title: Composition-tailored 2 D Mn(1-x)Ru(x)O(2) nanosheets and their reassembled nanocomposites: improvement of electrode performance upon Ru substitution.
abstract: Composition-tailored Mn1-x Rux O2 2 D nanosheets and their reassembled nanocomposites with mesoporous stacking structure are synthesized by a soft-chemical exfoliation reaction and the subsequent reassembling of the exfoliated nanosheets with Li(+) cations, respectively. The tailoring of the chemical compositions of the exfoliated Mn1-x Rux O2 2 D nanosheets and their lithiated nanocomposites can be achieved by adopting the Ru-substituted layered manganese oxides as host materials for exfoliation reaction. Upon the exfoliation-reassembling process, the substituted ruthenium ions remain stabilized in the layered Mn1-x Rux O2 lattice with mixed Ru(3+) /Ru(4+) oxidation state. The reassembled Li-Mn1-x Rux O2 nanocomposites show promising pseudocapacitance performance with large specific capacitances of approximately 330 F g(-1) for the second cycle and approximately 360 F g(-1) for the 500th cycle and excellent cyclability, which are superior to those of the unsubstituted Li-MnO2 homologue and many other MnO2 -based materials. Electrochemical impedance spectroscopy analysis provides strong evidence for the enhancement of the electrical conductivity of 2 D nanostructured manganese oxide upon Ru substitution, which is mainly responsible for the excellent electrode performance of Li-Mn1-x Rux O2 nanocomposites. The results underscore the powerful role of the composition-controllable metal oxide 2 D nanosheets as building blocks for exploring efficient electrode materials.
authors.affiliation: Center for Intelligent Nano-Bio Materials (CINBM), Department of Chemistry and Nano Sciences, College of Natural Sciences, Ewha Womans University, Seoul 120-750 (Korea), Fax: (+82) 2-3277-3419.
authors.forename: Su-Jeong
authors.initials: SJ
authors.lastname: Kim
authors.forename: In Young
authors.initials: IY
authors.lastname: Kim
authors.forename: Sharad B
authors.initials: SB
authors.lastname: Patil
authors.forename: Seung Mi
authors.initials: SM
authors.lastname: Oh
authors.forename: Nam-Suk
authors.initials: NS
authors.lastname: Lee
authors.forename: Seong-Ju
authors.initials: SJ
authors.lastname: Hwang
mesh_terms: D004553:Electric Conductivity; D004566:Electrodes; D008094:Lithium / Q000737:chemistry; D008345:Manganese / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D017975:Ruthenium Compounds / Q000737:chemistry*
chemical_list: D017975:Ruthenium Compounds; C029017:ruthenium dioxide; D008345:Manganese; D008094:Lithium
keywords: doping; layered compounds; nanostructures; self-assembly; supercapacitors