A parametric evaluation on a series of Co-rich La_0.5Sr_0.5Co_0.8Fe_0.2-xM_xO_3-&delta (M = Cu, Al, & Ni: x = 0 - 0.20) perovskite oxides were fabricated and systematically characterized. These oxides have a cubic structure with a space group of Pm3m. The LSCN_0.2 oxide showed the highest degree of oxygen non-stoichiometry. The oxygen evolution reaction (OER) behaviour study indicated that Al dopant improves the overall performance of the perovskite materials. This enhancement is attributed to increased oxygen vacancy concentration and surface area.   The stability behavior of the perovskites series was assessed. The LSCFA_0.1 oxide required a lower potential of &sim1.66 V vs. RHE to achieve 10 mA cm^-2 current density. Remarkably, LSCFA_0.1 oxides required less potential to reach 10 mA cm^-2 among studied oxides. The LSCN_0.2 oxide exhibited the highest conductivity, LSCFA0.1 showed the lowest, and the LSCC0.2 sample exhibited the intermediate. Sample LSCN_0.2 exhibited the highest K_chem and Dchem values measured at 650 oC, compared to other series of compositions, and has the potential as a membrane material for oxygen gas separation application.