Hierarchical Tiny-Sb encapsulated in MOFs derived-carbon and TiO2 hollow nanotubes for enhanced Li/Na-Ion half-and full-cell batteries

Abstract

MOFs-derived Sb nanoparticles encapsulated in carbon and TiO 2 hollow nanotubes (Sb⊂CTHNs) were synthesized via dramatically homogeneous hybridization of TiO 2 coating with Fe-MOFs as the precursor, the import of TiO 2 like a holder support the framework and allow Sb⊂CTHNs inherit the MOFs advantages of high surface area, hollow inner nanostructure and permanent porosity. Such anodes revealed great reversible capacity, long cycle life and excellent rate capability as a novel Li/Na-ion battery anode. • Sb⊂CTHNs were obtained via annealing reduction and galvanic replacement routes. • The import of TiO 2 like a holder support the framework of Sb⊂CTHNs. • Tiny Sb nanoparticles fully embedded in tight carbon and TiO 2 matrix walls. • Hierarchical hollow structure of Sb⊂CTHNs can buffer the volume expansion. • Sb⊂CTHNs show excellent electrochemical performances for Li/Na half and full cells. The serious volume changes during the alloy/dealloy process and poor electronic conductivity always limit antimony (Sb) development as Li/Na-ion batteries anode. In this work, we chose metal-organic frameworks (MOFs, MIL-88) as template and successfully synthesized hierarchical tiny-Sb encapsulated in MOFs derived-carbon and TiO 2 hollow nanotubes (Sb⊂CTHNs) by annealing reduction and galvanic replacement methods. The hybridization of TiO 2 like a holder maintain the framework of MIL-88 and the advantages of hollow inner nanostructure, intrinsic porosity and high specific surface area were delivered to Sb⊂CTHNs gradually. Tiny-Sb nanoparticles fully embedded in tight carbon matrix and TiO 2 walls with ultrastable structure could buffer the volume expansion, enhanced Li + /Na + diffusion and presented superior electrochemical performance as Li/Na-ion battery anode. For Li-ion battery, Sb⊂CTHNs delivered a reversible capacity of 607.2 mA h g −1 after 100 cycles at a current density of 100 mA g −1 and ultrahigh rate capability (434.8 mA h g −1 at 5000 mA g −1 ). Combined with LiMn 2 O 4 cathode, these Sb⊂CTHNs//LiMn 2 O 4 full cells also displayed superior capacity and long cycle life. For Na-ion battery, Sb⊂CTHNs exhibited a high initial reversible capacity of 640.8 mA h g −1 and high rate capability (374.1 mA h g −1 at 5000 mA g −1 ). Combined with Na 3 V 2 (PO 4 ) 3 /AC cathode, Sb⊂CTHNs//Na 3 V 2 (PO 4 ) 3 full cells also displayed excellent electrochemical performances.