Functional enhancement of laser deposited carbon-based supercapacitor electrodes upon post-annealing treatment.

The development of new synthetic methods is paramount for the versatile production of complex multicomponent electrodes for supercapacitors with enhanced performance. The reactive inverse matrix assisted pulsed laser evaporation (RIMAPLE) technique shows promise for the deposition of complex functional nanocomposites in a facile way. In this work, hybrid supercapacitor electrodes constituted by reduced graphene oxide (rGO) and carbon nanotubes (CNTs) decorated with a myriad of cerium and manganese oxide nanoparticles were obtained by using GO sheets, CNTs, CeO 2 nanoparticles and, for the first time, the (NH 4) 2 [Mn 2 (C 6 H 5 O 7) 2 (H 2 O) 2 ] coordination compound as precursors in the RIMAPLE targets. Compositional and structural characterizations revealed that post-annealing treatments at mild conditions (150-250 °C) induce a further reduction of the rGO and CNTs, besides an oxidation of the Ce oxide phases (Ce3+ to Ce4+) and a reduction of the Mn oxides (Mn3+ to Mn2+). The substantial change of the carbon and metal oxide nanostructures causes an up to 8-fold increase of the capacitance of the electrodes (63 F/cm3 @ 10 mV/s). Finally, the generation of a high quantity of edge defects at 250 °C and long dwell time leads to the drop of the electrode's capacitance. [ABSTRACT FROM AUTHOR]