▎ 摘　　要

Functionalized graphene was synthesized via the reduction of graphene oxide with poly(diallyldimethylammonium chloride) (PDDA). This reduced graphene oxide (RGO) changed from a negative to a positive charge. The negatively charged MnO2 nanosheets were then anchored on the positively charged surface of the PDDA- functionalized RGO (PFRGO) sheet by electrostatic self-assembly deposition. The strong interactions between the MnO2 nanosheet and the PFRGO sheet form a face-to-face assembly structure, which maximizes the exposure of MnO2 redox-active sites and accelerates charge transfer between the two components. The resulting MnO2-PFRGO composite electrode exhibits a high specific capacitance of 175 F g(-1), which was increased by 52% relative to pristine MnO2. Moreover, the equivalent series resistance (ESR) value of the composite (0.66 Omega) is over two-times smaller than pristine MnO2. The capacitance retention is 88.8% after 5000 charge-discharge cycles, demonstrating good cycling stability.