Development of Oleylamine‐Directed Nano‐OZIF‐67 Induced Microporous Carbon Nanofiber Conjugated with Tiny Fibrous PEDOT Polymer for Hybrid‐Capacitor Electrodes

Making nanostructured metal oxides intertwined with graphitic carbon materials is critically important to construct hybrid supercapacitors with high-performance, cost-affordable, and free-standing 1D hybrid electrode material and is of foremost importance to responding positively to the impending energy crisis. Fine-tuned nano-sized ZIF-67 particles of 5 - 25 nm width (OZIF-67) are achieved using oleylamine-involved synthesis and are seeded into fibrous poly-PAN-PVP. Porous N-doped carbon nanofibers impregnated with OZIF-67-derived Co₃O₄ (oz-Co₃O₄-PNCNF) are obtained by calcining the electrospun polymer. The surface area of oz-Co₃O₄-PNCNF is exceptionally high, 429 m² g^-1, with the pore size predominantly ≈2 - 5 nm. Thin conducting polymer films of poly-(3,4-ethylenedioxythiophene) are formed onto oz-Co₃O₄-PNCNF (oz-Co₃O₄-PNCNF/PEDOT). A porous, long nanofibrous structure (≈100 nm thick) of oz-Co₃O₄-PNCNF and a spongy needle-like network of PEDOT interconnecting outer layers are established from FESEM images. The material has shown excellent energy storage capability with the specific capacitance (C_S) of 417 F g^-1 (oz-Co₃O₄-PNCNF/PEDOT). Free-standing supercapacitor device delivers excellent performance in asymmetric assembly (oz-Co₃O₄-PNCNF/PEDOT//PNCNF) with 141.1 Wh kg^-1 and 84% C_S at the end of 5000 charge-discharge cycles. The excellent porous network, combined with finely-tuned nano-sized Co₃O₄ particles and an overlying thin electropolymer film, work together to establish high energy, efficient, and stable supercapacitors.