Synergistic interactions in LaMnO3/CuO composites with enhanced supercapacitive performance

Abstract

Composites of La-based perovskites with metal oxides have attracted significant attention in electrochemistry owing to their synergistic effects. In this work, LaMnO₃ (LMO)/CuO composites with varying ratios of (100–x)% LMO : x% CuO (where wt% x = 0, 10, 30, 50, and 100) were successfully synthesized via autocombustion technique followed by annealing at 1000 °C. The morphology and phase purity of the composites were confirmed by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. Among all compositions, LMO/CuO(9 : 1) exhibited the highest BET specific surface area of 14 m² g⁻¹ with an average pore size of 2.11 nm. Compared to single-phase LaMnO₃ or CuO, the composites demonstrated increased oxygen vacancies, as confirmed by XPS O 1s spectra. These structural features directly contributed to superior electrochemical performance, with LMO/CuO(9 : 1) achieving a specific capacitance (C_SP) of 646.8 F g⁻¹ at 1 mV s⁻¹ and 517.1 F g⁻¹ at 1 A g⁻¹. Furthermore, it delivered an energy density (E_d) of 25.8 Wh kg⁻¹ at a power density (P_d) of 397.6 W kg⁻¹, along with excellent cyclic stability, retaining 99.8% capacitance after 5000 charge/discharge cycles. These findings underscore the crucial role of synergistic interactions between LaMnO₃ and CuO in enhancing electrochemical performance, thereby positioning LMO/CuO composites as promising candidates for next-generation energy storage materials.