Herein, we report for the first time a novel and binder-free polyaniline sheathed 3D crumpled CoSe2 nanoparticles on Ni foam (PANI/CoSe2/NF) electrode was developed by a simple co-electrodeposition method for supercapacitor application. The as-electrodeposited 3D CoSe2 with PANI sheets on Ni foam morphology was confirmed through in-depth material characterizations. The PANI/CoSe2/NF as supercapacitor electrode delivered a superior specific capacitance of 1980 F g−1 or 3825 F g−1 (with the integral area) and a specific capacity of 792 C g−1 at 2 A g−1 in a three-electrode cell configuration. The assembled PANI/CoSe2/NF//sulfonated activated carbon from oak nutshell (AC) hybrid supercapacitor cell delivered excellent specific energy of 118 Wh kg−1 and good cyclic stability by retaining 82% of initial capacitance after 10,000 charge-discharge cycles. The high electrochemical performance of the electrode is due to the synergistic effect between PANI and CoSe2 nanostructures, high electrical conductivity, and hydrophilic functional groups of PANI contributing to the low internal resistance and effective diffusion of ions. These results demonstrate that the PANI/CoSe2/NF, with its unique 3D morphology, has great potential in energy applications. © 2021 Elsevier Ltd