Flexible symmetrical planar supercapacitors based on multi-layered MnO2/Ni/graphite/paper electrodes with high-efficient electrochemical energy storage

High-performance planar supercapacitors have attracted increasing attention because of their thin, light and flexible abilities. Here we developed novel flexible symmetrical planar supercapacitors (FSPSCs) by using the multi-layered MnO2/Ni/graphite/paper electrodes that were fabricated by sequentially coating a graphite layer, Ni layer, and MnO2 layer on ordinary cellulose paper. The MnO2/Ni/graphite/paper electrodes show a large specific capacitance (C-sp) of 175 mF cm(-2) at a scan rate of 5 mV s(-1). The assembled FSPSCs based on the multi-layered MnO2/Ni/graphite/paper electrodes exhibit a large volumetric C-sp (1020 mF cm(-3) at 5 mV s(-1)) and a superior long-term cycle stability (less 4% loss of the maximum C-sp after 6000 cycles). The FSPSCs based on the multi-layered MnO2/Ni/graphite/paper electrodes may open up new opportunities in developing novel supercapacitor devices because of the low-cost, high performance, and facile large-scale fabrication procedures.