Molybdenum-glycerate@zeolitic imidazolate framework spheres derived hierarchical nitrogen-doped carbon-encapsulated bimetallic selenides heterostructures for improved lithium-ion storage

In this work, the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitrogen-doped carbon shell are reported. Selenization temperature plays a significant role in determining the phases, morphology, and lithium-ion storage performance of the composite. Notably, the optimal electrode demonstrates an ultrahigh reversible capacity of 1298.2 mAh/g after 100 cycles at 0.2 A/g and an outstanding rate capability with the capacity still maintained 505.7 mAh/g after 300 cycles at 1.0 A/g, surpassing the calculated theoretical capacity according to individual component and most of the reported MoSe@C- or ZnSe@C-based anodes. Furthermore, ex-situ X-ray diffraction patterns reveal the combined conversion and alloying reaction mechanisms of the composite.