Metal-Organic-Framework Derived Core-Shell N-Doped Carbon Nanocages Embedded with Cobalt Nanoparticles as High-Performance Anode Materials for Lithium-Ion Batteries

To enhance the performance of Li-ion batteries, hierarchical carbon-based hollow frameworks embedded with cobalt nanoparticles are prepared by the pyrolysis of core-shell ZIF-8@ZIF-67 polyhedrals prepared via a seed-mediated growth method. The resultant hollow frameworks are composed of the N-doped carbon as the inner shells and the porous graphitic carbon embedded with cobalt nanoparticles as the outer shells. Benefiting from the unique hollow architecture with large surface area and good electrical conductivity, the electrode materials exhibit good electrochemical performance with improved specific capacities, high-rate capability, and good cycling stability for Li-ion batteries. More importantly, the quantitative kinetic analysis reveals the crucial contributions of N doping and the porous structure of graphitic carbon with cobalt nanoparticles for boosting the performance of carbon-based materials. The rational design of the unique carbon-based architecture and the understanding of the underlying mechanism for the charge storage process are crucial to construct advanced carbon-based materials for high-performance Li-ion batteries.