The possible reason suggested is that the XPS deconvoluted N 1s spectrum of as-synthesized N-doped CNTs revealed the existence of two nitrogens such as pyridinic and graphitic nitrogen whereas that of acid-treated N-doped CNTs contained pyridinic-N-oxide in addition to these two nitrogens. Because of the existence of pyridinic-N-oxide, the positive charge on the pyridinic-N-oxide enhance the electron conductance via carbon network that giving rise to the MWCNT displayed the specific capacitance of 246 F g -1 at 0.5 A g -1 in 5 M KOH solution which is comparatively higher than CuO@NMWCNT (100 F g -1 ). Also, the asymmetric cells were fabricated with CuO/Co2O4@N-MWCNT electrode as positive and carbon black as negative electrode and delivered the specific capacitance of 279 F g -1 at 0.5 A g -1 which is relatively higher than CuO@N-MWCNT (268 F g -1 ). Moreover, the former cell demonstrated that the 89% of capacitance retained after 5000 cycles suggesting that the synergetic effect from cobalt oxide to copper oxide over the MWCNT surface. Sivalingam Ramesh et al. bubbling through acetonitrile and acetylene at 800 °C for 10 minutes. The doping content of nitrogen in the obtained composite evaluated from XPS was found to be 4.4 at.%. The gravimetric capacitance of the N-doped CNT@CNF hybrid derived from the GCD curve at 0.5