Co(3)o(4) 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 electro-chemically 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.