A metal-organic-framework approach to engineer hollow bimetal oxide microspheres towards enhanced electrochemical performances of lithium storage.

Nanosized electrode materials with a hollow structure, larger specific surface area, and lower energy density as well as more void space are widely adopted for high-performance lithium-ion batteries. In this work, we obtained bimetal-organic frameworks of Fe/Mn-MOF-74 with a hollow microsphere morphology via a facile one-step microwave method and further used it to fabricate hollow Fe-Mn-O/C microspheres. Endowed with the metal-organic-framework-derived carbon-coated nanoparticle-assembled hollow structure with hierarchical porous characteristics and synergistic effects between two different metal species, the Fe-Mn-O/C electrode exhibits outstanding electrochemical performances as the anode of lithium-ion batteries. It achieves improved cycling performance (1294 mA h g-1 after 200 cycles at 0.1 A g-1) and good rate capability (722, 604, and 521 mA h g-1 at 0.2, 0.5 and 1 A g-1). The smart design of a hollow morphology with uniform two metal species can promote the synthesis of multimetal oxides and their carbon composites, as well as their further potential application for energy-storage.