Construction of tunable ZnCoOx/C-PANI electrode materials for high-performance supercapacitors

Abstract

Polyaniline (PANI) has been widely studied because of its unique physicochemical properties, but its practical significance in supercapacitors is seriously affected by its structural collapse during charging and discharging. We have successfully synthesized transition metal oxide/carbon-polyaniline composite electrode materials by in situ growth of polyaniline using the electrodeposition method with a metal-organic skeleton as a sacrificial template. This method not only can obtain high capacitance materials but also carbon materials provide buffer space during long-term charge/discharge to improve the overall stability. ZnCoOx/C-PANI-3 has a smaller charge transfer resistance and solution resistance compared to other materials, indicating that the interfacial coupling between PANI and ZnCoOx/C shortens the ion transport path between electrolyte and electrode surface, which is beneficial for rapid ion transfer and thus enhances its electrochemical performance. ZnCoOx/C-PANI-3 as an electrode material in the three-electrode system, has remarkable specific capacitance (1055 F.g−1 at a current density of 1 A.g−1) and good cycling stability (85.7% capacitance retention after 10,000 cycles of charge and discharge at high current density). Similarly, the asymmetric supercapacitor (ZnCoOx/C-PANI-3//AC) assembled with ZnCoOx/C-PANI-3 as the positive electrode material and activated carbon as the negative electrode material has a maximum energy density of 42.77 Wh.kg−1 at a power density of 705 W.kg−1 and a remarkable cycle life with a capacitance retention rate of 80% after 5000 cycles. This research opens up new avenues for studying polyaniline/MOF derivatives (transition metal oxide-carbon) composites.