Redox Active Polyaniline-h-MoO₃ Hollow Nanorods for Improved Pseudocapacitive Performance

Combinatorial approaches in preparing nanocomposites of transition metal oxides with conductive polymers have gained enormous attention due to their outstanding pseudocapacitive properties which are mainly associated with the solid-state diffusion of electrolyte ions as well as surface or near-surface reversible redox reactions. Here, we elaborate on the interplay of surface-controlled and diffusion-controlled redox reactions based on polyaniline and hexagonal molybdenum trioxide (h-MoO₃) hollow nanorods to realize improved electrochemical performance of the nanocomposite electrode. The cationic species (Ferric ions) were used as the oxidants to polymerize aniline monomers and assist in the formation of h-MoO₃ hollow nanorods. The formation of h-MoO₃ hollow nanorods was realized through the cation exchange-assisted Kirkendall effect driven by ferric ions. The resultant core-shell architecture of the polymerized h-MoO₃ showed improved pseudocapacitive performance (270 F/g) when compared to the pristine h-MoO₃ hollow nanorods (126 F/g) or polyaniline (180 F/g) at a current density of 1 A/g, with enhanced cycling stability.