FULL PAPER www.afm-journal.de © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1801111 (1 of 9) High-Performance Supercapacitors Based on a Zwitterionic Network of Covalently Functionalized Graphene with Iron Tetraaminophthalocyanine Aristides Bakandritsos, Demetrios D. Chronopoulos, Petr Jakubec, Martin Pykal, Klára C ˇ épe, Theodore Steriotis, Sergii Kalytchuk, Martin Petr, Radek Zbor ˇil,* and Michal Otyepka* Graphene derivatives are promising candidates as electrode materials in supercapacitor cells, therefore, functionalization strategies are pursued to improve their performance. A scalable approach is reported for preparing a covalently and homogenously functionalized graphene with iron tetraami- nophthalocyanine (FePc-NH 2 ) with a high degree of functionalization. This is achieved by exploiting fluorographene’s reactivity with the diethyl bromom- alonate, producing graphene-dicarboxylic acid after hydrolysis, which is con- jugated with FePc-NH 2 . The material exhibits an ultrahigh gravimetric specific capacitance of 960 F g -1 at 1 A g -1 and zero losses upon charging–discharging cycling. The energy density of 59 Wh kg -1 is eminent among supercapacitors operating in aqueous electrolytes with graphene-based electrode materials. This is attributed to the structural and functional synergy of the covalently bound components, giving rise to a zwitterionic surface with extensive π–π stacking, but not graphene restacking, all being very beneficial for charge and ionic transport. The safety of the proposed system, owing to the benign Na 2 SO 4 aqueous electrolyte, the high capacitance, energy density, and poten- tial of preparing the electrode material on a large-scale and at low cost make the reported strategy very attractive for development of supercapacitors based on the covalent attachment of suitable molecules onto graphene toward high- synergy hybrids. DOI: 10.1002/adfm.201801111 Dr. A. Bakandritsos, Dr. D. D. Chronopoulos, Dr. P. Jakubec, Dr. M. Pykal, Dr. K. C ˇ épe, Dr. S. Kalytchuk, M. Petr, Prof. R. Zborˇil, Prof. M. Otyepka Regional Centre for Advanced Technologies and Materials Department of Physical Chemistry Faculty of Science Palacký University Olomouc 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic E-mail: radek.zboril@upol.cz; michal.otyepka@upol.cz Dr. Th. Steriotis Institute of Nanoscience and Nanotechnology NCSR “Demokritos,” 15341 Ag. Paraskevi Attikis, Athens, Greece and (photo)electronics, [2] up to sen- sors [3] and structural composites. [4] The application potential of graphene can be expanded by its covalent derivatiza- tion with appropriate functional groups, which can enhance graphene’s dispers- ibility in solvents, [5] establish selectivity for sensing, [6] or tune and enhance its mag- netic, [7] catalytic, [8] and energy storage [9] properties. However, direct chemical func- tionalization of graphene is hampered by its low reactivity and poor product yields due to its initial low dispersibility, which dictate usage of rather harsh chemical reactions. [10,11] For these reasons, gra- phene oxide (GO) is widely used since it can be produced in high yields with a high content of oxygen-bearing groups, [12,13] which can be exploited for further deri- vatization. [12–14] Fluorographene (FG) [15,16] shares some of the advantages of GO because it can also be prepared on a large scale from graphite or fluorographite (GrF). Furthermore, FG is a well-defined derivative [17] with high reactivity, selec- tivity, homogeneity, and excellent func- tionalization degree (FD) of its covalent derivatives. [18–20] Importantly, during covalent functionaliza- tion, FG is defluorinated back to graphene without affecting the already introduced functional groups, [20] unlike GO. Defluori- nation is triggered by nucleophiles, [16,21] which simultaneously initiate substitution and reductive defluorination. This process can be controlled in order to obtain practically fluorine-free derivatives, [19,20] which are conductive [20] with high FD (up to 15%) [20] and homogenously functionalized. [18–20,22] Up to now, FG has not been successfully modified with planar (photo) electrochemically active molecules, even though the immobili- zation of such species onto graphene has been shown to sig- nificantly expand the applicability of the obtained materials. For instance, phthalocyanine, [23] porphyrine, [24] or tetrathioful- vallene [25] conjugated to graphene with low FDs (up to 0.5%) render the materials exploitable in dye sensitized solar cells [26] or charge transfer applications. [25] In this work, we first subjected FG to the Bingel–Hirsch reac- tion and attack from the bromomalonate nucleophile [25,27,28] to produce diethyl-malonate units covalently attached to graphene, Graphene The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201801111. 1. Introduction The unique physicochemical properties of graphene can be exploited in numerous applications, ranging from spintronics [1] Adv. Funct. Mater. 2018, 1801111