Synthesis and performance of LiMnO2 as cathodes for Li-ion batteries

Two structure types of LiMnO2 were synthesized by sol-gel method and ion-exchange method respectively. The results indicate that orthorhombic phase LiMnO2 is more stable than layered LiMnO2, o-LiMnO2 can be synthesized directly by sol-gel methods followed by heat-treated in argon, but layered LiMnO2 was obtained only by indirect methods such as ion-exchange method. In this paper, we first synthesized layered NaMnO2 by the sol-gel method, and then obtained layered LiMnO2 by the ion-exchange method. The phase, constitution, chemical composition, and images of the products were tested by XRD, AAS (atomic absorption spectroscopy) and SEM. The electrochemical performances of the two structural types of LiMnO2 are obviously different during the initial few cycles, but later they both have a good capacity-retaining ability. The capacity of layered structure LiMnO2 is higher than that of o-LiMnO2.