Morphological tuning of hollow NiCo2Se4 nanotube arrays anchored on Ni/C at varied selenization duration for efficient battery-type supercapacitors

The rational design of transition bimetal selenides with porous hollow structures has attracted significant attention in supercapacitor applications. Herein, the hierarchical hollow nanotubes NiCo2Se4/NC (porous NC derived from Ni-MOF) arrays were synthesized by hydrothermal and selenide strategies. The porous NC substrate could provide additional capacitance and boost the electrochemical capacity of NiCo2Se4 nanotubes through synergistic effect. By comparing electrochemical properties, we found that the electrodes of selenization 6 h (NiCo-Se-6/NC) exhibit the highest capacity properties among other electrodes. As a result, NiCo-Se-6/NC (NiCo2Se4/NC) achieved a distinguished specific capacity performance of 306.4 mAh g−1 (1 A g−1) and maintained better rate performance (81.4 % at 20 A g−1). The assembled NiCo2Se4/NC//AC device exhibits an energy density of 69.2 Wh kg−1 at 750.0 W kg−1 and excellent cycle durability (86.6 % after 5000 cycles), indicating that the hierarchical layered hollow NiCo2Se4/NC composite has wonderful prospects for the use of energy storage applications.