Synthesis of rGO/PANi/MnO<sub>2</sub> ternary nanocomposite used for supercapacitor electrode by 3D printing and electrodeposition techniques

Three-dimensional (3D) printing has emerged as a promising method for fabricating advanced electrode materials. In this study, a ternary nanocomposite film of reduced graphene oxide (rGO), polyaniline (PANi), and MnO2 nanoparticles was prepared by 3D printing and electrochemical deposition for high-performance supercapacitors. A printable GO/aniline ink (1:1 mass ratio) was printed and electrochemically treated in 0.1 M H2SO4: first reduced at –0.8 V for 30 s, then electropolymerized by cyclic voltammetry (–0.4 to +0.95 V). MnO₂ was subsequently electrodeposited at +0.6 V for 200 s in MnSO4/H2SO4/KCl solution. FE-SEM/EDX confirmed uniform MnO2 distribution (~2 wt%). Electrochemical tests in 1 M H2SO4 showed enhanced capacitance and stability, with the rGO/PANi/MnO2 electrode reaching 740 F/g at 1 A/g and retaining 97% capacitance after 5000 cycles at 15 A/g.