title: Electrophoretic self-assembly of expanded mesocarbon microbeads with attached nickel nanoparticles as a high-rate electrode for supercapacitors.
abstract: Expanded mesocarbon microbeads (EMCMBs) with graphene oxide (GO) sheets were prepared by expanding graphitized mesocarbon microbeads (MCMBs) using a simple solution-based oxidative process. EMCMB-supported nickel nanoparticles with an average size of 4.6 nm were fabricated by an electrophoretic deposition (EPD) method in the presence of nickel nitrate additive. Nickel ions were self-assembled on the fluffy GO sheets resulting in a more positively charged EMCMB particle for facilitating EPD and dispersion. After heat treatment at 300 °C, GO could be converted to graphene which could provide a conductive network for facilitating the transport of electrons. Well-dispersed nickel nanoparticles on graphene sheets could act as a redox center to allow storage of extra charge and a nanospacer to prevent the graphene sheets from restacking. The specific capacitance of EMCMB-supported nickel electrode could reach 491 F g(-1), which is much higher than that of EMCMB electrode (43 F g(-1)) and bare nickel electrode (146 F g(-1)) at a discharge current of 5 A g(-1). More importantly, the EMCMB-supported nickel electrode is capable of delivering a high specific capacitance of 440 F g(-1) at a discharge current of 50 A g(-1), and could pave the way towards high-rate supercapacitors.
authors.affiliation: Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan. ms_wu@url.com.tw.
authors.forename: Mao-Sung
authors.initials: MS
authors.lastname: Wu
authors.forename: Yan-Hao
authors.initials: YH
authors.lastname: Fu
mesh_terms: D002244:Carbon / Q000737:chemistry*; D025802:Electric Capacitance; D004586:Electrophoresis; D053768:Metal Nanoparticles / Q000737:chemistry*; D008863:Microspheres; D009532:Nickel / Q000737:chemistry*
chemical_list: D002244:Carbon; D009532:Nickel