Synthesis and Application of Naphthalene Diimide as an Organic Molecular Electrode for Asymmetric Supercapacitors with High Energy Storage

Abstract A new redox‐active organic molecule, naphthalene diimide derivative (NDI), is synthesized through the condensation reaction for electrochemical energy storage, in which 1,4,5,8‐naphthalenetetracarboxylic dianhydride and 4‐aminophenol are used as skeleton and substituent, respectively. The NDI is acted as a guest molecule to non‐covalently modify reduced graphene oxide (rGO) and to form an organic molecular electrode (OMEs). The resultant electrode exhibits outstanding performance under the three‐electrode configuration, including specific capacitance (354 F g −1 at 5 mV s −1 ) and cycling performance (87.2% after 8000 cycles). Furthermore, the electrochemical behaviors of the OMEs are mainly controlled by surface reactions and pseudocapacitance contribution is up to 93% of the total capacity at 100 mV s −1 . In addition, a positive electrode (graphene hydrogel‐2,6‐dihydroxynaphthalene (GH‐DN)) is formed by hydrothermal method. At last, an asymmetric device (GH‐DN//rGO‐NDI, ASC) is assembled and a specific capacitance of 111.3 F g −1 is reached. The ASC can deliver a high energy density of 26.3 Wh kg −1 at power density of 0.6 kW kg −1 . Moreover, two ASC devices in series may light 81 light‐emitting diodes. It is believed that organic molecule electrodes are candidates for new green energy storage materials.