ZIF-67 derived hollow Ni-Co-Se nano-polyhedrons for flexible hybrid supercapacitors with remarkable electrochemical performances

Nano-polyhedral NiSe 2 /CoSe 2 (Ni-Co-Se) with hollow architectures are synthesized by selenizing the precursors of Ni-Co bimetallic hydroxides that are directly derived from ZIF-67. The as-fabricated Ni-Co-Se electrodes exhibit high specific capacitance of 1668 F/g at 1 A/g accompanying with outstanding rate capability (about 82.8% retention of the initial capacity at 20 A/g). The corresponding Ni-Co-Se//AC all-solid-state hybrid supercapacitors are assembled by directly using the Ni-Co-Se on carbon fabric as the positive electrode, which deliver high energy density and power density (38.5 Wh/kg at 802.1 W/kg, 32.0 Wh/kg at 8008.8 W/kg), excellent cyclic stability (82.3% retention after 5000 cycle) and robust mechanical flexibility (no obvious attenuation at bending to different angles). This work will provide a new and smart route for constructing transition metal selenides for supercapacitor devices.