ZnO nanoparticles encapsulated in a 3D hierarchical carbon framework as anode for lithium ion battery

A novel structure that ZnO nanoparticles encapsulated in a 3D hierarchical carbon framework (ZnO@CF) has been fabricated through hydrothermal method and subsequent post-processes. In this structure, the surface carbon coating layer combines with the inside carbon to form a stable 3D carbon framework that encapsulated and anchored the ZnO nanoparticles. The developed ZnO@CF structure can not only improve electronic conductivity, but also alleviates the structural strain associated with repeating Li⁺ insertion/extraction processes so as to maintain structural stability. When used as anode for lithium ion battery, the ZnO@CF electrode exhibits a high reversible capacity of 850 mAh g^-1 at a current density of 0.1 A g^-1 after 200 cycles. Moreover, it shows good rate capability even when cycled at 2 A g^-1.