Bimetallic Organic Framework Derivation of Three-Dimensional and Heterogeneous Metal Selenides/Carbon Composite for High-Performance Lithium-Ion Batteries
Heterogeneous structures are attracting increasing attention in energy storage and conversion applications due to the phase boundaries and synergistic effect of multi-components. Herein, bimetal organic framework analogues were introduced to construct a Zn/Co bimetallic selenide heterostructure within 3D-porous N-doped carbon matrix by a NaCl template-assisted lyophilization and annealing process. The cross-linked 3D network can enhance the transport kinetics for both lithium ions and electrons. The stress resulting from the cycling process can be released by the interconnected channels in the composite. The ZnSe and CoSe2 experience electrochemical reactions at different potentials, which can buffer the volume changes mutually to effectively increase the structural stability. Meanwhile, abundant active sites due to the heterostructure enhance pseudocapacitive performance and reaction kinetics, resulting in high specific capacity and good rate performance. As anode materials for lithium-ion batteries, the three-dimensional ZnSe/CoSe2-C composite exhibits superior cycling stability. It retains a high reversible capacity of 700 mA h g-1 after 500 cycles at 1 A g-1.