A process for preparing a metal oxide-containing powder that comprises conducting spray pyrolysis that comprises aerosolizing a slurry that comprises solid-phase particles in a liquid that comprises at least one precursor compound, which comprises one or more metallic elements of at least one metal oxide, to form droplets of said slurry, and calcining the droplets to at least partially decompose the at least one precursor compound and form the metal oxide-containing powder having a non-hollow morphology.