A promising binary nanocomposite of zinc cobaltite intercalated with polyaniline for supercapacitor and hydrazine sensor

Herein, zinc cobaltite (ZnCo₂O₄) nanoparticles (synthesized via hydrothermal treatment) were blended with polyaniline (PANI) (synthesized via chemical oxidative polymerization) to form PANI-ZnCo₂O₄ nanocomposite. The structural crystallinity and phase purity of PANI-ZnCo₂O₄ nanocomposite were authenticated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The morphological studies showed that the spinel structured ZnCo₂O₄ nanoparticles were well embedded on tubular-shaped PANI matrix, suggesting the effective connection between ZnCo₂O₄ nanoparticles with PANI matrix. The electrochemical performance studies of PANI-ZnCo₂O₄ nanocomposite for supercapacitor exhibited enhanced specific capacity of 398 C/g at a current density of 1 A/g as compared with ZnCo₂O₄ nanoparticles and PANI. The enhancement of electrochemical performance was contributed from the augmentation of electroactive sites for redox reaction, rapid electron transfer rate and the synergistic effect of ZnCo₂O₄ nanoparticles and highly conductive PANI. The fabricated PANI-ZnCo₂O₄//activated carbon based hybrid supercapacitor achieved high energy density (13.25 Wh/kg at 375 W/kg) as well as excellent cycling stability (∼90% retention after 3000 cycles). Furthermore, PANI-ZnCo₂O₄ nanocomposite was employed as a hydrazine sensor which exhibited good sensitivity of 0.43 μA μM⁻¹ in the linear range of 0.1–0.6 mM with a low detection limit of 0.2 μM. - Highlights: • The PANI-ZnCo₂O₄ nanocomposite was prepared via blending process. • Dual roles of PANI-ZnCo₂O₄ in supercapacitor and electrochemical sensor. • High energy and power density was obtained in asymmetric supercapacitor. • PANI-ZnCo₂O₄ showed high sensitivity towards hydrazine.