this field. This excellent performance is attributed to the unique bimodal porous structure of the electrode which consists of microporous channels facilitating rapid O-2 diffusion while the highly connected nanoscale pores provide a high density of reactive sites for Li-O-2 reactions. Further, we show that the defects and functional groups on graphene favor the formation of isolated nanosized Li2O2 particles and help prevent air blocking in the air electrode. The hierarchically ordered porous structure in bulk graphene enables its practical applications by promoting accessibility to most graphene sheets in this structure.