Microwave-assisted synthesis and testing of La-doped Mn3O4 nanocomposites for high-performance supercapacitor electrodes

This study is focused on the fabrication of La-doped Mn3O4 nanoparticles through microwave irradiation for the construction of supercapacitor electrodes. A series of La-doped Mn3O4 samples was synthesized and labeled as La 0, La 5, La 10, and La 15, corresponding to 0%, 5%, 10%, and 15% La concentrations. The structural analysis reveals a tetragonal structure of the electrode material, with an average crystallite size of 12 nm. The surface micrographs showed a rough spherical shape of the nanoparticles, where particle size increased with the La doping level. Electrochemical tests revealed that, at 1 A g−1, the 15% La-doped sample showed the highest specific capacitance of 900 F g−1, energy density of 63 Wh kg−1, and power density of 252 W kg−1. The pristine Mn3O4 electrode exhibited an equivalent series resistance of 10 Ω, which decreased to 3.3 Ω after reaching the maximum La-doping level. The dielectric constant (ε′), on the other hand, increased with La-doping level. However, at lower frequencies, the dielectric loss was higher than at higher frequencies. This indicates that La-doped Mn3O4 can be a promising electrode material for next-generation supercapacitors.