Electrophoretic deposition of manganese oxide and graphene nanoplatelets on graphite paper for the manufacture of supercapacitor electrodes

The preparation of coatings of manganese oxide and graphene nanoplatelets onto graphite paper by aqueous electrophoretic deposition is studied. This method is a fast and environmental friendly procedure for the manufacture of electrodes with enhanced specific capacitance for supercapacitors. The electrodes are prepared either sequentially, depositing consecutively the suspension of each material or simultaneously, from suspensions of mixtures of the two materials. Some of the electrodes show specific capacitances as high as 422 F g−1. The effects of (i) the electrophoretic deposition route chosen and (ii) the composition and load of the active electrode material deposited on the supercapacitor performance are studied. The symmetric supercapacitor cells show specific energy up to 9.2 W h kg−1 and specific power up to 1.8 kW kg−1 for 0.1 and 10 A g−1, respectively. The highest specific energy values are obtained in cells built with electrodes prepared by depositing first a layer of graphene nanoplatelets and then, manganese oxide.