High-Performance\nFlexible Symmetric Supercapacitor\nDevice Based on Nitroaniline-Functionalized Benzoquinone

A simple approach to design the molecular\narchitecture based on\nmodified benzoquinone and its flexible supercapacitor device is demonstrated.\nIn present work, two electron-withdrawing subunits such as 2-nitroaniline\n(<b>NA</b>) and 3,5-dinitro aniline (<b>DNA</b>) are utilized\nto functionalize benzoquinone (<b>BQ</b>) core. As-prepared\nelectrode materials based on <b>BQ-NA</b> and <b>BQ-DNA</b> on graphite foil (<b>GF</b>) are directly employed to fabricate\na three-electrode supercapacitor (SC) device in 1 M H<sub>2</sub>SO<sub>4</sub> electrolyte. At 0.5 A g<sup>–1</sup> current density,\nthe <b>BQ-DNA/GF</b> electrode-based SC can deliver higher specific\ncapacitance (<i>C</i><sub>sp</sub>) of 341.13 F g<sup>–1</sup> compared to the <b>BQ-NA/GF</b> SC device 322.47 F g<sup>–1</sup>. This could be ascribed to the higher electron-withdrawing effect\nof the four –NO<sub>2</sub> groups in <b>BQ-DNA</b>.\nMoreover, two-electrode <b>BQ-DNA/GF//BQ-DNA/GF</b> symmetric\nSC device and flexible symmetric supercapacitor (SSC) device were\ncreated using the <b>GF</b> surface. The <b>BQ-DNA/GF</b>-based FSSC device at a 0° bending angle exhibits noticeable <i>C</i><sub>sp</sub> with 81.66% <i>C</i><sub>sp</sub> retention after 5000 cycles at 1 mA cm<sup>–2</sup> current\ndensity. The highest energy density of 12.81 μW h cm<sup>–2</sup> at 1.36 mW cm<sup>–2</sup> power density was achieved for\nFSSC. The FSSC cell configuration at 180° bending angle also\nretains excellent <i>C</i><sub>sp</sub>. The present work\nprovides a way to design high-performance energy storage materials\nbased on organic compounds for flexible electronics and wearable device\narchitectures.