Electrochemical Studies on Novel LiMnPO4 Coated with Magnesium Oxide-Gold Composite Thin Film in Aqueous Electrolytes

Abstract

Abstract. Pristine LiMnPO4 and LiMnPO4/Mg-Au composite cathode materials were synthesized and their electrochemical properties interrogated using voltammetric, spectroscopic and microscopic techniques. The composite cathode exhibited better reversibility and kinetics than the pristine LiMnPO4. This was demonstrated in the values of the diffusion coefficient (D) and the charge and discharge capacities determined through cyclic voltammetry. For the composite cathode, D = 2.0 x 10-9 cm2/s while the pristine has a D value of 4.81 x 10-10 cm2/s. The charge and discharge capacities of LiMnPO4/Mg-Au at 10 mV/s were 259.9 mAh/g and 157.6 mAh/g, respectively. The corresponding values for pristine LiMnPO4 were 115 mAh/g and 44.75 mAh/g, respectively.. A similar trend was observed in the results obtained from electrochemical impedance spectroscopy measurements. These results indicate that LiMnPO4/Mg-Au composite has better conductivity and will facilitate faster electron transfer and better electrochemical performance than pristine LiMnPO4.