Hollow carbon spheres with encapsulation of Co ₃O ₄ nanoparticles as anode material for lithium ion batteries

Based on the high theoretical capacity of Co ₃O ₄ for lithium storage, a noval type of monodisperse hollow carbon spheres with encapsulation of Co ₃O ₄ nanoparticles (HCSE-Co ₃O ₄) were designed and synthesized. The monodisperse hollow carbon spheres not only can provide enough void volume to accommodate the volume change of encapsulated Co ₃O ₄ nanoparicles, but also can prevent the formation of solid electrolyte interface (SEI) films on the surface of Co ₃O ₄ nanoparticles and following direct contact of Co and SEI films upon lithium extraction. The HCSE-Co ₃O ₄ electrode exhibit highly reversible capacity, excellent cycle performance and rate capability attributed to the unique structure. The reversible capacity of HCSE-Co ₃O ₄ electrode is as high as 500 mAh g ^-1 at a current density of 744 mA g ^-1, while that of bare Co ₃O ₄ electrode is only around 80 mAh g ^-1.