Engineering NH3-induced 1D self-assembly architecture with conductive polymer for advanced hybrid Na-CO2 batteries via morphology modulation

Designing catalytic cathodes with excellent electrocatalytic activities and durability for Na-CO2 batteries has captured considerable attention so far. Here, a series of morphologically controlled low-crystalline CuCo2O4 was prepared by thermal oxidation of self-assembled Cu-Co precursors (p-CCO). One-dimensional (1D) rod-like of CuCo2O4 was subsequently encapsulated in polypyrrole shell (PPy) by in-situ polymerization of pyrrole monomers as an advanced catalyst (CCO/PPy) for high-performance Na-CO2 batteries. It was demonstrated that ammonia solution exerts an important influence on the surface morphology and size of the p-CCO crystallites by the rate of nucleation and growth. Particle size and 1D architecture modulation, associated with the encapsulation of conductive PPy effectively improve the directional transfer rate of ions and the conductivity of the electrode. More importantly, PPy introduction not only induces interfacial reconstruction of CuCo2O4, arousing more oxygen vacancies and catalytic active sites, but also contributes to the corrosion protection of the active material from the electrolyte during long-term operation. Bestowed by these advantages, the fabricated hybrid Na-CO2 battery manifested prominent electrochemical performance with a superior areal discharge capacity of 31.3 mAh cm−2, low discharge-charge voltage gap of 0.6 V, over 400 cycles. [Display omitted] •The 1D rod-like CuCo2O4 with oxygen vacancies was obtained by morphology modulation.•A mechanism for the directional growth of NH3-induced Cu-Co precursors was proposed.•CCO/PPy exhibited enriched active sites with superior CRR and CER performance.•A high areal capacity of 31.3 mAh·cm−2 and over 400 cycles were achieved.