Mechanochemical synthesis of α-Fe2O3 nanoparticles and their application to all-solid-state lithium batteries

α-Fe2O3 fine particles have been prepared by a mechanochemical process and a solution process. α-Fe2O3 nanoparticles with aggregates composed of the several tens nm primary particles were produced by the mechanochemical process. The nanoparticles were applied to the electrode as an active material for all-solid-state lithium batteries and the electrochemical properties of the cell were investigated. Typical charge–discharge curves, as seen in the liquid type cell using the α-Fe2O3 nanoparticles as an electrode were observed in the all-solid-state cell. The first discharge capacity of the cell of about 780 mAh g−1 was, however, smaller than the capacity of a cell using α-Fe2O3 particles prepared by the solution process, which were monodispersed particles of 250 nm without aggregates. In order to develop electrochemical performance of all-solid-state batteries, it is important to use the electrode particles without aggregation which lead to the formation of good solid–solid interface between active material and solid electrolyte particles.C