Enhanced electrochemical performance of laser scribed graphene films decorated with manganese dioxide nanoparticles

High-performance supercapacitor electrode films of laser scribed graphene (LSG) decorated with manganese dioxide (MnO2) are produced on flexible substrates by two methods. One composite film of small diameter MnO2 particles directly added into graphene oxide sheets is reduced by a facile laser scribing technology. The other composite film is fabricated by in situ synthesis and laser scribing technology. The as-prepared films are characterized by Fourier transform infrared spectrum, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. Cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charging-discharging techniques are carried out to test the electrochemical performances. Film fabricated by in situ synthesis and laser scribing method displays much improved electrochemical properties. The volumetric capacity is as high as 202.98 F/cm(3). The film also exhibits excellent charge/discharge rate and good cycling stability, retaining 91.2 % of its initial charge after 5500 cycles. The enhanced electrochemical performance benefits from facile preparation method and magnified synergetic effect. Furthermore, the volumetric density of laser scribed graphene/MnO2-microsupercapacitor achieves 2.59 mWh/cm(3), which is approximately three times higher than that of LSG-microsupercapacitor unit. Such composite film indicates a promising future as electrode material for electrochemical energy storage devices.