Structural and Electrochemical Properties of S Doped LaMnO ₃ Perovskite Electrode for High-Performance Symmetric and Asymmetric Photoassisted Charging Supercapacitors

The gradual depletion of fossil fuels and growing energy demands necessitate efficient renewable energy solutions. Photorechargeable supercapacitors (PSc) offer a promising approach by converting light into electrical energy for storage. This study synthesized sulfur-doped perovskite LaMnSxO3–x (LMSx, x = 0, 0.03, 0.05, 0.1, 0.3) using the modified sol–gel method. The optimized LMS0.05 single-electrode yields a specific capacity of 712.73 F/g at 2 A/g in 1 M KOH. The constructed LMS0.05//LMS0.05 symmetric supercapacitor achieves 230 F/g specific capacity at a current density of 3 A/g under 95 mW/cm2 light intensity, which is 4.41 times higher than dark conditions. The capacity retention rates are 99.48% and 72.47% at a current density of 10 A/g after 10,000 charge/discharge cycles under light and dark conditions, respectively. Coulombic efficiencies are 100% under both conditions. The constructed MnO2//LMS0.05 asymmetric supercapacitor achieves a specific capacity of 550 F/g at a current density of 3 A/g under 95 mW/cm2 light intensity, corresponding to a 5.53-times enhancement relative to dark conditions. The capacity retention rates are 99.87% and 98.68% at a current density of 10A/g after 10,000 charge/discharge cycles under light and dark conditions, respectively. Coulombic efficiencies are 100% under both conditions. Moreover, the MnO2//LMS0.05 attains a specific capacity of 35.17 F/g under photocharging, yielding a PCE of 0.117% in only 3 min at 91% of the maximum voltage. This research, for the first time, provides a promising approach to explore nonmetal doping to advance perovskite supercapacitors for applications in energy devices and renewable energy storage solutions.