Flexible naphthalene-based polyimide nanofiber cathode with hierarchical micro/nanoporous structure for high-performance organic sodium-ion batteries

A flexible composite nanofibrous organic cathode, consisting of naphthalene-based polyimide/nitrogen-doped carbon/carbon nanotubes (NPI/NC/CNT) with hierarchical micro/nanoporous structure, is designed for sodium-ion batteries (SIBs). The in-situ formed three-dimensional conductive network can achieve a uniform distribution and increased interfacial contact between electroactive NPI and electrolyte, thereby leading to high utilization of NPI. As a result, the free-standing NPI/NC/CNT cathode delivers high reversible capacity, superior rate capability, and excellent cycling stability for SIBs.