NOVELTY - Covered active material particles (10) comprising active material particles (1) containing lithium, and a layer (2) comprising niobium oxide reactive with lithium carbonate, are prepared. An active material layer (12) is formed on a substrate (11) using particles (10). A counter-diffusion portion (3) containing lithium-niobium-oxygen compound, is formed by heat-processing the active material layer, and reacting lithium carbonate component in the surface of active material particles with the niobium oxide layer, to obtain an electrode component (20).    USE - Manufacture of electrode component (claimed) for batteries e.g. lithium cell (preferably all-solid-state battery). Uses include but are not limited to personal computers, video cameras, mobile telephones, communication apparatus, electric vehicles, motor vehicles, and hybrid vehicles.    ADVANTAGE - The method enables manufacture of electrode components which provide high-capacity batteries which can be repeatedly charged/discharged.    DETAILED DESCRIPTION - Covered active material particles comprising active material particles containing lithium, and a niobium oxide layer comprising niobium oxide reactive with lithium carbonate, formed on the active material particles, are prepared. An active material layer is formed on a substrate using the covered active material particles. A counter-diffusion portion containing lithium-niobium-oxygen compound, is formed by heat-processing the active material layer, and reacting lithium carbonate component in the surface of active material particles with the niobium oxide layer, to obtain an electrode component. An INDEPENDENT CLAIM is included for electrode component.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view explaining the manufacturing method of electrode component.    Active material particles (1)    Niobium oxide layer (2)    Counter-diffusion portion (3)    Covered active material particles (10)    Substrate (11)    Active material layer (12)    Electrode component (20)