Doping P heteroatoms into thin-wall polypyrrole hollow nanobelts with enhanced electrochemical performance for aqueous Zn ion storage

Abstract

The aqueous zinc-ion batteries are promising to be large-scale energy technologies for solving the contradiction between the intermittency of renewable energy and the immediacy of growing electricity demand. Conductive polymers have been utilized as cathode materials for Zn ion storage but suffered from inadequate active sites, resulting in poor specific capacity. In this work, P doping polypyrrole hollow nanobelts (P-PPy HNBs) with long aspect ratio have been prepared by in-situ polymerization of pyrrole on a template of MoO3 nanotubes. Owing to the long-aspect-ratio hollow structure, the P-PPy HNBs perform thin wall, large surface area, porous structure with micropores and mesopores, which is beneficial to high and fast Zn ion storage. Remarkably, the as-obtained P-PPy HNBs cathodes in this work deliver favorable electrochemical performance for Zn2+ storage in terms of good capacity, rate capability and cycling stability. Moreover, kinetic analysis quantitatively confirms the capacitive contribution of NPCNTs is dominant for aqueous Zn ion storage. The capacitive properties are contributed that the synergistic effect of porous and hollow nanobelt structure construction and P doping strategy can provide abundant active sites and promote electronic conductivity and ion transport. Generally, the strategy for hollow structure with a long aspect ratio and heteroatom doping in our work causes excellent-performance properties, possibly bringing light on the future design of other cathodes for aqueous Znic-based energy storage devices.