ZnCo₂O₄ Nanorods Coated with Annealed Polypyrrole/Poly(vinyl alcohol) Composites as Anode Materials for Lithium-Ion Batteries

An annealed polypyrrole (PPy)/poly(vinyl alcohol) PVA film was successfully applied to the ZnCo2O4 nanorod surface via a liquid-phase synthesis approach and a subsequent annealing process. PVA played a pivotal role in the formation and performance of ZnCo2O4@PPy/PVA nanocomposites by inhibiting the aggregation of PPy nanospheres, guaranteeing firm adhesion between PPy and ZnCo2O4, and suppressing the huge volume expansion of ZnCo2O4 during cycling. The uniform dispersion and high conductivity of PPy nanospheres, the superior mechanical flexibility of PVA, and the unique nanorod structure of ZnCo2O4 made the electrochemical performance of ZnCo2O4@PPy/PVA significantly better than that of similar anodes based on pure ZnCo2O4. When used as anode materials, the ZnCo2O4@PPy/PVA nanocomposites exhibited a high reversible capacity of 1020 mA h g–1 at a 500 mA g–1 current density capacity for 300 cycles. Generally, our work proposes PPy/PVA composites to improve the cycling stability and rate performance of ZnCo2O4 for lithium-ion batteries.