Engineering 2D multi-layer graphene-like Co3O4 thin sheets with vertically aligned nanosheets as basic building units for advanced pseudocapacitor materials

Olivaceous two-dimensional (2D) multi-layer graphene-like Co3O4 thin sheets (CQU-Chen-Co-O-1) with vertically aligned nanosheets as basic building units were first prepared on a large scale by direct hydrothermal decomposition of a mixed aqueous solution of cobalt(II) nitrate and acetic acid without the assistance of any template or surfactant. The resulting products exhibited excellent pseudocapacitive performance with a high specific capacitance of 1752 and 1862 F g(-1) at the current density of 5 mV s(-1) and 1 A g(-1), respectively, as well as good rate capability (63.64% capacitance surplus) and high cycling performance (99.5% surplus after 2000 cycles).