High-conductivity reduced-graphene-oxide/copper aerogel for energy storage

Abstract This work reports a room-temperature, solution-phase and one-pot method for macro-assembly of a three-dimensional (3D) reduced-graphene-oxide/copper hybrid hydrogel. The hydrogel is subsequently transformed into a highly conductive aerogel via freeze-drying. The aerogel, featuring reduced graphene oxide (rGO) networks decorated with Cu and Cu x O nanoparticles (Cu/Cu x O@rGO), exhibits a specific surface area of 48 m 2 /g and an apparent electrical conductivity of ∼33 and ∼430 S/m prior to and after mechanical compression, respectively. The compressed Cu/Cu x O@rGO aerogel delivers a specific capacity of ∼453 mAh g −1  at a current density of 1 A/g and ∼184 mAh g −1  at 50 A/g in a 3 M KOH aqueous electrolyte evidenced by electrochemical measurements. Galvanostatic cycling tests at 5 A/g demonstrates that the Cu/Cu x O@rGO aerogel retains 38% (∼129 mAh g −1 ) of the initial capacity (∼339 mAh g −1 ) after 500 cycles. The straightforward manufacturing process and the promising electrochemical performances make the Cu/Cu x O@rGO aerogel an attractive electrode candidate in energy storage applications.