<p>Advancing supercapacitor (SC) technology demands smarter electroactive materials to achieve higher performance. Herein, we display the preparation of niobium pentoxide (Nb₂O₅) and its mesoporous carbon composite using a less toxic hexam- ethylenetetramine (HMTA) as structure directing agent. The prepared nanostructures were explored towards SC electrode applications in Potassium (K⁺) based electrolyte as an alternate for Lithium (Li) based electrolytes. The morphological investigations reveal the as prepared Nb₂O₅ exhibiting rod like morphology and the composite sample showing firm attachment of porous carbon. As a SC electrode material porous carbon embedded Nb₂O₅ nanorods showing specific capacitance of 518 Fg^− 1 at a current rate of 1 Ag^− 1 in 0.5 M K₂SO₄ electrolyte with good cyclic life (91% after 5000 cycles) and rate performance (48% retention at 10 Ag^− 1). The lesser value of charge transfer resistance of porous carbon embedded Nb₂O₅ facilitating the possibility of perform charging and discharging at higher current rates. In addition, an asymmetric type SC device was assembled and analysed using Nb₂O₅/ C and activated carbon as electrodes. This device facilities capacitance of 179 Fg^− 1 with an energy density and power density of 21 Wh kg^− 1 and 417&#xa0;W kg^− 1 respectively. These interesting results indicating the porous carbon embedded Nb₂O₅ nanorods as a better material alternate for SC applications.</p>