Graphene‐Indanthrone Donor–π–Acceptor Heterojunctions for High‐Performance Flexible Supercapacitors.

To overcome the low energy density bottleneck of graphene‐based supercapacitors and to organically endow them with high‐power density, ultralong‐life cycles, etc., one rational strategy that couple graphene sheets with multielectron, redox‐reversible, and structurally‐stable organic compounds. Herein, a graphene‐indanthrone (IDT) donor–π–acceptor heterojunction is conceptualized for efficient and smooth 6H+/6e− transfers from pseudocapacitive IDT molecules to electrochemical double‐layer capacitive graphene scaffolds. To construct this, water‐processable graphene oxide (GO) is employed as a graphene precursor, and to in situ exfoliate IDT industrial dyestuff, followed by a hydrothermally‐induced reduction toward GO and self‐assembly between reduced GO (rGO) donors (D) and IDT acceptors (A), affording rGO‐π‐IDT D–A heterojunctions. Electrochemical tests indicate that rGO‐π‐IDT heterojunctions deliver a gravimetric capacitance of 535.5 F g−1 and an amplified volumetric capacitance of 685.4 F cm−3. The assembled flexible all‐solid‐state supercapacitor yields impressive volumetric energy densities of 31.3 and 25.1 W h L−1, respectively, at low and high power densities of 767 and 38 554 W L−1, while exhibiting an exceptional rate capability, cycling stability, and enduring mechanically‐challenging bending and distortions. The concept and methodology may open up opportunities for other two‐dimensional materials and other energy‐related devices. [ABSTRACT FROM AUTHOR]