Nickel oxide aerogel for high performance supercapacitor electrodes

Monolithic NiO aerogels were prepared by a facile citric acid assisted sol-gel method for supercapacitor electrodes. The highly porous aerogel microstructure is composed of a rigid nanoparticle backbone, which offers a large number of surface active sites for pseudocapacitive reactions and a high pore volume to facilitate ion transfer. As a result, the electrode made from the NiO aerogel annealed at 250 °C shows a high reversible specific capacitance of 901 F g^-1 at 0.5 A g^-1, a high rate capability (436 F g^-1 at the charge/discharge current density of 20 A g^{- 1}) and good capacitance retention (93% of the initial specific capacitance after 3000 cycles at 10 A g^-1). The result obtained in this work demonstrated that the nickel oxide aerogel holds great promise for supercapacitor applications.