Novel Synthesis and Characterization of Flexible MnO2/CNT Composites Co-deposited on Graphite Paper as Supercapacitor Electrodes

Although MnO2 possesses many advantages, such as a high theoretical specific capacity, resource abundance, easy synthesis and environmental friendliness, its poor electrical conductivity and low utilization seriously hinder its large-scale application as an electrode in supercapacitors. A MnO2 and carbon nanotube (CNT) composite is co-deposited on flexible expanded graphite paper (EGP) by a facile method of composite brush plating. The three-dimensional conductive net of CNT in the composite greatly improves the supercapacitve and mechanical properties of MnO2 electrode. The paper mainly studied (i) the choice of composite brush plating voltage and (ii) the effect of the concentration of active substance CNTs deposited on the performance of supercapacitor. When the current density is 20 A g(-1), the mass specific capacitance of the flexible CNT@MnO2/EGP electrode with an operation potential of 10 V in an electrolyte of 1.5 g L-1 CNTs dropped is 146 F g(-1). The CNT@MnO2/EGP/active carbon (AC)/carbon fibre cloth (CFC) flexible aqueous asymmetric supercapacitor (ASC) exhibits an energy density of 36.3 Wh kg(-1) at a power density of 126.2 W kg(-1) and high cycling stability with 91% capacitance retention after 4000 cycles. This study paves the way to provide a simple and novel technique for the mass production of flexible MnO2 supercapacitor electrodes. [GRAPHICS] .

Automated summary

This study presents a simple method for the mass production of flexible MnO2 supercapacitor electrodes by depositing a MnO2 and carbon nanotube composite on flexible expanded graphite paper. The composite exhibits improved supercapacitive and mechanical properties due to the three-dimensional conductive network of carbon nanotubes. The resulting flexible electrode demonstrates high capacitance retention and cycling stability, making it a promising candidate for large-scale applications.