A novel ternary composite aerogel for high-performance supercapacitor

Despite the attractive features of existing supercapacitors (SCs), SC devices still exhibit low mass loading, limited working voltage, low specific capacitance, short cycle life, and unsatisfactory energy density. In this study, we introduced novel self-suspended polyaniline (S-PANI) into a combination of manganese dioxide (MnO₂) and reduced graphene oxide (RGO) to propose an efficient SC electrode for energy storage applications. The unique addition of lightweight, highly conductive, exceptionally water-soluble, and unique fibrillar structure S-PANI increased the conductivity of composite aerogels and reduced the ionic diffusion resistance of electrode materials. The introduction of S-PANI significantly improved the dispersion of MnO₂ particles and enabled MnO₂ to give full play to its pseudopotentiability. The MnO₂/S-PANI/P-RGO ternary composite aerogel was prepared by the self-assembly hydrothermal technique where different mass ratios of MnO₂, S-PANI, and RGO were used and analyzed. Physical analyses showed that MnO₂/S-PANI/P-RGO composite aerogels had a 3D porous network structure and MnO₂ nanospheres are evenly disseminated on the surface of RGO nanosheets. The flowable S-PANI reduced the solid-solid contact resistance in the electrode. The developed 3D MnO₂/S-PANI/P-RGO composite aerogel electrode displayed a specific capacitance of 571 F g⁻¹ at the current density of 1 A g⁻¹ along with the specific capacitance of 413 F g⁻¹ with an increased current density of 40 A g⁻¹ and the capacity retention rate of 72.6 %. Also, the initial capacitance retention of 96.7 % was attained after 10,000 cycles at a current density of 20 A g⁻¹ is attained, displaying significant and long-term stability of the composite aerogel electrode. In summary, MnO₂/S-PANI/P-RGO composite aerogels reported in this study are promising in energy storage applications demanding high specific capacitance and cycle life.