title: Preparation of a reduced graphene oxide wrapped lithium-rich cathode material by self-assembly.
abstract: A lithium-rich cathode material wrapped in sheets of reduced graphene oxide (RGO) and functionalized with polydiallyldimethylammonium chloride (PDDA) was prepared by self-assembly induced from the electrostatic interaction between PDDA-RGO and the Li-rich cathode material. At current densities of 1000 and 2000 mA g(-1), the PDDA-RGO sheet wrapped samples demonstrated increased discharge capacities, increasing from 125 to 155 mA h g(-1) and from 82 to 124 mA h g(-1), respectively. The decreased resistance implied by this result was confirmed from electrochemical impedance spectroscopy results, wherein the charge-transfer resistance of the pristine sample decreased after wrapping with the PDDA-RGO sheets. The PDDA-RGO sheets served as a protective layer sand as a conductive material, which resulted in an improvement in the retention capacity from 56 to 81% after 90 cycles.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea), Fax: (+82) 42-350-3910.
authors.forename: Sung Nam
authors.initials: SN
authors.lastname: Lim
authors.forename: Wook
authors.initials: W
authors.lastname: Ahn
authors.forename: Sun-Hwa
authors.initials: SH
authors.lastname: Yeon
authors.forename: Seung Bin
authors.initials: SB
authors.lastname: Park
keywords: cathode materials; graphene; lithium-ion batteries; polydiallyldimethylammonium chloride; self-assembly