Uniqueness of Co3O4/Nitrogen-Doped Carbon Nano-spheres Derived from Metal-Organic Framework: Insight of Superior Lithium Storage Capabilities Beyond Theoretical and Electrochemical Features in High Voltage Battery

Abstract

Developing versatile strategy to create new structured materials with hetero-atomic doping has become one of the fascinating research topics owing to their fantastic properties, while the popular metal-organic-framework opens a promising avenue to design diverse architectures. Herein, an intriguing kind of spherical N-doped porous carbon (i.e., N-C) particles containing numerous Co3O4 nanocrystals (i.e., Co3O4/N-C) is introduced, in which the Zn-Co based Prussian blue analogue act as a sacrificial template and carbon source while the volatilization of zinc and oxidation of Co can produce rich pores and form highly active Co3O4 nanocrystals. The resultant Co3O4/N-C particles has an extremely high lithium storage capacity of 1255 mA h g-1 and excellent rate capability even to the current of 2000 mA g-1. The long cycle life over 500 cycles at 1000 mA g-1 with the high capacity of 798 mAh g-1 further demonstrates its prominent properties. Our kinetics analysis reveals that the high performances beyond theoretical mainly stem from the active Co3O4 nanocrystals, fast diffusion of lithium ions within the structure and pseudocapacitive behaviors; therefore it further demonstrates impressive stability and rate capabilities in lithium ion battery versus the cathode of lithium layered oxide even at high voltage conditions.