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

Nano-polyhedral NiSe;/CoSe;（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.