Supercapacitor application of Sr-doped LaCo0.2Fe0.8O3 perovskite oxide: Investigation of structural and electrochemical properties

In this study, La1-xSrxCo0.2Fe0.8O3 (LSCF-x, x = 0.0, 0.2, 0.5, 0.8) perovskite oxides were synthesized as a supercapacitor electrode material using the combustion sol-gel method. A comprehensive analysis was conducted to examine the structural and electrochemical properties of LSCF-x. The partial substitution of Sr instead of La in the A site had a notable impact on the content of oxygen vacancies and the enhancement in the oxidation states of the B site cation. Among the synthesized samples, LSCF-0.8 showed excellent electrochemical performance. This sample demonstrated a distinct capacitance value of 318.7 F.g(-1) at a current density of 2 A.g(-1), also, LSCF-0.8 had a lower intrinsic resistance in 1 M KOH. Efficient energy storage in LSCF-x due to the redox reaction of B site cations occurring at the surface. Adjusting the Sr doping ratio has a significant effect on this reaction. In addition, the symmetric cell of LSCF-0.8 showed an energy density of 177.056 W.h.kg(-1) at a power density of 2000 W.g(-1), this cell was able to sustain 86 % of its original specific capacitance after 5000 cycles of charge-discharge.