Novel sulfonated polyaniline/graphene oxide electrode with high cycling stability for all-solid-state flexible supercapacitors

Polyaniline (PANi) has high theoretical specific capacitance by storing energy through redox reactions and thus is widely used in supercapacitors. However, the skeleton of PANi expands and contracts during the process of ion inhalation and exfoliation, which leads to a decrease in electrochemical performance. To solve this problem, we graft the sulfonic acid group onto the PANi backbone via a borate ester bond, which serves as a proton reservoir to provide protons for PANi to undergo redox reactions and provide pseudocapacitance. SPANi is then polymerized in situ on graphene oxide (GO), and its comprehensive performance of the electrode is further enhanced by designing ordered structures and synergistic interactions. The SPANi5/GO5 composite that are created in-situ have a fantastic specific capacitance of 460.56 F g−1 at 1 A g−1 and maintained 85.19% of the primary capacitance after 10,000 cycles. The device is assembled with PAAM/H2SO4/GO as the gel electrolyte, which achieves a specific capacitance of 137.75 F g−1, and the capacitance is retains at 90.74% after 10,000 cycles. The supercapacitor exhibits a large energy density of 13.76 Wh kg−1 when the power density is 200.27 W kg−1. The present study presents a novel and efficient approach for the fabrication of high-performance supercapacitor electrodes.