Hybridizing conductivity and stability: PANI–LaVO4 nanocomposites in aqueous asymmetric supercapacitors for bridging energy density and durability

Abstract

Lanthanum vanadate (LaVO₄) nanoparticles and PANI–LaVO₄ nanocomposites with varying LaVO₄ loadings (2, 4 and 6 wt%) were synthesized and systematically investigated for supercapacitor applications. XRD confirmed the monoclinic crystal structure of LaVO₄, while FESEM and EDX analyses revealed uniform incorporation of nanoparticles within the PANI matrix. Electrochemical characterization demonstrated that the PANI–LaVO₄ 2 wt% nanocomposite exhibited superior capacitive performance, delivering a high specific capacitance of 1013 F g⁻¹ at 2 A g⁻¹ with excellent cycling stability (>95% retention after 2000 cycles). To harness this performance, an asymmetric supercapacitor device (ASC) was fabricated using PANI–LaVO₄ (2 wt%) as the positive electrode and activated carbon (AC) as the negative electrode, achieving a specific capacitance of 546 F g⁻¹ at 1 A g⁻¹. The device exhibited outstanding stability with 90% capacitive retention after 2000 cycles, alongside an energy density of 75 Wh kg⁻¹ and a maximum power density of 8.3 kW kg⁻¹. These findings highlight the promising potential of PANI–LaVO₄ nanocomposites, particularly at optimized loading for superior electrochemical storage technologies.