Porous Co16S16O96 (COD database code: 591-0314) nanosheets have been fabricated by a simple and low-cost hydrothermal approach. The as-fabricated Co16S16O96 nanostructures are characterized by a porous interconnected sheet-like network and prove to be highly crystalline. Electrochemical tests reveal that the Co16S16O96 nanosheets can be reversibly charged and discharged in a potential window between −0.05 and 0.4 V vs. saturated calomel electrode at various specific current densities ranging from 0.5 A g−1 to 50 A g−1. The specific capacitance of these nanosheets is 333 F g−1 at 1 A g−1 in the beginning of cycling test, and increases with cycle numbers up to 386 F g−1, then remaining constant till 4000 cycles. More remarkably, even at a current density as high as 50 A g−1, the nanosheets still possess a specific capacitance of 170 F g−1, and only lose 15.3% of the initial capacitance value after 4000 cycles, showing great promise for use as high-performance supercapacitor electrodes.