Co3O4 Nanospheres Embedded in a Nitrogen-Doped Carbon Framework: An Electrode with Fast Surface-Controlled Redox Kinetics for Lithium Storage

Herein, we develop a Co3O4-based anode material with a hierarchical structure similar to that of a lotus pod, where single yolk–shell-structured Co3O4@Co3O4 nanospheres are well embedded in a nitrogen-doped carbon (N–C) conductive framework (Co3O4@Co3O4/N–C). This distinctive architecture contains multiple advantages of both the yolk–shell structure and conductive N–C framework to improve the Li ion storage performance. Especially, the doping of the N atom in N–C increases the interaction between the carbon and adsorbents, which is confirmed by the theoretical calculations in this work, making the carbon framework much more electrochemically active. As a result, the Co3O4@Co3O4/N–C exhibits fast surface-controlled kinetics, which corroborate the high counterion mobility and the ultrafast electron-transfer kinetics of the electrode. Due to these synergetic effects, desired capacity stability (1169.6 mAh g–1 at 200 mA g–1 after 100 cycles) and superior rate performance (633.4 mAh g–1 at 10 A g–1) have been realized in this Co3O4@Co3O4/N–C electrode.