In the past decade, nanostructured polypyrrole (PPy) has been widely studied because of its many specific properties, which have obvious advantages over bulk-structured PPy. This review outlines the main structures, preparation methods, physicochemical properties, potential applications, and future prospects of PPy nanomaterials. The preparation approaches include the soft micellar template method, hard physical template method and templateless method. Due to their excellent electrical conductivity, biocompatibility, environmental stability and reversible redox properties, PPy nanomaterials have potential applications in the fields of energy storage, biomedicine, sensors, adsorption and impurity removal, electromagnetic shielding, and corrosion resistant. Finally, the current difficulties and future opportunities in this research area are discussed.

Polypyrrole (PPy) has attracted widespread attention due to its excellent environmental stability, high conductivity, simple synthesis, good biocompatibility, and reversible redox properties. PPy derivatives not only inherit the advantages of polypyrrole, but also have some unique properties. The side and N-site substitution of PPy can not only yield polymers with good solubility, but it also endows polymers with special functionalities by controlling the introduced functional groups. The performance of copolymers can also be adjusted by the type of monomer or polymerization ratio. In this review, an overview of the different types, main preparation methods, and the application prospects of PPy derivatives reported to date are summarized and presented. The current challenges and future opportunities in this research area are also prospected.

Composite polymer electrolytes (CPEs) are promising for all-solid-state sodium batteries, yet interfacial instability limits their practical applications. The commonly used NaTFSI can electrochemically form an NaF–Na2CO3–Na2O-rich solid electrolyte interphase (SEI) to regulate sodium-ion deposition, but the resulting protective layer still suffers from early failure. Herein, a boron-enriched interphase is introduced by incorporating NaDFOB into a polyethylene-oxide based CPE, enabling stable and dendrite-free Na plating/stripping. Experimental results reveal that DFOB− preferentially decomposes over TFSI−, forming an Na4B2O5–NaF–Na2CO3–Na2O SEI with synergistic ion-conductive and electron-blocking properties. Moreover, theoretical calculations are performed to investigate the synergistic ionic-enhanced and electronic-restricted capability of the SEI layer. Benefiting from the stabilized SEI, the Na||Na symmetric cell exhibits outstanding cyclic stability (5,000 h at 0.5 mA cm−2) and full cell delivers a high initial capacity of 99.4 mAh g−1 with 92.38% retention at 3 C after 9,000 cycles.