Kinetic engineering of diffusion and surface-controlled charge storage in a LaCoO3/PANI hybrid supercapacitors
摘要
The escalating demand for next-generation electrochemical energy-storage systems has intensified research toward the development of high-performance asymmetric supercapacitors, which strategically integrate inorganic and organic electrode materials to exploit complementary charge-storage mechanisms and enhance overall electrochemical performance. In this work, we report a LaCoO3-PANI composite and a hybrid asymmetric supercapacitor (HASC) employing LaCoO3 perovskite as the positive electrode and polyaniline (PANI) as the negative electrode, separated by a filter paper membrane in 3 M KOH electrolyte. The LaCoO3 was synthesized via solid-state reaction, while the PANI was obtained through oxidative polymerization using Citrus limetta extract as a natural dopant. Structural and morphological characterizations (XRD, HR-SEM, XPS, BET) confirmed the phase-pure 57.54 nm LaCoO3 and the porous, globular PANI nanostructure. Electrochemical analyses demonstrated excellent performance: the composite electrode delivered 318 F g⁻1 at 1 mV s⁻1 and 1040 F g⁻1 at 1 A g⁻1. Dunn and Trasatti’s analyses indicated a mixed charge-storage mechanism, with diffusion-controlled processes dominant at low scan rates (≈87.35% at 1 mV s⁻1) and capacitive contributions increasing at higher rates (≈50.55% at 50 mV s⁻1). The asymmetric device achieved 228 F g⁻1 at 1 A g⁻1 and retained 95.98% capacitance after 3000 cycles at 5 A g⁻1, delivering a high energy density of 192.4 Wh kg⁻1 and a power density of 7.56 kW kg⁻1. The synergistic interaction between LaCoO3 redox activity and the conductive PANI framework provides a promising pathway for next-generation energy-storage devices with balanced energy and power outputs.