title: Expanded graphite as superior anode for sodium-ion batteries.
abstract: Graphite, as the most common anode for commercial Li-ion batteries, has been reported to have a very low capacity when used as a Na-ion battery anode. It is well known that electrochemical insertion of Na(+) into graphite is significantly hindered by the insufficient interlayer spacing. Here we report expanded graphite as a Na-ion battery anode. Prepared through a process of oxidation and partial reduction on graphite, expanded graphite has an enlarged interlayer lattice distance of 4.3 Å yet retains an analogous long-range-ordered layered structure to graphite. In situ transmission electron microscopy has demonstrated that the Na-ion can be reversibly inserted into and extracted from expanded graphite. Galvanostatic studies show that expanded graphite can deliver a high reversible capacity of 284 mAh g(-1) at a current density of 20 mA g(-1), maintain a capacity of 184 mAh g(-1) at 100 mA g(-1), and retain 73.92% of its capacity after 2,000 cycles.
authors.affiliation: 1] Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA [2].
authors.forename: Yang
authors.initials: Y
authors.lastname: Wen
authors.affiliation: 1] Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA [2].
authors.forename: Kai
authors.initials: K
authors.lastname: He
authors.affiliation: 1] Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA [2].
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Fudong
authors.initials: F
authors.lastname: Han
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Isamu
authors.initials: I
authors.lastname: Matsuda
authors.affiliation: 1] Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA [2] Center for Structural Biology, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ishii
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: John
authors.initials: J
authors.lastname: Cumings
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Wang