CoO hierarchical mesoporous nanospheres@TiO2@C for high-performance lithium-ion storage

Highlights: • CoO nanocrystalline-assembled hierarchical mesoporous nanospheres. • Co-glycerate inorganic-organic hybrid spheres as the precursor. • High specific capacity, excellent cycling performance and rate capability. The hierarchical mesoporous structure is an ideal active material structure for lithium-ion batteries and other energy storage devices. In this work, we report a universal chelation-carbonization-oxidation path to synthesize CoO nanocrystalline-assembled hierarchical mesoporous nanospheres with Co-glycerate inorganic-organic hybrid spheres as the precursor, followed by the coating of TiO₂ and amorphous carbon. The electrochemical measurements demonstrate, as an anode of lithium-ion batteries, as-prepared CoO@TiO₂@C exhibits high reversible capacity, stable cycling performance and good rate capability. It can deliver discharge capacity of 1136 mAh g⁻¹ after 200 cycles at current density of 0.5 A g⁻¹ and average discharge capacity of 493 mAh g⁻¹ even at high current density of 5 A g⁻¹. The excellent lithium storage performance benefits from the multiple structural advantages. The nanocrystalline-assembled hierarchical mesoporous nanosphere endows CoO with high electrochemical activity. The robust TiO₂ and amorphous carbon shells improve structure stability and electronic conductivity of CoO hierarchical mesoporous nanospheres.