Synthesis and characterization of MnO₂ incorporated in BNC/PPy.CuCl₂ membranes for super capacitors

Full text: Flexible supercapacitors are energy storage systems of great interest to key technological applications, such as wearable devices and electrical vehicles. Metal oxides like manganese oxide (MnO₂) and conductive polymers like polypyrrole (PPy) have a charge/discharge mechanism based on redox reactions and have received attention as electrode materials. MnO₂ have a low cost and is abundant on earth, while PPy has a facile chemical synthesis and a high capacitance. Bacterial nanocellulose (BNC) membranes consist of a network of intertwined cellulose nanofibers that can be used as a flexible substrate for electrode materials. In this work PPy was polymerized using copper chloride dehydrate as an oxidant agent on the surface of hydrated BNC membranes coated with MnO₂ to be used as electrodes for supercapacitors. Two different concentrations of pyrrole (Py) were used in the synthesis: 0.04 and 0.08 mol/L. The BNC/MnO₂/PPy.CuCl₂ membranes were characterized by X-ray diffractometry and scanning electron microscopy. Conductivity analysis was also performed. Devices were assembled to study their electrical properties by cyclic voltammetry, charge/discharge behaviour and stability. A specific capacitance as high as 1073 mF/cm² and a good stability were obtained, which revealed that the combination of MnO₂, PPy and BNC membranes is promising as electrodes for supercapacitors. References: [1] W. He and C. Wang, Nano Ener., 35., 242 (2017) [2] R. K. Sharma and A. C. Rastogi, Electrochim. Acta, 53., 7690 (2008). (author)