Hierarchical ternary composites using coaxial polyphosphazene-coated MoO3 nanowires as substrate for advanced supercapacitors

Supercapacitors with outstanding merits including extraordinary cycle stability, safety and high power density are complementary energy storage devices to batteries. The construction of one-dimensional hierarchical ternary composites is conducive to the synergy between different materials, and can be used to assemble high-performance asymmetric supercapacitors. To this end, coaxial polyphosphazene (PZS)-coated MoO3 nanowires are used as the substrate, and CoFe layered double hydroxide (CoFe-LDH) or Ni(OH)2 is grown in-situ on the nanowires followed by high-heat treatment to form MoO3 NWs @ PZSC / CoFe2O4 and MoO3 NWs @ PZSC / NiO as the negative and positive electrodes, respectively, as confirmed by a series of spectroscopic measurements. Electrochemical characterizations confirm the excellent electrochemical performance of both electrode materials. The supercapacitors exhibit a potential window of 1.7 V in KOH aqueous electrolyte, with the maximum specific capacity of 48.55 mAh g−1 at 2 A g−1 and the energy density of 41.27 Wh kg−1 at 1707.72 W kg−1. This work provides an applicable approach to utilize the synergistic effect between PZSC and transition metal oxides in order to enhance the performance of supercapacitors.