Supercapacitor performance of perovskite La_1−xSr_xMnO₃

In this study, Sr-doped lanthanum manganite perovskites (La_1-xSr_xMnO₃, LSM) as electrode materials for supercapacitors were prepared via an improved sol-gel method. Among LSM, the x = 0.15 sample shows superior electrochemical performance, delivering the highest specific capacitance of 102 F g^-1 at a current density of 1 A g^-1 and lower intrinsic resistance in 1 M KOH. The effective charge storage of LSM is due to the redox reaction of the anion intercalation corresponding to the surface redox processes of Mn²⁺/Mn³⁺ and Mn³⁺/Mn⁴⁺ occurring within the electroactive materials. The maximum energy density of 3.6 W h kg^-1 was achieved at a power density of 120 W kg^-1 for the symmetric supercapacitor with a long cycling life after 5000 charging and discharging cycles. With the increase of cycle times, the element leaching phenomenon leads to the decrease of electrochemical performance. Our work indicated that the perovskite manganite La_0.85Sr_0.15MnO₃ shows potential applications in the field of pseudocapacitance electrode materials and is worthy of further investigation.