title: Hierarchically porous graphene as a lithium-air battery electrode.
abstract: The lithium-air 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 Li(2)O(2) 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.
authors: Pacific Northwest National Laboratory, Richland, Washington 99352, United States. jie.xiao@pnnl.gov
authors: Jie
authors: J
authors: Xiao
authors: Donghai
authors: D
authors: Mei
authors: Xiaolin
authors: X
authors: Li
authors: Wu
authors: W
authors: Xu
authors: Deyu
authors: D
authors: Wang
authors: Gordon L
authors: GL
authors: Graff
authors: Wendy D
authors: WD
authors: Bennett
authors: Zimin
authors: Z
authors: Nie
authors: Laxmikant V
authors: LV
authors: Saraf
authors: Ilhan A
authors: IA
authors: Aksay
authors: Jun
authors: J
authors: Liu
authors: Ji-Guang
authors: JG
authors: Zhang
mesh_terms: D000388:Air; D011211:Electric Power Supplies; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D016062:Porosity
chemical_list: D006108:Graphite; D008094:Lithium