Co3O4@C nanocomposites derived from the thermal decomposition of Co-based metal-organic frameworks for lithium storage

Abstract

To address the homogeneous dispersion in the preparation process of transition metal oxides and to overcome significant volume expansion issues during charging and discharging in lithium-ion batteries, thermal decomposition of metal-organic frameworks (MOFs) emerges as a promising approach for obtaining carbon-supported composite nanomaterials comprising transition metal oxides. Herein, a Co-based MOF, namely Co₆(TBA)₄(H⁺)₂(H₂O)₂(Py) (Co-TBA) was fabricated from hydrothermal synthesis with Co(NO₃)₂·6H₂O and 4,4′,4″-s-triazine-2,4,6-tricarbonic acid (TBA) as starting materials. Subsequently, homogenous thermal decomposition of Co-TBA was performed to obtain Co₃O₄@C nanocomposites. The resulting Co₃O₄@C nanomaterials exhibited approximately a sixteen-fold increase in discharge specific capacity (777.5 mAh g⁻¹) during cycling tests at a high current density of 1.0 A g⁻¹ compared to that of Co-TBA (47.4 mAh g⁻¹). The galvanostatic intermittent titration technique revealed that Co₃O₄@C exhibited significantly enhanced ion diffusion rates (10⁻¹⁰-10⁻¹³) compared to Co-TBA (10⁻¹⁴-10⁻¹⁷). Moreover, the Co₃O₄@C nanocomposite exhibits the hybrid supercapacitor-battery behavior confirmed by the analysis results of cyclic voltammetry kinetic analysis.