Abstract
Here we describe the development of large-area, highly uniform, ultrathin, nitrogen and boron co-doped graphene (BNG)films for high-performance MSCs. The BNG film was prepared using a layer-by-layer (LBL) assembly of anionic graphene oxide(GO) nanosheets and cationic poly-L-Lysine (PLL) as a nitrogen containing precursor, followed by intercalation of H3BO3 within the layers and annealing treatment. The PLL and H3BO3 incorporated into the assembled multilayer films not only serve as nitrogen- and boron-rich precursors, respectively, but also generate micropore fillers to promote the formation of porous, yet densely packed BNG films during the thermal treatment. All-solid-state planar MSCs were manufactured by lithographically dry-etching the as-produced BNG films on silicon wafers, providing a pronounced pseudocapacitive behavior with ultrahigh volumetric capacitance (∼488 F/cm 3 ). This is the highest value reported to date for graphene-based supercapacitors and an ultrahigh operation scan rate of up to 2000 V/s.