(475h) Hybrid Ternary Carbon Nanotube–Manganese Oxide–Paper Nanocomposites for Flexible Supercapacitors
Modern portable electronic devices create a strong demand for flexible energy storage devices. Paper based nanocomposites are attractive for such applications. In this work, hybrid ternary nanocomposites, comprised of rice paper, single-walled carbon nanotube (SWCNT) and manganese oxide nanoparticles, were synthesized using two approaches. The first approach is to use paper as a physical substrate for SWCNTs, and then chemically deposit manganese oxide on nanotubes. The second one directly explores the chemical reactivity of paper. Our results show that the second approach is more favorable because functional groups on cellulose fibers in paper can react with adsorbed permanganate ions, resulting in uniformly depositing manganese oxide nanoparticles on cellulose fibers. Furthermore, SWCNTs coated on top of manganese oxide form a highly conductive network connecting individual manganese oxide particles. The optimum deposition temperature was found to be around 80 oC. Using the hybrid ternary composites as electrodes, the assembled two-electrode supercapacitors achieved the specific capacitance of 256.2 F/g at the charge-discharge current density of 1 A/g in 0.5 M Na2SO4 aqueous solution. The supercapacitor also demonstrated high performance in specific energy (58.8 Wh/kg), specific power (8.9 kW/kg), and cycle stability (12 % drop after 3000 cycles). In addition, the nanocomposites have good mechanical strength (tensile stress at 17.32 MPa) and excellent mechanical flexibility, and their capacitance has negligible changes after bending more than 100 times. The new hybrid ternary composite exhibits high potential for flexible energy storage device applications.