title: Fluorine-doped Fe(2)O(3) as high energy density electroactive material for hybrid supercapacitor applications.
abstract: Nanostructured α-Fe2 O3 with and without fluorine substitution were successfully obtained by a green route, that is, microwave irradiation. The hematite phase materials were evaluated as a high-performance electrode material in a hybrid supercapacitor configuration along with activated carbon (AC). The presence of fluorine was confirmed through X-ray photoelectron spectroscopy and transmission electron microscopy. Fluorine-doped Fe2 O3 (F-Fe2 O3 ) exhibits an enhanced pseudocapacitive performance compared to that of the bare hematite phase. The F-Fe2 O3 /AC cell delivered a specific capacitance of 71 F g(-1) at a current density of 2.25 A g(-1) and retained approximately 90 % of its initial capacitance after 15 000 cycles. Furthermore, the F-Fe2 O3 /AC cell showed a very high energy density of about 28 W h kg(-1) compared to bare hematite phase (∼9 W h kg(-1) ). These data clearly reveal that the electrochemical performance of Fe2 O3 can be improved by fluorine doping, thereby dramatically improving the energy density of the system.
authors.affiliation: Faculty of Applied Chemical Engineering, Chonnam National University, Gwang-ju 500-757 (Korea); Department of Mechanical and Materials Engineering, The University of Western Ontario, London, Ontario, N6A 5B9 (Canada).
authors.forename: Kaliyappan
authors.initials: K
authors.lastname: Karthikeyan
authors.forename: Samuthirapandian
authors.initials: S
authors.lastname: Amaresh
authors.forename: Sol Nip
authors.initials: SN
authors.lastname: Lee
authors.forename: Vanchiappan
authors.initials: V
authors.lastname: Aravindan
authors.forename: Yun Sung
authors.initials: YS
authors.lastname: Lee
keywords: activated carbon; energy storage; fluorine doping; hybrid supercapacitor; iron oxide