Engineering Cobalt-Based Nanoparticles Encapsulated in Hierarchical Porous N-doped Carbon As an Efficient Electrode for Li Storage

To improve the application of transition metal oxides (TMOs) in lithium-ion batteries (LIBs), this study aims to construct electrodes using three strategies, i.e., engineering nano-sized TMOs, introducing different TMOs as hybrid heterostructures, and compositing carbonaceous structures with TMOs. This study presents an efficient procedure to synthesize bimetallic MOFs (Fe@Z67s) as precursors. During the synthesis of MOFs, two key parameters are investigated, i.e., the use of Ar inert gas (O2-free environment) and the optimization of the iron molar content. After successive carbonization and oxidation, Fe@Z67s are metamorphosed into a hierarchical porous nitrogen-doped carbon (NC) comprising cobalt-based nanoparticles (Co/Co3O4/ CoFe2O4(CCF)). Under the optimized conditions, the resultant L-CCF/NC-Ar electrode (derived from the synthesized Fe@Z67 under the O2-free environment (Ar) with a low amount of iron (L)), discloses the best electrochemical performance as LIB anode. This engineered electrode delivers a remarkable reversible capacity of 1020 mA h g-1 after 500 cycles with an excellent capacity retention of 95% at a high current density of 1 A g-1. The outstanding electrochemical performance of the developed electrode can be ascribed to the synergistic effect of an optimal ratio of TMOs hybrid/ porous graphitic carbon, hollow nanostructured anode material, high surface area, appropriate N-doping, and the homogeneous distribution of the active sites. (c) 2021 Elsevier B.V. All rights reserved.