New polypyrrole (PPy)-graphene sheet (GS) nanocomposites have been synthesized after making reduced GS react with tetrazine derivatives through inverse electron demand Diels-Alder reaction. The functionalized GS was coated on an electrode, and PPy was deposited by electrochemical polymerization. The obtained nanocomposites were characterized by FTIR, SEM, TGA, XRD and XPS, while the electrochemical performances were assessed by cyclic voltammetry, electrochemical impedance spectroscopy and
charge-discharge experiments. Symmetrical coin cells were made to measure the capacitance in a two-electrode configuration. PPy-GS nanocomposites containing 40% PPy show the best electrochemical performances, with a very large capacitance per weight (250 F g-1 at 2 A g-1) and a small resistance due to a good ion accessibility, which makes it one of the best electrode materials for supercapacitors so far.