Metal-secondary-battery negative-electrode material and method for reducing dendrites in metal-secondary-battery negative electrode

The provision of a metal-secondary-battery negative-electrode material in which dendrite formation is inhibited. A metal-secondary-battery negative-electrode material characterized by comprising a nanosheet of a metal oxide supported on a carbonaceous conductive support. Said metal-secondary-battery negative-electrode material is further characterized in that the metal in the metal oxide is titanium, ruthenium, or niobium.