The synthesis of stable polynitrogen compounds with high-energy density has long been a major challenge. The cyclo-pentazolate anion (cyclo-N5 -) is successfully converted into aromatic and structurally symmetric bipentazole (N10) via electrochemical synthesis using highly conductive multi-walled carbon nanotubes (MWCNTs) as the substrate and sodium pentazolate hydrate ([Na(H2O)(N5)]·2H2O) as the raw material. Attenuated total refraction Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and density functional theory calculations confirmed the structure and homogeneous distribution of N10 in the sidewalls of the MWCNTs (named MWCNT-N10-n m). The MWCNT-N10-2.0 m is further used as a catalyst for electrochemical oxygen reduction to synthesize hydrogen peroxide from oxygen with a two-electron selectivity of up to 95%.