Facile synthesis of CuO hollow nanospheres assembled by nanoparticles and their electrochemical performance

► CuO hollow nanospheres were prepared by thermal oxidation of Cu2O solid nanospheres. ► The formation of CuO hollow nanospheres mainly results from the Kirkendall effect. ► CuO hollow nanospheres can be used as anode materials for lithium ion batteries. ► CuO hollow nanospheres show better electrochemical properties than nanoparticles.