Supercapacitor Based on Nanostructured Multilayer Films Consisting of Polyelectrolyte/Graphene Oxide‐MnO2‐ZnO for Energy Storage Applications

Abstract

The development of new technologies has increased the demand for energy storage devices with high performance. In this sense, supercapacitors appear as a prominent alternative due to their high power density, fast charge–discharge time, environment friendly, and long‐term cycle stability. Carbon materials and transition metal oxides have been reported as attractive materials to achieve supercapacitors with enhanced properties. This study investigates nanostructured films, using the layer‐by‐layer (LbL) method, consisting of MnO2‐ZnO nanostructures embedded into reduced graphene oxide (rGO) and combined with polyallylamine hydrochloride (PAH) polyelectrolyte for supercapacitor applications. The film morphology and the incorporation of MnO2‐ZnO nanostructures in rGO layers are analyzed by scanning electron microscopy images. The electrochemical properties are evaluated by cyclic voltammetry and galvanostatic charge–discharge measurements. A high capacitance is reached for a 20‐bilayer PAH/rGO‐MnO2‐ZnO LbL film at a 1 mV s−1 and 1.15 A g−1 with values of 1650 F g−1 and 26 mF cm−2. Furthermore, the film exhibits high energy and power densities of 112.3 Wh kg−1 and 404.4 W kg−1, respectively, as well as high capacitive retention and cycle stability. These findings indicate the potential application of PAH/rGO‐MnO2‐ZnO LbL films as supercapacitor electrodes and envisage further studies of LbL nanostructured systems for energy storage applications.