Synthesis and Characterizations of Mn_1+XCo_2-XO₄ Solid Solution Catalysts for Highly Efficient Li/Air Secondary Battery

Abstract

: Mn 1+X Co 2-X O 4 solid solutions with various Mn/Co ratios were synthesized by a combustion method, and used as cathode catalysts for lithium/air secondary battery. Their electrochemical and physicochemical properties were investigated. The morphology was examined by transmission electron microscopy (TEM), and the crystallinity was confirmed by X-ray diffraction (XRD) analyses. For the measurement of electrochemical properties, charge and discharge measurements were carried out at a constant current density of 0.2 mA/ cm 2 , monitoring the voltage change. Electrochemical impedance spectroscopy (EIS) analyses were also employed to examine the change in charge transfer resistance during charge-discharge process. Mn 1+X Co 2-X O 4 solid solutions showed enhanced cycleability as a cathode of Li/air secondary battery, and the performance was found to be strongly dependent on Mn/ Co ratio. Among synthesized catalysts, Mn 1.5 Co 1.5 O 4 exhibited the best performance and cycleability, due to high charge transfer rate.