N-doped carbon nanocapsules as nanoreactors to boost lithium storage performance of Co-based oxide nanocrystallines

Uniform cubic Co-based metal-organic framework has been synthesized thorough a facile co-precipitate reaction. Then monodispersed Co3O4 nanocrystallines encapsulated into N-doped carbon nanocapsules (Co3O4@NCN) was successfully prepared by successive annealing processes of precursor under nitrogen and air atmosphere. Such porous Co3O4@NCN hybrid exhibits excellent electrochemical characteristics in lithium ion storage due to N-doped carbon nanocapsules as nanoreactors with plentiful cavities to accommodate volume changing and outstanding transport kinetic to maintain mechanical stability of electrode materials. Especially, the Co3O4@ NCN electrode manifests ultra-long cycling capability and rate performance, exhibiting a high discharging specific capacity of 751 mAh g(-1) at 1.0 A g(-1). Hence, this special design presents a synthetic strategy for other metals oxides with controllable morphology and good electrochemical property in energy storage areas.