Journal of Materials Science, Vol.37, No.7, 1315-1320, 2002
Lithiation reactions of Zn- and Li-birnessites in non-aqueous solutions and their stabilities
Zn- and Li-birnessites were synthesized from Na-birnessite by ion-exchange reactions. The ion-exchange reaction, chemical lithiation reaction in non-aqueous solution, and stability for these birnessites were investigated by XRD, TG-DTA, and chemical analyses. The Zn-birnessite showed greater thermal stability than Li-birnessite. The Zn- and Li-birnessites can be lithiated up to Li/Mn molar ratios of 0.45 and 1.08, respectively, by reaction in a LiI-acetonitrile solution. The lithiation of Zn-birnessite progressed by a redox topotactic reaction, but the Li-birnessite was unstable during the lithiation reaction. The lithiated Zn-birnessite showed greater thermal stability than lithiated Li-birnessite. The Zn species in the interlayer space of lithiated Zn-birnessite acts as a pillar for the stabilization of the layered structure.